Instruction Manual
XP BOILER
MODELS: XB/XW
1000, 1300, 1700
2000, 2600, 3400
SERIES 100/101
INSTALLATION - OPERATION -
MAINTENANCE - LIMITED WARRANTY
25589 Highway 1
McBee, SC 29101
WARNING: If the information in these
instructions is not followed exactly, a fire
or explosion may result causing property
damage, personal injury or death.
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS:
Do not try to light any appliance.
•
Do not touch any electrical switch; do
not use any phone in your building.
•
Immediately call your gas supplier
from a neighbor’s phone. Follow the
gas supplier’s instructions.
•
If you cannot reach your gas supplier,
call the fire department.
•
Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
Thank you for buying this energy efficient boiler.
We appreciate your confidence in our products.
PRINTED IN THE U.S.A. 0711
320741-002
TABLE OF CONTENTS
TABLE OF CONTENTS.......................................................................... 2
SAFE INSTALLATION, USE AND SERVICE.......................................... 3
GENERAL SAFETY................................................................................ 4
INTRODUCTION.................................................................................... 5
Model Identification............................................................................ 5
Abbreviations Used ........................................................................... 5
Qualifications..................................................................................... 5
DIMENSIONS AND CAPACITY DATA.................................................... 6
FEATURES AND COMPONENTS ....................................................... 10
Component Description................................................................... 12
CONTROL COMPONENTS ................................................................. 13
BOILER INSTALLATION CONSIDERATIONS ..................................... 15
Hydronic System ............................................................................. 15
Hot water boiler system - general water line connections ............... 16
GENERAL REQUIREMENTS .............................................................. 21
Location........................................................................................... 21
Fresh air openings for confined spaces........................................... 23
VENTING.............................................................................................. 25
Vent Installation Considerations ...................................................... 25
Venting Supports ............................................................................. 27
CONDENSATE DISPOSAL.................................................................. 37
GAS SUPPLY CONNECTIONS ........................................................... 38
BOILER START UP AND OPERATIONS ............................................. 40
LIGHTING AND OPERATING INSTRUCTIONS .................................. 42
CONTROL SYSTEM ............................................................................ 45
Burner Control System .................................................................... 45
Burner control operation.................................................................. 46
General operational sequence ........................................................ 47
Local operator interface: display system ......................................... 49
Installation instructions (S7999B OI Display) .................................. 50
Starting up the S7999B OI Display.................................................. 51
Page Navigation .............................................................................. 51
TROUBLESHOOTING ......................................................................... 61
MAINTENANCE PROCEDURES......................................................... 76
Maintenance schedules................................................................... 76
General maintenance ...................................................................... 76
Burner maintenance ........................................................................ 77
Venting maintenance....................................................................... 78
Heat exchanger maintenance.......................................................... 78
Handling ceramic fiber materials ..................................................... 79
Replacement parts .......................................................................... 79
PIPING DIAGRAMS............................................................................. 80
LIMITED WARRANTY.......................................................................... 82
2
SAFE INSTALLATION, USE AND SERVICE
The proper installation, use and servicing of this boiler is extremely important to your safety and the safety of others.
Many safety-related messages and instructions have been provided in this manual and on your boiler to warn you and others of a
potential injury hazard. Read and obey all safety messages and instructions throughout this manual. It is very important that the
meaning of each safety message is understood by you and others who install, use, or service this boiler.
This is the safety alert symbol. It is used to alert you to
potential personal injury hazards. Obey all safety
messages that follow this symbol to avoid possible
injury or death.
DANGER indicates an imminently
hazardous situation which, if not avoided,
will result in injury or death.
DANGER
WARNING indicates a potentially hazardous
situation which, if not avoided, could result
in injury or death.
WARNING
CAUTION indicates a potentially hazardous
situation which, if not avoided, could result in
minor or moderate injury.
CAUTION
CAUTION used without the safety alert
symbol indicates a potentially hazardous
CAUTION
situation which, if not avoided, could result in
property damage.
All safety messages will generally tell you about the type of hazard, what can happen if you do not follow the safety message, and
how to avoid the risk of injury.
The California Safe Drinking Water and Toxic Enforcement Act requires the Governor of California to publish a list of substances
known to the State of California to cause cancer, birth defects, or other reproductive harm, and requires businesses to warn of
potential exposure to such substances.
This product contains a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm. This
boiler can cause low level exposure to some of the substances listed in the Act.
IMPORTANT DEFINITIONS
Gas Supplier: The Natural Gas or Propane Utility or service who supplies gas for utilization by the gas burning
appliances within this application. The gas supplier typically has responsibility for the inspection and code approval of
gas piping up to and including the Natural Gas meter or Propane storage tank of a building. Many gas suppliers also
offer service and inspection of appliances within the building.
APPROVALS
3
GENERAL SAFETY
GROUNDING INSTRUCTIONS
HIGH ALTITUDE INSTALLATIONS
This boiler must be grounded in accordance with the National
Electrical Code, Canadian Electrical Code and/or local codes.
Boiler is polarity sensitive; correct wiring is imperative for proper
operation.
This boiler must be connected to a grounded metal, permanent
wiring system, or an equipment grounding conductor must be
run with the circuit conductors and connected to the equipment
grounding terminal or lead on the boiler.
INLET WATER CONSIDERATIONS
Circulating water through the boiler and to the remote storage
tank (if applicable) is accomplished by a pump on XW models
only. For hot water heating systems using the XB model, the
circulating pump is NOT provided on standard models (optional)
and must be field installed.
CORRECT GAS
Make sure the gas on which the boiler will operate is the same as
that specified on the boiler rating plate. Do not install the boiler if
equipped for a different type of gas; consult your supplier.
PRECAUTIONS
Rated inputs are suitable up to 2000 feet (610 m) elevation. Consult
If the unit is exposed to the following, do not operate until all the factory for installation at altitudes over 2000 feet (610 m).
corrective steps have been made by a qualified service agent:
FIELD INSTALLED COMPONENTS
1. Exposure to fire.
2. If damaged.
3. Firing without water.
4. Sooting.
When installing the boiler, the following components must be
installed:
•
•
•
Circulating Pump (Hydronic)
If the boiler has been exposed to flooding, it must be replaced.
Remote Temperature Sensor/Header Sensor
Storage Tank (Temperature & Pressure Relief Valve)
LIQUEFIED PETROLEUM GAS MODELS
Boilers for propane or liquefied petroleum gas (LPG) are different
from natural gas models.Anatural gas boiler will not function safely
on LP gas and no attempt should be made to convert a boiler from
natural gas to LP gas.
LP gas must be used with great caution. It is highly explosive
and heavier than air. It collects first in the low areas making its
odor difficult to detect at nose level. If LP gas is present or even
suspected, do not attempt to find the cause yourself. Leave
the building, leaving doors open to ventilate, then call your gas
supplier or service agent. Keep area clear until a service call
has been made.
At times you may not be able to smell an LP gas leak. One
cause is odor fade, which is a loss of the chemical odorant that
gives LP gas its distinctive smell. Another cause can be your
physical condition, such as having a cold or diminishing sense
of smell with age. For these reasons, the use of a propane gas
detector is recommended.
If you experience an out of gas situation, do not try to relight
appliances yourself. Call your local service agent. Only trained
LP professionals should conduct the required safety checks in
accordance with industry standards.
4
INTRODUCTION
This Instruction Manual covers XP Boiler models XB/XW 1000,
QUALIFICATIONS
1300, 1700, 2000, 2600, 3400 - Series 100/101. The instructions
and illustrations contained in this Instruction manual will provide
you with troubleshooting procedures to diagnose and repair
common problems and verify proper operation.
QUALIFIED INSTALLER OR SERVICE AGENCY
Installation and service of this boiler requires ability equivalent
to that of a Qualified Agency, as defined by ANSI below. In the
field involved. Installation skills such as plumbing, air supply,
venting, gas supply and electrical supply are required in addition
to electrical testing skills when performing service.
MODEL IDENTIFICATION
Check the rating plate affixed to the Boiler. The following
information describes the model number structure:
ANSI Z21.13 - CSA 4.9: “Qualified Agency” - “Any individual,
firm, corporation or company that either in person or through
a representative is engaged in and is responsible for (a) the
installation, testing or replacement of gas piping or (b) the
connection, installation, testing, repair or servicing of appliances
and equipment; that is experienced in such work; that is familiar
with all precautions required; and that has complied with all the
requirements of the authority having jurisdiction.”
SERIES-100/101 DESIGNATION:
• XP = Extreme Performance
MODEL (APPLICATION):
• XB = Hydronic Heating Boiler
• XW = Domestic Hot Water Supply Boiler
SIZE:
• 1000 = 920,000 Btu/hr input
• 1300 = 1,300,000 Btu/hr input
• 1700 = 1,700,000 Btu/hr input
• 2000 = 2,000,000 Btu/hr input
• 2600 = 2,600,000 Btu/hr input
• 3400 = 3,400,000 Btu/hr input
If you are not qualified (as defined by ANSI above) and licensed
or certified as required by the authority having jurisdiction
to perform a given task do not attempt to perform any of the
procedures described in this manual. If you do not understand
the instructions given in this manual do not attempt to perform
any procedures outlined in this manual.
FUEL:
This product requires a formal Start-Up by an authorized service/
start-up provider that has been approved by the manufacturer for
this specific product. Call 1-800-527-1953 to locate the nearest
authorized start-up provider and arrange a factory start-up.
Please provide as much notice as possible, preferably 2 weeks.
Please have the model and serial number ready when you call.
This start-up is required to activate the warranty and ensure safe,
efficient operation.
N = Natural gas
P = Propane
NOTE:
XB models are equipped with 50 psi pressure relief valve. (pump
is optionally installed)
XW models are factory installed circulating pump (standard),
with 125 psi pressure relief valve.
XB models can be special ordered with a factory installed pump
and XW models can be special ordered without the factory
installed pump. These factory configurations can also be
changed in the field by installing circulation pumps and changing
pressure relief valves to accommodate domestic and hydronic
hot water system requirements.
Warranty on this product is limited and could be void in the event
the unit is not installed per the instructions in this manual and/or
not started up by an authorized factory trained service/start-up
provider.
Properly installed and maintained, it should give you years of
trouble free service.
ABBREVIATIONS USED
Abbreviations found in this Instruction Manual include :
• ANSI - American National Standards Institute
• ASME - American Society of Mechanical Engineers
• NEC - National Electrical Code
• NFPA - National Fire Protection Association
• UL - Underwriters Laboratory
• CSA - Canadian Standards Association
• AHRI - Air-Conditioning, Heating and Refrigeration Institute
5
DIMENSIONS AND CAPACITY DATA
FIGURE 1. SINGLE HEAT EXCHANGER BOILER
TABLE 1. ROUGH IN DIMENSIONS (SINGLE)
Models
XB/XW-1000
inches
XB/XW-1300
inches
XB/XW-1700
inches
Dimensions
Flue Outlet Diameter
Air Intake Diameter
Water Inlet
mm
152
152
mm
152
152
mm
203
203
6
6
8
6
8
8
2 inch NPT
2 inch NPT
2 inch NPT
2 1/2 inch NPT
Water Outlet
2 1/2 inch NPT
2 inch NPT
Gas Inlet
A
B
C
D
E
F
47
67
29
37
23
9
1199
1702
737
49
68
29
38
23
9
1245
1727
737
57
76
29
37
24
9
1448
1930
737
940
610
229
940
965
584
584
229
229
G
H
J
34
44
6
864
1118
152
279
34
45
6
864
1143
152
34
45
6
864
1143
152
K
11
11
279
11
279
L
12
305
11
279
12
305
TABLE 2. OPERATING CHARACTERISTICS
Manifold Pressure
Inches W.C.
Maximum Supply Pressure Minimum Supply Pressure
Models
(XB/XW)
Type of Gas
kPa
Inches W.C.
kPa
Inches W.C.
kPa
Min Fire -0.2 to -0.3 -0.05 to -0.07
Max Fire -3.0 to -3.9 -0.75 to -0.97
Min Fire -0.1 to -0.3 -0.025 to -0.07
Natural
14.0
3.49
4.0
1.0
1000, 1300, 1700
2000, 2600, 3400
Propane
14.0
3.49
4.0
2.0
Max Fire -3.6 to -4.9 -0.90 to -1.22
6
FIGURE 2. DOUBLE HEAT EXCHANGER BOILER
TABLE 3. ROUGH IN DIMENSIONS (DOUBLE)
Models
XB/XW-2000
inches
XB/XW-2600
inches
XB/XW-3400
inches
Dimensions
mm
203
203
mm
203
203
mm
254
254
Flue Outlet Diameter
8
8
8
8
10
10
Air Intake Diameter
Water Inlet
Water Outlet
Gas Inlet
3 inch NPT
3 inch NPT
2 inch NPT
4 inch NPT
4 inch NPT
3 inch NPT
A
47
1194
49
1245
57
1448
B
C
D
E
F
78
36
22
40
7
1981
914
80
37
22
41
6
2032
940
91
37
22
41
6
2311
940
559
559
559
1016
178
1041
152
1041
152
G
10
254
10
254
10
254
H
J
4
102
508
305
4
102
483
305
4
102
483
330
20
12
19
12
19
13
K
TABLE 4. RECOVERY CAPACITIES
Temperature Rise - ΔT °F (°C)
Input Rating Output Rating Water
Models
40
(22)
60
(33)
70
(39)
80
(44)
90
(50)
100
(56)
120
(67)
140
(78)
(Btu/hr)
(Btu/hr)
Flow
GPH
LPH
GPH
LPH
GPH
LPH
2,593
9,815
3,664
13,868
4,791
1,728
6,543
2,442
9,246
3,194
1,482
5,608
2,094
7,925
2,738
1,296
4,907
1,832
6,934
2,395
9,068
1,152
4,362
1,628
6,164
2,129
8,060
1,037
3,926
1,465
5,547
1,916
7,254
864
3,272
1,221
4,623
1,597
6,045
741
2,804
1,047
3,962
1,369
5,182
XW-1000
920,000
854,680
XW-1300 1,300,000
1,207,700
XW-1700 1,700,000
XW-2000 2,000,000
XW-2600 2,600,000
1,579,300
1,858,000
2,415,400
18,136
12,090
10,363
GPH
LPH
GPH
LPH
GPH
5,636
21,336
7,327
27,737
9,582
3,758
14,224
4,885
18,491
6,388
3,221
12,192
4,187
15,850
5,475
2,818
10,668
3,664
13,868
4,791
2,505
9,483
3,257
12,327
4,259
2,255
8,534
2,931
11,095
3,833
1,879
7,112
2,442
9,246
3,194
1,610
6,096
2,094
7,925
2,738
XW-3400 3,400,000
3,158,600
LPH
36,271
24,181
20,726
18,136
16,121
14,508
12,090 10,363
7
RATINGS
TABLE 5. IBR RATINGS
MODELS
(XB/XW)
INPUT
MBH
GROSS
OUTPUT MBH
NET I=B=R RATINGS WATER MBH
(NOTE 2)
(NOTE 1)
MAX
MIN
1000
1300
920
100
130
856
744
1300
1209
1051
1700
2000
2600
3400
1700
2000
2600
3400
170
100
130
212
1581
1860
2418
3162
1375
1617
2103
2750
Notes:
1. The ratings are based on standard test procedures prescribed by the United States Department of Energy.
2. Net I=B=R ratings are based on net installed radiation of sufficient quantity for the requirements of the building and nothing need
be added for normal piping and pickup. Ratings are based on a piping and pickup allowance of 1.15.
3. Ratings have been confirmed by the Hydronics Institute, Section of AHRI.
ELECTRICAL REQUIREMENTS
TABLE 6. ELECTRICAL REQUIREMENTS
MODELS SUPPLY VOLTAGE FREQUENCY CURRENT
ELECTRICAL NOTES
(XB/XW)
(VOLTS)
(HZ)
(AMPS)
1000
120
60
30
30
A dedicated, single phase, 30/60 amp circuit breaker
with a grounded neutral should be provided to supply
power to the boiler.
1300
120
60
1700
2000
2600
3400
120
120
120
120
60
60
60
60
30
60
60
60
A dedicated, single phase, 60/60 amp circuit breaker
with a grounded neutral should be provided to supply
power to the boiler.
8
FLOW, HEAD AND TEMPERATURE RISE
TABLE 7. XB MODELS - FLOW, HEAD AND TEMPERATURE RISE
Temperature Rise - ΔT °F
Flow Rate
Input
(Btu/hr)
Output
(Btu/hr)
Water
Flow
Models
20
30
40
Maximum
Minimum
GPM
LPM
ΔP FT
ΔP M
GPM
LPM
ΔP FT
ΔP M
GPM
LPM
86
325
26
7.9
120
453
32.5
9.9
156
592
56
211
12
3.7
80
302
15
4.6
104
395
43
162
7
2.1
60
226
8
2.4
78
86
325
26
7.9
120
453
32.5
9.9
156
592
43
162
7
2.1
60
226
8
2.4
78
XB-1000
XB-1300
920,000
855,600
1,300,000
1,209,000
296
296
XB-1700
1,700,000
1,581,000
ΔP FT
ΔP M
35
14
8
35
8
10.7
4.3
2.4
10.7
2.4
GPM
LPM
ΔP FT
ΔP M
GPM
LPM
ΔP FT
ΔP M
GPM
LPM
184
696
26
7.9
239
905
32.5
9.9
313
1184
123
464
12
3.7
159
604
15
4.6
209
789
92
348
7
2.1
120
453
8
2.4
156
592
184
696
26
7.9
239
905
32.5
9.9
313
1184
92
348
7
2.1
120
453
8
2.4
156
592
XB-2000
XB-2600
2,000,000
2,600,000
1,860,000
2,418,000
XB-3400
3,400,000
3,162,000
ΔP FT
ΔP M
35
14
8
35
8
10.7
4.3
2.4
10.7
2.4
Note: Head Loss shown is through the boiler only and allows for no additional piping.
9
FEATURES AND COMPONENTS
FIGURE 3. SINGLE HEAT EXCHANGER BOILER COMPONENTS
10
FIGURE 4. DOUBLE HEAT EXCHANGER BOILER COMPONENTS
11
19. Heat exchanger access covers
COMPONENT DESCRIPTION
Allows access to the combustion side of the heat exchanger
coils.
1. Front access door:
Provides access to the gas train, burner controllers and the heat
exchanger.
20. High gas pressure switch
Switch provided to detect excessive supply gas pressure.
2. Air Filter Box:
21. Spark Igniter
Provides direct spark for igniting the burners.
Allows for the connection of the PVC air intake pipe to the boiler
through a standard PVC adapter. It uses a filter to prevent dust
and debris from entering the boiler.
22. Boiler power supply terminals (not visible)
The main power to the boiler is supplied through the terminals
housed inside the high voltage junction box.
3. Automatic air vents:
Designed to remove trapped air from the heat exchanger coils.
23. Low gas pressure switch
Switch provided to detect low gas supply pressure.
4. Blowers:
The blowers pull in air and gas through the venturis. Air and gas
mix inside the venturi and are pushed into the burners, where
they burn inside the combustion chamber.
24. High voltage connection box
This box has terminals for connecting the main power supply
(120V) to the boiler and outputs power supply (120V) for the
pumps from the boiler control. This box has terminals for low
voltage devices such as condensate trap and flow switch.
5. Boiler inlet temperature sensors
These sensors monitor system return water temperature.
6. Boiler outlet temperature sensors/High Limits
These sensors monitor boiler outlet water temperature. The boiler
modulates based on the Lead Lag Sensor connected to the tank.
25. Sensors/Communication Box
Connects sensors to tank sensor/header sensor and external
connections to building managements systems through MODBUS.
7. Burners
26. Low water cutoff board and sensor probe (LWCO)
Made with metal fiber and stainless steel construction, the
burners use pre-mixed air and gas and provide a wide range of
firing rates.
Device used to ensure adequate water is supplied to the boiler.
In the event of inadequate water levels, LWCO will ensure boiler
shut down. LWCO board is connected to the electronic panel,
whereas the sensor probe is connected to the heat exchanger.
8. Condensate Trap
Disposes the condensate produced from heat exchanger and
houses a switch that detects in case of blockage.
27. Main power supply switch
Turns 120 VAC ON/OFF to the boiler.
9. Control modules
28. Pump relay
The control modules respond to internal and external signals and
control the blowers, gas valves, and pumps to meet the heating
demand.
The pump relays are used tfor providing power to the XW Boiler
models.
29. Pressure relief valve
Protects the heat exchangers from an over pressure condition.
The relief valve will be set at particular PSI, depending on models.
10. Touch Screen Display
Digital controls with touch screen technology and full color
display.
30. Reset switch (optional) (not visible)
Reset switch for the low water cutoff.
11. Sight glass
The quartz sight glass provides a view of the flame for inspection
31. Stainless steel heat exchangers
purposes.
Allows system water to flow through specially designed coils.
12. Flame sensors
32. Venturi
Used by the control module to detect the presence of burner
flame.
The venturi is a gas/air mixing unit that allows modulation of a
premix burner with constant gas/air ratio.
13. Flap valves
33. Water inlet
Prevents recirculation of flue products when only one burner is
Water connection that return water from the system to the heat
exchangers.
running.
14. Flue gas sensors (not visible)
34. Water outlets
A NPT water connection that supplies hot water to the system.
These sensors monitor the flue gas exit temperature. The control
modules will modulate and shut down the boiler if the flue gas
temperature gets too hot. This protects the flue pipe from
overheating.
35. Enable/Disable Switch
This is an emergency boiler turn off switch which disconnects
the interlock voltage to the control board, hence turning off the
power supply to the gas valves. Do not use this switch for
turning off the boiler, this should be done from the touch
screen display, using the Operational Switch on the Lead
Lag screen.
15. Flue pipe adapter (not visible)
Allows for the connection of the PVC vent pipe system to the
boiler.
16. Gas shutoff valves (Internal unit)
Manual valves used to isolate the gas valves from the burners.
36. Vent outlet
Provides an outlet for combustion gases to outdoor.
17. Main gas shutoff valve (External unit)
Manual valve used to isolate the boiler from the gas supply.
18. Automatic modulating gas valve
The gas valve with the addition of venturi and blower are used for
modulating premix appliances.
12
CONTROL COMPONENTS
THE CONTROL SYSTEM
The R7910A1138 is a burner control system that provides heat
control, flame supervision, circulation pump control, fan control,
boiler control sequencing, and electric ignition function. It will
also provide status and error reporting.
FIGURE 7. LOW/HIGH GAS PRESSURE SWITCH
GAS VALVE
The gas valve is a normally closed servo regulated gas valve.
The valve opens only when energized by the burner control and
closes when the power is removed. The burner control supplies
24 volts to the gas valve during operation.
FIGURE 5. BURNER CONTROL SYSTEM
SPARK IGNITER
The spark igniter is a device that ignites the main burner. When
power is supplied to the igniter electrode, an electric arc is
created between the electrode and the ground terminal which
ignites the main burner.
FIGURE 6. SPARK IGNITER
FIGURE 8. GAS VALVE
LOW/HIGH GAS PRESSURE SWITCH
WATER FLOW SWITCH
This XP boiler is equipped with a low gas pressure switch which
meets the CSD-1 code requirements.
The water flow switch activates when sufficient water flow has
been established. Switch will not close when water flow is not
present.
The Low Gas Pressure Switch is normally open and remains
open unless the pressure falls below the preset pressure.
The High Gas Pressure Switch is normally closed and is used to
detect excessive gas pressure.
FIGURE 9. WATER FLOW SWITCH
13
FLAME SENSOR
WATER TEMPERATURE SENSORS
Each burner is equipped with a flame sensor to detect the
presence of the burner flames at high and low fire conditions. If
no flame is sensed, the gas valve will close automatically. The
voltage sensed by the flame sensor will also be displayed on the
Burner Screen.
FIGURE 12. WATER TEMPERATURE SENSORS
Temperature sensors are threaded immersion probes.
Temperature probes have embedded temperature sensors
(thermistors). The boiler’s control system monitors these sensors
to determine water temperature at various points in the system.
FIGURE 10. FLAME SENSOR
WATER TEMPERATURE LIMIT CONTROLS
INLET AND OUTLET TEMPERATURE SENSORS
All models have two inlet and two outlet temperature sensors
for each heat exchanger, factory installed to monitor the water
temperature entering and leaving the boiler. The Inlet Probe is
a temperature sensor only and has two leads. The Outlet probe
also contains the manual reset high temperature limit switch
and has four leads. The control system displays the Inlet and
Outlet water temperatures sensed from these two sensors on the
default Temperatures screen.
The “XB/XW” models incorporate an outlet water sensor having
dual sensors, that are factory set at 210°F (99°C).
REMOTE SENSORS
All models are supplied from the factory with a remote sensor.
The remote sensor is used to control system water temperature
for a single boiler in a domestic hot water storage tank or in the
return line from a primary/secondary hydronic heating system.
MAIN POWER SUPPLY SWITCH
The main power supply switch is a padlockable switch. This switch
provides 120V from the power supply to the boiler.
This switch needs to be turned off when servicing the boiler.
Note: The Enable/Disable Switch on the front of the boiler
does not interrupt electrical power to the boiler.
The boiler will modulate its firing rate in response to the
actual system temperature and load conditions. The control
system displays the temperature sensed from the remote sensor
as the “Lead Lag” temperature on the default Temperatures
screen.
LOW WATER CUTOFF DEVICE (LWCO)
Low water cutoff device is normally a closed switch that opens
when water drops below a preset level. Each model is equipped
with a factory installed LWCO. LWCO board is connected to the
electronic panel, whereas the sensor probe is connected to the
heat exchanger.
FIGURE 11. MAIN POWER SUPPLY SWITCH
FIGURE 13. LWCO BOARD AND PROBE
14
BOILER INSTALLATION CONSIDERATIONS
If the system is of the open type, a pressure reducing valve will not
GENERAL
be required as the water supply to the system will be controlled by
a manually operated valve. An overhead surge tank is required. A
minimum pressure of 15 psi (100 kPa) must be maintained on the
boiler at all times to ensure avoidance of potential damage to the
boiler which may not be covered by the warranty.
If the system is to be filled with water for testing or other purposes
during cold weather and before actual operation, care must be taken
to prevent freezing of water in the system. Failure to do so may cause
the water in the system to freeze with resulting damage to the system.
Damage due to freezing is not covered by the warranty.
EXPANSION TANK
Figure 78 on Page 80 shows a typical primary, secondary piping
method. This is the preferred piping method for most stainless steel
boilers. Other piping methods, however, may provide good system
operation. A prime concern when designing heating systems is the
maintenance of proper flow through the unit during boiler operation.
The secondary pump should be sized per the recommended flow
rate of the boiler, see Dimension and Capacity Data section in this
manual.
If the system is of the closed type, install an expansion tank. The
sizing of the expansion tank for a closed system is very important and
is directly related to the total water volume of the system.
An air separator as shown in the piping diagrams is recommended
especially for modern commercial hydronic systems. See Figure 78
on Page 80.
VENT VALVES
It is recommended that automatic, loose key or screw-driver type
vent valves be installed at each convector or radiator.
Before locating the boiler:
1. Check for nearby connection to:
• System water piping
• Venting connections
• Gas supply piping
SYSTEM HEADERS
Split systems with individual supply and return lines from the
boiler room should normally have this piping connected to
supply and return manifold headers near the boiler. To achieve
good water distribution with maximum pressure drop for several
circuits, manifolds should be larger than system mains.
• Electrical power
2. Locate the boiler so that if water connections should leak,
water damage will not occur. When such locations cannot
be avoided, it is recommended that a suitable drain pan,
adequately drained, be installed under the appliance.
The pan must not restrict combustion air flow. Under no
circumstances is the manufacturer to be held responsible
for water damage in connection with this appliance, or any
of its components.
The circuits should be spaced on the heater at a minimum of 3”
(76 mm) center to center. Install a balancing cock in each return
line.
Manifold headers are recommended for split systems with
or without zone valves and also those installations with zone
circulators. If the system is to be split at remote points, good
practice requires special attention be given to main pipe sizing to
allow balancing of water flow.
3. Check area around the boiler. Remove any combustible
CHECK VALVES
materials, gasoline and other flammable liquids.
Check valves must be installed to isolate each boiler in
installations where multiple boilers/pumps are installed in the
same zone.
4. Make sure the gas control system components are protected
from dripping or spraying water or rain during operation or
service.
COOLING PIPING
5. If a new boiler will replace an existing boiler, check for and
correct system problems, such as:
When the boiler is used in conjunction with a refrigeration system
it must be installed so that the chilled medium is piped in parallel
with the boiler. Appropriate flow control valves, manual or
motorized, must be provided to prevent the chilled medium from
entering the boiler.
• System leaks causing oxygen corrosion or heat
exchanger cracks from hard water deposits.
• Lack of freeze protection in boiler water causing system
and boiler to freeze and leak.
If the boiler is connected to chilled water piping or its heating coils
are exposed to refrigerated air, the boiler piping system must be
equipped with flow valves or other automatic means to prevent
gravity circulation through the boiler during the cooling cycle.
HYDRONIC SYSTEM
The following is a brief description of the equipment required
for the installations noted in this manual. All installations must
comply with local code.
Primary/secondary pumping of both the chiller(s) and the boiler(s) is
an excellent winter-summer change-over method, because cooling
flow rates are so much more than heating flow rates. In this way each
system (heating or cooling) is circulated independently.
WATER SUPPLY LINE
These boilers can be used only in a forced circulation hot water
heating system. Since most forced circulation systems will be of
the closed type, install the water supply line as shown on piping
diagram.
Fast filling of large pipe, old radiator installations and pressure
purging of series loop systems (where high pressures are not
available) requires bypassing of the pressure reducing valve.
Generally, pressure purging is not possible with a well pump
system. High point air venting is essential.
15
CIRCULATING PUMP
HOT WATER BOILER SYSTEM - GENERAL WATER
LINE CONNECTIONS
A circulating pump is used when a system requires a circulating
loop or there is a storage tank used in conjunction with the boiler.
Install in accordance with the current edition of the National
Electrical Code, NFPA 70 or the Canadian Electrical Code,
CSA C22.1. All bronze circulating pumps are recommended
for use with commercial boilers. Some circulating pumps are
manufactured with sealed bearings and do not require further
lubrication. Some circulating pumps must be periodically oiled.
Refer to the pump manufacturer’s instructions for lubrication
requirements.
Piping diagrams will serve to provide the installer with a
reference for the materials and methods of piping necessary for
installation. It is essential that all water piping be installed and
connected as shown on the diagrams. Check the diagrams to
be used thoroughly before starting installation to avoid possible
errors and to minimize time and material cost. It is essential that
CLOSED WATER SYSTEMS
XB HYDRONIC BOILERS: The circulating pump is not provided
on standard models (optional) and must be obtained and installed
in the field.
Water supply systems may, because of code requirements
or such conditions as high line pressure, among others, have
installed devices such as pressure reducing valves, check
valves, and back flow preventers. Devices such as these cause
the water system to be a closed system.
XW HOT WATER BOILERS: The circulating pump is integral to
the XW models. This pump has been lubricated at the factory,
and future lubrication should be in accordance with the motor
manufacturer’s instructions provided as a supplement to this
manual.
THERMAL EXPANSION
PRIMARY SYSTEM CONTROL
All XP boiler installations require a “Primary System Control” that
senses and reacts to water temperature inside the storage tank
on domestic water applications or in the return line on primary/
secondary hydronic heating systems. The Primary System
Control will activate and deactivate boiler heating cycles based
on its setpoint and current system water temperature. There are
three suitable methods to configure a Primary System Control.
One of these three methods must be used.
As water is heated, it expands (thermal expansion). In a closed
system the volume of water will increase when it is heated. As the
volume of water increases there will be a corresponding increase
in water pressure due to thermal expansion. Thermal expansion
can cause premature failure (leakage). This type of failure is not
covered under the limited warranty. Thermal expansion can also
cause intermittent Temperature-Pressure Relief Valve operation:
water discharged from the valve due to excessive pressure build
up. This condition is not covered under the limited warranty.
The Temperature-Pressure Relief Valve is not intended for the
constant relief of thermal expansion.
1.
The Primary System Control can be the boiler’s
control system working with the factory supplied Header
Sensor, installed inside the storage tank on domestic water
applications or in the return line on primary/secondary
hydronic heating systems.
A properly sized thermal expansion tank must be installed on
all closed systems to control the harmful effects of thermal
expansion. Contact a local plumbing service agency to have a
thermal expansion tank installed.
2.
Alternatively, the Burner Control system can be used
as a Primary System Control. It will also provide boiler status
and error reporting. Multiple boilers can be joined together
to heat a system instead of a single, larger burner or boiler.
Using boilers in parallel is more efficient, costs less, reduces
emissions, improves load control, and is more flexible than
the traditional large boiler.
PRESSURE RELIEF VALVE
An ASME rated pressure relief valve is furnished with the boiler.
A fitting for the relief valve is provided in the top of the boiler.
Never operate the heating elements without being certain the
boiler is filled with water and a properly sized pressure relief
valve is installed in the relief valve opening provided.
3.
MB2 and COM2 ports can be used for Building
Management Systems.
The pressure rating of the relief valve should be equal to or less
than the rated pressure capacity of any component in the system
INTERNAL CONTAMINANTS
The hydronic system must be internally cleaned and flushed including the boiler. Should the valve need to be replaced, call
after a new or replacement boiler has been installed, to remove the toll free phone number listed on the back of this manual for
contaminants that may have accumulated during installation. further technical assistance
This is extremely important when a replacement boiler is installed
into an existing system where Stop Leak or other boiler additives
have been used.
Failure to clean and flush the system can produce acid
concentrations that become corrosive, and leads to heat
exchanger failure.
All hot water heating systems should be completely flushed with
a grease removing solution to assure trouble-free operation. Pipe
joint compounds, soldering paste, grease on tubing and pipe all
tend to contaminate a system
Failure to flush contaminants from a system can cause solids
to form on the inside of boiler exchangers, create excessive
blockage of water circulation, deterioration of the pump seals
and impellers.
16
In addition, a CSA design-certified and ASME-rated temperature
and pressure (T&P) relief valve must be installed on each and
every water storage tank in hot water supply system. The T&P
relief valve must comply with applicable construction provisions
of Standard for Relief Valves for Hot Water Supply Systems,ANSI
Z21.22 or CSA 4.4. T&P relief valve must be of automatic reset
type and not embody a single-use type fusible plug, cartridge or
linkage.
Explosion Hazard
Relief Valve must comply with
ASME code.
Properly sized Relief Valve must
be installed in opening provided.
T&P relief valve should have a temperature rating of 210°F
(99°C), a pressure rating not exceeding lowest rated working
pressure of any system component, and a discharge capacity
exceeding total input of water boilers supplying water to storage
tank.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.
Locate the T&P relief valve (a) in the top of the tank, or (b) in
the side of the tank on a centerline within the upper 6 inches
The tapping should be threaded in accordance with the current
edition of the Standard for Pipe Threads, General Purpose
(inch), ANSI/ASME B1.20.1. The location of, or intended location
for, the T&P relief valve should be readily accessible for servicing
or replacement.
A discharge pipe from the relief valve should terminate at an
adequate floor drain. Do not thread, plug, or cap the end of
drain line.
CAUTION
Water Damage Hazard
GAS CONNECTIONS
•
Pressure Relief Valve discharge pipe must
terminate at adequate drain.
The Discharge Pipe:
• Shall not be smaller in size than the outlet pipe size of the
valve, or have any reducing couplings or other restrictions.
• Shall not be plugged or blocked.
• Shall not be exposed to freezing temperatures.
• Shall be of material listed for hot water distribution.
• Shall be installed so as to allow complete drainage of both
the relief valve and the discharge pipe.
• Must terminate a maximum of six inches above a floor
drain or external to the building. In cold climates, it is
recommended that the discharge pipe be terminated at an
adequate drain inside the building.
Make sure the gas on which boiler is to operate is same as that
specified on the rating plate. Do not install boiler if equipped for a
different type of gas. Consult your gas supplier.
• Shall not have any valve or other obstruction between the
relief valve and the drain.
This boiler is not intended to operate at gas supply pressure
other than shown on the rating plate. A lock-up or positive shut-
off type regulator must be installed in gas supply line. For proper
gas regulation the lock-up style regulators must be installed no
closer than a minimum of 3 feet from the boiler and a maximum
of 8 feet away from the boiler. Exposure to higher gas supply
pressure may cause damage to gas valves which can result in
fire or explosion. If overpressure has occurred such as through
improper testing of gas lines or emergency malfunction of supply
system, the gas valves must be checked for safe operation.
Make sure that the outside vents on supply regulators and the
Once the boiler is installed and filled with water and the system
is pressurized, manually test the operation of the pressure relief
valve. See the Maintenance Procedures section of this manual
for instructions.
Your local code authority may have other specific safety relief
valve requirements not covered below. If any pressure relief
valve is replaced, the replacement valve must comply with the
current version of the ASME Boiler and Pressure Vessel Code,
Section IV (“HEATING BOILERS”).
XB HYDRONIC BOILERS, are shipped with a 50 psi (345 kPa) safety vent valves are protected against blockage. These are
pressure relief valve. This relief valve must be installed in the
water outlet as near to the boiler as possible.
parts of the gas supply system, not boiler. Vent blockage may
occur during ice build-up or snowstorms.
XW HOT WATER BOILERS, are shipped with a 125 psi (860
kPa) pressure relief valve that must be installed in the water out-
let as near to the boiler as possible.
The boiler must be isolated from the gas supply piping system by
closing its main manual gas shut off valve during any pressure
testing of the gas supply piping system at test pressures equal
to or less than 1/2 psig.
This ASME-rated valve has a discharge capacity that exceeds
maximum boiler input rating and a pressure rating that does not
exceed maximum working pressure shown on boiler rating plate.
Disconnect the boiler and its main manual gas shut-off valve
from the gas supply piping during any pressure testing of the
gas supply system over 1/2 psig. The gas supply line must be
capped when not connected to the boiler.
17
It is important to guard against gas valve fouling from
contaminants in the gas ways. Such fouling may cause improper
operation, fire or explosion. If copper supply lines are used they
must be approved for gas service.
TABLE 8.
SINGLE UNIT INSTALLATION, SUGGESTED GAS PIPE
SIZING. MAXIMUM EQUIVALENT PIPE LENGTH (IN FEET).
2”
2-1/2”
3”
4”
BTU
When local codes require a main manual shut-off valve outside
the boiler jacket, a suitable main manual shut-off valve must be
installed in a location complying with those codes.
Input
Nat
70
Pro
Nat
Pro
-----
200
Nat
-----
-----
Pro
-----
-----
Nat
-----
-----
Pro
-----
-----
920,000
150 175
1,300,000 40
1,700,000 20
2,000,000 20
2,600,000 10
3,400,000 -----
100
60
100
70
50
30
20
Before attaching gas line be sure that all gas pipe is clean
on inside. To trap any dirt or foreign material in the gas supply
line, a drip leg (or sediment trap) must be incorporated in piping.
The drip leg must be readily accessible and not subject to
freezing conditions. Install in accordance with recommendations
of serving gas supplier. Refer to the current edition of the National
Fuel Gas Code, ANSI Z223.1/NFPA 54 or the Natural Gas and
Propane Installation Code, CAN/CSA B149.1
150
100
70
200
150
90
-----
-----
200
-----
-----
-----
-----
-----
-----
-----
50
30
-----
40
50
125 200
3
@
@
Natural gas 1000 Btu/ft^ , 0.60 specific gravity
0.3 in. w.c. pressure drop.
0.3 in. w.c. pressure drop.
Size of gas supply piping may be larger than heater connection
on installations where a significant run of piping is required.
3
Propane gas 2500 Btu/ft^ , 1.50 specific gravity
TABLE 9.
To prevent damage, care must be taken not to apply too much
torque when attaching gas supply pipe to boiler gas inlet. When
installing and tightening gas piping use a second wrench to hold
the gas valve to keep the valve from turning. To prevent damage
to the gas valve do not use pipe wrench on the valve body.
SINGLE UNIT INSTALLATION, SUGGESTED GAS PIPE
SIZING. MAXIMUM EQUIVALENT PIPE LENGTH (IN FEET).
2”
2-1/2”
3”
4”
BTU
Input
Nat
125
Pro
Nat
Pro
-----
-----
Nat
-----
-----
Pro
-----
-----
Nat
-----
-----
Pro
-----
-----
Fittings and unions in gas line must be of metal to metal type.
Apply joint compounds (pipe dope) sparingly and only to the
male threads of pipe joints. Do not apply compound to the first
two threads. Use compounds resistant to the action of liquefied
petroleum gases. The boiler and its gas connection must be leak
tested before placing the boiler in operation.
920,000
200 200
1,300,000 80
1,700,000 40
2,000,000 30
2,600,000 20
3,400,000 10
175
100
80
175
100
80
-----
200
125
70
-----
200
150
90
-----
-----
-----
200
-----
-----
-----
-----
-----
-----
-----
-----
50
50
GAS SUPPLY LINE SIZING
30
30
The gas piping installation must be capable of supplying the
maximum probable gas demand without excessive pressure loss.
Depending on local practices, the ALLOWABLE PRESSURE
LOSS between the gas meter, or service regulator and each
appliance is generally 0.3 or 0.5 inches of water column (0.075
or 0.124 kPa).
3
@
@
Natural gas 1000 Btu/ft^ , 0.63 specific gravity
0.5 in. w.c. pressure drop.
0.5 in. w.c. pressure drop.
3
Propane gas 2500 Btu/ft^ , 1.50 specific gravity
CORROSIVE MATERIALS AND CONTAMINATION
SOURCES
iron pipe or equivalent gas supply line size to be used with single
unit.
Products to avoid:
• Spray cans containing chloro/fluorocarbons
For multiple boiler installation or installations of a single boiler
on Page 20 to size iron pipe or equivalent gas supply line. These
tables are taken from the current edition of the National Fuel Gas
Code, ANSI Z223.1/NFPA 54 or the Natural Gas and Propane
Installation Code, CAN/CSA B149.1.
• Permanent wave solutions
• Chlorinated waxes/cleaners
• Chlorine-based swimming pool chemicals
• Calcium chloride used for thawing
• Sodium chloride used for water softening
• Refrigerant leaks
column (0.124 kPa), and a gas with a specific gravity of
0.60 and a heating value of 1,000 BTU/ft3, approximately
that of Natural Gas.
• Paint or varnish removers
• Hydrochloric acid/muriatic acid
• Cements and glues
column (0.124 kPa), and a gas with a specific gravity of
1.53 and a heating value of 2,500 BTU/ft3, approximately
that of Propane Gas.
• Antistatic fabric softeners used in clothes dryers
• Chlorine-type bleaches, detergents, and cleaning
solvents found in household laundry rooms
Where it is necessary to use more than the average number of
fittings (i.e., elbows, tees and valves in gas supply line) use a
pipe larger than specified to compensate for increased pressure
drop.
• Adhesives used to fasten building products and other
similar products
Areas likely to have contaminants:
• Dry cleaning/laundry areas and establishments
length for a single unit installation. It does not take into account
other appliances that may be connected to the gas line.
For installation of multiple units, or instances where several
• Swimming pools
• Metal fabrication plants
• Beauty shops
• Refrigeration repair shops
• Photo processing plants
18
LOW VOLTAGE CONTROL WIRING
• Auto body shops
1. Header Terminals: In case of Hydronic Boilers, the header
terminals are connected to the hydronic loop header sensor.
Whereas in case of Hot water Boilers the header terminals
are connected to the tank sensor where the temperature can
• Plastic manufacturing plants
• Furniture refinishing areas and establishments
• New building construction
• Remodeling areas
Common household products, pool and laundry products may
contain fluorine or chlorine compounds. When these chemicals
come in contact with the boiler, they react and can form strong
acids. The acid can spoil the boiler wall, causing serious damage
and may result in flue gas spillage or boiler water leakage into
the building.
2. Outdoor Terminals: In case of Hydronic Boilers, they are
connected to the outdoor sensors. But in case of Hot water
sensors must be mounted with cable inlet facing down
connecting from the boiler to the outdoor sensor must be no
more than 50 feet.
If the above mentioned contaminants and corrosive materials
chemicals are present near the location of the boiler, make sure
to remove the boiler permanently or relocate air inlet and vent
terminations to other areas.
3. MB2 and COM2 terminals are meant for building
management systems.
FIELD WIRING
120 VAC POWER SUPPLY WIRING
8) circuit breaker with a grounded neutral should be provided to
supply power to the boilers. Use #10 AWG wire for the 120 VAC
power supply to the boiler. All 120 VAC power supply connections
should be made at the rear of the unit where a wiring junction
box is provided. Field installed power supply wiring to the boiler
should be installed in conduit. This conduit and wiring should
be separate from any other conduit/wiring to guard against EMI
(electromagnetic interference).
FIGURE 15. LOW VOLTAGE CONTROL WIRING
POWER SUPPLY CHECK
To reduce the possibility of electrical interference with the boiler’s
controlsystemthepowersupplyvoltage, polarityandgroundmust
be checked. Using an AC volt meter check the 120 VAC power
supply wiring from the breaker prior to making power supply
connections at the boiler. Confirm the power supply voltage &
polarity are correct and that an adequate ground connection is
present by performing the three voltage tests below. See Figure
All low voltage control wiring connections must be made as
rear of the unit where a wiring junction box is provided. Field
installed wiring inside 1/2 inch conduit is installed between the
junction box on the back of the boiler and the temperature probe
and/or field supplied external control being used. This conduit
and wiring should be separate from any other conduit/wiring to
guard against EMI (electromagnetic interference).
Confirm RMS voltage between:
•
•
•
H and GND = 108 VAC minimum, 132 VAC maximum.
N and H = 108 VAC minimum, 132 VAC maximum.
N and GND = < 1 VAC maximum.
FIGURE 16. OUTDOOR SENSOR
FIGURE 14. FIELD WIRING
The outdoor sensor must be mounted in a shaded location, to
avoid direct sunlight. It must be atleast 3 feet away from any
exhaust, dryer, bathroom or other building vents. It must be
located on the north side of th building, above the expected snow
line where ice and debris cannot cover it.
19
GENERAL REQUIREMENTS
REQUIRED ABILITY
REPLACING EXISTING COMMON VENTED BOILER
Installation or service of this boiler requires ability equivalent to
that of a licensed tradesman in the field involved. Plumbing, air
supply, venting, gas supply, and electrical work are required.
NOTE: This section does not describe a method for common
venting XP units. It describes what must be done when a unit
is removed from a common vent system. The XP units require
special vent systems and fans for common vent. Contact the
factory if you have questions about common venting XP units.
LOCATION
When an existing boiler is removed from a common venting
system, the common venting system is likely to be too large
for proper venting of the appliances remaining connected to it.
At the time of removal of an existing boiler, the following steps
should be followed with each appliance remaining connected to
the common venting system placed in operation, while the other
appliances remaining connected to the common venting system
are not in operation.
When installing the boiler, consideration must be given to proper
location. The location selected should provide adequate air
supply and be as centralized with the piping system as possible.
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion and deficiencies which could
cause an unsafe condition.
3. In so far as it is practical, close all building doors and
windows and all doors between the space in which the
appliances remaining connected to the common venting
system are located and other spaces of the building. Turn
on clothes dryers and any appliance not connected to the
common venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they will operate
at maximum speed. Do not operate a summer exhaust fan.
Close fireplace dampers.
4. Place in operation the appliance being inspected. Follow the
lighting instructions. Adjust thermostat so the appliance will
operate continuously.
5. Test for spillage at the draft hood relief opening after 5
minutes of main burner operation. Use the flame of a match
or candle, or smoke from a cigarette, cigar or pipe.
6. After it has been determined that each appliance remaining
connected to the common venting system properly vents
when tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas-burning
appliance to their previous condition of use.
7. Any improper operation of the common venting system
should be corrected so that the installation conforms with
the National Fuel Gas Code, ANSI Z223.1/NFPA 54 and/
or CSA B149.1, Installation Codes. When resizing any
portion of the common venting system, the common venting
system should be resized to approach the minimum size as
determined using the appropriate tables and guidelines in the
National Fuel Gas Code, ANSI Z223.1/NFPA 54 and/or CSA
B149.1, Installation Codes.
This boiler is intended for Indoor Installation only, and should not
be installed where freezing temperatures or any moisture could
damage the external components of the boiler.
21
LEVELING
PANELS AND COVERS
Because this unit is a Category IV appliance it produces some
amounts of condensation. The unit has a condensation disposal
system that requires this unit to be level to properly drain. Each
unit should be checked to be certain that it is level prior to starting
the unit.
All panels and covers (e.g. control and junction box covers; front,
side and rear panels of boiler) must be in place after service and/
or before operation of boiler. This will ensure that all gas ignition
components will be protected from water.
The XP is a low-pressure boiler (Category IV) to be used as
either hot water supply (domestic/commercial water heating) or
hot water heating (hydronic) application. Category IV appliances
are often termed “High Efficiency” appliances.
If the unit is not level, obtain and insert shims under the feet at
the frame base to correct this condition.
AIR REQUIREMENTS
CHEMICAL VAPOR CORROSION
Boiler corrosion and component failure can be caused by the
heating and breakdown of airborne chemical vapors. Spray can
propellants, cleaning solvents, refrigerator and air conditioning
refrigerants, swimming pool chemicals, calcium and sodium
chloride (water softener salt), waxes, and process chemicals
are typical compounds which are potentially corrosive. These
materials are corrosive at very low concentration levels with little
or no odor to reveal their presence.
Breathing Hazard - Carbon Monoxide Gas
Install appliance in accordance with
the Instruction Manual and NFPA 54 or
CAN/CSA-B149.1.
To avoid injury, combustion and ventilation
air must be taken from outdoors.
Do not place chemical vapor emitting
products near water heater.
Products of this sort should not be stored near boiler. Also, air
which is brought in contact with boiler should not contain any
of these chemicals. If necessary, uncontaminated air should be
obtained from remote or outside sources. Failure to observe this
requirement will void warranty.
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
INSTALLATION CLEARANCES
For safe operation an adequate supply of fresh uncontaminated
air for combustion and ventilation must be provided.
This boiler is approved for installation in an alcove with minimum
clearances to combustibles.
An insufficient supply of air can cause recirculation of combustion
products resulting in contamination that may be hazardous to
life. Such a condition often will result in a yellow, luminous burner
flame, causing sooting of the combustion chamber, burners and
flue tubes and creates a risk of asphyxiation.
TABLE 12. INSTALLATION CLEARANCES
RECOMMENDED
SERVICE
CLEARANCES
CLEARANCES FROM
COMBUSTIBLE
MATERIALS
Do not install the boiler in a confined space unless an adequate
supply of air for combustion and ventilation is brought in to that
space using the methods described in the Confined Space
section that follows.
Front
Rear
Left
30" (762 mm)
36" (610 mm)
24 " (610 mm)
24 " (610 mm)
24" (610 mm)
8" (203 mm)
24" (610 mm)
1" (25.4 mm)
2" (51 mm)
Never obstruct the flow of ventilation air. If you have any doubts
or questions at all, call your gas supplier. Failure to provide the
proper amount of combustion air can result in a fire or explosion
and cause property damage, serious bodily injury or death.
Right
Top
6" (152 mm)
UNCONFINED SPACE
2” (51 mm) clearance is allowable from combustible construction
for hot water pipes.
An unconfined space is one whose volume is not less than 50
cubic feet per 1,000 Btu/hr (4.8 cubic meters per kW) of the
total input rating of all appliances installed in the space. Rooms
communicating directly with the space, in which the appliances
are installed, through openings not furnished with doors, are
considered a part of the unconfined space.
Sufficient area should be provided at the front and rear of the
unit for proper servicing. In a utility room installation, the door
opening should be wide enough to allow the boiler to enter or
to permit the replacement of another appliance such as a boiler.
FLOORING AND FOUNDATION:
All models are approved for installation on combustible flooring,
but must never be installed on carpeting. Do not install the boiler
on carpeting even if foundation is used. Fire can result, causing
severe personal injury, death, or substantial property damage.
Makeup air requirements for the operation of exhaust fans,
kitchen ventilation systems, clothes dryers and fireplaces shall
also be considered in determining the adequacy of a space to
provide combustion, ventilation and dilution air.
If flooding is possible, elevate the boiler sufficiently to prevent
water from reaching the boiler.
UNUSUALLY TIGHT CONSTRUCTION
In unconfined spaces in buildings, infiltration may be adequate
to provide air for combustion, ventilation and dilution of flue
gases. However, in buildings of unusually tight construction (for
example, weather stripping, heavily insulated, caulked, vapor
barrier, etc.) additional air must be provided using the methods
described in the Confined Space section that follows.
22
CONFINED SPACE
OUTDOOR AIR THROUGH TWO OPENINGS
A confined space is one whose volume is less than 50 cubic
feet per 1,000 Btu/hr (4.8 cubic meters per kW) of the total input
rating of all appliances installed in the space.
Openings must be installed to provide fresh air for combustion,
ventilation and dilution in confined spaces. The required size for
the openings is dependent on the method used to provide fresh
air to the confined space and the total Btu/hr input rating of all
appliances installed in the space.
DIRECT VENT APPLIANCES
Appliances installed in a direct vent configuration that derive all
air for combustion from the outdoor atmosphere through sealed
intake air piping are not factored in the total appliance input Btu/
hr calculations used to determine the size of openings providing
fresh air into confined spaces.
FIGURE 17. OUTDOOR AIR THROUGH TWO OPENINGS
EXHAUST FANS
The confined space shall be provided with two permanent
openings, one commencing within 12 inches (300 mm) of the top
and one commencing within 12 inches (300 mm) of the bottom of
the enclosure. The openings shall communicate directly with the
Where exhaust fans are installed, additional air shall be provided
to replace the exhausted air. When an exhaust fan is installed
in the same space with a water heater, sufficient openings to
provide fresh air must be provided that accommodate the
requirements for all appliances in the room and the exhaust fan.
Undersized openings will cause air to be drawn into the room
through the water heater’s vent system causing poor combustion.
Sooting, serious damage to the water heater and the risk of fire
or explosion may result. It can also create a risk of asphyxiation.
Each opening shall have a minimum free area of 1 square inch
per 4,000 Btu/hr (550 mm2 per kW) of the aggregate input rating
of all appliances installed in the enclosure. Each opening shall
not be less than 100 square inches (645 cm2).
OUTDOOR AIR THROUGH ONE OPENING
LOUVERS AND GRILLES
The free areas of the fresh air openings in the instructions that
follow do not take in to account the presence of louvers, grilles or
screens in the openings.
The required size of openings for combustion, ventilation and
dilution air shall be based on the “net free area” of each opening.
Where the free area through a design of louver or grille or screen
is known, it shall be used in calculating the size of opening
required to provide the free area specified. Where the louver and
grille design and free area are not known, it shall be assumed
that wood louvers will have 25% free area and metal louvers and
grilles will have 75% free area. Non motorized louvers and grilles
shall be fixed in the open position.
FRESH AIR OPENINGS FOR CONFINED SPACES
The following instructions shall be used to calculate the size,
number and placement of openings providing fresh air for
combustion, ventilation and dilution in confined spaces. The
illustrations shown in this section of the manual are a reference
for the openings that provide fresh air into confined spaces
only. Do not refer to these illustrations for the purpose of vent
installation. See Venting section on Page 25 for complete venting
installation instructions.
FIGURE 18. OUTDOOR AIR THROUGH ONE OPENING
Alternatively a single permanent opening, commencing within 12
inches (300 mm) of the top of the enclosure, shall be provided.
least 1 inch (25 mm) from the sides and back and 6 inches (150
mm) from the front of the appliance. The opening shall directly
communicate with the outdoors or shall communicate through a
vertical or horizontal duct to the outdoors or spaces that freely
communicate with the outdoors and shall have a minimum free
area of the following:
1. 1 square inch per 3000 Btu/hr (700 mm2 per kW) of the total
input rating of all appliances located in the enclosure, and
2. Not less than the sum of the areas of all vent connectors in
the space.
23
The confined space shall be provided with two permanent vertical
ducts, one commencing within 12 inches (300 mm) of the top and
one commencing within 12 inches (300 mm) of the bottom of the
enclosure. The vertical ducts shall communicate directly with the
OUTDOOR AIR THROUGH TWO HORIZONTAL DUCTS
Each duct opening shall have a minimum free area of 1 square
inch per 4,000 Btu/hr (550 mm2 per kW) of the aggregate input
rating of all appliances installed in the enclosure.
When ducts are used, they shall be of the same cross sectional
area as the free area of the openings to which they connect.
The minimum dimension of rectangular air ducts shall be not less
than 3 inches.
AIR FROM OTHER INDOOR SPACES
FIGURE 19. OUTDOOR AIR THROUGH TWO HORIZONTAL
DUCTS
The confined space shall be provided with two permanent
horizontal ducts, one commencing within 12 inches (300 mm) of
the top and one commencing within 12 inches (300 mm) of the
bottom of the enclosure. The horizontal ducts shall communicate
Each duct opening shall have a minimum free area of 1 square
inch per 2,000 Btu/hr (1100 mm2 per kW) of the aggregate input
rating of all appliances installed in the enclosure.
When ducts are used, they shall be of the same cross sectional
area as the free area of the openings to which they connect.
The minimum dimension of rectangular air ducts shall be not less
than 3 inches.
FIGURE 21. AIR FROM OTHER INDOOR SPACES
OUTDOOR AIR THROUGH TWO VERTICAL DUCTS
The confined space shall be provided with two permanent
openings, one commencing within 12 inches (300 mm) of the top
and one commencing within 12 inches (300 mm) of the bottom of
The illustrations shown in this section of the manual are a
reference for the openings that provide fresh air into confined
spaces only.
Do not refer to these illustrations for the purpose of vent
installation.
Each opening shall communicate directly with an additional
room(s) of sufficient volume so that the combined volume of all
spaces meets the criteria for an Unconfined Space.
Each opening shall have a minimum free area of 1 square inch
per 1,000 Btu/hr (1100 mm2 per kW) of the aggregate input rating
of all appliances installed in the enclosure. Each opening shall
not be less than 100 square inches (645 cm2).
FIGURE 20. OUTDOOR AIR THROUGH TWO VERTICAL
DUCTS
24
VENTING
STAINLESS STEEL INSTALLATION:
Installations must comply with applicable national, state, and
local codes. Stainless steel vent systems must be listed as a UL-
1738 approved system for the United States and a ULC-S636
approved system for Canada.
Installation of the approved AL 29-4C stainless steel venting
material should adhere to the stainless steel vent manufacturer’s
installation instructions supplied with the vent system.
pipe sizes.
AIR INTAKE/VENT CONNECTIONS
1. Air Intake Adapter: Provides an inlet for combustion air
directly to the unit from outdoors.
Vent sizing, installation and termination should be in accordance
with this installation manual. This boiler must be vented using
PVC/CPVC or Stainless Steel materials.
2. Vent Outlet: Provides an outlet for combustion gases to
outdoors.
All electrical power and gas must be turned off prior to any
installation of the venting system.
VENTING SYSTEM
This boiler may be installed in six separate orientations
depending on the requirements of the building and
the appliance. The installer must decide which method is most
appropriate for each installation. These orientations are:
VENT INSTALLATION CONSIDERATIONS
This boiler is a category IV appliance that can be vented using
room air for intake combustion air, or direct vented so that all
intake air for combustion comes from the outside through a
sealed pipe. When installing this appliance as direct vent, special
vent kits are required.
1. Vertical Termination - vertical vent termination through
un-enclosed or enclosed areas with roof penetration, see
2. Through-the-Wall Termination (TWT) - horizontal vent
on Page 28.
In cold climates any water vapor remaining in the flue gases will
condense into a cloud of vapor at the point where the vent system
exits the building. Special consideration is recommended, before
locating the vent termination near walkways, windows and
building entrances.
3. Horizontal Direct Vent - using TWT to exhaust flue
products and PVC piping to bring combustion air to the boiler
on Page 30.
Direct venting into dead spaces such as alleys, atriums, and
inside corners can cause recirculation of flue gases. Recirculation
of flue gases will cause sooting, premature failure of the heat
exchanger, and icing of the combustion air intake during severe
cold weather. To prevent the recirculation of flue gases, maintain
as much distance as possible between the combustion air
intake and the exhaust vent terminal. Due to large volumes of
flue gases, multiple boiler applications also require additional
distance between the intake and the exhaust terminals.
4. Vertical Direct Vent - using a vertical vent termination to
exhaust flue products and PVC piping to bring combustion
GENERAL VENT INSTALLATION PROCEDURE
Prior to beginning the installation of the vent system,
determine and obtain all parts required for the installation.
Proper operation of the boiler and venting system is depen-
dent upon use of all specified parts and installation techniques;
both safety and proper performance of the system may suffer if
instructions are not followed.
This boiler can be vented with PVC/CPVC or an UL approved AL
29-4C Stainless Steel venting material which are explained in the
following pages.
PVC/CPVC INSTALLATION:
Installation must comply with local requirements and with the
National Fuel Gas Code, ANSI Z223.1 for U.S. installations or
CSA B149.1 for Canadian installations.
All PVC vent pipes must be glued, properly supported, and
the exhaust must be pitched a minimum of a 1/4 inch per foot
back to the boiler (to allow drainage of condensate).
This appliance requires a special venting system. Use only
the vent materials, primer, and cement specified in this
manual to make the vent connections. Failure to follow this
warning could result in fire, personal injury, or death.
Note: Make sure that for PVC venting installation, the
first 10 feet of vent must be CPVC or stainless steel and
the set point temperature of the boiler must not exceed
200 °F.
25
AIR INLET PIPE MATERIALS
VENT AND AIR PIPE INSTALLATION
Make sure the air inlet pipe(s) are sealed. The acceptable air 1. Measure from the boiler level to vent. Refer to the Table 14
inlet pipe materials are:
on Page 36 for the allowable lengths.
• PVC/CPVC
• AL 29-4C
2. Prepare pipes to the required lengths and deburr the inside
and outside of the pipe ends. Chamfer outside the pipe end
to ensure even cement distribution when joining.
An adapter is provided for transition between the air inlet
connection on the boiler and the plastic air inlet pipe.
3. Clean all pipe ends and fittings using a clean dry rag.
(Moisture will retard curing and dirt or grease will prevent
adhesion.)
Seal all joints and seams of the air inlet pipe using either
Aluminum Foil Duct Tape meeting UL Standard 723 or 181A-P or
a high quality UL Listed silicone sealant. Do not install seams of
vent pipe on the bottom of horizontal runs.
4. Dry fit vent or air piping to ensure proper fit before assembling
any joint. The pipe should go a third to two-thirds into the
fitting to ensure proper sealing after cement is applied.
Secure all joints with a minimum of 3 sheet metal screws or pop
rivets. Apply Aluminum Foil Duct Tape or silicone sealant to all
screws or rivets installed in the vent pipe.
5. Priming and Cementing:
• Handle pipes and fittings carefully to prevent
contamination of surfaces.
Make sure that the air inlet pipes are properly supported.
• Apply an even coat of primer to the fitting socket.
The PVC/ CPVC air inlet pipe must be cleaned and sealed with
the pipe manufacturer’s recommended solvents and standard
commercial pipe cement for the material used. The PVC, CPVC,
air inlet pipe should use a silicone sealant to ensure a proper seal
at the boiler connection and the air intake adapter connection.
Proper sealing of the air inlet pipe ensures that combustion air
will be free of contaminants and supplied in proper volume.
• Apply an even coat of primer to the pipe end to
approximately 1/2" beyond the socket depth.
• Apply a second primer coat to the fitting socket.
• While primer is still wet, apply an even coat of approved
cement to the pipe equal to the depth of the fitting
socket.
• While primer is still wet, apply an even coat of approved
cement to the fitting socket.
• Apply a second coat of cement to the pipe.
• While the cement is still wet, insert the pipe into the
fitting, if possible twist the pipe a 1/4 turn as you insert it.
Note: If voids are present, sufficient cement was not applied and
joint could be defective.
• Clear excess cement from the joint removing ring or
beads as it will needlessly soften the pipe.
When a sidewall or vertical rooftop combustion air supply system
is disconnected for any reason, the air inlet pipe must be resealed
to ensure that combustion air will be free of contaminants and
supplied in proper volume.
Failure to properly seal all joints and seams may result in flue
gas recirculation, spillage of flue products and carbon monoxide
emissions causing severe personal injury or death.
FIGURE 22. PVC/CPVC VENTING WITH ADAPTER
REQUIREMENTS FOR INSTALLATION IN CANADA
1. Installations must be made with a vent pipe system certified
to ULC-S636. IPEX is an approved vent manufacturer in
Canada supplying vent material listed to ULC-S636.
2. The initial 3 feet of plastic vent pipe from the appliance flue
outlet must be readily accessible for visual inspection.
3. The components of the certified vent system must not be
interchanged with other vent systems or unlisted pipe/
fittings.
FIGURE 23. PVC/CPVC VENTING - HORIZONTAL
26
(30.5 m). A maximum of three 90° elbows can be used.
Minimum vertical vent is 7 equivalent feet (2.1 m) for
direct vent installations. Standard minimum vertical vent
Figure 30 for differences between standard and direct
vent installations.
3. An AL 29-4C® Vent Vertical Vent Terminal must be used at
the termination.
4. Maintain a minimum of 6 feet (2.0 m) separation between
the air intake and the exhaust terminals.
HORIZONTAL INSTALLATION REQUIREMENTS
1. The vent system must terminate with the Through-the-Wall
Termination (TWT) kits. Do not locate the terminal within 8 feet
(2.5 m) of an inside corner of a building or adjacent to outside
walls, shrubs or other such objects that may cause adverse
wind conditions in the immediate area.
2. The TWT should be located not less than 12 inches (305
mm) above grade or, in geographical areas where snow
accumulates, no less than 12 inches (305 mm) above antici-
patedsnowline.EnsurethatTWTisprotectedagainstblockage
which may occur during ice buildup or snowstorms. The TWT
should terminate at least 3 feet (1.0 m) above any forced air
inlet within 10 feet (3.0 m), except when the forced air inlet
is the combustion air intake of a direct vent appliance. The
TWT should terminate at least 4 feet (1.2 m) below, 4 feet
(1.2 m) horizontally from or 1 foot (305 mm) above any door,
window or gravity air inlet into any building as provided in the
current edition of the national fuel gas code ANSI Z223.1.
Inaddition, aminimumclearanceof4feet(1.2m)horizontally
from, and in no case above or below, unless the 4 feet (1.2
m) of horizontal distance is maintained from electric meters,
gas meters, regulators and relief equipment.
FIGURE 24. PVC/CPVC VENTING - VERTICAL
VENTING SUPPORTS
Care must be taken in the installation of the venting system
that adequate support is maintained throughout the installation
process. When extending more than 10 feet (3.0 m) vertically,
vertical support kits are required once every 10 feet (3.0 m) of
vertical run. Vertical support is also required immediately after
any transition (elbow, tee, etc.) to vertical of over 10 feet (3.0 m)
of run and after any offset in the vertical run.
The support brackets (supplied in the Vertical Support Kit)
are to be securely fastened to a solid vertical member of the
building using the appropriate fasteners; i.e., wood screws for
wood framing, machine or tapping screws for structural steel
or masonry anchors for solid masonry. The bracket should be
located so that it will not interfere with any joints of the venting
system. The bottom most support bracket should be located
directly above the first transition from horizontal to vertical.
3. This horizontal exhaust vent system must pitch upward toward
the termination at 1/4 inch per foot (21 mm per meter).
4. The TWT is designed such that the building is protected from
degradation by flue gas and condensate. However, if additional
protection is desired, install against the wall a non-corrosive
metal sheet under the TWT.
If a means of support for the brackets is not available and
horizontal vent sections are present, install hanger straps
(made from non-combustible material) as close to the points of
transition as possible. If the horizontal portions of the vent and/or
vent connector are longer than 6 feet (2.0 m), then install hanger
straps every 6 feet (2.0 m) to support the connector.
5. Due to the normal formation of water vapor in the combustion
process, horizontal terminations must not be located over
areas of pedestrian or vehicular traffic, (i.e., public walkways
or over areas where condensate could create a nuisance or
hazard). This is especially true in colder climates where ice
buildup is likely to occur. A.O. Smith Corporation will not be
held liable for any personal injury or property damage due to
any dislodging of ice.
Do not rivet or screw the straps to the conduit or otherwise
puncture the conduit wall. Instead, wrap an extra loop of strap
around the conduit to hold it in position, or attach the strap to
the center screw of the double wall AL 29-4C® vent coupling,
if applicable.
DIRECT VENT INSTALLATION REQUIREMENTS
The labels in the Direct Vent Kit must be affixed to the boiler in
locations specified by the instruction sheet provided in the kit.
The following are requirements for the Air-Intake Terminal (AIT):
VERTICAL INSTALLATION REQUIREMENTS
1. The vent system must terminate at least 3 feet (1.0 m) and
no more than 6 feet (2.0 m) above the roof line and no closer
than 10 feet (3.0 m) from any wall or vertical structure. If the
exhaust vent terminal is within 10 feet (3.0 m) of a wall or
parapet, it must extend a minimum of 2 feet (610 mm) above
1. The Air-Intake System (AIS) must terminate with the venting
equipment provided with the boiler.
2. The AIT should not be located less than 3 feet (1.0 m) below
any exhaust vent within 10 feet (3.0 m).
3. The total horizontal distance of the AIS from the boiler’s
Blower Adapter to the outside of the “AIT” should not be
greater than 100 equivalent feet (30.5 m) of vent pipe nor
less than 3 feet (1.0 m), excluding elbows. A maximum of 3
elbows, equivalent to 10 feet (3.0 m) each of pipe may be
used.
2. For direct vent installations, the total distance of the vent
system from the boiler vent connector to the vertical
vent termination should not exceed 100 equivalent feet
27
MODELS
(XB/XW)
VENT KIT NUMBERS
(RAIN CAP)
1000
1300
320884-000
320884-001
1700
2000
2600
3400
320884-001
320884-001
320884-001
320884-002
FIGURE 25. VERTICAL VENTING
MODELS
(XB/XW)
VENT KIT NUMBERS
(TEE)
1000
1300
321765-000
321765-001
1700
2000
2600
3400
321765-001
321765-001
321765-001
321765-002
FIGURE 26. HORIZONTAL VENTING
28
MODELS
(XB/XW)
VENT
KIT NUMBERS
(TEE)
AIR INTAKE
KIT NUMBERS
(ELBOW)
1000
1300
1700
2000
2600
3400
321765-000
321765-001
321765-001
321765-001
321765-001
321765-002
321764-000
321764-000
321764-001
321764-001
321764-001
321764-002
FIGURE 27. DIRECT VENT HORIZONTAL
MODELS
(XB/XW)
VENT
KIT NUMBERS
(RAIN CAP)
AIR INTAKE
KIT NUMBERS
(ELBOW)
1000
1300
1700
2000
2600
3400
320884-000
320884-001
320884-001
320884-001
320884-001
320884-002
321764-000
321764-000
321764-001
321764-001
321764-001
321764-002
FIGURE 28. DIRECT VENT VERTICAL
29
MODELS
(XB/XW)
VENT
KIT NUMBERS
(RAIN CAP)
AIR INTAKE
KIT NUMBERS
(ELBOW)
1000
1300
1700
2000
2600
3400
320884-000
320884-001
320884-001
320884-001
320884-001
320884-002
321764-000
321764-000
321764-001
321764-001
321764-001
321764-002
FIGURE 29. DIRECT VENT, VERTICAL VENT HORIZONTAL INTAKE
MODELS
(XB/XW)
VENT
KIT NUMBERS
(TEE)
AIR INTAKE
KIT NUMBERS
(ELBOW)
1000
1300
1700
2000
2600
3400
321765-000
321765-001
321765-001
321765-001
321765-001
321765-002
321764-000
321764-000
321764-001
321764-001
321764-001
321764-002
FIGURE 30. DIRECT VENT, HORIZONTAL VENT VERTICAL INTAKE
30
TERMINATION CLEARANCES SIDEWALL POWER VENT
POWER VENT
(using room air for combustion)
EXTERIOR CLEARANCES FOR SIDEWALL VENT TERMINATION
G
V
H
D
A
E
v
L
B
v
B
B
B
V
C
B
D
E
X
I
F
E
D
CLOSED
E
X
I
OPERABL
F
V
M
V
V
X
CLOSED
V
E
X
OPERABL
V
F
B
K
J
A
VENT TERMINAL
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
V
X
FIGURE 31. POWER VENT
Vent terminal clearances for “Power Vent” installations. Power Vent configurations use room air for combustion.
1
2
1
2
CANADIAN INSTALLATIONS
US INSTALLATIONS
CANADIAN INSTALLATIONS
US INSTALLATIONS
Clearance to each side
of center line extended
above meter/regulator
assembly
3 feet (91 cm) within a
height 15 feet (4.5 m)
above the meter/regulator
assembly*
Clearance above grade,
veranda, porch, deck or 12 inches (30 cm)
balcony
3 feet (91 cm) within a height 15 feet
(4.5 m) above the meter/
regulator assembly
12 inches (30 cm)
A
B
H
I
6 inches (15 cm) for appliances up to
10,000 Btu/hr (3 kW), 12 inches (30
cm) for appliances between 10,000
4 feet (1.2 m) below
or to side of opening;
Btu/hr (3 kW) and 100,000 Btu/hr (30 1 foot (30 cm) above
kW), 36 inches (91 cm) for appliances opening
above 100,000 Btu/hr (30 kW)
Clearance to window
or door that may be
opened
Clearance to service
regulator vent outlet
3 feet (91 cm)
3 feet (91 cm)*
6 inches (15 cm) for appliances up
to 10,000 Btu/hr (3 kW), 12 inches
(30 cm) for appliances between
10,000 Btu/hr (3 kW) and 100,000
Btu/hr (30kW), 36 inches (91cm)
for appliances above 100,000 Btu/
hr (30 kW)
Clearance to a non
mechanical air supply
inlet into building or
combustion air inlet to
any other appliance
4 feet (1.2 m) below or to
side of opening; 1 foot
(30 cm) above opening.
Clearance to
permanently closed
window
12 inches (30 cm)*
12 inches (30 cm)*
C
J
Vertical clearance to
ventilated soffit located
above the terminal
within a horizontal
distance of 2 feet (61
cm) from the center line
of the terminal
3 feet (91 cm) above if
within
10 feet (3 m) horizontally
Clearance to a
mechanical air supply
inlet
12 inches (30 cm)*
12 inches (30 cm)*
12 inches (30 cm)*
12 inches (30 cm)*
6 feet (1.83 m)
7 feet (2.13 m)†
D
E
K
Clearance above paved
sidewalk or paved
driveway located on
public property
Clearance to
unventilated soffit
7 feet (2.13 m)
L
Clearance under
veranda, porch, deck, or 12 inches (30 cm) ‡
balcony
Clearance to outside
corner
2 feet (60 cm)*
8 feet (2.44 m)*
2 feet (60 cm)*
8 feet (2.44 m)*
12 inches (30 cm) ‡
F
M
Clearance to inside
corner
G
1 In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code.
2 In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code.
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Clearance in accordance with local installation codes and the requirements of the gas supplier and the manufacturer’s installation instructions.
31
TERMINATION CLEARANCES SIDEWALL DIRECT VENT
DIRECT VENT
(using outdoor air for combustion)
EXTERIOR CLEARANCES FOR SIDEWALL VENT TERMINATION
G
V
H
D
A
E
v
L
B
v
B
B
B
V
C
B
D
E
X
I
F
E
D
CLOSED
E
X
I
OPERABL
F
V
M
V
V
X
CLOSED
V
E
X
OPERABL
V
F
B
K
J
A
VENT TERMINAL
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
V
X
FIGURE 32. DIRECT VENT
Vent terminal clearances for “Direct Vent” installations. Direct Vent configurations use outdoor air for combustion.
1
2
1
2
CANADIAN INSTALLATIONS
US INSTALLATIONS
CANADIAN INSTALLATIONS
US INSTALLATIONS
Clearance to each side
of center line extended
above meter/regulator
assembly
Clearance above grade,
veranda, porch, deck or 12 inches (30 cm)
balcony
3 feet (91 cm) within a height 15
feet (4.5 m) above the meter/
regulator assembly
3 feet (91 cm) within a height
15 feet (4.5 m) above the
meter/regulator assembly*
12 inches (30 cm)
A
B
H
I
6 inches (15 cm)
for appliances up to
10,000 Btu/hr (3 kW),
9 inches (23 cm) for
appliances between
10,000 Btu/hr (3 kW)
and 50,000 Btu/hr (15
kW), 12 inches (30 cm)
for appliances above
50,000 Btu/hr (15 kW)
6 inches (15 cm) for appliances
up to 10,000 Btu/hr (3 kW), 12
inches (30 cm) for appliances
between 10,000 Btu/hr (3 kW)
and 100,000 Btu/hr (30 kW), 36
inches (91 cm) for appliances
above 100,000 Btu/hr (30 kW)
Clearance to window or
door that may be opened
Clearance to service
regulator vent outlet
3 feet (91 cm)
3 feet (91 cm)*
6 inches (15 cm) for
6 inches (15 cm) for appliances up
to 10,000 Btu/hr (3 kW), 12 inches
(30 cm) for appliances between
10,000 Btu/hr (3 kW) and 100,000
appliances up to 10,000
Btu/hr (3 kW), 9 inches (23
cm) for appliances between
10,000 Btu/hr (3 kW) and
50,000 Btu/hr (15 kW), 12
inches (30 cm) for appliances
above 50,000 Btu/hr (15 kW)
Clearance to a non
mechanical air supply
inlet into building or
Clearance to
permanently closed
window
6 inches (15 cm)*
6 inches (15 cm)*
C
J
combustion air inlet to Btu/hr (30 kW), 36 inches (91 cm)
any other appliance
for appliances above 100,000 Btu/
hr (30 kW)
Vertical clearance to
ventilated soffit located
above the terminal within
a horizontal distance of
2 feet (61 cm) from the
center line of the terminal
Clearance to a
mechanical air supply
inlet
3 feet (91 cm) above if within
10 feet (3 m) horizontally
12 inches (30 cm)*
12 inches (30 cm)*
12 inches (30 cm)*
12 inches (30 cm)*
6 feet (1.83 m)
D
E
K
Clearance above
Clearance to unventilated
soffit
paved sidewalk or
paved driveway located
on public property
7 feet (2.13 m)†
7 feet (2.13 m)†*
L
Clearance under
veranda, porch, deck,
or balcony
Clearance to outside
corner
2 feet (60 cm)*
8 feet (2.44 m)*
2 feet (60 cm)*
8 feet (2.44 m)*
12 inches (30 cm) ‡
12 inches (30 cm) ‡*
F
M
Clearance to inside
corner
G
1 In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code.
2 In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code.
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Clearance in accordance with local installation codes and the requirements of the gas supplier and the manufacturer’s installation instructions.
32
INSTALLATION REQUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS
For all side wall terminated, horizontally vented power vent, direct vent, and power direct vent gas fueled water heaters installed
in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by
the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the
area of the venting, including but not limited to decks and porches, the following requirements should be satisfied:
INSTALLATION OF CARBON MONOXIDE DETECTORS At the time of installation of the side wall horizontal vented gas fueled
equipment, the installing plumber or gasfitter should observe that a hard wired carbon monoxide detector with an alarm and battery
back-up is installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or gasfitter should
observe that a battery operated or hard wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling,
building or structure served by the sidewall horizontal vented gas fueled equipment. It should be the responsibility of the property owner
to secure the services of qualified licensed professionals for the installation of hard wired carbon monoxide detectors.
In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl space or an attic, the hard wired
carbon monoxide detector with alarm and battery back-up may be installed on the next adjacent floor level.
In the event that the requirements of this subdivision can not be met at the time of completion of installation, the owner should
have a period of thirty (30) days to comply with the above requirements provided that during said thirty (30) day period, a battery
operated carbon monoxide detector with an alarm should be installed.
APPROVED CARBON MONOXIDE DETECTORS Each carbon monoxide detector as required in accordance with the above
provisions should comply with NFPA 720 and be ANSI/UL 2034 listed and CSA certified.
SIGNAGE A metal or plastic identification plate should be permanently mounted to the exterior of the building at a minimum
height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating
appliance or equipment. The sign should read, in print size no less than one-half (1/2) inch in size, “GAS VENT DIRECTLY
BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS.”
INSPECTION The state or local gas inspector of the side wall horizontally vented gas fueled equipment should not approve
the installation unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accordance
with the provisions of 248 CMR 5.08(2)(a) 1 through 4.
EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled “Equipment Not Required To Be Vented” in the most current edition of NFPA 54
as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room or structure separate from the
dwelling, building, or structure used in whole or in part for residential purposes.
MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM PROVIDED When the manufacturer of Product
Approved side wall horizontally vented gas equipment provides a venting system design or venting system components with the equipment,
the instructions provided by the manufacturer for installation of the equipment and the venting system should include:
1. Detailed instructions for the installation of the venting system design or the venting system components; and
2. A complete parts list for the venting system design or venting system.
MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED When the manufacturer
of a Product Approved side wall horizontally vented gas fueled equipment does not provide the parts for venting the flue
gases, but identifies “special venting systems,” the following requirements should be satisfied by the manufacturer:
1. The referenced “special venting system” instructions should be included with the appliance or equipment installation instructions; and
2. The “special venting systems” should be Product Approved by the Board, and the instructions for that system should include
a parts list and detailed installation instructions.
A copy of all installation instructions for all Product Approved side wall horizontally vented gas fueled equipment, all venting
instructions, all parts lists for venting instructions, and/or all venting design instructions should remain with the appliance or
equipment at the completion of the installation.
33
Do not terminate closer than 4 feet (1.2 m) horizontally from
any electric meter, gas meter, regulator, relief valve, or other
equipment. Never terminate above or below any of these within
4 feet (1.2 m) horizontally.
DIRECT VENT: HORIZONTAL TERMINATION
Gas vent extending through an exterior wall must not terminate
adjacent to a wall or below building extensions such as eaves,
parapets, balconies, or decks. Failure to comply could result in
severe personal injury, death, or substantial property damage.
6. Locate terminations so they are not likely to be damaged by
foreign objects, such as stones or balls, or subject to buildup
of leaves or sediment.
Installation must comply with local requirements and with the
National Fuel Gas Code, ANSI Z223.1 for U.S. installations or
CSA B149.1 for Canadian installations.
VENT/AIR TERMINATION LOCATIONS:
Follow these guidelines for locating the vent/air terminations:
1. Make sure the total length of piping for vent or air do not
Page 36.
2. Consider the surroundings when terminating the vent and
air:
• While positioning the vent termination, ensure vapors
will not damage nearby shrubs, plants or air conditioning
equipment.
• The flue products will form a noticeable plume as they
condense in cold air. Avoid areas where the plume could
obstruct window views.
• Prevailing winds could cause freezing of condensate
and water/ice buildup where flue products impinge on
building surfaces or plants.
FIGURE 33. AIR/VENT TERMINATION - HORIZONTAL
• Do not allow accidental contact of flue products with
people or pets.
• Do not locate the terminations near building corners,
near adjacent buildings or surfaces, window wells,
stairwells, alcoves, courtyards, or other recessed areas,
where wind eddies could affect performance or cause
recirculation .
• Sidewall vent and air inlet terminations must terminate in
the same pressure zone.
• Do not terminate above any door or window, where
condensate can freeze, causing ice formations.
• Locate or monitor the vent to prevent condensate
damage to exterior finishes.
3. The air piping must terminate in a down-turned elbow, using
a mesh screen. This setup will avoid recirculation of flue
4. The vent piping must terminate with a Tee pointed upwards
Vent must terminate:
FIGURE 34. HORIZONTAL CLEARANCES - AIR/VENT
TERMINATION
• At least 6 feet (1.8 m) from adjacent walls.
• No closer than 12 inches (305 mm) below roof overhang.
• At least 7 feet (2.1 m) above any public walkway.
• At least 3 feet (0.9 m) above any forced air intake within
10 feet (3 m).
• No closer than 12 inches (305 mm) below or horizontally
from any door or window or any other gravity air inlet.
Air inlet must terminate at least 12 inches (305 m) above grade or
snow line; at least 12 inches (305 mm) below the vent termination;
and the vent pipe must not extend more than 24 inches (610 mm)
34
DIRECT VENTING: VERTICAL TERMINATION
Installation must comply with local requirements and with the
National Fuel Gas Code, ANSI Z223.1 for U.S. installations or
CSA B149.1 for Canadian installations.
VENT/AIR TERMINATION LOCATIONS:
Follow these guidelines for locating the vent/air terminations:
1. Make sure the total length of piping for vent or air do not
Page 36.
2. The vent must terminate at least 3 feet above the highest
place in which the vent penetrates the roof and at least 2
feet above any part of a building within 10 feet horizontal.
FIGURE 36. STAINLESS STEEL AIR/VENT TERMINATION -
VERTICAL
3. The air piping must terminate in a down-turned 180° elbow,
using a mesh screen, no further than 2 feet (0.6 m) from the
center of the vent pipe. This placement avoids recirculation
of flue products into the combustion air stream.
4. The vent piping must terminate in an up-turned rain cap as
mm) above the air inlet. The air inlet pipe and vent pipe
can be located in any desired position on the roof, but must
always be no further than 2 feet (0.6 m) apart and with the
vent termination at least 1 foot above the air intake.
5. Locate terminations so they are not likely to be damaged by
foreign objects, such as stones or balls, or subject to buildup
of leaves or sediment and also not blocked or restricted by
snow accumulation.
6. If installing both intake air and vent piping in a Direct Vent
configuration vertically through the roof; ensure that all
exterior vertical clearance requirements shown in Figure 35
are being maintained. These clearances and those cited by
local and national codes must be maintained.
Note: On flat roof installations the intake air and the vent
terminations must be a minimum of 24 inches (60 cm) above any
parapet, vertical wall or structure within 10 feet (3 m) horizontally.
FIGURE 37. VERTICAL TERMINATION - FLAT ROOF
CLEARANCES
PREPARE ROOF/WALL PENETRATIONS
1. Air pipe penetration:
Cut a hole for the air pipe. Size the air pipe hole as close as
desired to the air pipe outside diameter.
2. Vent pipe penetration:
Cut a hole for the vent pipe. For either combustible or
noncombustible construction, size the vent pipe hole with at least
a 1/2 inch clearance around the vent pipe outer diameter:
• 7½ inch (178 mm) hole for 6 inch (152 mm) vent pipe
• 8½ inch (203 mm) hole for 7 inch (178 mm) vent pipe
Insert a galvanized metal thimble in the vent pipe hole (when
required by local codes).
3. Space the air and vent holes to provide the minimum spacing
4. Follow all local codes for isolation of vent pipe when passing
through floors, ceilings, and roofs.
5. Provide flashing and sealing boots sized for the vent pipe
and air pipe.
FIGURE 35. PVC/CPVC AIR/VENT TERMINATION -
VERTICAL
35
TABLE 13. PVC, VENT PIPE, AND FITTINGS
ALL VENT PIPE MATERIALS AND FITTINGS MUST COMPLY WITH THE FOLLOWING:
ITEM
MATERIAL
STANDARDS FOR INSTALLATION IN:
UNITED STATES
CANADA
ANSI/ASTM D1785 CPVC and PVC venting must be ULC-S636 Certified.
ANSI/ASTM F441
Vent pipe and fittings
Pipe cement/primer
PVC schedule 40
CPVC schedule 40/80
PVC
ANSI/ASTM D2564 ULC-S636 Certified.
ANSI/ASTM F493
CPVC
NOTICE: DO NOT USE CELLULAR (FOAM) CORE PIPE
TABLE 14. DIRECT VENT ALLOWABLE AIR/VENT LENGTHS
MODEL
AIR INTAKE
DIAMETER
(INCH)
AIR INTAKE
MIN. LENGTH MAX. LENGTH DIAMETER
AIR INTAKE
VENT
VENT MIN.
LENGTH
(FT)
VENT MAX.
LENGTH
(FT)
(FT)
12
(FT)
100
100
100
100
100
100
(INCH)
XP 1000
XP 1300
XP 1700
XP 2000
XP 2600
XP 3400
6
6
6
8
12
12
12
12
12
12
100
100
100
100
100
100
12
8
12
8
8
12
8
8
12
8
10
12
10
When determining equivalent combustion air and vent length, add 5 feet (1.5 m) for each 90° elbow and 3 feet (0.9 m) for each 45°
elbow.
EXAMPLE: 20 feet (6 m) of PVC pipe + (4) 90° elbows + (3) 45° elbows = 49 equivalent feet (15 m) of piping.
TABLE 15. ROOM AIR ALLOWABLE VENT LENGTHS
MODEL
VENT DIAMETER
(INCH)
VENT MIN. LENGTH
(FT)
VENT MAX. LENGTH
(FT)
XP 1000
XP 1300
XP 1700
XP 2000
XP 2600
XP 3400
6
8
12
12
12
12
12
12
100
100
100
100
100
100
8
8
8
10
36
CONDENSATE DISPOSAL
CONDENSATE NEUTRALIZER
FIGURE 38. CONDENSATE DISPOSAL SYSTEM
FIGURE 40. CONDENSATE NEUTRALIZER
The condensate drains from the boiler have pH levels between
4.3 and 5.0. The pH measurement of a fluid is an indicator of
the acidity or alkalinity. Neutral fluids have pH of 7.0. Acid fluids
have pH below 7. Some local codes may require the use of a
condensate neutralizer to raise the pH level of the condensate
leaving the boiler. The condensate neutralizer be must installed
between the boiler and the drain and must be installed lower
Condensate Neutralizer Kit model must be selected with respect
TABLE 16. CONDENSATE NEUTRALIZER KIT MODELS
XP MODELS
AO SMITH CONDENSATE
NEUTRALIZER KIT NUMBERS
XP 1000
XP 1300
XP 1700
XP 2000
XP 2600
XP 3400
9007961005
9007962005
9007962005
9007962005
9007963005
9007963005
FIGURE 39. CONDENSATE TRAP
CONDENSATE TRAP
Installation of the Condensate Trap must conform with the
instructions in this manual and local building codes. Condensate
Neutralizer Kits are available. Contact your distributor or Service
Agency. Do not remove, modify or alter the factory installed
condensate trap. Install a commercially available neutralizing kit
if required by the local codes.
The boiler is factory fitted with a 24V condensate trap connected
to the controller. For safety reasons, if the condensate drain is
blocked, the control system will turn off all the firing burners and
bring the boiler to a safe shut down. If there is an air blockage
in the line, vent out the air by removing the cap. Cap acts as an
air vent for releasing any air block on down stream condensate
line. Flexible silicon hose connect from the trap through the
Condensate Neutralizer to the drain.
Due to the highly efficient operation of this unit, condensate is
formed during operation and must be removed by the conden-
sate drain systems. Inspect the condensate drains and tubes at
least once a month and insure they will allow the free flow of
condensate at all times. The system must be inspected more
frequently in cold weather if the drain system is located in an
area, such as along the floor, where freezing temperatures are
likely to occur. The condensate drain system must be protected
against freezing. Contact a qualified service agent to inspect
and correct the condition if freezing of the condensate lines is
a problem.
37
GAS SUPPLY CONNECTIONS
6. Use pipe sealing compound compatible with propane gases.
GAS SUPPLY PIPE CONNECTIONS
Apply sparingly only to male threads of the pipe joints so that
pipe dope does not block gas flow.
Failure to apply pipe sealing compound as detailed in this
manual can result in severe personal injury, death, or substantial
property damage.
7. Make sure the maximum inlet gas pressure do not exceed
the value specified. Minimum value specified is for input
adjustment only.
Make sure to use two wrenches when tightening gas piping at the
boiler, using one wrench to prevent the boiler gas line connection
from turning. Failure to support the boiler gas connection pipe to
prevent it from turning could damage gas line components. Do
not use wrench on valve body as damage would occur.
GAS PRESSURE REQUIREMENTS
The maximum allowable gas supply pressure for this boiler is
14 inches w.c. (3.5 kPa). Install a positive lock-up gas pressure
regulator in the gas supply line if inlet gas pressure can exceed
14 inches w.c. (3.5 kPa) at any time.
If a positive lock-up regulator is required follow these instructions:
1. Positive lock-up gas pressure regulators must be rated at or
above the input Btu/hr rating of the boiler they supply.
2. Positive lock-up gas pressure regulator(s) should be
installed no closer than 3 feet (1 meter) and no farther than
8 feet (2.4 meters) from the boiler’s inlet gas connection.
FIGURE 41. GAS SUPPLY PIPING
1. Make sure to install ground joint union for servicing.
3. After installing the positive lock-up gas pressure regulator(s),
an initial nominal supply pressure setting of 7 inches w.c.
(1.7 kPa) while the boiler is operating is recommended and
will generally provide good boiler operation. Some addition
adjustment maybe required later to maintain a steady gas
supply pressure.
In Canada – When using manual main shutoff to support the
weight of the piping with valves, ensure that it is identified by the
installer.
2. Install drip leg (sediment trap) per NFPA 54 for US and CAN
B149.1 for Canada.
4. When installing multiple boilers in the same gas supply
system it is recommended that individual positive lock-up
gas pressure regulators be installed at each unit.
3. Support the piping with hangers, not by the boiler or its
accessories. The gas valve and blower will not support the
weight of the piping. Failure to comply could result in severe
personal injury, death, or substantial property damage.
4. Purge all air from the gas supply piping.
5. Before setting the boiler in operation, check the boiler and its
gas connection for leaks.
• Disconnect the boiler from the gas supply piping system
during any pressure testing, at a test pressure in excess
of 1/2 PSIG (3.5 kPa)
• The boiler must be isolated from the gas supply piping
system by closing a manual shutoff valve during any
pressure testing, at test pressures equal to or less than
1/2 PSIG (3.5 kPa).
Do not check for gas leaks with an open flame, instead use the
bubble test. Failure to use the bubble test or check for gas leaks
can cause severe personal injury, death, or substantial property
damage.
38
PIPE SIZES FOR PROPANE GAS
Make sure to contact the gas supplier for pipe sizes, tanks, and
100% lockup gas pressure regulator.
PURGING GAS LINE
Gas line purging is required with new piping or systems in which
air has entered. Gas purging should be performed per NFPA 54
for US and CAN B149.1 for Canada.
CHECK GAS SUPPLY INLET PRESSURE
CSA or UL listed flexible gas connections are acceptable, but
make sure that the line has adequate capacity to allow your boiler
to fire at full rate. Consult with local codes for proper installation
or service procedures.
Do not adjust or attempt to measure gas valve outlet pressure.
Attempting to alter or measure the gas valve outlet pressure
could result in damage to the valve, causing potential severe
personal injury, death, or substantial property damage.
Make sure the gas piping are sized for the proper flow and length
of pipe, to avoid excessive pressure drop. The gas meter and
the gas regulator must be properly sized for the total gas load.
Perform the below steps when checking inlet gas supply:
1. Turn the main power switch to the “OFF” position.
2. Shut off gas supply.
3. Remove the 1/8" pipe plug on the main gas shutoff valve
and install a suitable 1/8" fitting (field supplied) for the
manometer tubing. Place the tubing of the manometer over
the tap once the 1/8" fitting is installed.
4. Slowly turn on the gas supply.
5. Ensure inlet pressure is within specified range.
6. If the gas pressure is out of range, contact the gas utility, gas
supplier, qualified installer or service agency to determine
the necessary steps to provide proper gas pressure to the
control.
CHECK FOR GAS LEAKS
Before operating the boiler, make sure to check the floor near and
around the boiler for gas odorant or any unusual odor. Remove
the top access panel and check for odor in the interior of the
boiler enclosure. Do not start the boiler if there is any indication
of a gas leak. Use an approved leak detection solution and repair
any leaks at once.
In the case of propane boilers, the supplier mixes an odorant
with the propane to make its presence detectable. But in some
instances, the odorant can fade, and the gas may no longer have
an odor. Before operating the boiler, make sure the propane
supplier verify the correct odorant level in the gas.
Do not adjust or attempt to measure gas valve outlet pressure.
The gas valve is factory set for the correct outlet pressure. This
setting is suitable for natural gas and propane, requiring no field
adjustment. Attempting to alter or measure the gas valve outlet
pressure could result in damage to the valve, causing potential
severe personal injury, death, or substantial property damage.
39
BOILER START UP AND OPERATIONS
IMPORTANT
Only an A.O. Smith Certified Start-up agent must perform the
initial firing of the boiler. At this time the user should not hesitate
to ask the start-up agent any questions regarding the operation
and maintenance of the unit. If you still have questions, please
contact the factory or your local A.O. Smith representative.
Contact Technical Support noted on the back cover for the name
of your closest Certified Start-Up agent.
Lighting and Operating instructions are included with this manual.
By using these instructions, the user may be able to make minor
operational adjustments and save unnecessary service calls.
However the user should not attempt repairs, but should contact
a service technician or gas supplier.
GENERAL
FIGURE 42. GAS TRAIN ASSEMBLY
Never operate the boiler without first making sure the boiler and
system are filled with water, in addition:
MANIFOLD PRESSURE CONNECTIONS
• Make sure a temperature and pressure relief valve
is installed in the storage tank for hot water supply
installations.
plug and inserting a suitable 1/8” NPT hose barb for connection to
the manometer/pressure gauge. Upon completion of measurements
and adjustments, remove the hose barb and replace the pipe
plug. Check for gas leaks and insure all connections are gas tight,
• Make sure that the boiler and system have been purged
of air and checked for leaks.
Also ensure to check the gas piping for leaks before beginning
the initial firing of the boiler.
FILLING AND PURGING OF HEATING BOILER
INSTALLATION
1. Fast fill system through bypass until pressure approaches
desired system pressure. Close bypass valve and permit
pressure to be established by the pressure reducing valve.
2. Vent all high points in system to purge system of air.
Provisions should be made to permit manual venting of radiators
or convectors.
FILLING HOT WATER SUPPLY BOILER
INSTALLATION
1. Close the system’s drain valve by turning handle clockwise.
2. Open a nearby hot water faucet to permit the air to escape
WATER TEMPERATURE REGULATION
3. Fully open the cold water inlet pipe valve allowing the boiler
and piping to be filled.
4. Close the hot water faucet as water starts to flow.
PURGING GAS LINE
Gas line purging is required with new piping or systems in which
air has entered.
INLET GAS PRESSURE
The inlet gas pressure is measured by removing the 1/8” NPT Plug
located on the upstream side of the supply gas valve, and insert
a 1/8” NPT hose barb fitting to be connected to a manometer or
pressure gauge. Once pressure has been checked and/or adjusted,
replace the plug and check for leaks. The maximum value specified
conditions (static and firing conditions). The combination gas valves
supplied with the boiler are for low pressure service. If upstream
pressure exceeds 14.0” W.C., an intermediate gas pressure
regulator of the lockup type must be installed.
40
HOT WATER CAN SCALD: Boilers are intended to produce hot
water. Water heated to a temperature which will satisfy space
heating, clothes washing, dish washing and other sanitizing
needs can scald and permanently injure you upon contact.
Some people are more likely to be permanently injured by hot
water than others. These include the elderly, children, the infirm
or physically/mentally disabled. If anyone using hot water in your
home fits into one of theses groups or if there is a local code or
state law requiring a specific temperature water at the hot water
tap, then you must take special precautions. In addition to using
the lowest possible temperature setting that satisfies your hot
water needs, a means such as a mixing valve should be used
at the hot water taps used by these people or at the hot water
supply tank. Mixing valves are available at plumbing supply
or hardware stores. Follow the manufacturer’s instructions for
installation of the valves. Before changing the thermostat setting
TABLE 18.
WATER HARDNESS MEDIUM (0-12 GRAINS PER GALLON)
XW MODEL
NO.
∆T ºF
GPM
∆P FEET
1000
1300
1700
2000
2600
3400
25
25
25
25
25
25
76
99
17.5
22
129
152
198
258
23
17.5
22
23
∆T ºF = Temperature rise ºF at the specified GPM.
GPM = Flow rate in gallons per minute.
∆P = Pressure loss through the heat exchanger in feet of head.
For systems over 5 grains per gallon; and for scale free
operation, boiler setpoint should not exceed 140 ºF.
Hot water temperatures required for automatic dishwasher
and laundry use can cause scald burns resulting in serious
personal injury and/or death. The temperature at which injury
occurs varies with the person’s age and time of exposure. The
slower response time of children, aged or disabled persons
increases the hazards to them. Never allow small children to
use a hot water tap, or to draw their own bath water. Never
leave a child or disabled person unattended in a bathtub
or shower.
Note: The factory installed/supplied pump on the above listed
model boilers is sized to maintian a 25 ºF ∆T through the boiler
when the boiler is firing at 100% fire.
In addtion to the pressure loss through the heat exchanger,
the factory supplied pump is sized for an additional 50 feet of
equivalent feet of piping between the boiler and a storage tank.
All piping between the boiler and the storage tank must be of
a pipe size equal to the inlet/outlets of the boiler. Installation
differences may slightly change these parameters.
The boiler should be located in an area that is inaccessible to the
general public.
TABLE 17. RISK OF SCALDS
FREEZE PROTECTION (HYDRONIC HEATING
INSTALLATION)
Time to Produce 2nd & 3rd
Water Temperature
Degree Burns on Adult Skin
1. Determine freeze protection fluid quantity using system
180°F (82°C)
170°F (77°C)
160°F (71°C)
150°F (66°C)
140°F (60°C)
130°F (54°C)
120°F (49°C)
Nearly instantaneous
Nearly instantaneous
About 1/2 second
water content, following fluid manufacturer’s instructions.
2. Local codes may require a backflow preventer or actual
disconnect from city water supply.
About 1-1/2 seconds
Less than 5 seconds
About 30 seconds
3. When using freeze protection fluid with automatic fill, install
a water meter to monitor water makeup. Freeze protection
fluid may leak before the water begins to leak, causing
concentration to drop, reducing the freeze protection level.
More than 5 minutes
Should overheating occur or the gas supply fail to shut off, turn
off the main manual gas shutoff valve to the boiler.
INSPECT/FILL CONDENSATE SYSTEM
Inspect/check condensate lines and fittings:
CHECK/CONTROL WATER HARDNESS
1. Inspect the condensate drain line, condensate PVC fittings
and condensate trap.
XW Model XP Boilers are approved for use in Domestic Water
Heating Systems with a water supply hardness of 0 grains per
recommend flow rate to maintain scale free operation with up to
a medium water hardness. For scale free operation in hard water
systems with a water hardness greater than 12 grains per gallon,
a water softener must be installed and maintained.
Fill condensate trap with water:
1. Remove the 2 inch PVC cap with the switch located at the
top of the trap.
2. Fill with fresh water until the water begins to pour out of the
drain.
3. Replace the cap. Press the cap onto the trap until the cap
makes contact with the drain.
The condensate trap must be filled with water during all times of
boiler operation to avoid flue gas emission from the condensate
drain line. Failure to fill the trap could result in severe personal
injury or death.
41
LIGHTING AND OPERATING INSTRUCTIONS
42
ADJUSTMENT
There must be sufficient load to operate the boiler at high fire to
perform the following adjustments. Start the boiler and observe
proper operating parameters for the system.
FIGURE 44. BURNER INFORMATION SCREEN
Required Tools:
Click on Operation button, and under the Modulation Menu, set
the required Firing rate (High/Low) by setting the RPM.
• TORX® T40 or 5 mm hex wrench
• 3 mm or 7/64 inch hex wrench
• Combustion analyzer
These boilers are equipped with a combined gas/air control
and gas safety shut off control valves. The valve functions in
parallel with the variable speed combustion blower to supply
the correct gas air ratio for optimum performance and efficiency.
The combustion blower speed is controlled automatically and
determines the amount of negative pressure experienced by the
gas safety shut off/control valves. The gas/air regulator adjusts
gas flow to maintain the proper pressure at the outlet nozzle of
the associated valve.
SETTING OF THE TEST MODE
On the Burner Home screen, select any individual boiler which
will guide to Burner Information screen.
FIGURE 45. OPERATION SCREEN
On the Firing Rate page, set the Firing rate RPM by selecting the
Manual in Run check box.
FIGURE 43. BURNER HOME SCREEN
FIGURE 46. FIRING RATE PAGE
43
HIGH FIRING RATE SETTING
Set the boiler to the high firing rate by setting the High Firing Rate RPM as described below. Check combustion readings using a
combustion analyzer. If combustion readings are not in accordance with the chart below adjust the gas valve as follows: remove the
flat, round, blue plastic cap from the cover. Using a 3 mm (7/64”) hex wrench, turn the adjustment screw counterclockwise to increase
or clockwise to decrease gas flow and achieve the desired CO2 level. Refer to the Table 19 for correct settings. There will be a slight
time delay between the adjustment and the response of the CO2 measuring instrument. Adjust the settings in small increments and
allow the combustion readings to stabilize before readjusting. When desired adjustments are complete, reinstall the blue plastic cap
on the cover. Combustion samples should be taken in the stack within two feet of the boiler. The carbon monoxide (CO) values in
the combustion sample should not exceed 150 PPM under any circumstances. Contact OEM for any abnormal conditions leading to
excessive CO above 150 PPM.
TABLE 19. HIGH FIRE RATE
RPM
CO2
*MANIFOLD PRESSURE
INCHES W.C
(APPROXIMATE FACTORY SET)
MODELS (XB/XW)
NATURAL
GAS
PROPANE
NATURAL
GAS
PROPANE
NATURAL GAS
PROPANE
1000 (920,000)
1300
4450
4850
5700
4700
5700
5700
4750
5100
5700
4750
5100
5700
8.5 - 9.2%
8.5 - 9.2%
8.5 - 9.2%
8.5 - 9.2%
8.5 - 9.2%
8.5 - 9.2%
9.3 - 10.2%
9.3 - 10.2%
9.3 - 10.2%
9.3 - 10.2%
9.3 - 10.2%
9.3 - 10.2%
-3.5
-3.0
-3.6
-3.9
-3.3
-3.5
-4.7
-3.6
-4.4
-4.9
-3.6
-4.4
1700
2000
2600
3400
LOW FIRING RATE SETTING
Set the boiler to the low firing rate by setting the Low Firing Rate RPM as described below. Check combustion readings using a
combustion analyzer. If combustion readings are not in accordance with the chart shown below adjust as follows: remove the cap
on the gas regulator using a slotted screwdriver. This will expose the offset adjustment screw. Using a TORX® T40 or a 5 mm hex
wrench, carefully adjust the low fire gas setting to achieve the CO2 level prescribed in Table 20.
Note: The rotation of the Low Fire adjustment is opposite of the High Fire as follows: Clockwise rotation increases gas flow,
counterclockwise rotation decreases gas flow.
Adjustments to the offset pressure regulators should not exceed 1/4 turn at a time before allowing the readings to respond and
stabilize.
After proper low fire offset adjustment is made, reinstall the slotted cap on the regulator.
Following all gas valve adjustments, check for proper light-off and verify correct fuel/air mix and combustion quality throughout the
entire firing range (from lowest to highest fan speed).
Note: Make sure the Manual Mode is set back to Automatic Mode to each of the burners, once the required settings are
done. Turn off the individual burner before proceeding to the next burner settings.
TABLE 20. LOW FIRE RATE
RPM
CO2
*MANIFOLD PRESSURE
INCHES W.C
(APPROXIMATE FACTORY SET)
MODELS (XB/XW)
NATURAL
GAS
PROPANE
NATURAL
GAS
PROPANE
NATURAL GAS
PROPANE
1000 (920,000)
1300
1650
1650
1700
1550
1700
1700
1540
1600
1700
1540
1600
1700
7.3 - 8.2%
7.3 - 8.2%
7.3 - 8.2%
7.3 - 8.2%
7.3 - 8.2%
7.3 - 8.2%
8.4 - 8.8%
8.4 - 8.8%
8.4 - 8.8%
8.4 - 8.8%
8.4 - 8.8%
8.4 - 8.8%
-0.3
-0.2
-0.2
-0.3
-0.2
-0.2
-0.25
-0.14
-0.23
-0.31
-0.14
-0.23
1700
2000
2600
3400
* NOTE: Values listed in Table 19 and Table 20 are tested under laboratory conditions with minimum vent length. Values may slightly vary depending on
ambient conditions and field equipment accuracy.
44
CONTROL SYSTEM
3. Three Pump Outputs with 5 selectable operation modes.
BURNER CONTROL SYSTEM
4. 24VAC:
• Output control of gas valve (Pilot and Main) and External
Ignition Transformer.
• Digital inputs for room limit control, high limit control, Gas
pressure switch, low water cutoff.
5. External spark transformer.
6. Flame Sensor.
7. Test jacks for flame signal measurement from either a flame
rod or UV flame sensor.
8. Alarm Output.
FIGURE 47. R7910A1138 CONTROL SYSTEM
The R7910A1138 is a burner control system that provide
heat control, flame supervision, circulation pump control,
fan control, boiler control sequencing, and electric ignition
function. It will also provide boiler status and error reporting.
Multiple boilers can be joined together to heat a system instead
of a single, larger burner or boiler. Using boilers in parallel is
more efficient, costs less, reduces emissions, improves load
control, and is more flexible than the traditional large boiler.
Control System consists of:
FIGURE 48. GENERAL R7910A1138 BOILER SCHEMATIC
• R7910A1138 Control Device.
The above figure shows two loops of heat control: Central
Heating (CH), and an optional second loop for Domestic Hot
Water (DHW) can be configured on each R7910A. The DHW
loop transfers heat from the boiler outlet to hot water appliances
in conjunction with the primary system heat loop. Priority
assignment to each heat loop can be configured to specify which
loop gets serviced first.
• S7999B Touchscreen Display—required for setup and
ModBus communication but not required for the system
to operate once the R7910A1138 is programmed.
• S7910A Local Keyboard Display Module.
• Flame Rod .
• Temperature Sensor, NTC Type 10KΩ at 77°F (25°C) or
12KΩ at 77°F (25°C).
• Limit Sensor, NTC Type 10KΩ at 77°F (25°C).
• 24V Digital I/O.
OVERVIEW
Functions provided by the R7910A1138 include automatic boiler
sequencing, flame supervision, system status indication, firing
rate control, load control, CH/DHW control, limit control, system
or self-diagnostics and troubleshooting.
The R7910 maximum version of the controller offers:
1. NTC-temperature sensor for:
• Outlet Limit And Temperature.
• Stack Temperature Limit and Temperature.
• Inlet Temperature.
• Outdoor Temperature (R7910 only).
2. Modulating output PWM-driven rotation speed controlled
DC-fan for optimal modulation control.
45
CSD-1 Acceptable.
COMMUNICATIONS AND DISPLAYS
Meets CSD-1 section CF-300 requirements as a Primary Safety
Control.
Two modes of communications are available to the R7910.
Meets CSD-1 section CW-400 requirements as a Temperature
Operation control.
Meets CSD-1 section CW-400 requirements as a Temperature
High Limit Control when configured for use with 10 kohm NTC
sensors.
Federal Communications Commission, Part 15,
Class B. Emissions.
1. The R7910 has two RS485 communication ports for
ModBus that allows for interfacing to one or all R7910s of
a system and presents them individually to the user. The
S7999B System Operator interface is a color touchscreen
displays used for configuration and monitoring of the
R7910A. Control Operation and display status in both test
and graphical modes can be shown along with the ability to
setup. The R7910 can also be remotely reset through the
S7999B display.
BURNER CONTROL OPERATION
2. Either ModBus RS485 communication port can be used to
allow configuration and status data to be read and written
to the R7910. Support a Master S7999B or a Building
Automation master to control the R7910 to respond to
a single ModBus address to service the requests of the
ModBus master in a Lead/Lag arrangement.
SAFETY SHUTDOWN OF BURNER CONTROL FUNCTIONS
Safety Shutdown (Lockout) occurs if any of the following occur
during the indicated period:
1. INITIATE PERIOD:
a. A/C line power errors occurred.
The local S7910 Keyboard display, the S7999B System Operator
interface, and the S7999C Local Operator Interface are optional
components.
b. Four minute INITIATE period has been exceeded.
2. STANDBY PERIOD:
a. Flame signal is present after 240 seconds.
b. Preignition Interlock is open an accumulative time of 30
seconds.
c. Interlock Start check feature is enabled and the Interlock
String (including Airflow Switch) is closed for 120 seconds with
the controller closed. (jumpered or welded Interlock).
d. Main Valve Terminal is energized.
The S7999B (or the DSP3944 which is a portable S7999B) or is
required configuration of the parameters of the R7910 but is not
needed for the operation of the system once configured.
SPECIFICATIONS
1. Electrical Ratings:
Operating voltage
• 24VAC (20 to 30 VAC, 60 Hz ±5%)
e. Internal system fault occurred.
3. PREPURGE PERIOD:
• 30 amps (Single Heat Exchanger)
a. Preignition Interlock opens anytime during PREPURGE
period.
b. Flame signal is detected for 10 seconds accumulated time
during PREPURGE.
• 60 amps (Double Heat Exchanger)
Connected Load for Valve and annunciator functions:
• 24VAC, 60Hz
c. Purge Rate Fan RPM or High Fire Switch fails to close within
four minutes and fifteen seconds after the firing rate motor
is commanded to drive to the high fire position at the start of
PREPURGE.
d. Light off Rate Fan RPM or Low Fire Switch fails to close
within four minutes and fifteen seconds after the firing rate motor
is commanded to drive to the low fire position at the end of
PREPURGE.
• 120VAC (+10%/-15%), 60Hz (±5%)
• Model Specific
2. Corrosion:
• R7910A must not be used in a corrosive environment.
3. Operating Temperature: -4°F to 150°F (-20°C to 66°C)
4. Storage/Shipping Temperature: -40°F to 150°F (-40°C to
66°C).
e. Lockout Interlock (if programmed) does not close within 10
seconds.
5. Humidity:
f. Lockout Interlock opens during PREPURGE.
g. Pilot Valve terminal is energized.
• Up to 95% Relative Humidity, noncondensing at 104°F for
14 days. Condensing moisture may cause safety shutdown.
h. Main Valve terminal is energized.
i. Internal system fault occurred.
6. Vibration: 0.0 to 0.5g Continuous (V2 level)
7. Enclosure: Nema 1/IP40.
8. Approvals:
4. PRE-IGNITION TIME
a. Lockout Interlock opens.
b. IAS Purge and Ignition enabled and the Interlock opens.
c. Preignition Interlock opens.
d. Pilot Valve terminal is energized.
e. Main Valve terminal is energized.
Underwriters Laboratories, Inc. (UL): Component Recognized:
File No. MP268 (MCCZ)
• R7910 is certified as UL372 Primary Safety Controls.
• The R7910 is certified as UL353 Limit Rated device when
using part number 50001464 dual element limit rated NTC
sensors.
5. PILOT FLAME ESTABLISHING PERIOD (PFEP):
a. Lockout Interlock opens (if enabled).
b. Pilot Valve terminal is not energized.
c. No flame is present at the end of the PFEP, or after programmed
number of retry attempts.
d. Main valve terminal is energized.
e. Internal system fault occurred.
46
6. MAIN FLAME ESTABLISHING PERIOD (MFEP):
GENERAL OPERATIONAL SEQUENCE
a. Lockout Interlock opens (if enabled).
b. Pilot valve terminal is not energized.
c. Main valve terminal is not energized.
d. No flame present at the end of MFEP.
e. Internal system fault occurred.
INITIATE
The R7910 enters the Initiate sequence on Initial Power up or:
• Voltage fluctuations vary less than 20VAC or greater than
30VAC.
7. RUN PERIOD:
• Frequency fluctuations vary +/-5% (57 to 63 Hz).
• If Demand, LCI, or Stat interrupt (open) during the Prepurge
Period.
a. No flame is present, or flame is lost (if enabled-lockout).
b. Lockout Interlock opens) if enabled).
c. IAS Purge and Ignition enabled and the Interlock opens.
d. Pilot terminal energized (if programmed as Interrupted Pilot).
e. Main valve terminal is not energized.
• After the reset button is pressed or fault is cleared at the
displays.
The Initiate sequence also delays the burner motor from being
energized and de-energized from an intermittent AC line input or
control input.
f. Internal system fault occurred.
8. POSTPURGE PERIOD:
If an AC problem exists for more than 240 seconds a lockout will
occur.
a. Preignition Interlock does not close in five seconds.
b. Pilot Valve terminal is energized.
c. Main Valve terminal is energized.
d. Internal system fault occurred.
e. Flame sensed 240 seconds accumulated time after the RUN
period.
HYDRONIC/CENTRAL HEATING
Start-up sequence central heating request (system in standby):
1. Heat request detected (On Setpoint - On Hysteresis).
2. The CH pump is switched on.
3. After a system Safe Start Check, the Blower (fan) is switched
on after a dynamic ILK switch test (if enabled).
4. After the ILK switch is closed and the purge rate proving fan
RPM is achieved (or High Fire Switch is closed) - prepurge
time is started.
SAFETY SHUTDOWN:
1. If the lockout interlocks open or a sensor designated as a
safety limit are read as defective, Control System will lockout
and the blower motor will be de-energized.
If these open during the firing period, all fuel valves will be de- 5. When the purge time is complete, the purge fan RPM is
energized, the system will complete postpurge, and will lockout
indicated by an alarm.
changed to the Lightoff Rate or if used, the damper motor is
driven to the Low Fire Position.
2. If the pilot flame is not detected by the end of the last (3 6. As soon as the fan-rpm is equal to the light-off rpm (or the
number recycle attempt), pilot trial for ignition period, the
pilot valve, and ignition transformer will be de-energized, the
Low Fire Switch closes), the Trial for Ignition or Pre-Ignition
Time is started.
system will complete post purge and will lockout indicated 7. Pre-Ignition Time will energize the ignitor and check for
by an alarm. flame.
3. If the main flame is not detected at the end of the last recycle 8. Trial for Ignition. Specifics for timings and device actions are
attempt of the main flame establishing period, all fuel valves defined by the OEM or installer.
will be de-energized, the device will complete postpurge, 9. The ignition and the gas valve are switched on.
and will lockout indicated by an alarm.
10. The ignition is turned off at the end of the direct burner
ignition period, or for a system that does use a pilot, at
the end (or optionally at the middle) of the Pilot Flame
Establishing Period (PFEP). For an interrupted pilot system
this is followed by a Main Flame Establishing Period (MFEP)
where the pilot ignites the main burner. For an intermittent
pilot there is no MFEP.
4. If the flame sensing signal is lost during the run period (if
lockout is selected), all fuel valves will be de-energized within
4 seconds after the loss of the flame signal, the device will
complete postpurge, and will lockout indicate by an alarm.
5. Manual reset is required following any safety shutdown.
Manual reset may be accomplished by pressing the push
button on the device, pressing the remote reset wired into 11. The fan is kept at the lightoff rate during the stabilization
connector J10, or through an attached display.
timer, if any.
12. Before the release to modulation, the fan is switched to
minimum RPM for the CH Forced Rate and Slow Start
Enable, if the water is colder than the threshold.
13. At the end of the CH-heat request the burner is switched off
and the fan stays on until post purge is complete.
14. A new CH-request is blocked for the forced off time set by
the Anti Short Cycle (if enabled).
Interrupting power to Control System will cause electrical resets,
but does not reset a lockout condition.
15. The pump stays on during the pump overrun time (if
enabled).
16. At the end of the pump overrun time the pump will be
switched off.
47
DOMESTIC HOT WATER
LEAD LAG (LL) MASTER GENERAL OPERATION
Start-up sequence DHW-request (system in standby):
The XP Boiler is a multiple burner application and it works on
the basis of the Lead Lag Operation. The XB Boiler is factory
configured for Hydronic/Central Heating application, whereas the
XWBoilerisfactoryconfiguredforDomesticHotWaterapplication.
The LL master coordinates the firing of its slave Control Systems.
To do this it adds and drops stages to meet changes in load, and
it sends firing rate commands to those that are firing.
1. Heat request detected (either DHW Sensor Only, DHW
Sensor and Remote Command or DHW Switch and Inlet
Sensor, whichever applies).
2. The pump is switched on (after the DHW Pump Start Delay).
3. After a system Safe Start Check, the Blower (fan) is switched
on after a dynamic ILK switch test (if enabled).
4. After the ILK switch is closed and the purge rate proving fan
RPM is achieved (or High Fire Switch is closed) - prepurge
time is started.
The LL master turns the first stage on and eventually turns the
last stage off using the same criteria as for any modulation
control loop:
5. When the purge time is complete, the purge fan RPM is
changed to the Lightoff Rate or if used, the damper motor is
driven to the Low Fire Position.
6. As soon as the fan-rpm is equal to the light-off rpm (or the
Low Fire Switch closes), the Trial for Ignition or Pre-Ignition
Time is started (depending on configuration).
7. Pre-Ignition Time will energize the ignitor and check for
flame.
8. Trial for Ignition. Specifics for timings and device actions are
defined by the OEM or installer.
•
When the operating point reaches the Setpoint minus the
On hysteresis, then the first Control System is turned on.
When the operating point reaches the Setpoint plus the Off
hysteresis then the last slave Control System (or all slave
Control Systems) are turned off.
•
The LL master PID operates using a percent rate: 0% is a
request for no heat at all, and 100% means firing at the maximum
modulation rate.
This firing rate is sent to the slaves as a percentage, but this is
apportioned to the slave Control Systems according to the rate
allocation algorithm selected by the Rate allocation method
parameter.
9. The ignition and the gas valve are switched on.
10. The ignition is turned off at the end of the direct burner
ignition period, or for a system that does use a pilot, at
the end (or optionally at the middle) of the Pilot Flame For some algorithms, this rate might be common to all slave
Establishing Period (PFEP). For an interrupted pilot system Control Systems that are firing. For others it might represent the
this is followed by a Main Flame Establishing Period (MFEP) total system capacity and be allocated proportionally.
where the pilot ignites the main burner. For an intermittent
pilot there is no MFEP.
11. The fan is kept at the lightoff rate during the stabilization
For example, if there are 4 slaves and the LL master's percent
rate is 30%, then it might satisfy this by firing all four slaves at
30%, or by operating the first slave at 80% (20% of the system’s
capacity) and a second slave at 40% (10% of the system’s
timer, if any.
12. Before the release to modulation, the fan is switched to
capacity).
minimum RPM for the DHW Forced Rate and Slow Start
The LL master may be aware of slave Control System’s minimum
Enable, if the water is colder than the threshold.
firing rate and use this information for some of its algorithms,
13. At the end of the DHW-heat request the burner is switched
but when apportioning rate it may also assign rates that are less
off and the fan stays on until post purge is complete.
than this. In fact, the add-stage and drop-stage algorithms may
14. A new DHW-request is blocked for the forced off time set by
assume this and be defined in terms of theoretical rates that are
the Anti Short Cycle (if enabled).
possibly lower than the actual minimum rate of the Burner Control
System. A Control System that is firing and is being commanded
to fire at less than its minimum modulation rate will operate at
its minimum rate: this is a standard behavior for a Buner control
15. The pump stays on during the pump overrun time (if
enabled).
16. At the end of the pump overrun time the pump will be
switched off.
system in stand-alone (non-slave) mode.
If any slave under LL Master control is in a Run-Limited condition,
then for some algorithms the LL master can apportion to that
LEAD LAG
stage the rate that it is actually firing at. Additionally when a
slave imposes its own Run-limited rate, this may trigger the LL
Master to add a stage, if it needs more capacity, or drop a stage
if the run-limiting is providing too much heat (for example if a
stage is running at a higher-than commanded rate due to anti-
condensation).
Burner Control System devices contain the ability to be a stand-
alone control, operate as a Lead Lag Master control (which also
uses the burner control function as one of the slaves), or to
operate solely as a slave to the lead lag system.
Control System devices utilize two ModBus™ ports (MB1
and MB2) for communications. One port is designated to
support a system S7999B display and the other port supports
communications from the LL Master with its slaves.
By adjusting the parameters in an extreme way it is possible
to define add-stage and drop-stage conditions that overlap or
even cross over each other. Certainly it is incorrect to do this,
and it would take a very deliberate and non-accidental act to
accomplish it. But there are two points in this:
The Lead Lag master is a software service that is hosted by a
Control System. It is not a part of that control, but is an entity
that is “above” all of the individual burner controls (including the
one that hosts it). The Lead Lag master sees the controls as a
set of Modbus devices, each having certain registers, and in this
regard it is entirely a communications bus device, talking to the
slave buner controls via Modbus.
1. LL master does not prevent it, and more important;
2. It will not confuse the LL master because it is implemented
as a state machine that is in only one state at a time;
The LL master uses a few of the host Buner Control's sensors
(header temperature and outdoor temperature) and also the
STAT electrical inputs in a configurable way, to provide control
information.
48
For example:
LOCAL OPERATOR INTERFACE: DISPLAY SYSTEM
— If its add-stage action has been triggered, it will remain in this
condition until either a stage has been added,
Or
— The criteria for its being in an add-stage condition is no longer
met; only then will it take another look around to see what state
it should go to next.
DEFINITIONS
Modulating stage: The modulating stage is the Control System
that is receiving varying firing rate requests to track the load.
First stage: This is the Control System that was turned on first,
when no slave Control Systems were firing.
Previous stage: The Control System that was added to those
stages that are firing Just prior to the adding of the Control
System that is under discussion.
Next stage: The Control System that will or might be added as
the next Control System to fire.
Last stage: The Control System that is firing and that was added
the most recently to the group of slaves that are firing. Typically
this is also the modulating stage, however as the load decreases
then the last-added stage will be at its minimum rate and the
previous stage will be modulating.
FIGURE 49. BURNER CONTROL S7999B DISPLAY SYSTEM
The S7999B is a microprocessor-based touchscreen Operator
Interface (OI) display that provide an operator interface for
monitoring and configuring parameters in the Burner Control
system.
Lead boiler: The Lead boiler is the Control System that is the
first stage to fire among those stages which are in the equalize
runtime (Lead/Lag) group. If a boiler is in the “Use first” group it
may fire before the Lead boiler fires.
The S7999B can be used to monitor an individual boiler but
is primarily used for multiple boiler applications in a lead/lag
arrangement. COM 2 port is available for Building Automation
applications. The S7999B display is flush mounted into a panel
cutout (8-1/8 in. W x 5-7/8 in. H). Wiring connections to the
S7999B are through a removable 9-pin wiring header.
First boiler: A Control System may be assigned to any of three
groups: “Use First”, “Equalize Runtime”, or “Use Last”. If one or
more Control Systems are in the “Use First” category, then one
of these (the one with the lowest sequence number) will always
be the first boiler to fire. If there is no Control System in the “Use
First” category and one or more are in the “Equalize Runtime”
category, then the First boiler is also the Lead boiler.
FEATURES
•
Individual boiler status, configuration, history, and
diagnostics.
•
Allows configuration and monitoring of the Burner Control
Controls burner control sequence, flame signal, diagnostics,
historical files, and faults.
•
S7999B OI Display only:
• Allows switching view between multiple boilers
• Allows viewing Lead-Lag Master
• Ethernet port for downloading software upgrades (when
required)
• Real-time data trending analysis and transferring saved
trend data to Excel spreadsheet.
• Audible Alarm
• COM 2 Modbus port for Building Automation System
applications.
• LED indicators:
• Power
• Network
• COM 2
• COM 1
•
Model used:
• S7999B1067 has Black Border
49
•
•
•
•
Allows for lead/lag commissioning.
Locates attached boiler(s).
Allows boiler naming.
10. Drill 1/4 in. holes through the panel at the marked locations
and secure the power supply with the two #6-32 screws
and nuts provided.
11. Remove the 9-pin connector plug from the back of the OI
Color 3.5 in. x 4.625 in. (5.7 in. diagonal) user interface
display.
Display.
12. Wire the connector to the power supply and the RS-485
•
•
•
Graphic user interface.
Touch screen.
cables.
13. Ensure the 9-pin connector plug is aligned with the header
pins when inserting the 9-pin connector plug back onto the
Display. Secure firmly.
Communication between the OI Displays and the Burner
Control Systems uses Modbus™.
•
•
•
•
•
•
Flush mounting.
Touch screen disable for screen cleaning.
12 VDC power supply (included).
Screen saver.
Contrast control.
Volume control.
SPECIFICATIONS
1. Electrical Ratings:
+12 VDC input, maximum of 500 mA current drain.
Included Power Supply for S7999B:
• Inputs: 85 to 264 VAC, 47 to 63 Hz; 120 to 370 VDC.
• Output: 12 VDC; 0 to 2.1 A.
• Power: 25 W.
FIGURE 50. S7999B OI DISPLAY CONNECTOR TERMINALS
2. Operating Temperature: 32°F to 122°F (0°C to 50°C)
3. Storage/Shipping Temperature: -40°F to 158°F (-40°C to
70°C).
QUICK SETUP (S7999B OI DISPLAY)
4. Humidity: 85% maximum relative humidity.
5. Approvals:
1. Make sure the S7999B 9-pin connector is properly aligned
and pressed firmly in place.
FCC Part 15, Class A Digital Device
2. Make sure the wires between the 9-pin connector and the
Underwriter’s Laboratories, Inc. (UL) Component Recognized
(for non-continuous operation): File Number MH20613 (MCCZ)
controller are properly wired and secure.
WARNING: Electrical Shock Hazard. Can cause severe injury,
death or equipment damage. Line voltage is present at the 120
VAC power supply.
Canada: ICES-003
INSTALLATION INSTRUCTIONS (S7999B OI DISPLAY)
MOUNTING THE S7999B OI DISPLAY AND POWER SUPPLY
3. Make sure the power supply is connected securely to the
120 VAC power source.
The OI Display can be mounted on the door panel of an
electrical enclosure.
1. Select the location on the door panel to mount the display;
note that the device will extend into the enclosure at least
one inch past the mounting surface.
2. Provide an opening in the panel door 8-1/8 in. wide by
5-7/8 in. high.
3. Place the OI Display in the opening and use it as a
template to mark the location of the four mounting screw
holes. Remove the device.
4. Using pilot holes as guides, drill 1/4 in. holes through the
door panel.
5. Place the display in the opening, aligning the mounting
holes in the device with the drilled holes in the panel.
6. Secure the display to the panel with four #6-32 screws and
nuts provided.
7. Select a location inside the enclosure for mounting the
power supply.
8. Using the power supply as a template, mark the locations
of the two mounting holes in the enclosure.
9. Remove the power supply.
50
On System applications, each Burner Control System is
represented on the Home page by an icon and name. Pressing
the icon allows the user to zoom in on that boiler and see its
specific details. These details are provided on a new page, which
can include additional buttons that display additional detail and
operation information, which itself leads to other pages. The
pages are traversed in a tree structure method, as shown in
STARTING UP THE S7999B OI DISPLAY
POWER-UP VALIDATION
The Home page will appear and the “Power” LED will be blinking
when the device is properly powered. Select the Setup button to
adjust the contrast and sound as desired.
If the screen is dim, check the pin 1 and 2 wiring connections.
Note: An Advanced Startup screen displays for five seconds after
power-up before the Home page displays. This screen allows the
user to upgrade the software in the System Display and should
normally be bypassed.
The Control System icons will appear in one of four colors
indicating the boiler status.
• Blue: Normal operation
• Red: Lockout condition
Three LEDs exist for I/O traffic: one for the Ethernet network port
and two for Modbus™ ports. Modbus Com Port 2 is not active
on this device.
• Gray: Standby mode (burner switch off)
• Gray and crossed out: communication error
(disconnected or powered off)
1. Make sure the Power and COM1 LEDs are blinking.
2. If the LEDs are not blinking:
• Yellow: Preparing for Start-up.
• Make sure the proper connections have been made
between the Modbus COM1 Port and the first controller
device in the Modbus network.
Up to 8 Systems can be displayed on the Home page. The name
of each boiler is displayed next to the Control System icon button.
When Lead Lag is enabled, the system header temperature and
firing rate are displayed for each System. When the burner is in
standby or not firing the firing rate is not displayed.
• Ensure proper wiring of the OI Display 9-pin Header
Connections.
3. If connected to a BAS application, COM2 LED will blink Note: The boiler name may be cut off on the Home page when
indicating BAS traffic.
all icons are present.
HOME PAGE (S7999B OI DISPLAY)
The Home page also includes a System Analysis button that
allows the user to view status information on a system-wide
(that is, multiple boiler) basis. The user can choose which status
information to compare from the Burner Controls in the system.
Display has completely powered up.
Pressing the Setup button on the Home page displays
miscellaneous setup and diagnostic functions. It also contains
the setup configuration for BAS applications, under theAdvanced
Setup button. Pressing the Control System icon opens that
control’s status page.
PAGE NAVIGATION
The Burner Control System OI Displays present information
and options in a paged manner. Pages are displayed in a tree
structure in which the user navigates up and down to arrive at
are provided below so that you can understand the purpose of
each and view the selections, parameters, and information that
is available or required on each.
FIGURE 51. S7999B HOME PAGE
(BOILER 1 IN NORMAL OPERATION)
COMMON OI DISPLAY PAGE SYMBOLS
Most pages have a Home button in the top-left corner of the
screen and a Back button in the top-right corner of the screen.
The Home button returns the user to the Home page and
terminates any operation in progress. The Back button returns
the user to the previous page.
Two other icons may be noticed near the boiler name.
A bell will be displayed if the system is in Lockout that reset will
be required.
A padlock will be shown on screens that require a password
to change the parameter. An unlocked padlock indicates the
password has been entered to change the parameter.
FIGURE 52. S7999B LEAD LAG HOME PAGE
51
STATUS OR HOME PAGE
CONFIGURE BUTTON
A status (summary) page (Figure 54) is displayed when the Pressing the Configure button (bottom left) on the Status page
S7999B display is connected. This status page appears on the opens the Configuration page.
S7999B when the Burner control icon is pressed on the “Home” The S7999B Configuration page does not have a “Display Setup”
page. The status page displays the current condition of the burner button.
control and displays some of the more important configuration
settings.
Theconfigurationpageallowstheusertoviewandsetparameters
that define how the connected R7910A functions in the hydronic
The boiler name associated with the burner control is displayed heating system. All parameters are factory configured and only
in the title on the status page.
a Field Service Agent must perform the configuration settings.
Note: When the burner control has no boiler name defined, The configuration page contains a menu of parameters grouped
Modbus address is used to identify the boiler.
into functional areas that the user selects for configuration (see
The initial status page displayed contains summary status
information as shown in Figure 54. Any status information not No specific order for configuration is required. All parameters
applicable for the installation is grayed/blanked out on the screen. are enabled for editing, though some may not be applicable
(e.g., a configuration parameter may disable a control feature).
Selecting a parameter group from the menu displays parameters
exclusively applicable for the functional group on the page (see
Figure 56). These parameters can be edited, and when the user
Buttons on this screen include:
• Configure: used to configure the burner control
(password protected).
• Operation: used to perform daily or frequent functions
is finished, control returns back to the configuration menu page.
with the burner control, such as setpoint adjustment, etc.
Each parameter is displayed in its group. If there are more
parameters than will fit on the screen, a vertical scroll bar allows
the user to scroll up and down to view all parameters. The
parameter name is displayed on the left and the current setting is
displayed in the text box on the right.
• Diagnostic: used to view burner control diagnostic
information.
• Details: used to view burner control detail status
information.
• History: used to view burner control history
• Pump: used to expand the pump status information.
• Modulation: used to toggle between status displays:
pump, setpoints, and modulation.
FIGURE 55. CONFIGURATION MENU PAGE
FIGURE 54. SUMMARY STATUS PAGE
FIGURE 56. SAMPLE CONFIGURATION PAGE
53
CONFIGURATION PASSWORD
KEYBOARD
Some parameters require a valid configuration password be Some pages request user entry of characters. When this type of
entered by the user before the parameter can be changed. The input is required, a keyboard page appears, as shown in Figure
password need only be entered once while the user remains on 58. The text box at the top of the screen displays the current (or
the configuration pages. Leaving the configuration pages ends default) setting of the user input. The user can add to this text,
the scope of the password.
clear it, or change it.
Three levels of access to Burner Control parameters are The Shift key on the left side of the screen shifts between upper
permitted. Each access level has defined rights when interfacing and lowercase characters. Pressing the Shift key toggles the
with configuration and status parameters within the controls.
keyboard from one mode to the other (continuous pressing of the
Shift button is not required). The OK button should be pressed
when the user is done entering the text input. The Cancel button
on the bottom of the screen allows the user to ignore any text
changes that have been made and keep the original text value.
Pressing the OK or Cancel buttons returns the user to the page
displayed prior to the keyboard page.
• End user: The end user can read or view the control
parameters and be allowed to change some operating
parameters, CH setpoint as an example.
• Installer: The installer can read all control parameters
and change default allowed parameters. This access
level is used to customize the control for a particular
installation.
LOGIN
Pressing the Login button allows entering the password from a
the OK button is selected. The Cancel button aborts the password
login.
• OEM: The OEM can read and change all parameters,
change sensor limits and burner control safety
parameters.
Different passwords exist in the Burner Control for each access
level. The end user level requires no password, but the installer
and OEM levels have unique passwords defined for them.
The installer and OEM passwords can be changed in the Burner
Control after logging in with the current password. When the
password is changed, it is saved for all future logins.
Note: For the S7999B System OI display, each boiler in a
multi-boiler configuration has its own set of installer and OEM
passwords. To avoid user confusion, the passwords should be
changed to the same password in each control, but there is no
requirement to do so. Make sure to record your password.
The user is notified that a new password is needed to change
a parameter (or until a password is entered successfully)—see
Figure 57. The user can continue viewing the configuration
parameters regardless of whether a password is entered
successfully.
The Burner Controls maintain a password time-out that limits the
scope of the password entry. Once a password is successfully
entered, the control starts an internal timer that expires after 10
minutes of inactivity. After the timer expires, the user is required
to re-enter a password before a parameter can be changed.
FIGURE 58. DEVICE LOGIN SCREEN
WARNING: Explosion Hazard. Improper configuration can cause
fuel buildup and explosion. Improper user operation may result in
property loss, physical injury or death.
The user is not required to enter a configuration password for a
parameter that has a lower access level than the access level
achieved by an earlier password entry for any configuration
group (as long as the user stays in the configuration pages). The
user only needs to enter a password once until a parameter that
has a higher access level is selected.
Using the OI Displays to change parameters must be attempted
by only experienced and/or licensed burner/boiler operators and
mechanics.
CHANGE PARAMETER SETTINGS
Change parameter settings by selecting the parameter on the
page. A dialog box displays for the parameter with controls
After changing the setting to a new value, press the OK button.
Pressing the Cancel button leaves the parameter unchanged.
The changed setting is reflected on the screen and sent to the
control when the OK button is pressed.
FIGURE 57. LOGIN REQUIRED
54
Note: When the installer proceeds with the safety parameter
configuration, the control unlocks the safety parameters in this
group and marks them unusable. Failure to complete the entire
safety configuration procedure leaves the control in an un-
runnable state (lockout 2).
All safety configuration parameters in the group should have the
same access level. If this condition isn’t so, the user is asked to
enter another password when a higher access level is needed.
Successful login is noted by the lock icon, which changes
to “unlocked” on the page. The installer may begin to change
safety parameters (or any other parameters) at that time (see
Figure 61). If the Burner Control is in an unconfigured (or new)
state, then this warning doesn’t appear. All parameters that need
changes should be changed during the login.
FIGURE 59. EXAMPLE OF CHANGE CONFIGURATION
PARAMETER PAGE
VERIFY
Pressing the Verify button displays safety configuration
parameters for an additional verification step to commit the
changes.
Safety parameters are grouped into blocks that include only
safety parameters, not a mixture of safety data and non-safety
data.All parameters within the safety group undergo a verification
process. A safety parameter group is identified on the display to
indicate when the configuration parameters are safety-related.
Each safety parameter group is verified one at a time until all
FIGURE 61. EDIT SAFETY DATA
If the safety configuration session is terminated after it has
started (in the Edit or Verify stages), the Burner Control is left in
an unconfigured (unrunnable) state.
The installer can terminate the session by pressing the Menu
button or by attempting to leave the Verification page with
the Home or Back buttons (top-left and -right screen corners,
respectively). However, leaving the session at this point leaves
the control in an unrunnable state and confirms whether the
installer still wants to do so.
The settings of all parameters in each safety block must be
verified to save them in the control.
When the installer is done changing safety parameters,
pressing the Verify button on the configuration screen begins
the Verification process. The settings for all safety parameters
in each changed block are presented and Verified by the installer
FIGURE 60. SAFETY VERIFICATION
Like operating parameters, safety parameters can be viewed
without the need to enter a password.
Safety parameter blocks that have been changed require
verification. The verification steps do not have to be completed
immediately; the installer can move between and change
parameter groups before the verification is done. A Verify button
is enabled that allows the installer to conduct verification sessions
because the installer hasn’t logged in).
55
FAULT/ALARM HANDLING
Each Burner Control reports to the OI display when a safety
lockout or an Alert occurs.
Safety lockouts are indicated on each configuration page as an
alarm bell symbol. At the status page (for S7999B), the History
button turns red. If the S7999B is displaying the system status
icons, the control in alarm will turn red.
The lockout history can be displayed by pressing on the History
button. The state information about each lockout is displayed
Note: In the event of a power interruption, the date/time must be
reset. The OI Display does NOT have a backup means.
TABLE 21. BURNER CONTROL LOCKOUT HISTORY
DATA
Lockout time
COMMENT
Set by display
FIGURE 62. SAFETY PARAMETER CONFIRMATION
Fault Code
Unique code defining which
lockout occurred.
Press the Yes button to confirm each safety parameter block. If
the No button is selected, the safety parameter block remains
unconfirmed and the Configuration menu page is displayed. The
control remains in an unconfigured state in this case.
Annunciator first out
First interlock in limit string
results in a shutdown.
Description
Fault description
After all safety parameter blocks have been confirmed, the
installer is asked to press and hold the Reset button on the
Burner Control to complete the safety verification session (see
Burner Lockout/Hold
Source/reason for lockout/
hold
Burner control state
Sequence time
Burner control state timer at
time of fault
Cycle
Burner control cycle
Burner control hours
Run Hours
I/O
All digital I/O status at time of
fault
Annunciator 1-8 states
Fault data
All annunciator I/O status at
time of fault
Fault dependent data
An alert log can be displayed for each control by pressing theAlert
button on the bottom of the history status page. A description of
the alert is displayed along with the time when the alert occurred
TABLE 22. BURNER CONTROL ALERT LOG
DATA
COMMENT
Set by display
Alert Line
FIGURE 63. SAFETY PARAMETER RESET
Alert Code
Unique Code defining which
fault occured.
When the Reset button is pressed and held for 3 seconds the
confirmed safety parameters are saved in the control. The
above Reset dialog box automatically closes when this step is
completed.
Description
Alert description
If this step is not performed, the control remains in a safety lockout
state until the installer resolves the unverified safety parameters.
HISTORY BUTTON
The History button on the Home page serves not only as a
button, but also displays Burner Control lockouts, holds, and
alerts as they occur. The History button can be selected at any
time, regardless of which type of information is displayed, to view
history information. Pressing the History button displays a dialog
the type of history to view. The user can also silence an audible
alarm generated by the control during a lockout or alert by alarm
condition.
56
This History dialog box provides an exploded view of the status
information displayed in the History button (the font is larger).
One of the four buttons (OK, Lockouts, Alerts, or Silence) can
be selected. If none of these buttons are selected the dialog box
closes after 30 seconds.
Note: The system time can be set in the OI display to ensure that
correct timestamps are given to the controls’ lockouts and alerts.
Power interruptions will require the time to be reset as the display
DOES NOT have a time backup means.
The Clear Lockout button allows the user to acknowledge and
clear (reset) the lockout when in lockout state, much the same
as pressing the reset button on the front of the Burner Control.
The user can toggle between displaying the controls’ lockout
history and alert log by pressing the Alerts or Lockouts button on
the bottom of the pages.
FIGURE 64. EXAMPLE OF HYDRONIC HISTORY
Two types of historical data can be displayed on the history page:
lockout history and alert log.
The entire 15 fault code history is displayed in a scrollable list
with the most recent fault displayed first followed by the next
most recent fault. Summary information is displayed for each
fault entry, including the burner cycle count, fault code, and fault
number with description. Detailed information for a specific fault
entry that also includes burner control sequence state, burner
run-time hours, annunciation status, etc., is viewed by selecting
(touching the History line) the lockout entry in the list.
FIGURE 66. EXAMPLE OF ALERT SHOWN
To see additional detail about a lockout or alert, touching on the
lockout or alert in the list expands the view of that lockout or alert,
FIGURE 67. CONTROL EXPANDED LOCKOUT DETAIL
FIGURE 65. EXAMPLE OF LOCKOUT HISTORY
The date and time that each fault occurred is displayed in the
lockout history. The lockout timestamp displays in both the
lockout summary and detail information.
The Burner Control does not maintain date or time of day
information. The date and time stamp is assigned by the OI
display. When the OI display first obtains the lockout and alert
history from the control (during the display data synchronization),
no timestamps are assigned since the times that the lockouts
occurred are unknown. All new lockouts that occur after the
synchronization are assigned timestamps.
57
FIGURE 68. CONTROL EXPANDED ALERT DETAIL
OPERATION BUTTON
FIGURE 70. PROGRAMMABLE ANNUNCIATION
The operation button displays the Burner Control running
operation, including setpoint and firing rate values. From this page
the user can change setpoints, manually control the boiler’s firing
rate, manually turn pumps on, view annunciation information,
and switch between hydronic heating loops (Central Heat and
required to change any of the settings on this page, the user can
press the Login button to enter the password.
FIGURE 71. FIXED ANNUNCIATION
FIGURE 69. HYDRONIC OPERATION PAGE
58
DIAGNOSTICS BUTTON
SYSTEM CONFIGURATION (S7999B OI DISPLAY ONLY)
The Diagnostics button displays analog and digital I/O status
of the Burner Control. A snapshot of the diagnostic status is
displayed and updated once per second as it changes in the
control.
The OI Display has some functions related to general
configuration for the control in the end user installation. Pressing
the Display Refresh button invokes a search procedure (see
Figure 74). A new R7910A Hydronic Control or R7911 Steam
Control is identified by “Unknown” status next to its name in
configuration data has not been retrieved from the control yet.
The digital I/O data is displayed as LEDs that are either on
displayed at the same time on the page, so a horizontal scroll bar
is used to move the view left and right to show all digital I/O data.
FIGURE 74. SYSTEM REFRESH
FIGURE 72. DIAGNOSTICS PAGE (DIGITAL I/O)
The control analog I/O can also be viewed on the OI Display. A
snapshot of the diagnostic status is displayed and updated as it
changes in the control.
The analog I/O data is displayed as bar charts with I/O level
not enabled for the installation displays a blank I/O level. Not all
analog I/O can be displayed at the same time on the page, so
a horizontal scroll bar is used to move the view left and right to
show all analog I/O status.
FIGURE 75. SYSTEM CONFIGURATION PAGE
The control connected to the Modbus network is indicated to the
user after the search procedure has concluded.
Once the control is located it must be synchronized with the OI
Display before it can be displayed. New controls are not displayed
on the Home page until this synchronization is performed.
FIGURE 73. DIAGNOSTIC PAGE (ANALOG I/O)
59
SYSTEM SYNCHRONIZATION (S7999B OI DISPLAY ONLY)
CONFIGURATION
The user can manually synchronize configuration data from the The Burner Control can be configured from the OI Display. The
connected controls at any time.
control configuration is grouped into the functional groups as
A new control is visible when configuration and status data is
gathered from it. This collection procedure takes a few minutes.
The control is marked as “Unknown” when no configuration
information exists. Normally, control configuration data collection
only needs to be performed when the control is initially installed.
However, a re synchronization is necessary after the OI Display
TABLE 23. FUNCTIONAL CONFIGURATION GROUPS
HYDRONIC CONTROL
System Identification and
Access
CH - Central Heat
Outdoor Reset
TheuserpressestheSynchronizebuttontobeginsynchronization
DHW - Domestic Hot Water
DHW Storage
DHW Plate
Warm Weather Shutdown
Demand Priority
Modulation Configuration
Pump Configuration
Statistics Configuration
High Limit
Stack Limit
Delta T Limits
T-Rise Limit
Heat Exchanger High Limit
Anti-condensation
Frost Protection Configuration
Annunciation Configuration
Burner Control Interlocks
Burner Control Timings and Rates
Burner Control Ignition
Burner Control Flame Failure
System Configuration
Fan Configuration
FIGURE 76. SYSTEM SYNCHRONIZATION
Status of the synchronization is reflected in the dialog box. The
synchronization can be aborted by selecting the Cancel button.
Sensor Configuration
Lead Lag Slave Configuration
Lead Lag Master Configuration
Most of this configuration is performed by the Service Agent
or at A.O. Smith. Each functional group is displayed on the
Configuration menu page.
Parameters in functional groups that are not applicable for
the installation can be ignored. In some cases, features in a
functional group are disabled by default and are enabled when
needed for the installation.
60
TROUBLESHOOTING
To support the recommended Troubleshooting, the R7910 has an Alert File. Review the Alert history for possible trends that may have
been occurring prior to the actual Lockout.
Note Column: H= Hold message; L=Lockout message; H or L= either Hold or Lockout depending on Parameter Configuration.
TABLE 24. TROUBLESHOOTING CODES
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
Safety Data Faults
1
Unconfigured safety data
1. New Device, complete device configuration and
safety verification.
L
2. If fault repeats, replace module.
2
Waiting for safety data verification
1. Device in Configuration mode and safety
parameters need verification and a device needs
reset to complete verification.
L
2. Configuration ended without verification, re enter
configuration, verify safety parameters and reset
device to complete verification.
3. If fault repeats, replace module.
Internal Operation Errors
3
Internal fault: Hardware fault
Internal Fault.
H
1. Reset Module.
2. If fault repeats, replace module.
4
Internal fault: Safety Relay key feedback error
Internal fault: Unstable power (DCDC) output
Internal fault: Invalid processor clock
Internal fault: Safety relay drive error
Internal fault: Zero crossing not detected
Internal fault: Flame bias out of range
Internal fault: Invalid Burner control state
Internal fault: Invalid Burner control state flag
Internal fault: Safety relay drive cap short
Internal fault: PII shorted to ILK
H
5
H
6
H
7
H
8
H
9
H
10
11
12
13
14
15
L
L
H
H or L
H or L
L
Internal fault: HFS shorted to LCI
Internal fault: Safety relay test failed due to
feedback ON
16
17
18
Internal fault: Safety relay test failed due to safety
relay OFF
L
L
L
Internal fault: Safety relay test failed due to safety
relay not OFF
Internal fault: Safety relay test failed due to
feedback not ON
19
20
21
22
23
Internal fault: Safety RAM write
L
Internal fault: Flame ripple and overflow
Internal fault: Flame number of sample mismatch
Internal fault: Flame bias out of range
H
H
H
H
Internal fault: Bias changed since heating cycle
starts
24
25
Internal fault: Spark voltage stuck low or high
H
H
Internal fault: Spark voltage changed too much
during flame sensing time
26
27
Internal fault: Static flame ripple
H
H
Internal fault: Flame rod shorted to ground
detected
28
29
Internal fault: A/D linearity test fails
H
H
Internal fault: Flame bias cannot be set in range
61
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
30
Internal fault: Flame bias shorted to adjacent pin
Internal fault: SLO electronics unknown error
Internal fault: Safety Key 0 through 14
System Errors
Internal Fault.
1. Reset Module.
2. If fault repeats, replace module.
H
31
H
32 - 46
L
47
48
49
Flame Rod to ground leakage
Static flame (not flickering)
H
H
H
24 VAC voltage low/high
1. Check the Module and display connections.
2. Check the Module power supply and make sure
that both frequency, voltage and VA meet the
specifications.
50
51
52
Modulation fault
Pump fault
Internal sub-system fault.
1. Review alert messages for possible trends.
2. Correct possible problems.
H
H
H
Motor tachometer fault
3. If fault persists, replace module.
53
AC inputs phase reversed
1. Check the Module and display connections.
2. Check the Module power supply and make
sure that both frequency and voltage meet the
specifications.
L
3. On 24 VAC applications, assure that J4-10 and
J8-2 are connected together.
54
Safety GVT model ID does not match application's Contact the service professional.
model ID
L
L
55
Application configuration data block CRC errors
RESERVED
Contact the service professional.
56 - 57
58
Internal fault: HFS shorted to IAS
Internal Fault: Mux pin shorted
Normal Event Status
Internal Fault.
1. Reset Module.
2. If fault repeats, replace module.
L
L
59
60
61
62
63
Internal Fault: HFS shorted to LFS
Anti short cycle
L
Will not be a lockout fault. Hold Only.
H
H
H
Fan speed not proved
LCI OFF
1. Check wiring and correct any faults.
2. Check Interlocks connected to the LCI to assure
proper function.
3. Reset and sequence the module; monitor the LCI
status.
4. If code persists, replace the module.
64
PII OFF
1. Check wiring and correct any faults.
2. Check Preignition Interlock switches to assure
proper functioning.
H or L
3. Check the valve operation.
4. Reset and sequence the module; monitor the PII
status.
5. If code persists, replace the module.
65
66
Interrupted Airflow Switch OFF
Interrupted Airflow Switch ON
1. Check wiring and correct any possible shorts.
2. Check airflow switches to assure proper
functioning.
H or L
H or L
3. Check the fan/blower operation.
4. Reset and sequence the module; monitor the
airflow status.
5. If code persists, replace the module.
62
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
67
ILK OFF
ILK ON
1. Check wiring and correct any possible shorts.
2. Check Interlock (ILK) switches to assure proper
function.
H or L
H or L
68
3. Verify voltage through the interlock string to the
interlock input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
69
70
Pilot test hold
1. Verify Run/Test is changed to Run.
2. Reset Module.
3. If fault repeats, replace module.
H
H
Wait for leakage test completion
1. Internal Fault. Reset Module.
2. If fault repeats, replace module.
71 - 77
78
RESERVED
Demand Lost in Run
1. Check wiring and correct any possible errors.
2. If previous steps are correct and fault persists,
replace the module.
H
79
80
81
Outlet high limit
DHW high limit
Delta T limit
1. Check wiring and correct any possible errors.
2. Replace the Outlet high limit.
3. If previous steps are correct and fault persists,
replace the module.
H or L
1. Check wiring and correct any possible errors.
2. Replace the DHW high limit.
3. If previous steps are correct and fault persists,
replace the module.
H or L
1. Check Inlet and Outlet sensors and pump circuits H or L
for proper operation.
2. Recheck the Delta T Limit to confirm proper
setting.
3. If previous steps are correct and fault persists,
replace the module.
82
Stack limit
1. Check wiring and correct any possible errors.
2. Replace the Stack high limit.
H or L
3. If previous steps are correct and fault persists,
replace the module.
83
84
85
86
87
88
89
90
Delta T exchanger/outlet limit
Delta T inlet/exchanger limit
Inlet/outlet inversion limit
Exchanger/outlet inversion limit
Inlet/exchanger inversion limit
Outlet T-rise limit
Not Applicable.
Not Applicable.
Not Applicable.
Not Applicable.
Not Applicable.
Check for adequate flow.
Not Applicable.
Not Applicable.
H or L
H or L
H or L
H or L
H or L
H or L
H or L
H or L
Exchanger T-rise limit
Heat exchanger high limit
Sensor Faults
91
92
93
Inlet sensor fault
1. Check wiring and correct any possible errors.
2. Replace the Inlet sensor.
3. If previous steps are correct and fault persists,
replace the module.
H
H
H
Outlet sensor fault
DHW sensor fault
1. Check wiring and correct any possible errors.
2. Replace the Outlet sensor.
3. If previous steps are correct and fault persists,
replace the module.
1. Check wiring and correct any possible errors.
2. Replace the DHW sensor.
3. If previous steps are correct and fault persists,
replace the module.
63
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
94
Header sensor fault
1. Check wiring and correct any possible errors.
2. Replace the header sensor.
H
3. If previous steps are correct and fault persists,
replace the module.
95
96
Stack sensor fault
1. Check wiring and correct any possible errors.
2. Replace the stack sensor.
3. If previous steps are correct and fault persists,
replace the module.
H
H
Outdoor sensor fault
1. Check wiring and correct any possible errors.
2. Replace the outdoor sensor.
3. If previous steps are correct and fault persists,
replace the module.
97
Internal Fault: A2D mismatch.
Internal Fault.
1. Reset Module.
2. If fault repeats, replace module.
L
L
L
H
98
Internal Fault: Exceeded VSNSR voltage
Internal Fault: Exceeded 28V voltage tolerance
Pressure Sensor Fault
99
100
1. Verify the Pressure Sensor is a 4-20 ma source.
2. Check wiring and correct any possible errors.
3. Test Pressure Sensor for correct operation.
4. Replace the Pressure sensor.
5. If previous steps are correct and fault persists,
replace the module.
101-104 RESERVED
Flame Operation Faults
105
Flame detected out of sequence
1. Check that flame is not present in the combustion H or L
chamber. Correct any errors.
2. Make sure that the flame detector is wired to the
correct terminal.
3. Make sure the F & G wires are protected from
stray noise pickup.
4. Reset and sequence the module, if code
reappears, replace the flame detector.
5. Reset and sequence the module, if code
reappears, replace the module.
106
107
108
109
Flame lost in MFEP
Flame lost early in run
Flame lost in run
Ignition failed
1. Check pilot valve (Main Valve for DSI) wiring and
operation - correct any errors.
2. Check the fuel supply.
3. Check fuel pressure and repeat turndown tests.
4. Check ignition transformer electrode, flame
detector, flame detector siting or flame rod
position.
L
L
L
L
5. If steps 1 through 4 are correct and the fault
persists, replace the module.
110
Ignition failure occurred
Hold time of recycle and hold option. Will not be a
lockout fault. Hold Only.
H
111
112
Flame current lower than WEAK threshold
Pilot test flame timeout
Internal hardware test. Not a lockout,
H
Interrupted Pilot or DSI application and flame lost
when system in “test” mode.
L
1. Reset the module to restart.
113
Flame circuit timeout
Flame sensed during Initiate or off cycle, hold 240
seconds, if present after 240 seconds, lockout.
L
114-121 RESERVED
Rate Proving Faults
122
123
Lightoff rate proving failed
Purge rate proving failed
1. Check wiring and correct any potential wiring
errors.
2. Check VFDs ability to change speeds.
3. Change the VFD
L
L
4. If the fault persists, replace the module.
64
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
124
High fire switch OFF
1. Check wiring and correct any potential wiring
errors.
2. Check High Fire Switch to assure proper function
(not welded or jumpered).
H
125
High fire switch stuck ON
H
3. Manually drive the motor to the High Fire position
and adjust the HF switch while in this position
and verify voltage through the switch to the HFS
input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
126
127
Low fire switch OFF
1. Check wiring and correct any potential wiring
errors.
2. Check Low Fire Switch to assure proper function
(not welded or jumpered).
H
Low fire switch stuck ON
H or L
3. Manually drive the motor to the High Fire position
and adjust the LF switch while in this position and
verify voltage through the switch to the LFS input
with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
128
129
130
131
132
Fan speed failed during prepurge
Fan speed failed during preignition
Fan speed failed during ignition
Fan movement detected during standby
Fan speed failed during run
1. Check wiring and correct any potential wiring
errors.
2. Check VFDs ability to change speeds.
3. Change the VFD
H or L
H or L
H or L
H
4. If the fault persists, replace the module.
H
133-135 RESERVED
Start Check Faults
Interrupted Airflow Switch failed to close
136
1. Check wiring and correct any possible wiring
errors.
2. Check Interrupted Airflow switch(es) to assure
proper function.
3. Verify voltage through the airflow switch to the
IAS input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
H
H
137
ILK failed to close
1. Check wiring and correct any possible shorts.
2. Check Interlock (ILK) switches to assure proper
function.
3. Verify voltage through the interlock string to the
interlock input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
138-142 RESERVED
FAULT CODES 149 THROUGH 165 ARE
OEM SPECIFIC FAULT CODES.
Internal fault: Flame bias out of range 1
Internal fault: Flame bias out of range 2
Internal fault: Flame bias out of range 3
Internal fault: Flame bias out of range 4
Internal fault: Flame bias out of range 5
Internal fault: Flame bias out of range 6
Flame detected
143
144
145
146
147
148
149
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
L
L
L
L
L
L
OEM Specific
H or L
1. Holds if flame detected during Safe Start check
up to Flame Establishing period.
65
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
150
Flame not detected
OEM Specific
H
1. Sequence returns to standby and restarts
sequence at the beginning of Purge after the HF
switch opens. If flame detected during Safe Start
check up to Flame Establishing period.
151
High fire switch ON
OEM Specific
H or L
1. Check wiring and correct any potential wiring
errors.
2. Check High Fire Switch to assure proper function
(not welded or jumpered).
3. Manually drive the motor to the High Fire position
and adjust the HF switch while in this position
and verify voltage through the switch to the HFS
input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
152
153
Combustion pressure ON
Combustion pressure Off
OEM Specific
H or L
H or L
1. Check wiring and correct any errors.
2. Inspect the Combustion Pressure Switch to make
sure it is working correctly.
3. Reset and sequence the relay module.
4. During STANDBY and PREPURGE, measure
the voltage between Terminal J6-5 and L2 (N).
Supply voltage should be present. If not, the
lockout switch is defective and needs replacing.
5. If the fault persists, replace the relay module.
154
155
156
157
Purge Fan switch On
OEM Specific
1. Purge fan switch is on when it should be off.
H or L
H
Purge Fan switch Off
Combustion pressure and Flame ON
Combustion pressure and Flame OFF
OEM Specific
1. Check that flame is not present in the combustion
chamber. Correct any errors.
H or L
L
2. Make sure that the flame detector is wired to the
correct terminal.
3. Make sure the F & G wires are protected from
stray noise pickup.
4. Reset and sequence the module, if code
reappears, replace the flame detector.
158
159
Main valve ON
Main valve OFF
OEM Specific
1. Check Main Valve terminal wiring and correct any
errors.
L
L
2. Reset and sequence the module. If fault persist,
replace the module.
160
161
Ignition ON
Ignition OFF
OEM Specific
1. Check Ignition terminal wiring and correct any
errors.
L
L
2. Reset and sequence the module. If fault persist,
replace the module.
162
163
Pilot valve ON
Pilot valve OFF
OEM Specific
1. Check Pilot Valve terminal wiring and correct any
errors.
L
L
2. Reset and sequence the module. If fault persist,
replace the module.
66
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
164
165
Block intake ON
Block intake OFF
OEM Specific
L
1. Check wiring and correct any errors.
2. Inspect the Block Intake Switch to make sure it is
working correctly.
L
3. Reset and sequence the module.
4. During Standby and Purge, measure the voltage
across the switch. Supply voltage should
be present. If not, the Block Intake Switch is
defective and needs replacing.
5. If the fault persists, replace the relay module.
166-171 RESERVED
Feedback
172
173
174
175
176
177
178
Main relay feedback incorrect
Pilot relay feedback incorrect
Internal Fault.
1. Reset Module.
2. If fault repeats, replace module.
L
L
L
L
L
L
L
Safety relay feedback incorrect
Safety relay open
Main relay ON at safe start check
Pilot relay ON at safe start check
Safety relay ON at safe start check
179-183 RESERVED
Parameter Faults
184
185
186
187
188
189
190
191
Invalid BLOWER/HSI output setting
Invalid Delta T limit enable setting
Invalid Delta T limit response setting
Invalid DHW high limit enable setting
Invalid DHW high limit response setting
Invalid Flame sensor type setting
1. Return to Configuration mode and recheck
selected parameters, reverify and reset module.
2. If fault repeats, verify electrical grounding.
3. If fault repeats, replace module.
L
L
L
L
L
L
L
L
Invalid interrupted air switch enable setting
Invalid interrupted air switch start check enable
setting
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
Invalid igniter on during setting
Invalid ignite failure delay setting
Invalid ignite failure response setting
Invalid ignite failure retries setting
Invalid ignition source setting
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
1. Return to Configuration mode and recheck
selected parameters, reverify and reset module.
2. If fault repeats, verify electrical grounding.
3. If fault repeats, replace module.
Invalid interlock open response setting
Invalid interlock start check setting
Invalid LCI enable setting
Invalid lightoff rate setting
Invalid lightoff rate proving setting
Invalid Main Flame Establishing Period time
Invalid MFEP flame failure response setting
Invalid NTC sensor type setting
Invalid Outlet high limit response setting
Invalid Pilot Flame Establishing Period setting
Invalid PII enable setting
Invalid pilot test hold setting
Invalid Pilot type setting
Invalid Postpurge time setting
Invalid Power up with lockout setting
67
CODE
DESCRIPTION
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
NOTE
212
Invalid Preignition time setting
1. Return to Configuration mode and recheck
selected parameters, reverify and reset module.
2. If fault repeats, verify electrical grounding.
3. If fault repeats, replace module.
L
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
Invalid Prepurge rate setting
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
Invalid Prepurge time setting
Invalid Purge rate proving setting
Invalid Run flame failure response setting
Invalid Run stabilization time setting
Invalid Stack limit enable setting
Invalid Stack limit response setting
Unconfigured Delta T limit setpoint setting
Unconfigured DHW high limit setpoint setting
Unconfigured Outlet high limit setpoint setting
Unconfigured Stack limit setpoint setting
Invalid DHW demand source setting
Invalid Flame threshold setting
Invalid Outlet high limit setpoint setting
Invalid DHW high limit setpoint setting
Invalid Stack limit setpoint setting
Invalid Modulation output setting
Invalid CH demand source setting
Invalid Delta T limit delay setting
Invalid Pressure sensor type setting
Invalid IAS closed response setting
Invalid Outlet high limit enable setting
Invalid Outlet connector type setting
Invalid Inlet connector type setting
Invalid DHW connector type setting
Invalid Stack connector type setting
Invalid S2 (J8-6) connector type setting
Invalid S5 (J8-11) connector type setting
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Not Applicable.
Exchanger sensor not allowed with stack
connector setting
242
243
Invalid DHW auto detect configuration
Not Applicable.
L
L
Invalid UV with spark interference not compatible
with Ignitor on throughout PFEP
Contact the service professional.
244
245
246
Internal fault: Safety relay test invalid state
Invalid Outlet connector type setting for Trise
Contact the service professional.
Contact the service professional.
Contact the service professional.
L
L
L
4-20mA cannot be used for both modulation and
setpoint control
247
248
249
Invalid ILK bounce detection enable
Invalid forced recycle interval
Not Applicable.
Not Applicable.
Not Applicable.
L
L
L
STAT cannot be demand source when Remote
Stat is enabled
250
Invalid Fan speed error response
1. Check fan cables secured properly. If fault
L
persists contact the service professional.
251-255 RESERVED
68
TABLE 25. ALERTS
CODE
DESCRIPTION
CODE
DESCRIPTION
EE Management Faults
None (No alert)
37
Program Module application parameter revision
differs from application processor
0
38
Program Module safety parameter revision differs
from safety processor
1
2
Alert PCB was restored from factory defaults
Safety configuration parameters were restored
from factory defaults
39
40
41
42
43
PCB incompatible with product contained in
Program Module
3
Configuration parameters were restored from
factory defaults
Parameter PCB in Program Module is too large for
product
4
Invalid Factory Invisibility PCB was detected
Invalid Factory Range PCB was detected
Invalid range PCB record has been dropped
EEPROM lockout history was initialized
Range PCB in Program Module was too large for
product
5
6
Alert PCB in Program Module was too large for
product
7
IAS start check was forced on due to IAS enabled
System Operation Faults
8
Switched application annunciation data blocks
Switched application configuration data blocks
Configuration was restored from factory defaults
9
44
45
46
47
48
Low voltage was detected in safety processor
High line frequency occurred
10
11
Backup configuration settings was restored from
active configuration
Low line frequency occurred
12
13
14
Annunciation configuration was restored from
factory defaults
Invalid subsystem reset request occurred
Write large enumerated Modbus register value
was not allowed
Annunciation configuration was restored from
backup
49
50
51
52
Maximum cycle count was reached
Maximum hours count was reached
Illegal Modbus write was attempted
Safety group verification table was restored from
factory defaults
15
16
17
Safety group verification table was updated
Invalid Parameter PCB was detected
Invalid Range PCB was detected
Modbus write attempt was rejected (NOT
ALLOWED)
53
54
55
56
57
58
Illegal Modbus read was attempted
System Parameter Errors
Safety processor brown-out reset occurred
Application processor watchdog reset occurred
Application processor brown-out reset occurred
Safety processor watchdog reset occurred
Alarm was reset by the user at the control
Demand/Rate Command Faults
18
19
20
21
Alarm silence time exceeded maximum
Invalid safety group verification table was detected
Backdoor Password could not be determined
Invalid safety group verification table was not
accepted
22
CRC errors were found in application configuration
data blocks
59
60
61
62
63
Burner control firing rate was > absolute max rate
Burner control firing rate was < absolute min rate
Burner control firing rate was invalid, % vs. RPM
Burner control was firing with no fan request
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Backup Alert PCB was restored from active one
RESERVED
Lead Lag operation switch was turned OFF
Lead Lag operation switch was turned ON
Safety processor was reset
Burner control rate (nonfiring) was > absolute max
rate
64
Burner control rate (nonfiring) was < absolute min
rate
Application processor was reset
Burner switch was turned OFF
65
66
Burner control rate (nonfiring) was absent
Burner switch was turned ON
Burner control rate (nonfiring) was invalid, %
vs.RPM
Program Module (PM) was inserted into socket
Program Module (PM) was removed from socket
Alert PCB was configured
67
68
69
70
Fan off cycle rate was invalid, % vs. RPM
Setpoint was overridden due to sensor fault
Modulation was overridden due to sensor fault
Parameter PCB was configured
Range PCB was configured
No demand source was set due to demand priority
conflicts
Program Module (PM) incompatible with product
was inserted into socket
71-73
RESERVED
69
CODE
DESCRIPTION
CODE
DESCRIPTION
Fan Parameter Errors
114
MIX modulation range (max minus min) was too
small (< 4% or 40 RPM)
74
Periodic Forced Recycle
Modulation Operation Faults
75
Absolute max fan speed was out of range
Absolute min fan speed was out of range
Fan gain down was invalid
115
116
117
118
119
120
Fan was limited to its minimum duty cycle
Manual rate was > CH max modulation rate
Manual rate was > DHW max modulation rate
Manual rate was < min modulation rate
Manual rate in Standby was > absolute max rate
76
77
78
Fan gain up was invalid
79
Fan minimum duty cycle was invalid
Fan pulses per revolution was invalid
Fan PWM frequency was invalid
RESERVED
80
Modulation commanded rate was > CH max
modulation rate
81
82-83
121
122
Modulation commanded rate was > DHW max
modulation rate
Modulation Parameter Errors
84
85
Lead Lag CH 4-20 mA water temperature setting
Modulation commanded rate was < min
modulation rate
No Lead Lag add stage error threshold was
configured
123
124
125
126
Modulation rate was limited due to outlet limit
Modulation rate was limited due to Delta-T limit
Modulation rate was limited due to stack limit
86
87
88
No Lead Lag add stage detection time was
configured
No Lead Lag drop stage error threshold was
configured
Modulation rate was limited due to
anticondensation
No Lead Lag drop stage detection time was
configured
127
128
129
Fan Speed out of range in RUN
Modulation rate was limited due to IAS was open
89
90
91
92
RESERVED
Slow start ramp setting of zero will result in no
modulation rate change
Modulation output type was invalid
Firing rate control parameter was invalid
130
No forced rate was configured for slow start ramp
CH parameter Errors
Forced rate was out of range vs. min/max
modulation
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
CH demand source was invalid
CH P-gain was invalid
93
94
95
96
97
98
99
100
Forced rate was invalid, % vs. RPM
Slow start ramp value was invalid
CH I-gain was invalid
Slow start degrees value was invalid
CH D-gain was invalid
Slow start was ended due to outlet sensor fault
Slow start was end due to reference setpoint fault
CH max modulation rate was invalid, % vs. RPM
CH max modulation rate was > absolute max rate
CH OFF hysteresis was invalid
CH ON hysteresis was invalid
CH sensor type was invalid
CH hysteresis step time was invalid
CH remote control parameter was invalid
CH ODR not allowed with remote control
Steam P-gain was invalid
CH modulation range (max minus min) was too
small (< 4% or 40 RPM)
101
102
DHW max modulation rate was invalid, % vs.RPM
DHW max modulation rate was > absolute max
rate
Steam I-gain was invalid
103
DHW modulation range (max minus min) was too
small (< 4% or 40 RPM)
Steam D-gain was invalid
Steam OFF hysteresis was invalid
Steam ON hysteresis was invalid
CH Operation Faults
104
105
106
107
108
109
110
111
112
113
Min modulation rate was < absolute min rate
Min modulation rate was invalid, % vs. RPM
Manual rate was invalid, % vs. RPM
146
147
148
149
CH control was suspended due to fault
CH header temperature was invalid
CH outlet temperature was invalid
CH steam pressure was invalid
CH Parameter errors (continued)
Steam setpoint source parameter was invalid
Slow start enabled, but forced rate was invalid
Analog output hysteresis was invalid
Analog modulation output type was invalid
IAS open rate differential was invalid
IAS open step rate was invalid
150
151
MIX max modulation rate was invalid, % vs. RPM
Minimum water temperature parameter was
greater than setpoint
MIX max modulation rate was >absolute max or <
absolute min rates
70
CODE
DESCRIPTION
CODE
191
DESCRIPTION
152
Minimum water temperature parameter was
greater than time of day setpoint
Lead Lag base load common setting was invalid
Lead Lag DHW demand switch setting was
Lead Lag Mix demand switch setting was invalid
Lead Lag modulation sensor setting was invalid
192
153
154
Minimum pressure parameter was greater than
193
setpoint
194
Minimum pressure parameter was greater than
time of day setpoint
195
Lead Lag backup modulation sensor setting was
invalid
155
156
CH modulation rate source parameter was invalid
196
197
198
199
200
201
202
Lead Lag slave mode setting was invalid
Lead Lag rate allocation setting was invalid
Lead selection setting was invalid
Steam modulation rate source parameter was
invalid
DHW Parameter Errors
Lag selection setting was invalid
157
158
159
160
161
162
163
164
165
166
167
168
169
170
DHW demand source was invalid
DHW P-gain was invalid
Lead Lag slave return setting was invalid
Lead Lag add stage method setting was invalid
DHW I-gain was invalid
STAT may not be a Lead Lag CH demand source
when Remote Stat is enabled
DHW D-gain was invalid
DHW OFF hysteresis was invalid
DHW ON hysteresis was invalid
DHW hysteresis step time was invalid
DHW sensor type was invalid
203
Lead Lag base load rate setting was invalid
Lead Lag Operation Faults
204
205
206
207
Lead Lag master was suspended due to fault
Lead Lag slave was suspended due to fault
Lead Lag header temperature was invalid
Inlet sensor type was invalid for DHW
Outlet sensor type was invalid for DHW
DHW Storage OFF hysteresis was invalid
DHW Storage ON hysteresis was invalid
DHW modulation sensor type was invalid
Lead Lag was suspended due to no enabled
Program Module installed
208
209
210
211
212
213
Lead Lag slave session has timed out
Too many Lead Lag slaves were detected
Lead Lag slave was discovered
DHW modulation sensor was not compatible for
AUTO mode
Incompatible Lead Lag slave was discovered
No base load rate was set for Lead Lag slave
DHW Operation Faults
171
172
173
174
175
176
DHW control was suspended due to fault
DHW temperature was invalid
Lead Lag slave unable to fire before demand to
fire delay expired
DHW inlet temperature was invalid
DHW outlet temperature was invalid
DHW high limit must be disabled for AUTO mode
214
Adding Lead Lag slave aborted due to add
requirement change
215
216
No Lead Lag slaves available to service demand
DHW sensor type was not compatible for AUTO
mode
No Lead Lag active service was set due to
demand priority conflicts
177
178
DHW priority source setting was invalid
DHW priority method setting was invalid
CH Operation Faults (continued)
CH S5 (J8 terminal 11) sensor was invalid
CH inlet temperature was invalid
CH S10 (J10 terminal 7) sensor was invalid
Lead Lag CH setpoint source was invalid
Lead Lag Parameter errors
217
218
219
No Lead Lag add stage method was specified
No Lead Lag drop stage method was specified
Using backup lead lag header sensor due to
sensor failure
179
180
181
182
Frost Protection Faults
220
221
222
223
224
Lead Lag frost protection rate was invalid
Lead Lag drop stage method setting was invalid
CH frost protection temperature was invalid
CH frost protection inlet temperature was invalid
DHW frost protection temperature was invalid
183
184
185
186
187
188
189
190
Lead Lag P-gain was invalid
Lead Lag I-gain was invalid
225-226 RESERVED
Lead Lag D-gain was invalid
227
DHW priority override time was not derated due to
invalid outdoor temperature
Lead Lag OFF hysteresis was invalid
Lead Lag ON hysteresis was invalid
Lead Lag slave enable was invalid
Lead Lag hysteresis step time was invalid
No Lead lag Modbus port was assigned
228
Warm weather shutdown was not checked due to
invalid outdoor temperature
229
230
Lead Lag slave communication timeout
RESERVED
71
CODE
231
DESCRIPTION
CODE
DESCRIPTION
Lead Lag CH setpoint was invalid
274
Abnormal Recycle: Demand off during Pilot Flame
Establishing Period
232
Lead Lag CH time of day setpoint was invalid
LL outdoor temperature was invalid
275
276
277
Abnormal Recycle: LCI off during Drive to Purge
233
Rate
234
Lead Lag ODR time of day setpoint was invalid
Abnormal Recycle: LCI off during Measured Purge
Time
235
Lead Lag ODR time of day setpoint exceeded
normal setpoint
Abnormal Recycle: LCI off during Drive to Lightoff
236
237
Lead Lag ODR max outdoor temperature was
invalid
Rate
278
279
280
Abnormal Recycle: LCI off during Pre-Ignition test
Abnormal Recycle: LCI off during Pre-Ignition time
Lead Lag ODR min outdoor temperature was
invalid
Abnormal Recycle: LCI off during Main Flame
Establishing Period
238
239
Lead Lag ODR low water temperature was invalid
Lead Lag ODR outdoor temperature range was
too small (minimum 12°C / 22°F)
281
282
Abnormal Recycle: LCI off during Ignition period
Abnormal Recycle: Demand off during Drive to
240
Lead Lag ODR water temperature range was too
small (minimum 12°C / 22°F)
Purge Rate
283
284
285
286
287
288
289
290
291
292
Abnormal Recycle: Demand off during Measured
Purge Time
241
242
243
244
245
246
247
248
249
250
Lead Lag DHW setpoint was invalid
Lead Lag Mix setpoint was invalid
Lead Lag CH demand switch was invalid
Lead Lag CH setpoint source was invalid
RESERVED
Abnormal Recycle: Demand off during Drive to
Lightoff Rate
Abnormal Recycle: Demand off during Pre-Ignition
test
Abnormal Recycle: Demand off during Pre-Ignition
time
CH setpoint was invalid
CH time of day setpoint was invalid
CH outdoor temperature was invalid
CH ODR time of day setpoint was invalid
Abnormal Recycle: Flame was on during Safe
Check
Abnormal Recycle: Flame was on during Drive to
Purge Rate
CH ODR time of day setpoint exceeds normal
setpoint
Abnormal Recycle: Flame was on during
Measured Purge Time
251
252
253
254
255
256
257
258
259
260
261
262
263
264
CH max outdoor setpoint was invalid
CH min outdoor setpoint was invalid
CH min water setpoint was invalid
CH outdoor temperature range was too small
CH water temperature range was too small
Steam setpoint was invalid
Abnormal Recycle: Flame was on during Drive to
Lightoff Rate
Abnormal Recycle: Flame was not on at end of
Ignition period
Abnormal Recycle: Flame was lost during Main
Flame Establishing Period
Steam time of day setpoint was invalid
Steam minimum pressure was invalid
CH ODR min water temperature was invalid
RESERVED
293
294
295
296
Abnormal Recycle: Flame was lost early in Run
Abnormal Recycle: Flame was lost during Run
Abnormal Recycle: Leakage test failed
Abnormal Recycle: Interrupted air flow switch was
off during Drive to Purge Rate
DHW setpoint was invalid
DHW time of day setpoint was invalid
DHW storage setpoint was invalid
297
298
299
300
301
302
303
Abnormal Recycle: Interrupted air flow switch was
off during Measured Purge Time
Abnormal Recycle: Interrupted air flow switch was
off during Drive to Lightoff Rate
STAT may not be a DHW demand source when
Remote Stat is enabled
Abnormal Recycle: Interrupted air flow switch was
off during Pre-Ignition test
265-266 RESERVED
267
STAT may not be a CH demand source when
Remote Stat is enabled
Abnormal Recycle: Interrupted air flow switch was
off during Pre-Ignition time
268
269
270
271
272
273
CH 4mA water temperature setting was invalid
CH 20mA water temperature setting was invalid
Steam 4mA water temperature setting was invalid
Steam 20mA water temperature setting was invalid
Abnormal Recycle: Pressure sensor fault
Abnormal Recycle: Safety relay drive test failed
Abnormal Recycle: Interrupted air flow switch was
off during Main Flame Establishing Period
Abnormal Recycle: Ignition failed due to
interrupted air flow switch was off
Abnormal Recycle: ILK off during Drive to Purge
Rate
72
CODE
DESCRIPTION
CODE
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
DESCRIPTION
304
Abnormal Recycle: ILK off during Measured Purge
Time
Abnormal Recycle: Hardware SLO electronics
Abnormal Recycle: Hardware processor clock
Abnormal Recycle: Hardware AC phase
Abnormal Recycle: Hardware A2D mismatch
Abnormal Recycle: Hardware VSNSR A2D
Abnormal Recycle: Hardware 28V A2D
Abnormal Recycle: Hardware HFS IAS shorted
Abnormal Recycle: Hardware PII INTLK shorted
Abnormal Recycle: Hardware HFS LCI shorted
Abnormal Recycle: Hardware HFS LFS shorted
Abnormal Recycle: Invalid zero crossing
Abnormal Recycle: fault stack sensor
Abnormal Recycle: stack limit
305
Abnormal Recycle: ILK off during Drive to Lightoff
Rate
306
307
308
Abnormal Recycle: ILK off during Pre-Ignition test
Abnormal Recycle: ILK off during Pre-Ignition time
Abnormal Recycle: ILK off during Main Flame
Establishing Period
309
310
311
Abnormal Recycle: ILK off during Ignition period
Run was terminated due to ILK was off
Run was terminated due to interrupted air flow
switch was off
312
313
314
Stuck reset switch
Run was terminated due to fan failure
Abnormal Recycle: Fan failed during Drive to
Abnormal Recycle: delta T limit
Purge Rate
Abnormal Recycle: fault outlet sensor
Abnormal Recycle: outlet high limit
315
316
317
318
319
320
321
322
323
Abnormal Recycle: Fan failed during Measured
Purge Time
Abnormal Recycle: fault DHW sensor
Abnormal Recycle: DHW high limit
Abnormal Recycle: Fan failed during Drive to
Lightoff Rate
Abnormal Recycle: fault inlet sensor
Abnormal Recycle: Check Parameters Failed
Internal Errors
Abnormal Recycle: Fan failed during Pre-Ignition
test
Abnormal Recycle: Fan failed during Pre-Ignition
time
361
Internal error: No factory parameters were
detected in control
Abnormal Recycle: Fan failed during Ignition
period
362
363
Internal error: PID iteration frequency was invalid
Abnormal Recycle: Fan failed during Main Flame
Establishing Period
Internal error: Demand-Rate interval time was
invalid
Abnormal Recycle: Main Valve off after 10
seconds of RUN
364
Internal error: Factory calibration parameter for
modulation was invalid
Abnormal Recycle: Pilot Valve off after 10 seconds
365
366
367
368
369
370
371
Internal error: CH PID P-scaler was invalid
Internal error: CH PID I-scaler was invalid
Internal error: CH PID D-scaler was invalid
Internal error: DHW PID P-scaler was invalid
Internal error: DHW PID I-scaler was invalid
Internal error: DHW PID D-scaler was invalid
of RUN
Abnormal Recycle: Safety Relay off after 10
seconds of RUN
324
325
326
327
328
329
330
330
332
Abnormal Recycle: Hardware flame bias
Abnormal Recycle: Hardware static flame
Abnormal Recycle: Hardware flame current invalid
Abnormal Recycle: Hardware flame rod short
Abnormal Recycle: Hardware invalid power
Abnormal Recycle: Hardware invalid AC line
Abnormal Recycle: Hardware SLO flame ripple
Abnormal Recycle: Hardware SLO flame sample
Internal error: Lead Lag master PID P-scaler was
invalid
372
373
Internal error: Lead Lag master PID I-scaler was
invalid
Internal error: Lead Lag master PID D-scaler was
invalid
Abnormal Recycle: Hardware SLO flame bias
374
375
376
377
378
Abnormal Recycle: Hardware flame bias high
Abnormal Recycle: Hardware flame bias low
Abnormal Recycle: Hardware flame bias delta high
Abnormal Recycle: Hardware flame bias delta low
range
333
334
335
336
337
338
339
340
Abnormal Recycle: Hardware SLO flame bias heat
Abnormal Recycle: Hardware SLO spark stuck
Abnormal Recycle: Hardware SLO spark changed
Abnormal Recycle: Hardware SLO static flame
Abnormal Recycle: Hardware SLO rod shorted
Abnormal Recycle: Hardware SLO AD linearity
Abnormal Recycle: Hardware SLO bias not set
Abnormal Recycle: Hardware SLO bias shorted
Abnormal Recycle: Hardware flame bias dynamic
high
379
Abnormal Recycle: Hardware flame bias dynamic
low
380
381
Abnormal Recycle: Fan Speed Not Proven
Abnormal Recycle: Fan Speed Range Low
73
CODE
DESCRIPTION
CODE
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
DESCRIPTION
382
Abnormal Recycle: Fan Speed Range High
Internal error: Safety key bit 4 was incorrect
Internal error: Safety key bit 5 was incorrect
Internal error: Safety key bit 6 was incorrect
Internal error: Safety key bit 7 was incorrect
Internal error: Safety key bit 8 was incorrect
Internal error: Safety key bit 9 was incorrect
Internal error: Safety key bit 10 was incorrect
Internal error: Safety key bit 11 was incorrect
Internal error: Safety key bit 12 was incorrect
Internal error: Safety key bit 13 was incorrect
Internal error: Safety key bit 14 was incorrect
Internal error: Safety key bit 15 was incorrect
Internal error: Safety relay timeout
383-450 RESERVED
Circulator Errors
451
452
453
454
455
456
457
458
459
Circulator control was invalid
Circulator P-gain was invalid
Circulator I-gain was invalid
Circulator temperature was invalid
Circulator outlet temperature was invalid
Circulator inlet temperature was invalid
Circulator outdoor temperature was invalid
Circulator sensor choice was invalid
Circulator PID setpoint was invalid
Debug Faults
460
461
LCI lost in run
Internal error: Safety relay commanded off
Internal error: Unknown safety error occurred
Internal error: Safety timer was corrupt
Internal error: Safety timer was expired
Internal error: Safety timings
Abnormal Recycle: Demand lost in run from
application
462
463
464
465
466
Abnormal Recycle: Demand lost in run due to high
limit
Abnormal Recycle: Demand lost in run due to no
flame
Internal error: Safety shutdown
RESERVED
LCI lost in Combustion Pressure Establishing
Period
MIX Errors
LCI lost in Combustion Pressure Stabilization
Period
502
503
504
505
506
Mix setpoint was invalid
Mix time of day setpoint was invalid
Mix outdoor temperature was invalid
Mix ODR time of day setpoint was invalid
RESERVED
Internal Data Faults
467
468
469
470
471
472
Internal error: EEPROM write was attempted
before EEPROM was initialized
Mix ODR time of day setpoint exceeds normal
setpoint
Internal error: EEPROM cycle count address was
invalid
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
Mix ODR max outdoor temperature was invalid
Mix ODR min outdoor temperature was invalid
Mix ODR low water temperature was invalid
Mix ODR outdoor temperature range was invalid
Mix ODR water temperature range was invalid
Mix demand switch was invalid
Internal error: EEPROM days count address was
invalid
Internal error: EEPROM hours count address was
invalid
Internal error: Lockout record EEPROM index was
invalid
Mix ON hysteresis was invalid
Internal error: Request to write PM status was
invalid
Mix OFF hysteresis was invalid
Mix ODR min water temperature was invalid
Mix hysteresis step time was invalid
Mix P-gain was invalid
473
474
Internal error: PM parameter address was invalid
Internal error: PM safety parameter address was
invalid
Mix I-gain was invalid
475
Internal error: Invalid record in lockout history was
removed
Mix D-gain was invalid
476
477
Internal error: EEPROM write buffer was full
Mix control was suspended due to fault
Mix S10 (J10-7) temperature was invalid
Mix outlet temperature was invalid
Mix inlet temperature was invalid
Internal error: Data too large was not written to
EEPROM
478
479
480
481
Internal error: Safety key bit 0 was incorrect
Internal error: Safety key bit 1 was incorrect
Internal error: Safety key bit 2 was incorrect
Internal error: Safety key bit 3 was incorrect
Mix S5 (J8-11) temperature was invalid
Mix modulation sensor type was invalid
Mix ODR min water temperature setpoint was
invalid
74
CODE
527
DESCRIPTION
Mix circulator sensor was invalid
Mix flow control was invalid
Mix temperature was invalid
Mix sensor was invalid
CODE
571
DESCRIPTION
Heat exchanger high limit response was invalid
Heat exchanger high limit was exceeded
528
572
529
573
Heat exchanger high limit wasn't allowed due to
stack limit setting
530
574
575
Heat exchanger high limit wasn't allowed due to
stack connector setting
531
Mix PID setpoint was invalid
532
STAT may not be a Mix demand source when
Remote Stat is enabled
Heat exchanger high limit delay was not
configured for recycle response
533-539 RESERVED
Pump Errors
540
541
542
543
544
545
546
547
548
549
Delta T inlet/outlet enable was invalid
576
577
578
579
580
581
CH pump output was invalid
DHW pump output was invalid
Boiler pump output was invalid
Auxiliary pump output was invalid
System pump output was invalid
Mix pump output was invalid
Delta T exchanger/outlet enable was invalid
Delta T inlet/exchanger enable was invalid
Delta T inlet/outlet degrees was out of range
Delta T exchanger/outlet degrees was out of range
Delta T inlet/exchanger degrees was out of range
Delta T response was invalid
582-589 RESERVED
DHW Plate Heat Exchanger Errors
Delta T inversion limit response was invalid
Delta T rate limit enable was invalid
590
591
592
593
594
595
596
597
598
599
DHW plate preheat setpoint was invalid
Delta T exchanger/outlet wasn't allowed due to
stack limit setting
DHW plate preheat ON hysteresis was invalid
DHW plate preheat OFF hysteresis was invalid
Tap detect degrees was out of range
550
551
552
553
554
555
556
Delta T inlet/outlet limit was exceeded
Delta T exchanger/outlet limit was exceeded
Delta T inlet/exchanger limit was exceeded
Inlet/outlet inversion occurred
Tap detect ON hysteresis was invalid
Inlet - DHW tap stop degrees was out of range
Outlet - Inlet tap stop degrees was out of range
DHW tap detect on threshold was invalid
DHW plate preheat detect on threshold was invalid
DHW plate preheat detect off threshold was invalid
Exchanger/outlet inversion occurred
Inlet/exchanger inversion occurred
Delta T exchanger/outlet wasn't allowed due to
stack connector setting
557
558
559
Delta T inlet/exchanger wasn't allowed due to
stack limit setting
Delta T inlet/exchanger wasn't allowed due to
stack connector setting
Delta T delay was not configured for recycle
response
T Rise Errors
560
561
562
563
564
565
566
Outlet T-rise enable was invalid
Heat exchanger T-rise enable was invalid
T-rise degrees was out of range
T-rise response was invalid
Outlet T-rise limit was exceeded
Heat exchanger T-rise limit was exceeded
Heat exchanger T-rise wasn't allowed due to stack
limit setting
567
568
569
Heat exchanger T-rise wasn't allowed due to stack
connector setting
Outlet T-rise wasn't allowed due to outlet
connector setting
T-rise delay was not configured for recycle
response
Heat Exchanger High Limit Errors
570
Heat exchanger high limit setpoint was out of
range
75
MAINTENANCE PROCEDURES
MAINTENANCE SCHEDULES
INSPECT BOILER AREA
Yearly procedures for Service Technician:
• Check for reported problems.
1. Verify that boiler area is free of any combustible materials,
gasoline and other flammable vapors and liquids.
2. Verify that air intake area is free of any of the contaminants.
If any of these are present in the boiler intake air vicinity,
they must be removed. If they cannot be removed, reinstall
the air and vent lines per this manual.
• Check the interior; clean and vacuum if needed.
• Clean the condensate trap and fill with fresh water.
• Check for water/gas/flue/ condensate leaks.
• Ensure flue and air lines in good condition and sealed
tight
Inspect boiler interior:
1. Remove the front access cover and inspect the interior of
• Check system water pressure/system piping/expansion
tank
the boiler.
2. Vacuumanysedimentfrominsidetheboilerandcomponents.
• Check control settings.
Remove any obstructions.
• Check spark igniter and flame sensors. Clear and clean
any deposits.
GENERAL MAINTENANCE
This is a pre-mix burner system. The flame is not supposed to be
directly on the burner. The flame should be just above the burner
deck approximately 1/8” and blue in color, see Figure 77.
• Check wiring and connections.
• Perform start-up checkout and performance verification.
• Flame inspection (stable, uniform)
• Flame signal (at least 10 microamps at high fire)
• Clean the heat exchanger if flue temperature is more
than 54°F (30°C) above return water temperature.
• Test low water flow conditions.
• Clean the heat exchanger.
• Remove and clean burner using compressed air.
Maintenance by Owner:
Daily:
• Check boiler area .
• Check pressure/temperature gauge.
Monthly:
FIGURE 77. BURNER FLAMES
Visually check flame characteristics through the view port located
condition.
• Check vent piping.
• Check air intake piping (Direct Vent).
• Check air and vent termination screens.
• Check relief valve.
These boilers are designed to give many years of efficient and
satisfactory service when properly operated and maintained.
To assure continued good performance, the following
recommendations are made.
• Check condensate drain system.
• Check automatic air vents .
Every 6 months:
The area around the unit should be kept clean and free from lint
and debris. Sweeping the floor around the boiler should be done
carefully. This will reduce the dust and dirt which may enter the
burner and heat exchanger, causing improper combustion and
sooting.
• Check boiler piping (gas and water) for leaks.
• Check and operate the pressure relief valve.
End of season months:
MAIN BURNER
• Shut the boiler down (unless boiler used for domestic hot
water)
Check main burner every three months for proper flame
characteristics. The main burner should display the following
characteristics:
Make sure the maintenance of the boiler must be performed to
assure maximum boiler efficiency and reliability. Failure to service
and maintain the boiler and system could result in equipment
failure.
• Provide complete combustion of gas.
• Cause rapid ignition and carry over of flame across entire burner.
Make sure to turn off power to the boiler before any service
operation on the boiler except as noted otherwise in this
instruction manual. Failure to turn off electrical power could result
in electrical shock, causing severe personal injury or death.
• Give reasonably quiet operation during initial ignition, operation
and extinction.
• Cause no excessive lifting of flame from burner ports.
76
If the preceding burner characteristics are not evident, check for 5. Loosen the seven bolts on the blower adapter at the base
accumulation of lint or other foreign material that restricts or blocks
the air openings to the burner or boiler. To check burners:
and move the burner ground wire (Green) aside.
6. Lift the blower adapter and remove the manifold assembly
up from the 6 studs located on the cover plate and remove
the burner gasket.
1. Shut off all gas and electricity to unit. Allow unit to cool.
2. Remove main burners from unit.
7. Remove any loose foreign material such as dust or lint with a
vacuum. Check all ports for blockage. Dislodge any foreign
material causing blockage. Remove any soot or carbon
deposits with a rag making sure to remove any lint left on
the burner by vacuuming again.
3. Check that burner ports are free of foreign matter.
4. Clean burner with vacuum cleaner. Do not distort burner
ports.
5. Reinstall burners in unit. Ensure that all the screws on the
burner flange are tightened securely so that the gasket will
provide a good seal.
8. Reverse the steps to reassemble the unit.
9. Restore electrical power and gas supply to the boiler.
6. Also check for good flow of combustion and ventilating air
• Put the boiler back in operation by following the Lighting
and Operating instructions in this manual.
to the unit.
After placing the boiler in operation, check the ignition system
safety shut-off devices for proper operation. To accomplish this
with the main burner operating, close the valve on the manifold.
Within four seconds the main burners should extinguish. If this
does not occur immediately, discontinue gas supply by closing
main manual shut-off and call a qualified serviceman to correct
the situation. If the burners extinguish, then light boiler in
accordance with lighting and operating instructions.
• Check for gas leaks and proper boiler and vent
operation.
PRESSURE RELIEF VALVE
The pressure relief valve should be opened at least twice a year
to check its working condition. This will aid in assuring proper
pressure relief protection. Lift the lever at the top of the valve
several times until the valve seats properly and operates freely.
Any safety devices including low water cutoffs used in conjunction
with this boiler should receive periodic (every six months)
inspection to assure proper operation. A low water cutoff device
of the float type should be flushed every six months. Periodic
checks, at least twice a year, should be made for water leaks.
More frequent inspections may be necessary depending on
water conditions.
The boiler-mounted gas and electrical controls have been
designed to give both dependable service and long life.
However, malfunction can occur, as with any piece of equipment.
It is therefore recommended that all components be checked
periodically by a qualified serviceman for proper operation.
BLOWER COMPARTMENT
The blower compartment should be cleaned annually to remove
any dirt and lint that may have accumulated in the compartment
or on the blower and motor. Buildups of dirt and lint on the
blower and motor can create excessive loads on the motor
resulting in higher that normal operating temperatures and
possible shortened service life.
BURNER MAINTENANCE
Qualified service agent should follow this procedure when the
boiler’s burner needs cleaning.
1. Turn off the electrical power to the boiler and close the main
manual gas shutoff valve(s). Allow the boiler parts to cool
before disassembly.
AIR FILTER BOX
2. Loosen the flange and separate the gas train from the
manifold assembly.
The air filter box should be cleaned every three months to remove
any dust and debris that may have accumulated in the air filter
or the filter housing. Buildups of dust on the air filter can block
the air intake into the boiler. Air filter can washed and cleaned
with water.
3. Separate the burner from the blower adapter by first
removing the four (4) bolts and subsequently, the blower
gaskets. The blower should be free to move at this point.
4. For Direct Vent units: It is necessary to loosen and slide
the rubber coupling on the blower adaptor in order to
move the blower.
77
CONDENSATE REMOVAL SYSTEM
1. Turn off the electrical power, and manual gas shut-off.
• Allow boiler parts to cool before disassembly.
Due to the highly efficient operation of this unit, condensate
is formed during operation and must be removed by the
condensate drain systems. Inspect the condensate drains
and tubes at least once a month and insure they will allow
the free flow of condensate at all times. The system must
be inspected more frequently in cold weather if the drain
system is located in an area, such as along the floor, where
freezing temperatures are likely to occur. The condensate
drain system must be protected against freezing. Contact a
qualified service agent to inspect and correct the condition if
freezing of the condensate lines is a problem.
2. Remove the vent pipe.
• Check parts and chimney for obstructions and clean as
necessary.
3. Remove burner from boiler and other metal parts as required
to clean as necessary.
• Refer to parts list for disassembly aid.
4. Clean and reinstall the parts removed in steps 2 and 3.
• Be sure the vent pipe has a minimum upward pitch of 1/4"
per foot (2 cm/m) of length and is sealed as necessary.
The transparent drain lines and condensate drain on the bottom
of the vent collector should be visually inspected at one month
intervals for blockage, particularly in the areas of the loops in the
lines which trap a small amount of condensate, and the exit point
of the vent collector drain. Condensate in portions of the line
other than the loop area indicates a blockage in the drain line.
Flush the lines with air or water and clear or replace the blocked
portions of the line as necessary. Note that areas of the drain
line which include a sag or low spot in the line will also form a
condensate trap which can be removed by levelling the tube and
does not indicate a blocked system.
5. Restore electrical power and gas supply to boiler.
• Check for gas leaks and proper boiler and vent operation.
HEAT EXCHANGER MAINTENANCE
1. Shut down the boiler:
• Turn Off gas to the boiler.
• Do not drain the boiler unless it will be exposed to
freezing temperatures. If using freeze prevention fluid in
system, do not drain.
Inspect the metal vent drain and vent collector drain connectors
at six month intervals. Remove the hoses from the connections,
then check with a small wooden dowel or plastic rod passed
up through the metal connection to insure the passage is clear,
using caution to not bend or damage the connector. Call a
qualified service agent to inspect and correct the problem if any
obstructions are found in the connectors. Replace all hoses and
clamps immediately after inspection and before starting the boiler
in accordance with the Lighting and Operating Instructions. Do not
operate the boiler unless all condensate drain lines are properly
connected and working. When a means to neutralize condensate
has been installed you must also follow operating, inspection and
maintenance procedures specified by the manufacturer of the
product. Inspect the installed device to insure that it does not
cause condensate to remain in the boiler or vent for any reason.
2. Ensure the boiler cools down to room temperature.
3. Remove the nuts securing the heat exchanger access cover
to the heat exchanger and set aside.
4. Remove the heat exchanger access cover, burner, and gas
train assembly.
Note: The boiler contains ceramic fiber materials. Failure to
comply could result in severe personal injury.
5. Remove the condensate hose from the heat exchanger end.
Connect a field supplied 3/4" diameter hose to a drain pan.
6. Use a vacuum cleaner to remove any deposits/ debris on the
boiler heating surfaces. Do not use any solvent.
7. Brush the heat exchanger while dry using a nylon bristle
brush. Re-vacuum the heat exchanger.
8. Finish cleaning using a clean cloth dampened with warm
VENTING MAINTENANCE
water. Rinse out debris with a low pressure water supply.
9. Allow the heat exchanger to dry completely.
It is recommended that the intake and exhaust piping of the
boiler be checked every 6 months for dust, condensate leakage, 10. Remove the rear refractory cover from the back of the
deterioration and carbon deposits.
combustion chamber of the heat exchanger and reassemble.
11. Close isolation valves on piping to isolate the boiler from
system. Attach a hose to the boiler drain and flush boiler
thoroughly with clean water by using purging valves to allow
water to flow through the water make-up line to the boiler.
12. Replace the access cover and restore the boiler for operation.
Qualified service agent should follow this procedure when the
boiler’s intake and exhaust piping need cleaning:
78
HANDLING CERAMIC FIBER MATERIALS
Removal of combustion chamber lining:
The combustion chamber insulation in this boiler contains ceramic
fiber material. Ceramic fibers can be converted to cristobalite in
very high temperature applications. The International Agency for
Research on Cancer (IARC) has concluded, “Crystalline silica
in the form of quartz or cristobalite from occupational sources
is carcinogenic to humans (Group 1).” Normal operating
temperatures in this boiler are below the level to convert ceramic
fibers to cristobalite.
The ceramic fiber material used in this boiler is an irritant; hence
when handling or replacing the ceramic materials it is advisable
that the installer follow these safety guidelines.
1. Avoid breathing dust and contact with skin and eyes.
• Use NIOSH certified dust respirator (N95). This type
of respirator is based on the OSHA requirements for
cristobalite at the time this document was written. Other
types of respirators may be needed depending on the
job site conditions. Current NIOSH recommendations
gov/niosh/homepage.html. NIOSH approved respirators,
manufacturers, and phone numbers are also listed on
this website.
• Wear long-sleeved, loose fitting clothing, gloves, and eye
protection.
2. Apply enough water to the combustion chamber lining to
prevent airborne dust.
3. Remove the combustion chamber lining from the boiler and
place it in a plastic bag for disposal.
4. Wash potentially contaminated clothes separately from
other clothing. Rinse clothes washer thoroughly.
NIOSH stated First Aid:
• Eye: Irrigate immediately.
• Breathing: Fresh air.
REPLACEMENT PARTS
Replacement parts may be ordered through A. O. Smith dealers,
authorized servicers or distributors. Refer to the Yellow Pages
for where to call or contact (in United States) the A. O. Smith
Water Products Company, 500 Tennessee Waltz Parkway,
Ashland City, TN 37015, 1-800-433-2545 or (in Canada) A.
O. Smith Enterprises Ltd., 599 Hill Street West, Fergus, ON
N1M2X1, 1-888-479-2837. When ordering parts be sure to state
the quantity, part number and description of the item including the
complete model and serial number as it appears on the product.
Refer to the parts list for more information.
For Technical Assistance call A. O. Smith Technical Information
Center at 1-800-527-1953.
79
LIMITED WARRANTY
A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this boiler:
1. If within TEN years after initial installation of the boiler, a heat exchanger or gas burner should prove upon examination by the warrantor to be defective in
material or workmanship, the warrantor, at his option will exchange or repair such part or portion. This term is reduced to FIVE years if this boiler is used
for water heating purposes other than hydronic space heating.
a. This warranty is extended to the owner for all other parts or portion during the FIRST year following initial installation of this boiler.
b. The warranty on the repair or replacement of the part or portion will be limited to the unexpired term of the original warranty.
2. CONDITIONS AND EXCEPTIONS
This warranty should apply only when the boiler is installed in accordance with local plumbing and building codes, ordinances and regulations, the printed
instructions provided with it and good industry practices. In addition, a pressure relief valve, certified by C.S.A. and approved by the American Society of
Mechanical Engineers, must have been installed and fresh water used for filling and make-up purposes.
a. This warranty should apply only when the boiler is used:
(1) with outlet water temperatures not exceeding the maximum setting of its operative and/or high limit control;
(2) at water pressure not exceeding the working pressure shown on the boiler;
(3) when filled with boiler water, free to circulate at all times and with the heat exchanger free of damaging scale deposits;
(4) in a non-corrosive and non-contaminated atmosphere;
(5) in the United States, its territories or possessions, and Canada;
(6) at a water velocity flow rate not exceeding or below the boiler’s designed rates;
(7) indoor installation only.
b. Any accident to the boiler, any misuse, abuse (including freezing) or alteration of it, any operation of it in a modified form, or any attempt to repair leaks
in the heat exchanger will void this warranty.
3. SERVICE AND REPAIR EXPENSE
Under this limited warranty the warrantor will provide only a replacement part. The owner is responsible for all other costs. Such costs may include but are
not limited to:
a. Labor charges for service, removal, repair, or reinstallation of the component part;
b. Shipping, delivery, handling, and administrative charges for forwarding the replacement part from the nearest distributor and returning the claimed defec-
tive part to such distributor.
c. All cost necessary or incidental for any material and/or permits required for installation of the replacement.
4. LIMITATIONS ON IMPLIED WARRANTIES
Implied warranties, including any warranty of merchantability imposed on the sale of this boiler under state or provincial law are limited to one (1) year
duration for the boiler or any of its parts. Some states and provinces do not allow limitations on how long an implied warranty lasts, so the above limitation
may not apply to you.
5. CLAIM PROCEDURE
Any claim under this warranty should be initiated with the dealer who sold the boiler, or with any other dealer handling the warrantor’s products. If this is
not practicable, the owner should contact:
U.S. Customers
Canadian Customers
A. O. Smith Corporation
500 Tennessee Waltz Parkway
Ashland City, TN 37015
Telephone: 800-527-1953
A. O. Smith Enterprises Ltd.
599 Hill Street West
Fergus, ON N1M 2X1
Telephone: 1-888-479-2837
a. The warrantor will only honor replacement with identical or similar parts thereof which are manufactured or distributed by the warrantor.
b. Dealer replacements are made subject to in-warranty validation by warrantor.
6. DISCLAIMERS
NO OTHER EXPRESS WARRANTY HAS BEEN OR WILLBE MADE ON BEHALF OF THE WARRANTOR WITH RESPECTTO THE MERCHANTABILITY OF
THE BOILER OR THE INSTALLATION, OPERATION, REPAIR OR REPLACEMENT OF THE BOILER. THE WARRANTOR Should NOT BE RESPONSIBLE
FOR WATER DAMAGE, LOSS OF USE OF THE UNIT, INCONVENIENCE, LOSS OR DAMAGE TO PERSONALPROPERTY, OR OTHER CONSEQUENTIAL
DAMAGE. THE WARRANTOR Should NOT BE LIABLE BY VIRTUE OF THIS WARRANTY OR OTHERWISE FOR DAMAGE TO ANY PERSONS OR
PROPERTY, WHETHER DIRECT OR INDIRECT, AND WHETHER ARISING IN CONTRACT OR TORT.
a. Some states and provinces do not allow the exclusion or limitation of the incidental or consequential damage, so the above limitations or exclusions may
not apply to you.
b. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state or province to province.
Fill in the following for your own reference. Keep it. Registration is not a condition of warranty. The model and serial number are found on the boiler’s rating plate.
Owner______________________________________________________________________________________________________________________________________
InstallationAddress_________________________________________________________________________________________________________________________
City and State__________________________________________________________________________________ Zip Code __________________________________
Date Installed____________________ Model No. __________________________________________Serial No. ___________________________________________
Dealer’s Name___________________________________________________________________________ Phone No._______________________________________
Dealer’s Address ________________________________________________________________________________________________________________________
______________________________________________________________________________________________________________________________________
FILL IN WARRANTY AND KEEP FOR FUTURE REFERENCE
82
25589 Highway 1, McBee, SC 29101
Technical Support: 800-527-1953 • Parts: 800-433-2545 • Fax: 800-644-9306
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