GAS-FIRED COMMERCIAL
COPPER BOILERS
FOR HYDRONIC HEATING
AND HOT WATER SUPPLY
GB/GW-200, -300, -400, -500, -650, -750
USER'S INFORMATION MANUAL
SERIES 200, 201, 202, 203
LIGHTING INSTRUCTIONS
These models have an automatic hot surface ignition system
mounted on the combustion chamber panel inside the front jacket.
This hot surface igniter ignites the main burner gas whenever the
system control calls for heat.
Before proceeding with operation of the unit, make sure the boiler
and system are filled with water and all air is expelled from the boiler,
radiator tank(s) and piping.
WARNING: If the information in this
manual is not followed exactly, a fire
or explosion may result causing
property damage, personal injury or
loss of life.
WARNING
THE MAIN MANUAL GAS SHUT-OFF VALVE MUST HAVE BEEN
CLOSED FOR AT LEAST FIVE (5) MINUTES BEFORE
LIGHTING. This waiting period is an important safety step.
Its purpose is to permit gas that might have accumulated in
the combustion chamber to clear. IF YOU DETECT GAS AT
THE END OF THE PERIOD DO NOT PROCEED WITH
LIGHTING. RECOGNIZE THAT GAS ODOR, EVEN IF IT SEEMS
WEAK, MAY INDICATE PRESENCE OF ACCUMULATED GAS
SOMEPLACE IN THE AREA WITH A RISK OF FIRE OR
EXPLOSION.
• 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
• Extinguish any open flame.
• Do not try to light any appliance.
WARNING
THERE IS A RISK IN USING FUEL BURNING APPLIANCES SUCH
AS GAS WATER BOILERS IN ROOMS, GARAGES OR OTHER
AREAS WHERE GASOLINE AND OTHER FLAMMABLE LIQUIDS
ARE USED OR STORED, OR ENGINE-DRIVEN EQUIPMENT OR
VEHICLES ARE STORED, OPERATED OR REPAIRED.
FLAMMABLE VAPORS ARE HEAVY AND TRAVEL ALONG THE
FLOOR AND MAY BE IGNITED BY THE BOILER'S MAIN BURNER
FLAMES CAUSING FIRE OR EXPLOSION. Some local codes
permit operation of gas appliances if installed 18 inches or more
above the floor. This may reduce the risk if location in such an
area cannot be avoided.
• 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
INDEX
PAGE
supplier, call the fire department.
GENERAL . . . . . . . . . . . . . . . . . . . . . . .
LIGHTING INSTRUCTIONS . . . . . . . .
OPERATING SEQUENCE,
IGNITION CONTROL AND DIA-SCAN II
INSTRUCTIONS. . . . . . . . . . . . . .
MAINTENANCE . . . . . . . . . . . . . .
CONNECTION DIAGRAM
1
2 - 3
• Installation and service must be
performed by a qualified installer,
service agency or the gas
supplier.
4 - 8
8
9
WARNING
WARRANTY. . . . . . . . . . . . . . . . . . . . . .
10
Should overheating occur or the gas supply fail to shut off, do
not turn off or disconnect the electrical supply to the pump.
Instead, shut off the gas supply at a location external to the
appliance.
WARNING
A DIVISION OF A.O. SMITH CORPORATION
EL PASO, TX MC BEE, SC RENTON, WA
STRATFORD, ONTARIO
Do not use this boiler if any part has been under water.
Immediately call a qualified service technician to inspect the
boiler and to replace any part of the control system and any
gas control which has been under water.
VELDHOVEN, THE NETHERLANDS
PLEASEKEEPTHESEINSTRUCTIONSADJACENTTOBOILERAND
NOTIFYOWNERTOKEEPFORFUTUREREFERENCE.
PART NO. 210890-000 REV. 1
PRINTED IN U.S.A. 2527 300
SUPERSEDES PART NO. 210311-000
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THE UNIT SHOULD NOT BE INSTALLED DIRECTLY ON A BE PLACED ON OR ADJACENT TO THE BOILER. OPEN
CARPETED FLOOR. A FIRE HAZARD MAY RESULT. Instead, CONTAINERS OF FLAMMABLE MATERIAL SHOULD NOT BE
the boiler must be installed on the A. O. Smith Combustible Floor STORED OR USED IN THE SAME ROOM WITH THE BOILER.
Kit Base or concrete blocks extending beyond the full width and
depth of the boiler by at least 3 (76.2mm) inches. If the boiler is Light the unit in accordance with the instructions on the lighting and
installed in a carpeted alcove, the entire floor must be covered with operating label attached to the boiler. These instructions are
concrete blocks, or use the A. O. Smith Combustible Floor Kit Base. repeated on the following two pages.
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST NEVER
Lighting Instructions for the G(B/W) 200 through 500 models
2
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Lighting Instructions for the G(B/W) 650 and 750 models
3
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ELECTRONIC HOT SURFACE
IGNITION CONTROL BOARD
8.
9.
If a flame is confirmed, the control will enter the heating
mode where it will continue heating until the set-point tem-
perature is reached, and the thermostat circuit opens. At
that point, the gas valve is closed and the control enters
the post-purge and post-circulating cycles.
The combustion blower will run for a 25 second post purge
cycle. When the post purge cycle is complete, the blower
is de-energized and will coast to a stop. The circulating
pump will continue with the post-circulate cycle for the
selected amount of time, factory default is 45 seconds.
See circulating pump adjustment procedure on page 5
and 6 of this manual.
The control now enters the idle state while continuing to
monitor temperature and the state of other system de-
vices. If the outlet temperature drops below the set-point
value minus the switching differential, and the thermostat
circuit or tank probe circuit closes, the control will auto-
matically return to step 2 and repeat the entire operating
cycle. During this idle state, if the control detects an im-
proper operating state for external devices such as the
ECO switch, air pressure switch, gas pressure switch,
etc., the appropriate LED(s) on the Display Board will illu-
minate indicating the nature of the fault.
ALL MODELS - The WHC1502 ignition control board is a fully
integrated, state of the art electronic control system. The ignition
control board includes a microprocessor, which governs all
temperature and ignition control functions for the appliance. Inherent
in the design are the normal operating sequences and safety features
associated with a gas ignition control system. The ignition control
continuously performs various diagnostic tests to verify proper
appliance and control operation. Should an unsafe condition occur,
the control will shut down the burner and illuminate the appropriate
diagnostic indicators on the Display Board, indicating a need for
service. All operating programs are stored in permanent memory
on the ignition control and a second programmable memory is used
for retaining user-specific operating parameters in the event main
power is ever interrupted.
10.
Line Polarity Indicator
A green LED is mounted on the ignition control to indicate line volt-
age polarity is properly connected. When 120 VAC input power is
properly connected to the Ignition Control Board, the green LED will
illuminate. If an error is made when connecting 120 VAC input
power, this LED will not light. Improperly connecting the input power
may result in a false flame sensor failure.
DIA-SCAN II DISPLAY BOARD OPERATING PROCEDURES
Fuse Protection
The Display Board provides a user-friendly interface to the
WHC1502 Ignition Control Board. With the Display Board, the
user can control appliance functions and view the overall oper-
ating status of the appliance. If an error condition occurs, the
Display Board will scroll a message across the LED display,
indicating the error code. Under normal operating conditions,
the four digit LED display on the Display Board will continuously
illustrate the water temperature sensed at temperature probe
#1 (Outlet). The push buttons on the Display Board allow the
user to program and view the desired water temperature set
point. The Display Board is connected to the Ignition Control
Board through a 6 conductor cable assembly with modular plug
terminations. In addition, an 8 conductor modular jack on the
Display Board allows for connecting a remote display board.
The 24 VAC circuitry is protected with a 3 amp auto fuse. If the fuse
opens, a red LED located near the fuse will light. If the red LED is
illuminated, replace the fuse (recommended replacement part is
Little fuse p/n 257003 automotive fuse). Repeated failure of the
fuse is an indication of possible damage to the ignition con-
trol board.
NOTE: One extra fuse is supplied with the boiler.
Typical Control/Appliance Operating Sequence
1.
When power is applied to the WHC1502 ignition control,
the Display board will initially run through a self-diagnostic
routine, and then go into its operating mode, displaying
the temperature sensed at temperature probe #1 (Out-
let).
When power is applied to the WHC1502 System, the Display Board
will initially run through a self-diagnostic test, and then display the
Outlet temperature. To display a specific setting or temperature,
press the SELECT push-button until the appropriate LED is illumi-
nated (see figure 1). After 5 seconds, the Display Board will auto-
matically revert to displaying the Outlet temperature. Pressing the
ENTER/RESET push-button will hold the display in the indicated
mode until the SELECT push-button is pressed.
2.
If the ignition control board determines the actual outlet
water temperature at the temperature sensing probe
(probe #1) is below the programmed temperature set-point
less the switching differential, and the thermostat circuit
or tank probe circuit closes, call for heat is activated.
The ignition control board then performs selected system
diagnostic checks. This includes confirming the proper
state of the ECO/High Limit device, flow switch, and pres-
sure switches.
3.
4.
With the Display Board, the user can make adjustments to many of
the appliance’s control features. This includes the following:
If all checks are successfully passed, the circulating pump
circuit is energized, then the combustion blower is ener-
gized for the 20 second pre-purge cycle.
Options/Features Setting Procedures
5.
6.
When the pre-purge cycle is complete, the ignitor is ener-
gized. The pump and blower should continue to run.
The ignition control board will verify ignitor current. After
the verification, the gas valve will open, allowing gas to
enter the burner.
After an additional 1 second, the ignition control board will
monitor the flame sense probe to confirm a flame is
present. If a flame is not verified within 4 seconds, the gas
valve is immediately closed, and the ignition control board
will return to step 2, unless jumper J30 is in place (ON),
see figure 2.
•
•
•
•
•
•
Set Appliance Temperature Set-point Value
Set Appliance Switching Differential Value
Select Appliance Post-Circulate Time
7.
Set Appliance Circulating Pump to Continuous ON Mode
Check Appliance Cycle Count
Control the water temperature in a storage tank
4
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NOTE: The boiler must complete a full cycle in order for the
new setting to take effect. If the unit is turned off
prior to a complete cycle the setting will be lost and
the previous setting will remain in effect.
If the ADJUST push-button is held down long enough, the set-point
will reach 110°F, the minimum value (or 240°F, the maximum value)
and stop. At this point, if the desired set-point is not obtained, re-
lease the ADJUST push-button and depress it again. The set-point
value will now restart at 110°F (240°F) and once again increase
(decrease) in value for as long as the ADJUST push-button is
pressed.
Switching Differential Adjustment Procedure
Figure 1. Dia-Scan II Display Board.
To facilitate proper operation and maximize appliance performance,
the control has a programmable operating switching differential or
"hysteresis" about the set point. This means a call for heat will
become active when the water temperature measured at the outlet
temperature sensing probe (Probe #1) drops to the set-point value
minus the switching differential value. The burner will remain on
until the water temperature measured at probe #1 reaches the set-
point value. The switching differential value is fully programmable
from 5°F to 50°F using the push-button(s) located on the Display
Board. The default is set at 20°F.
Green Status Lights
LED 1: Call for Heat
LED 2: Flow Switch
LED 3: Pressure Switch
LED 4: Ignitor Current
LED 5: Gas Valve
LED 6: Flame Sense
Red Fault Lights
LED 7: Ignition Fail
LED 8: Circulate Failure
LED 9: Blower Failure
LED 10: Blocked Inlet
To change or view the current programmed switching differential:
LED 11: Blocked Flue
1. Press the SELECT push-button on the display board until
the Set-Pt differential LED (LED 16, see figure 1) is illumi-
nated.
Water Temperature Set Lights
LED 12: Inlet Water Temperature *
LED 13: Outlet Water Temperature
LED 14: Inlet/Outlet Differential Temperature
LED 15: Set-Point Temperature
LED 16: Outlet/Set-Point Differential Temperature
* Defaults to tank probe temperature when tank probe is used.
2. The LED display will show the current switching differential.
3. Press and hold the ADJUST push-button. The displayed value
will either increase or decrease. To alternate between increas-
ing or decreasing the switching differential, release then press
and hold the ADJUST push-button.
Temperature Set-point Adjustment Procedure
The control board has a standard programmable temperature set-
point range of 110°F to 240°F. The user can easily change the
temperature set-point at any time by using the following procedure.
In all cases, the boiler must be energized. The factory default set-
ting is 180°F.
4. When the desired switching differential is reached, release
the ADJUST push-button.
5. Press the ENTER/RESET push-button once, this enters the
selected switching differential value into controller memory.
To change or view the current programmed temperature set-point
value:
6. The appliance will now control temperature utilizing the de-
sired switching differential value.
1. Press the SELECT push-button on the display board until both
the Set-Pt LED (LED 15, see figure 1) and Outlet Water Tem-
perature LED (LED 13, see figure 1) are illuminated.
If the ADJUST push-button is held down long enough, the switching
differential setting will reach 5, the minimum value (or 50, the maxi-
mum value) and stop. At this point, if the desired switching differen-
tial is not obtained, release the ADJUST push-button and depress it
again. The switching differential value will now restart at 5 (50) and
once again increase (decrease) in value for as long as the ADJUST
push-button is pressed.
2. The LED display will show the current set-point temperature.
3. Press and hold the ADJUST push-button. The displayed tem-
perature will either increase or decrease. To alternate between
increasing or decreasing the temperature, release then press
and hold the ADJUST push-button.
Circulating Pump Adjustment Procedure
4. When the desired set-point temperature is reached, release
the ADJUST push-button.
The Controller is factory set with a 45 second post circulate func-
tion. Using the Display Board, the user has the capability to choose
between a 45, 90, or 180 second post circulate time period, or turn
the pump on continuously. This provides flexibility in selecting the
post circulate time to meet specific application requirements, and
improves the efficiency of the circulating pump operation.
5. Press the ENTER/RESET push-button once, this enters the
selected set-point temperature into controller memory.
6. The appliance will now control the temperature to the desired
set-point value.
5
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To change or view the current programmed post-circulating time:
3. The display will illustrate Circ. Press the SELECT push-but-
ton until the display illustrates Count. Enter this mode by press-
ing the ENTER/RESET push-button.
4. The display will now illustrate the current number of cycles the
appliance has cycled through.
1. Press the SELECT push-button on the display board until the
LED display reads OPt (Options).
2. To enter into the options mode, press the ENTER/RESET push-
button.
3. The display will illustrate Circ. Enter this mode by pressing the
ENTER/RESET push-button.
5. The display will automatically resort to illustrating the outlet tem-
perature.
4. The display will now illustrate the current post circulate time.
Press the ADJUST push-button to select the desired post cir-
culate time (45, 90, 180, On).
5. When you have selected the desired post circulate time mode,
press the ENTER/RESET push-button once, this enters the
selected post circulate time into controller memory.
6. The display will automatically resort to illustrating the outlet tem-
perature.
TANK PROBE INSTALLATION PROCEDURE
A tank probe is supplied with each hot water supply boiler. When
installed on a tank, the inlet water temperature on the Dia-Scan II
will default to the tank temperature. See figures 2 and 3 to add
the tank jumper to the control board so that the tank probe is
active.
A tank probe is NOT supplied with the hydronic heating boilers
(GB's). Therefore, a loop or operating thermostat must be provided.
This field-supplied operating thermostat should be wired to the
BROWN wires at the junction box. The jumper at location J33 on
the control board must NOT be on. Refer to figures 2 and 3 for the
location of this jumper.
Display Current Mode
In this mode, the Display Board will illustrate the current functional
step in the appliance operational sequence. For example, if the
appliance is performing Ignitor Warm-up, the display will illustrate
IGnt. To enter into this mode, perform the following steps:
Tank Probe Set-Point Adjustment
1. Press the SELECT push-button on the display board until the
LED display reads OPt (Options).
2. To enter into the options mode, press the ENTER/RESET push-
button.
3. The display will illustrate Circ. Press the SELECT push-but-
ton until the display illustrates StEP. Enter this mode by press-
ing the ENTER/RESET push-button.
4. The display will illustrate the current appliance operating step.
5. The display will automatically resort to illustrating the outlet tem-
perature. To keep the display in the Display Step Mode, press
ENTER/RESET twice in step 3.
When tank probe is installed in a storage water tank, and the tank
probe is used with the WHC1502 system, the controller will monitor
and control the temperature of the water at the tank probe location.
Setting the tank probe set-point temperature is accomplished
through the Display Board control panel. The standard program-
mable temperature range for the indirect water tank is 110°F to
190°F. The switching differential of the probe is fixed at 5°F.
Tank Probe Temperature Set-point Adjustment Procedure
The user can easily change the tank probe water temperature set-
point at any time by using the following procedure:
Display Message
Appliance Mode
Idle state
IdLe
NoSn
CrSn
Circ
1.
Press the SELECT push-button on the display board until
both the Set-Pt LED (LED 15, see figure 1) and Inlet Wa-
ter Temperature LED (LED 12, see figure 1) are illumi-
nated.
Wait for No Sensor Inputs
Wait for Circulate Sense
Circulate Pump is ON
Wait for Blower Pressure
Sense
PrSn
NOTE 3: When a tank probe is connected to the board
at location CN10, the Inlet Water Temperature
LED defaults to Tank Water Temperature.
The LED display will show the current tank set-point tem-
perature.
Press and hold the ADJUST push-button. The displayed
temperature will either increase or decrease. To alternate
between increasing or decreasing the temperature, re-
lease then press and hold the ADJUST push-button.
When the desired set-point temperature is reached, re-
lease the ADJUST push-button.
PreP
IGnt
rEdn
Pre-Purge state
Ignitor Warm-up
2.
3.
Turn ON redundant Gas
Valve relay
Turn ON Gas Valves
Turn OFF Ignitor and wait for
Flame Sense Stabilization
Heat Mode
Post Purge and Post Circu-
late
Post Circulate
IAct
StAb
HEAt
PoPC
4.
5.
Press the ENTER/RESET push-button once, this enters
the selected tank set-point temperature into controller
memory.
Po C
Display Total Cycle Count
6.
The appliance will now control the tank water temperature
to the desired set-point value.
The Main Control Board counts the number of cycles the appliance
has operated. In the Main Control Board, a cycle is counted every
time the gas valve is energized. To access this number, perform
the following procedure:
If the ADJUST push-button is held down long enough, the set-point
will reach 110°F, the minimum value (or 190°F, the maximum value)
and stop. At this point, if the desired set-point is not obtained, re-
lease the ADJUST push-button and depress it again. The set-point
value will now restart at 110°F (190°F) and once again increase
(decrease) in value for as long as the ADJUST push-button is
pressed.
1. Press the SELECT push-button on the display board until the
LED display reads OPt (Options).
2. To enter into the options mode, press the ENTER/RESET push-
button.
6
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TANK PROBE JUMPER J33 IS ON AS DEFAULT, READY FOR
USE WITH TANK PROBE SUPPLIED WITH THE BOILER (GW
MODELS ONLY. SEE FIGURE 3 FOR CONNECTION DIAGRAM).
FOR STANDARD TANK CONTROLS (e.g., 24 VAC
HONEYWELL AQUASTAT) REMOVE THIS JUMPER AND
CONNECT THE CONTROL TO THE BROWN WIRES IN THE
JUNCTION BOX ON THE BACK OF THE BOILER.
TROUBLESHOOTING IGNITION SYSTEM
Display Board LED Indicators
Figure 2. WHC 1502 Ignition Control Board
DANGER
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 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.
The Display Board contains eleven (11) solid state LED indicators
for viewing various states of appliance operation and for trouble-
shooting if problems occur. Under normal operating conditions, the
appropriate LED’s will sequence with steady illumination according
to the particular appliance operating state. In cases where prob-
lems or a lockout occurs, the appropriate LED’s will illuminate indi-
cating the general area where the problem exists.
A description of the LED’s and their corresponding functions are
as follows.
THE WATER HEATER SHOULD BE LOCATED IN AN AREA
WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO
SET TEMPERATURES.
LED
Controller Function
Call for Heat
Monitors Outlet water temperature minus
Switching Differential and thermostat circuit or
tank probe circuit. LED is ON when the tem-
perature at Outlet Water Probe is less than the
set-point minus the switching differential, and the
thermostat circuit or tank probe circuit is closed.
Monitors the condition of the flow switch. LED
is ON when the flow switch closes, indicating
water flow through the system.
It is recommended that lower water temperatures be used to
avoid the risk of scalding. It is further recommended, in all cases,
that the water temperature be set for the lowest temperature
which satisfies the user's hot water needs. This will also provide
the most energy efficient operation of the water heater and
minimize scale formation.
Flow Switch
SETTING THE WATER HEATER TEMPERATURE AT 120°F WILL
REDUCE THE RISK OF SCALDS. Some states require settings
at specific lower temperatures. Table 1 below shows the
approximate time-to-burn relationship for normal adult skin.
Pressure Switch Monitors the condition of the pressure switch(s).
LED is ON when the pressure switch(s) are in
their correct state.
Ignitor Current
Monitors current flow through the ignitor element.
LED is ON when current flow through the ignitor
is sensed.
Monitors Gas Valve output. LED is ON when
the output relays supplying power to the gas
valve(s) is closed.
Monitors the Flame Sense Rod. LED is ON
when a signal from the flame rod is sufficient to
indicate flame.
Indicates a blockage or interference at the ap-
pliance air inlet.
Indicates a blockage or interference at the ap-
pliance flue.
Indicates an error/malfunction in the blower
motor circuit.
Indicates an error/malfunction in the circulating
pump circuit.
Indicates a malfunction in the ignition system
circuit.
Table 1: Risk of Scalds
Temperature
Setting
Over 170°F
160°F
Time to Produce 2nd & 3rd
Degree Burns on Adult Skin
Nearly instantaneous
About 1/2 second
Gas Valve
Flame Sense
150°F
140°F
130°F
About 1-1/2 seconds
Less than 5 seconds
About 30 seconds
Blocked Inlet
Blocked Flue
Blower Fail
Circulate Fail
Ignition Fail
120°F or less
More than 5 minutes
7
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Troubleshooting
surrounding air pressure. Inspection of the boiler and vent system
is necessary to insure that flue gas leakage to the surrounding area
The WHC1502 Series Control System has many inherent diagnos- does not occur.
tic and fault detection routines built into its operating hardware and
software. These routines, in conjunction with the four (4) digit LED Inspect the external surfaces of the vent system every 3 months for
display and eleven (11) LED status indicators on the Display Board, corrosion and leakage. Inspect the vent terminations for corrosion
can greatly assist any service person in quickly pinpointing the source and foreign matter which may be blocking the exhausting flue
of a problem which may occur within the appliance. Under certain products. Call a qualified service agent to replace or repair any
circumstances, multiple LED’s will illuminate to better pinpoint the corroded or leaking parts.
target area(s).
Qualified service agent must inspect internal surfaces of the vent
The following list defines the error code messages that scroll across system and the boiler at least once a year.
the LED display:
BURNER SYSTEM
ERRORMESSAGE
REPORTEDERROR
OPEn InLEt ProbE
No probe detected at connec-
tor CN1 on Control Board.
To maintain safe operation and the greatest efficiency for the boiler,
observe the burner flame through the observation port on the left
jacket panel, once a month for proper flame characteristics.
OPEn OutLEt ProbE
Circulation FAIL
Inducor FAIL
No probe detected at connec-
tor CN2 on Control Board.
The burners should display the following characteristics:
No flow detected at flow
switch.
•
•
Provide complete combustion of gas.
Cause rapid ignition and carry over across all burners and across
the entire burner.
No pressure detected at pres-
sure switch.
•
•
Give quiet operation during ignition, burning and extinction.
Cause no excessive lifting of flames from the burner ports.
FLAmE SenSE FAIL
SenSor FAIL
Flame sense detected before
gas valve is turned on.
One of the sensors, Flow, If the preceding characteristics are not evident, check for
Pressure, Hi Gas, or Lo Gas accumulation of lint or other foreign material that restricts the inlet
was not in the correct state.
air or burner ports. Ensure there is the proper amount of air to
the burner. Flame lifting from the burner is caused by too much
air to the burner.
Ignitor FAIL
No Ignition
No Ignitor current sensed.
Flame not detected after 1 or
3 tries.
The burners must be inspected by a qualified service technician at
least once a year.
ECO FAIL
ECO/High Limit switch
opened.
DO NOT STORE COMBUSTIBLE MATERIALS, GASOLINE, OR
OTHER FLAMMABLE VAPORS, LIQUIDS IN THE AREA OF THE
APPLIANCE. NONCOMPLIANCE MAY RESULT IN FIRE OR
EXPLOSION. DO NOT OBSTRUCT THE FLOW OF COM-
BUSTION OR VENTILATION AIR TO THE APPLIANCE.
Control FAIL
Relay did not open or close
properly.
BLOCKED VENT SHUT-OFF SYSTEM
CHEMICAL VAPOR CORROSION
The Boiler is equipped with a blocked vent shut-off system which
will close the gas valve and shut off the main burner gas when there
is excessive pressure in the vent system due to a partially or
completely blocked vent system. The DIA-SCAN II display on the
front panel will indicate this failure condition.
Boiler corrosion and component failure can be caused by airborne
chemical vapors. Spray can propellants, cleaning solvents,
refrigerants, calcium or sodium chloride (water softener salts),
waxes, and process chemicals are typical compounds that are
potentially corrosive. These materials are corrosive at very low
concentration levels with little or no odor to reveal their presence.
Products of this sort should not be stored near the boiler. Air which
is brought in contact with the boiler should not contain any of these
chemicals. The boiler should be provided with air from outdoors
when installed in environments having corrosive atmospheres.
DO NOT ATTEMPT TO OPERATE THE BOILER if this situation
occurs. Shut the boiler off before performing all the steps shown
in "TO TURN OFF GAS TO APPLIANCE" section of the Lighting
and Operating Instructions.
Contact a qualified service agent to inspect the unit and vent system
and correct the problem.
CIRCULATION PUMP
Refer to the pump manufacturer's schedule of maintenance for
frequency and method of lubricating the pump and motor. Inspect
the pump once a month for leaky mechanical seals and/or O-rings
and loose or damaged components. Contact a qualified service
agent to replace or repair parts as required.
VENT SYSTEM
The flue products are corrosive in nature and if the boiler is vented
horizontally the flue gases are at a higher pressure than the
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FIGURE 3. POINT TO POINT WIRING DIAGRAM
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NEW BOILER LIMITED WARRANTY
A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this hydronic boiler:
1. If within TEN years after initial installation of the boiler, the heat exchanger shall 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 volume hot water supply 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 shall 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, an appropriately sized safety relief valve certified to the ASME
Boiler and Pressure Vessel Code must have been installed and fresh water used for filling and makeup purposes;
a. This warranty shall apply only when the boiler is used:
(1) at 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 noncorrosive 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 flow rates;
b. Any accident to the boiler, any misuse, abuse (including freezing) or alteration of it, any operation of it in a modified form 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 defective 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 law are limited to one (1) year
duration for the boiler or any of its parts. Some states or 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 the 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 practical, the owner should contact:
U.S. Customers
Canadian Customers
A. O. Smith Water Products Company
5621 West 115th Street
Alsip, IL 60803
A. O. Smith Enterprises Ltd.
P. O. Box, 310 - 768 Erie Street
Stratford, Ontario N5A 6T3
Telephone: (519) 271-5800
Telephone: 800 323-2636
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 WILL BE MADE ON BEHALF OF THE WARRANTOR WITH RESPECT TO THE BOILER OR THE
INSTALLATION, OPERATION, REPAIR OR REPLACEMENT OF THE BOILER. THE WARRANTOR SHALL NOT BE RESPONSIBLE FOR WATER
DAMAGE, LOSS OF USE OF THE UNIT, INCONVENIENCE, LOSS OR DAMAGE TO PERSONAL PROPERTY OR OTHER CONSEQUENTIAL
DAMAGE. THE WARRANTOR SHALL 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 or 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_________________________________________________________________________________________________________________________
Installation Address_____________________________________________________________________________________________________________
City and State or Province__________________________________________________________________________________________________________
Date Installed_________________________________Model No.____________________________Serial No. ___________________________________
Dealer’s Name__________________________________________________________________________________________________________________
Dealer’s Address______________________________________________________________________Phone No.________________________________
FILL IN WARRANTY AND KEEP FOR FUTURE REFERENCE
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