AO Smith Fan 160M User Guide

MODELS HW-120M, 160M, 200M, 225M  
COMMERCIAL GAS COPPER HEAT EXCHANGER WATER HEATER  
BURKAY UP-FLOW MODELS  
Including Models with Intermittent Pilot Ignition (I.I.D.)  
Installation Operation Maintenance Limited Warranty  
WARNING: If the information in these  
instructions are 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  
CAUTION  
Do not try to light any appliance.  
Do not touch any electrical switch;  
TEXT PRINTED OR OUTLINED IN RED CONTAINS  
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE READ  
THOROUGHLY BEFORE USING APPLIANCE.  
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.  
A DIVISION OF A.O. SMITH CORPORATION  
McBEE, SOUTH CAROLINA, USA  
RENTON, WA, USA  
STRATFORD, ONTARIO, CANADA  
— Installation and service must be  
performed by a qualified installer,  
service agency or the gas supplier.  
VELDHOVEN, THE NETHERLANDS  
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER  
AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE  
PART NO. 212626-000  
PRINTED IN U.S.A. 0905  
SUPERSEDES PART NO. 192011-000 REV.4  
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ROUGH-IN-DIMENSIONS  
TABLE 1 - ROUGH-IN DIMENSIONS  
Models  
Dimensions Inches  
HW-120M  
HW-160M  
Inches  
HW-200M  
Inches  
53 1/4  
33 1/8  
27 1/8  
20 3/4  
5 1/2  
10  
11 13/16  
7
HW-200M  
Inches  
mm  
1254  
772  
600  
527  
140  
254  
300  
152  
678  
527  
mm  
1273  
772  
600  
527  
140  
254  
300  
178  
678  
527  
mm  
1353  
841  
689  
527  
140  
254  
300  
178  
678  
527  
mm  
1524  
841  
689  
527  
140  
254  
300  
178  
678  
527  
A
B
C
D
E
F
G
H
49 3/8  
30 3/8  
23 5/8  
20 3/4  
5 1/2  
10  
11 13/16  
6
50 1/8  
30 3/8  
23 5/8  
20 3/4  
5 1/2  
10  
11 13/16  
7
60  
33 1/8  
27 1/8  
20 3/4  
5 1/2  
10  
11 13/16  
7
J
K
26 11/16  
20 3/4  
26 11/16  
20 3/4  
26 11/16  
20 3/4  
26 11/16  
20 3/4  
L
M
1 1/4 NPT  
1 NPT  
1 1/4 NPT  
1 NPT  
1 1/4 NPT  
1 NPT  
1 1/4 NPT  
1 NPT  
N
1/2 NPT  
1/2 NPT  
1/2 NPT  
1/2 NPT  
W
1 3/4  
44  
1 3/4  
44  
1 3/4  
44  
1 3/4  
44  
Approx.  
Shipping  
Weight  
120 lbs.  
54 Kg. 155 lbs. 70 Kg. 165 Lbs. 75 Kg.  
175 lbs.  
79 Kg.  
HEATER PERFORMANCE DATA  
NOTE: To compensate for the effects of high altitude areas above 2000 feet, input rating, and therefore recovery ratings, should be  
reduced approximately 4% for each 1000 feet above sea level.  
TABLE 2 - RECOVERY CAPACITIES  
U.S. Gallons/Hrs. and Litres/Hr. at TEMPERATURE RISE INDICATED  
Input  
Btuh  
F°  
20F° 30F° 36F° 40F°  
50F° 54F° 60F° 70F° 72F° 80F° 90F° 100F° 108F° 110F° 120F° 126F° 130F° 140F°  
Model  
KW C° 11.1C° 16.6C° 20C° 22.2C° 27.7C° 30C° 33.3C° 38.8C° 40C° 44.4° 50C° 55.5C° 60C° 61.1C° 66.6C° 70C° 72.2C° 77.7C°  
120,000  
160,000  
199,000  
225,000  
GPH 605  
35 LPH 2290 1527 1272 1145  
GPH 777 518 432 388  
47 LPH 2941 1961 1634 1471  
GPH 987 658 548 494  
58 LPH 3737 2491 2076 1869  
GPH 1096 731 609 548  
66 LPH 4149 2766 2305 2074  
403  
336  
303  
242  
916  
311  
224  
848  
288  
202  
763  
259  
980  
329  
173  
654  
222  
840  
282  
168  
636  
216  
817  
274  
151  
573  
194  
735  
247  
934  
274  
134  
509  
173  
654  
219  
830  
244  
121  
458  
155  
588  
197  
747  
219  
830  
112  
242  
144  
545  
183  
692  
203  
768  
110  
416  
141  
535  
179  
679  
199  
754  
101  
382  
129  
490  
165  
623  
183  
691  
96  
93  
86  
HW-120M  
364  
123  
467  
157  
593  
174  
659  
352  
120  
452  
152  
575  
169  
638  
327  
111  
420  
141  
534  
157  
593  
HW-160M  
1176 1089  
395 366  
HW-200M  
1495 1384 1246 1068 1038  
438 406 365 313 304  
HW-2250M  
1659 1537 1383 1185 1152 1037 922  
Recovery rating of models shown in chart above are obtained by actual efficiency test data by recognized Certification Agency.  
NOTE: Recovery rate shown on each models rating plate is based on the requirements of ANSI Standard Z21.10.3, which stipulates  
the data to be based on energy efficiency of 75%.  
TABLE 3 - CAPACITY AND GAS AND ELECTRIC CHARACTERISTICS  
Manifold Pressure  
Maximum Supply Pressure Electrical Characteristics  
Model  
Type of Gas  
Inches W.C.  
kPa  
0.87  
2.49  
Inches W.C.  
10.5  
kPa  
2.61  
3.23  
Volts/Hz  
120/60  
120/60  
Amperes  
HW-120M thru 225M  
HW-120M thru 200M  
NATURAL  
PROPANE  
3.5  
10  
<5  
<5  
13.0  
Minimum Supply Pressure, Natural Gas: 4.5 inches W.C. (1.12 kPa)  
Minimum Supply Pressure, Propane Gas: 11.0 inches W.C. (1.74 kPa)  
Minimum Pressure must be maintained under both load and no load (static and dynamic) conditions.  
2
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FOREWORD  
The factory warranty will be void if the unit(s) have been improperly  
installed or operated.  
This design complies with the latest edition of the ANSI Standard  
Z21.10.3 for gas water heaters Vol. III Storage Water Heaters  
with input ratings above 75,000 BTU per hour Circulating and  
Instantaneous.  
In addition to these instructions, the boiler(s) shall be installed in  
accordance with those installation regulations in force in the local  
area where the installation is to be made. These shall be carefully  
followed in all cases. Authorities having jurisdiction should be  
consulted before installations are made.  
Detailed installation diagrams are in this manual. These diagrams  
will serve to provide the installer with a reference for the materials  
and method of piping suggested. IT IS ESSENTIAL THAT ALL  
WATER AND GAS PIPING AND THE ELECTRICAL WIRING BE  
INSTALLEDAND CONNECTEDAS SHOWN IN THE DIAGRAMS.  
In absence of local codes, the installation must comply with the  
latest editions.  
You should thoroughly read and understand this manual before  
installation and operation of this unit.  
In the United States:  
The National Fuel Gas Code, ANSI Z223.1 and the National  
Electric Code, NFPA 70.  
CHECK THE DIAGRAMS THOROUGHLY BEFORE STARTING  
INSTALLATION TO AVOID POSSIBLE ERRORS AND TO  
MINIMIZE TIME AND MATERIALS COST.  
In Canada:  
Particular attention should be given to the installation of  
thermometers at the locations indicated in the diagrams as these  
are necessary for checking the operation of the heater.  
The Installation Code CAN/CGA B149.1 and .2 (latest edition)  
and the Canadian Electric Code, CSA C22.1.  
These are available from the Canadian Standards Association,  
8501 East Pleasant Valley Road, Cleveland, OH 44131, USA, or,  
Canadian Gas Association Laboratories, 55 Scarsdale Road, Don  
Mills, Ontario M3B 2R3, Canada.  
MAKE SURE THE GAS ON WHICH THE HEATER WILL  
OPERATE IS THE SAMEAS THAT SPECIFIED ON THE HEATER  
MODEL AND RATING PLATE.  
TABLE OF CONTENTS  
PAGE  
PAGE  
ROUGH-IN DIMENSIONS ..................................................................  
FOREWORD .......................................................................................  
GENERAL SAFETY INFORMATION ..................................................  
2
3
3
PIPING DIAGRAMS ............................................................................ 11-13  
Gas Connections ........................................................................... 14-15  
Electrical Information ..................................................................... 15-16  
Precautions .................................................................................... 3-4  
OPERATION ........................................................................................  
Important .......................................................................................  
General ...........................................................................................  
Filling ..............................................................................................  
Purging Of Gas Line ......................................................................  
Operating Instructions For I.I.D Models. .......................................  
Checking And Adjusting The Input .................................................  
SERVICE INFORMATION ..................................................................  
Pilot And Main Burner Maintenance ...............................................  
17  
17  
17  
17  
17  
18  
19  
20  
20  
Grounding Instructions ...................................................................  
Chemical Vapor Corrosion .............................................................  
Liquid Petroleum Models ................................................................  
High Altitude Installations ...............................................................  
FEATURES .........................................................................................  
Automatic Gas Shutoff Control .......................................................  
Protector Switch (Coil High Limit) ...................................................  
Thermal Balancer ...........................................................................  
4
4
4
4
5
5
5
5
Intermittent Ignition Control Module ................................................ 5-6  
I.I.D. Pilot Burner ........................................................................... 20-21  
Circulating Pump ............................................................................  
Tank Temperature Control (Not Supplied) ......................................  
Safety Flow Switch (Not Supplied) ................................................. 6-7  
6
6
Protector Switch (Coil High Limit-All Heaters) ...............................  
Tank Temperature Control ..............................................................  
Automatic Gas Shutoff Control .....................................................  
Thermal Balancer ...........................................................................  
21  
21  
21  
21  
Drain Valve (Not Supplied) .............................................................  
Thermometers (Not Supplied) ........................................................  
INSTALLATION INSTRUCTIONS .......................................................  
Important ........................................................................................  
Required Ability ..............................................................................  
Location .........................................................................................  
Installation Clearances ...................................................................  
Levelling .........................................................................................  
7
7
8
8
8
8
8
8
Inspecting The Heat Exchanger And Venting System .................. 21-22  
Gas Pressure Regulator ................................................................  
Relief Valve ...................................................................................  
Circulating Pump ............................................................................  
Electrical Service ...........................................................................  
Replacement Parts ........................................................................  
PREVENTIVE MAINTENANCE ...........................................................  
Recommended Procedure For Periodic Removal Of Lime  
22  
22  
22  
22  
22  
22  
Air Requirements ........................................................................... 8-9  
Venting ...........................................................................................  
Relief Valve .................................................................................... 9-10  
Hard Water .....................................................................................  
Closed Water System ....................................................................  
Water Line Connections ................................................................  
Water (Potable) Heating ................................................................  
9
Deposits From Coil Type Commercial Water Heaters ................. 22-23  
Deliming Solvents ..........................................................................  
Removing Light Deposits ..............................................................  
23  
23  
10  
10  
10  
10  
Heavy Lime Deposits ................................................................... 23-24  
CHECKOUT ........................................................................................ 24-27  
LIMITED WARRANTY ........................................................................  
28  
GENERAL SAFETY INFORMATION  
3. IF DAMAGED.  
PRECAUTIONS  
4. FIRING WITHOUT WATER.  
5. SOOTING.  
If the unit is exposed to the following, do not operate heater until  
all corrective steps have been made by a qualified serviceman:  
KEEP THE HEATER AREA CLEAR AND FREE FROM  
COMBUSTIBLE MATERIALS, GASOLINE AND OTHER  
FLAMMABLE VAPORSAND LIQUIDS. AREAAROUND HEATER  
MUST NOT CONTAIN OBSTRUCTING MATERIAL TO THE  
FLOW OF COMBUSTION AND VENTILATING AIR.  
1. FLOODING TO LEVEL OF BURNER OR CONTROLS OR  
HIGHER.  
2. EXPOSURE TO FIRE.  
3
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SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL  
TO SHUT OFF, TURN OFF THE MANUAL GAS CONTROL  
VALVE TO THE APPLIANCE.  
HIGH ALTITUDE INSTALLATIONS  
WARNING  
INSTALLATIONSABOVE 2000 FEETREQUIRE REPLACEMENT  
OF THE BURNER ORIFICE IN ACCORDANCE WITH SECTION  
8.1.2 OFTHE NATIONALFUEL GAS CODE (ANSI Z223.1). FOR  
CANADIAN INSTALLATIONS CONSULT CANADIAN  
INSTALLATION CODES AND CAN/CGA B149. FAILURE TO  
REPLACE THE ORIFICES WILL RESULT IN IMPROPER AND  
INEFFICIENT OPERATION OF THE APPLIANCE RESULTING  
IN THE PRODUCTION OF INCREASED LEVELS OF CARBON  
MONOXIDE GAS IN EXCESS OF SAFE LIMITS WHICH COULD  
RESULT IN SERIOUS PERSONAL INJURY OR DEATH.  
Heater must be protected from freezing downdrafts during  
shutdown periods.  
GROUNDING INSTRUCTIONS  
This water heater must be grounded in accordance with the  
National Electric Code and/or local codes. These must be followed  
in all cases.  
This water heater 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 water heater.  
You should contact your gas supplier for any specific changes  
which may be required in your area.  
As elevation above sea level is increased, there is less oxygen  
per cubic foot of gas. Therefore, the heater input rate should be  
reduced at high altitudes for satisfactory operation with the reduced  
oxygen supply. Failure to make this reduction could result in an  
overfiring of the heater, causing sooting, poor combustion and/or  
unsatisfactory heater performance.  
CHEMICAL VAPOR CORROSION  
WARNING  
CORROSION OF THE FLUEWAYS AND VENT SYSTEM MAY  
OCCUR IF AIR FOR COMBUSTION CONTAINS CERTAIN  
CHEMICAL VAPORS. SUCH CORROSION MAY RESULT IN  
FAILURE AND RISK OF ASPHYXIATION.  
U.S. REQUIREMENTS  
Ratings specified by manufacturers for most appliances apply for  
elevations up to 2000 feet (610m). For elevations above 2000  
feet (610m), ratings must be reduced at the rate of 4% for each  
1000 feet (305m) above sea level. For example, if a heater is  
rated at 120,000 Btuh (35 Kwh) at sea level, to rate the heater at  
4000 feet (1219m), you subtract 4 (once for each thousand feet)  
x .04 (4% input reduction) x 120,000 (original rating) from the  
original rating. Therefore, to calculate the input rating at 4,000  
feet (121.9m): 4 x .04 x 120,000=19,200 Btuh (5.6 Kwh), 120,000  
(35 Kwh) - 19,200 (5.6Kwh)=100,000 Btuh (29.4 Kwh). At 6000  
feet (1829m) the correct input rating should be 91,200 Btuh (26.7  
Kwh).  
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.  
Do not store products of this sort near the heater. Also, air which  
is brought in contact with the heater should not contain any of  
these chemicals. If necessary, uncontaminated air should be  
obtained from remote or outside sources. The limited warranty is  
voided when failure of water heater is due to a corrosive  
atmosphere. (Refer to the limited warranty for complete terms  
and conditions.)  
CANADIAN REQUIREMENTS  
LIQUID PETROLEUM MODELS  
Appliances with inputs up to and including 400,000 BTU (117.2  
Kw) must be factory equipped with orifices for operation at specific  
elevations. Standard (sea level) orifices permit operation up to  
2000’ (610m) elevation. For operation between 2000’ (610m)  
and 4500’ (1370m) specify “HIGHALTITUDE OPERATION” when  
ordering the heater(s). For operation above 4500’ (2370m) consult  
factory before ordering.  
Water heaters for propane or liquefied petroleum gas (LPG) are  
different from natural gas models. A natural gas heater will not  
function safely on LP gas and no attempt should be made to  
convert a heater from natural to LP gas.  
LP gas must be used with great caution. It is highly explosive  
and heavier than air. It collects first in low areas making odor  
difficult to detect at nose level. If LP gas is present or even  
suspected, do not attempt to find the cause yourself. Go to a  
neighbor’s house, leaving your doors open to ventilate the house,  
then call your gas supplier or service agent. Keep area clear  
until a service call has been made.  
Field conversion for operation at altitudes other than that  
specified on the heater rating plate is not permitted.  
The input reduction is primarily achieved by reducing the size of  
the main burner orifice. To do this, the main burner orifices require  
replacement with orifices sized for the particular installation  
elevation. Correct orifice sizing and parts may be obtained from  
A.O. Smith Water Products Company. When ordering, be sure  
to state the model number and the altitude of the location where  
the water heater is being installed.  
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.  
Upon completion of derating of the heater, adjustment to the gas  
pressure regulator may be required. See CHECKING THE INPUT  
section in this manual for inlet and manifold pressure  
requirements.  
IF YOU EXPERIENCE AN OUT-OF-GAS SITUATION, DO NOT  
TRY TO RELIGHT APPLIANCES YOURSELF. Only trained LP  
professionals should conduct the required safety checks in  
accordance with industry standards.  
Also due to the input rating reduction required at high altitudes,  
the output rating of the appliance is reduced and should be  
compensated for in the sizing of the equipment for the application.  
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FEATURES  
TABLE 4.  
Control Device  
Factory Setting  
Field Adjustment  
1950F (90.5°C) cut out temp.  
Fixed 1900F (87.7°C) cut in temp.  
2500F (121°C) cut out temp.  
Fixed 2000F (93.3°C) cut in temp.  
Field Supplied and Installed  
Heater Automatic Gas Shutoff Control  
Non-adjustable  
Heater Protector Switch  
Tank Temperature Control  
Safety Flow Switch  
Non-adjustable  
Adjust to Requirements  
Field Adjustable  
See Table 1  
AUTOMATIC GAS SHUTOFF CONTROL  
The automatic gas shutoff control, fig. 1, is an automatic safety  
device which activates at a water temperature of approximately  
1950F (90.5°C). This limits the water outlet temperature to a  
maximum of 2000F (87.7°C).  
The device is wired in series with the gas valve. The control will  
automatically reset when the water temperature cools to  
approximately 190oF (87.7°C).  
Should the automatic gas shutoff control activate during a heating  
cycle, the heater’s gas valve will close; extinguishing the main  
burners. The pilot burner will also be extinguished. The circulating  
pump will continue operating as long as the storage tank  
thermostat continues to “call for heat”. When the water  
temperature in the heater drops to 1800F (82.2°C) or below the  
control module will begin an ignition cycle which will relight the  
pilot burner and main burners. Re-ignition of the main burners  
will occur if the storage tank thermostat continues to call for heat.  
Otherwise, the normal operating cycle will resume on the  
thermostat’s next call for heat.  
FIGURE 2  
DO NOT RESET THIS SWITCH WITHOUT PERFORMING THE  
SYSTEM CHECKS OUTLINED UNDER PROTECTOR SWITCH  
IN THE SERVICE INFORMATION SECTION. ALSO, SEE CHART  
ONE UNDER THE CHECKOUT SECTION. IF NECESSARY,  
CALL A QUALIFIED SERVICEMAN. Once the cause of the  
protector switch activation has been determined and corrected, it  
will be necessary to restart the heater following the LIGHTING  
AND OPERATING instructions.  
THERMAL BALANCER  
The thermal balancer (standard on Models HW-200M and  
HW-225M, optional on Models HW-120M and HW-160M) is a  
snap-acting single-pole thermal relay used only on Cer-Temp 80  
Recovery systems. It gives immediate pump start but delay of  
pump shutoff for approximately 2 minutes. Residual heat in the  
heat exchanger is then recovered after shutdown. This improves  
efficiency and balances heater temperature with tank temperature  
at shutdown.  
AUTOMATIC GAS SHUTOFF CONTROL  
FIGURE 1  
INTERMITTENT IGNITION CONTROL MODULE  
The Honeywell S-8600 control module contain the electronic  
components of the system and also serve as a central wiring  
system for the controls mounted on the heater. The control module  
performs the following functions:  
PROTECTOR SWITCH (Coil High Limit)  
This heater is equipped with a manually reset protector switch,  
Figure 2, located under the small cover on the side of the jacket.  
This device provides positive shutdown of the heater in the event  
of heater or system malfunction. Should the surface temperature  
of the copper tubing heat exchanger reach 2500F (121.1°C), the  
protector switch will activate. The gas valve will close, and the  
pilot and main burners will be extinguished. To resume heater  
operation, the protector switch must be manually reset (remove  
the protector switch cover and push the reset button) after the  
coil surface temperature cools to less than 2000F(93.3°C).  
1. Checks for safe-start by sensing for a flame or false flame  
condition on start-up.  
2. Generates a potential of 15,000 volts for spark ignition of the  
pilot burner.  
3. Opens the pilot valve.  
5
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4. Discontinues ignition spark when the pilot flame is established. Follow the same oiling procedure if a replacement circulator is  
The S-8600 control used on propane gas models provides installed into the system.  
safety lockout if the pilot fails to ignite within the pilot flame  
establishing period. The S-8600 control used on natural gas  
models continues trial for ignition until pilot flame is established.  
TANK TEMPERATURE CONTROL  
(Not Supplied)  
5. After proof-of-pilot flame, opens the main valve.  
DANGER  
6. On a power loss, shuts the heater down. When power is  
USE ANTI-SCALD VALVE(S) in the hot water system to reduce  
the risks of scalds at points of use such as lavatories, sinks and  
restored it will begin a new ignition cycle.  
bathing facilities.  
7. On a loss of flame, shuts off main gas and starts trial for pilot  
ignition.  
The tank temperature control is located in the lower portion of the  
hot water storage tank, see PIPING DIAGRAMS. It is the primary  
operating control of the system and regulates the water  
temperature in the tank.  
The storage tank thermostat should have contact ratings that  
exceed the maximum electrical requirements of the system.  
Typically, the thermostat should have motor full load and locked  
rotor current ratings which exceed the total amount of current  
required to drive the pump(s) controlled by the thermostat.  
The thermostat should have a temperature range of 1000F  
(37.7°C) to 1800F (82.2°C) or more. The preferred initial setting  
for the storage tank thermostat is 1200F (48.8°C). However, for  
normal use, the thermostat should be adjusted to the lowest setting  
which produces an acceptable hot water supply temperature. This  
will always give the most energy efficient operation. Do not adjust  
the thermostat to achieve a storage temperature of 190oF (87.7°C)  
INTERMITTENT IGNITION CONTROL MODULE (I.I.D.)  
FIGURE 3  
or above. This action may cause the automatic gas shutoff control  
to activate shutting down the heater.  
Intermittent ignition device and circulator start and stop  
simultaneously as the tank thermostat contacts open and close.  
This basic action, water flowing whenever the burner operates,  
must not be altered.  
CIRCULATING PUMP  
Constant circulating pump operation of the heater voids the  
warranty. Constant water flow through the unit will “wash” away  
the copper’s natural protective coating. This is called velocity  
erosion. This erosion is not as great a problem when intermittent  
circulating operation is used per the recommended installation  
procedure. Constant circulation of water between the storage  
tank and the building is permissible as long as the water does not  
constantly flow through the heater.  
SAFETY FLOW SWITCH  
(Not Supplied)  
The safety flow switch is a safety device installed at the water  
outlet of the unit to prevent main burner operation in the event of  
inadequate water flow through the unit.  
Only all bronze circulators are used with commercial water heaters.  
An accessory package A.O.S. No. 211480 containing a safety  
flow switch is available for this application.  
Although circulators are oiled and operated by the manufacturer,  
THEY MUST BE OILED AGAIN BEFORE OPERATED. Oil the  
three oil cups (2 on the motor, 1 on the pump) as instructed by  
manufacturer. See fig. 4.  
This switch may be mounted in a horizontal pipe line or a vertical  
pipe line with upward water flow. Do not install the switch where  
the water flow is downward.  
Thereafter, lubricate the three oil cups at least once every 4  
months.  
For proper performance mount the switch in a section of pipe  
where there is a straight run of at least 5 pipe diameters on each  
side of the flow switch (i.e. do not locate adjacent to valves, elbows,  
orifices, etc.).  
The flow switch shall be mounted in a standard 1" x 1" x 1" tee for  
a 1" pipe application. For larger pipe sizes use a reducing tee in  
order to keep the switch as close to the pipe as possible. Install  
the flow switch in the branch (top) opening of the reducing tee  
and provide adequate paddle length in the flow stream. For  
example in a 2" pipe installation use a 2" x 2" x 1" reducing tee.  
For 1", 2" or 3" pipe use the paddle segments as supplied. For  
other pipe sizes (i.e. 1 1/4", 1 1/2", and 2 1/2") trim the paddle to  
the proper pipe size, see fig. 5. If a standard tee is used, install a  
face or hex bushing in the top opening. The paddle must be  
TYPICAL CIRCULATING PUMP  
FIGURE 4  
Use 2 or 3 teaspoonsful in bearing oil cups, and 10 or 12 drops in adjusted or trimmed to the size of the pipe in which it will be  
the motor oil cups. Use no. 20 non-detergent motor oil. installed.  
6
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CAUTION: The paddle must be trimmed at the dotted arc. It must not touch the pipe or any restrictions when installed.  
FIGURE 5  
The installer is cautioned to follow the manufacturer’s instructions  
CAUTION  
exactly when inserting this switch into a pipe tee. This is necessary  
Any part of the paddle must not touch the pipe or any restrictions  
in order to assure positive action of the switch with water flow.  
in the pipe. Screw the flow switch in position so the flat of the  
Once the minimum flow rate (Table 5) through the heater is  
paddle is at right angles to the flow. The arrow on the side case  
reached, the safety flow switch contacts close and consequently,  
must point in the direction of the flow.  
main burner operation is achieved.  
The safety flow switch may be field adjusted to obtain higher  
minimum flow rates than those shown in Table 5.  
DRAIN VALVE (Not Supplied)  
To adjust the flow rate setting:  
A drain valve must be obtained and installed on each heater and  
tank for draining purposes, see installation diagrams in this  
manual.  
1. Remove the flow switch cover.  
2. For higher flow rate—turn the range adjusting screw clockwise.  
3. For lower flow rate—turn the range adjusting screw  
counterclockwise.  
THERMOMETERS (Not Supplied)  
Thermometers should be obtained and field installed as shown  
in the installation diagrams.  
CAUTION  
The switch is factory set at approximately the minimum flow rate,  
see Table 5. It must not be set lower than the factory setting as  
this may result in the switch failing to return at a  
“no flow” condition.  
Thermometers are installed in the system as a means of detecting  
a possible liming condition in the heater. An increase of 50F over  
the normal temperature rise through the heater is an indication  
that lime is present. The term “temperature rise” designates the  
difference between the heater inlet and outlet water temperatures.  
4. Replace the flow switch cover.  
TABLE 5 - SAFETY FLOW SWITCH SETTINGS  
Minimum Flow Rate (GPM)  
An increase of 50F (3°C) above the recorded temperature rise  
may signify a liming condition in the coils or heat exchanger. Refer  
to PREVENTIVE MAINTENANCE section of this manual for  
deliming instructions.  
Contacts Close  
GPM LPM  
Contacts Close  
GPM  
0.3  
Pkg.  
No.  
Model  
HW-120M,160M  
HW-200M  
LPM  
1.1  
0.6  
4.2  
2.3  
211480  
211480  
15.9  
2.5  
9.5  
HW-225M  
5.8  
22.0  
3.7  
14.0  
211480  
Record temperature rise at initial start-up for future reference.  
7
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INSTALLATION INSTRUCTIONS  
For appliance installation in locations with elevations above 2,000  
feet (600M), refer to HIGH ALTITUDE INSTALLATIONS section  
of this manual for input reduction procedure.  
IMPORTANT  
Strict adherence to installation wiring diagrams shown in this  
manual is required to prevent constant pump operation when the  
system temperature control is satisfied, otherwise the warranty is  
void as stipulated under item 2a (6) of the LIMITED WARRANTY.  
INSTALLATION CLEARANCES  
These units are approved for installation in an alcove having  
minimum clearances from combustible construction of 44"  
(1,118mm) from top of the jacket, 6" (152.4mm) from sides, and  
6" (152.4mm) from rear and vent connections.  
REQUIRED ABILITY  
INSTALLATION OR SERVICE OF THIS WATER HEATER  
REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED  
TRADESMAN IN THE FIELD INVOLVED. PLUMBING, AIR  
SUPPLY, VENTING, GAS SUPPLY AND ELECTRICAL WORK  
ARE REQUIRED.  
All models may be installed on combustible flooring.  
DO NOT INSTALL THIS WATER HEATER DIRECTLY ON A  
CARPETED FLOOR. A FIRE HAZARD MAY RESULT. Instead  
the water heater must be placed on a metal or wood panel  
extending beyond the full width and depth by at least 3 inches  
(76.2mm) in any direction. If the heater is installed in a carpeted  
alcove, the entire floor shall be covered by the panel. Also, see  
the DRAIN REQUIREMENTS.  
LOCATION  
When installing the heater, consideration must be given to proper  
location. Location selected should be as close to the stack or  
chimney as practicable with adequate air supply, and as  
centralized with piping system as possible.  
It is recommended that at least 24" (610mm) be provided on the  
left side and front of the unit for accessibility and proper servicing.  
In a utility room installation, the door shall be wide enough to  
allow the heater to enter or to permit the replacement of another  
appliance.  
THE HEATER SHOULD NOTBE LOCATED INANAREAWHERE  
IT WILL BE SUBJECT TO FREEZING.  
LOCATE IT NEAR A FLOOR DRAIN. THE HEATER SHOULD  
BE LOCATED IN AN AREA WHERE LEAKAGE FROM THE  
HEATER OR CONNECTIONS WILL NOT RESULT IN DAMAGE  
TO THE ADJACENT AREA OR TO LOWER FLOORS OF THE  
STRUCTURE.  
LEVELLING  
Each unit should be checked after installation to be certain that it  
is level.  
WHEN SUCH LOCATIONS CANNOT BEAVOIDED, ASUITABLE  
DRAIN PAN SHOULD BE INSTALLED UNDER THE HEATER.  
Such pans should be fabricated with sides at least 2" (50.8mm)  
deep, with length and width at least 2" (50.8mm) greater than the  
diameter of the heater and must be piped to an adequate drain.  
The pan must not restrict combustion air flow.  
If the unit is not level, obtain and insert metal shims under the  
base ring of the unit to correct this condition.  
AIR REQUIREMENTS  
Should the heater be installed in a garage, the heater must be  
located, or protected, so it is not subject to physical damage by a  
moving vehicle.  
WARNING  
FOR SAFE OPERATION AN AMPLE SUPPLY OF AIR MUST BE  
PROVIDED FOR PROPER COMBUSTIONAND VENTILATION.  
AN INSUFFICIENT SUPPLY OF AIR WILL RESULT IN A  
YELLOW/LUMINOUS BURNER FLAME, CAUSING CARBONING  
OR SOOTING OF THE FINNED HEAT EXCHANGER AND  
CREATING A RISK OF ASPHYXIATION. DO NOT OBSTRUCT  
THE FLOW OF COMBUSTION AND VENTILATION AIR.  
WARNING  
THERE IS A RISK IN USING FUEL BURNING APPLIANCES  
SUCH AS HEATERS IN ROOMS OR AREAS WHERE  
GASOLINE, OTHER FLAMMABLE LIQUIDS 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 IGNITER OR MAIN BURNER FLAMES  
CAUSING FIRE OR EXPLOSION. SOME LOCAL CODES  
PERMIT OPERATION OF GAS APPLIANCES IN SUCH AREAS  
IF THEY ARE INSTALLED 18 INCHES OR MORE ABOVE THE  
FLOOR. THIS MAY REDUCE THE RISK IF LOCATION IN SUCH  
UNCONFINED SPACE  
In buildings of conventional frame, brick, or stone construction,  
unconfined spaces may provide adequate air for combustion,  
ventilation and draft hood dilution.  
AN AREA CANNOT BE AVOIDED.  
If the unconfined space is within a building of tight construction  
(buildings using the following construction: weather stripping,  
heavy insulation, caulking, vapor barrier, etc.), air for combustion,  
ventilation, and draft hood dilution must be obtained from outdoors.  
The installation instructions for confined spaces in tightly  
constructed buildings must be followed to ensure adequate air  
supply.  
WARNING  
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY  
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST  
NEVER BE PLACED ON OR ADJACENT TO THE HEATER.  
OPEN CONTAINERS OF FLAMMABLE MATERIAL SHOULD  
NOT BE STORED OR USED IN THE SAME ROOM WITH THE  
HEATER.  
8
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Do not install without draft hood and do not install any damper  
in flueway. Be sure that the vent pipe does not extend beyond  
the inside wall of the chimney.  
CONFINED SPACE  
When drawing combustion and dilution air from inside a  
conventionally constructed building to a confined space, such a  
space shall be provided with two permanent openings, ONE IN 2. Where a continuous or intermittent back draft is found to exist,  
OR WITHIN 12 INCHES (30.5cm) OF THE ENCLOSURE  
BOTTOM. Each opening shall have a free area of at least one  
square inch per 1000 Btuh (2,225mm2/Kw)of the total input of all  
appliances in the enclosure, but not less than 100 square inches  
(645 square cm).  
the cause must be determined and corrected. A special vent  
cap may be required.  
FAILURE TO CORRECT BACK DRAFTS MAY CAUSE AIR  
CONTAMINATION AND UNSAFE CONDITIONS.  
If the confined space is within a building of tight construction, air  
for combustion, ventilation and draft hood dilution must be  
obtained from outdoors. When directly communicating with the  
outdoors or communicating with the outdoors through vertical  
ducts, two permanent openings, located in the above manner,  
shall be provided. Each opening shall have a free area of not  
less than one square inch per 4000 Btuh (8,900mm2/Kw) of the  
total input of all appliances in the enclosure. If horizontal ducts  
are used, each opening shall have a free area of not less than  
one square inch per 2000 Btuh (4,450mm2/Kw) of the total input  
of all appliances in the enclosure. For Canadian installations  
consult CAN/CGA B149.  
If the back draft cannot be corrected by the normal methods  
or if a suitable draft cannot be obtained, ablower type flue  
gas exhauster must be employed to assure proper venting  
and correct combustion.  
3. Do not connect the heater to a common flue or chimney with  
solid fuel burning equipment. This practice is prohibited by  
many local building codes as is the practice of venting gas  
fired equipment to the duct work of ventilation systems.  
Where a separate vent connection is not available and the  
vent pipe from the heater must be connected to a common  
flue with an oil burning furnace, the vent pipe should enter the  
common flue or chimney at a point above the flue pipe from oil  
furnace.  
Where an exhaust fan is installed in the same room with a heater,  
sufficient openings for air must be provided in the walls.  
UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN  
INTO THE ROOM THROUGH THE CHIMNEY, CAUSING POOR  
COMBUSTION. SOOTING MAY RESULT AND RISK OF  
ASPHYXIATION WILL OCCUR.  
4. Where two or more appliances vent into a common vent  
connector or manifold, the area of the common vent should at  
least equal the area of the largest flue or vent connector plus  
50% of the areas of the additional draft hood outlets.  
VENTING  
5. Refer to the National Fuel Gas Code for information pertaining  
to multiple heater venting. The ASHRAE HVAC SYSTEMS &  
EQUIPMENT HANDBOOK 2000, as well as many  
manufacturers’ gas vent and chimney sizing handbooks  
contain information on multiple heater manifold venting.  
WARNING  
THE INSTRUCTIONS IN THIS SECTION ON VENTING THE  
HEATER MUST BE FOLLOWED TO AVOID CHOKED  
COMBUSTION OR RECIRCULATION OF FLUE GASES. SUCH  
CONDITIONS CAUSE SOOTING OR RISKS OF FIRE AND  
ASPHYXIATION.  
RELIEF VALVE  
An ASME-rated pressure relief valve (Supplied) must be installed  
in the hot water outlet line as near to the heater as possible. This  
pressure relief valve is rated in accordance with and comply with  
the ANSI/ASME Boiler and Pressure Vessel Code, Section IV  
(“Heating Boilers”), 1989 edition (or latest edition).  
In the United States:  
Vent sizing, installation and termination shall be in accordance  
with the NATIONAL FUELGAS CODE.ANSI Z223.1-1999 or most  
recent edition.  
In Canada:  
A C.S.A design-certified and ASME-rated temperature and  
pressure relief valve (Not Supplied) must be installed on each  
and every water storage tank. This relief valve shall comply with  
the Standard for Relief Valves andAutomatic Gas Shutoff Devices  
for Hot Water Supply systems, “ANSI Z21.22-1986 or latest  
edition”. This relief valve should have a temperature rating of  
2100F (98.8°C), a pressure rating not exceeding the lowest rated  
working pressure of any system component and a discharge  
capacity exceeding the total input of the water heaters supplying  
water to the storage tank.  
With Canadian Installation Code CAN/CGA B149 (latest edition)  
Type B venting may be used with these heaters. All local and  
utility regulations on venting should be followed.  
Remove all soot or other obstructions from chimney which will  
retard free draft.  
1. Install and size the vent pipe as necessary. The connection  
from the heater to the chimney should be run full size and  
should have a minimum pitch upward to the chimney of one  
quarter inch per foot length.  
Select a relief valve with a discharge capacity exceeding the  
maximum heater input rating and a pressure rating not exceeding  
the working pressure shown on the rating plate of the heater.  
Locate the T & P relief valve in the top of the tank, or in the side of  
the tank on centerline within the upper 6 inches from the top of  
the tank. See installation diagrams. Tapping shall be threaded in  
accordance with the latest version of the Standard for Pipe  
Threads, General Purpose (inch), ANSI/ASME B1.20.1. Mark  
location with a Class III label. See ANSI Z21.10.1, Part 1,  
MARKING.  
PROPER VENT PIPE INSTALLATION  
FIGURE 6  
9
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Your local code authority may have other specific relief valve  
requirements not covered in this section.  
WATER LINE CONNECTIONS  
This manual provides detailed installation diagrams for typical  
methods of application. See piping diagrams.  
THE PURPOSE OF A RELIEF VALVE IS TOAVOID EXCESSIVE  
PRESSURE OR TEMPERATURE INTO THE STEAM RANGE,  
WHICH MAY CAUSE SCALDING AT FIXTURES, TANK  
EXPLOSION, SYSTEM OR HEATER DAMAGE.  
Cer-Temp 80 Recovery System (for one temperature water).  
These diagrams will serve to provide the installer with a reference  
for the materials and method of piping necessary for installation.  
It is essential that all water and gas piping, vent connections,  
electrical wiring and check and flow regulating valves be installed  
as shown on the diagrams.  
TO AVOID SCALDING OR WATER DAMAGE, A DRAIN LINE  
MUST BE CONNECTED TO A RELIEF VALVE TO DIRECT  
DISCHARGE TO A SAFE LOCATION. A DRAIN LINE MUST  
NOT BE REDUCED FROM THE SIZE OF THE VALVE OUTLET  
AND IT MUST NOT CONTAIN ANY VALVES BETWEEN THE  
HEATERAND THE RELIEF VALVE OR THE RELIEF VALVEAND  
THE DRAIN LINE EXIT. IN ADDITION, THERE SHOULD NOT  
BE ANY RESTRICTIONS IN A DRAIN LINE NOR SHOULD IT  
BE ROUTED THROUGH AREAS WHERE FREEZING  
CONDITIONS MIGHT OCCUR. DO NOT THREAD OR CAP THE  
DRAIN LINE EXIT. RESTRICTING OR BLOCKING A DRAIN  
LINE WILL DEFEAT THE PURPOSE OF THE RELIEF VALVE  
AND MAY CREATE AN UNSAFE CONDITION. INSTALL A  
DRAIN LINE WITH A DOWNWARD SLOPE SUCH THAT IT  
NATURALLY DRAINS ITSELF.  
Consult the installation diagrams for appropriate locations to  
install the safety flow switch(es), drain valves, thermometers,  
relief valves and the circulating pump(s). Apply suitable pipe  
thread sealing compounds to only the male threads of parts to  
be connected. If any of these parts are being replaced in a  
functioning system, remember to shut off the manual gas and  
control valve(s) and close off the water inlet(s). Open a nearby  
faucet to relieve pressure and drain the heater and/or system  
before attempting to install the new parts.  
Recommended locations of relief valves are shown in the  
installation diagrams.  
Check the diagrams thoroughly before starting installation to  
avoid errors and minimize time and material costs.  
HARD WATER  
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 a downdraft entering the heater or  
freezing air from contacting 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.  
Where hard water conditions exist, water softening or the threshold  
type of water treatment is recommended. This will protect the  
dishwashers, coffee urns, water heaters, water piping and other  
equipment. When water softening or water treatment is not  
practical, a comparatively easy method of periodic lime removal  
from the heater may be employed by installing gate valves, drain  
valve and acid fill opening as shown in PREVENTIVE  
MAINTENANCE section of this manual.  
WATER (POTABLE) HEATING  
CLOSED WATER SYSTEM  
1. All piping components connected to this unit for space  
heating applications shall be suitable for use with potable  
water.  
A closed system will exist if a back-flow prevention device (check  
valve), pressure reducing valve, or other similar device is installed  
in the cold water line between the water heater and the street  
main (or well). Excessive pressure may develop due to the  
thermal expansion of heated water causing premature tank  
failure or intermittent relief valve operation. This is not a warranty  
failure. An expansion tank may be necessary in the cold water  
supply to alleviate this situation. Contact the local plumbing  
authority.  
2. Toxic chemicals, such as those used for boiler treatment,  
shall NEVER be introduced into this system.  
3. This unit may NEVER be connected to any existing heating  
system or component(s) previously used with a non-potable  
water heating appliance.  
10  
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PIPING DIAGRAMS  
DANGER  
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE AT  
FIXTURES. SEE WATER TEMPERATURE CONTROL WARNING ON PAGE 19. IF HIGHER  
PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER  
OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.  
(USE THIS DIAGRAM FOR STRAIGHT RECOVERY  
SYSTEMS SUPPLYING HOT WATER AT ONE  
TEMPERATURE ONLY)  
FIGURE 7  
11  
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DANGER  
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE  
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE CONTROL  
WARNING ON PAGE 19. IF HIGHER PREHEAT TEMPERATURES ARE  
NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN  
ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.  
FIGURE 8  
12  
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DANGER  
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE  
AT FIXTURES. SEE WATER TEMPERATURE CONTROL WARNING ON  
PAGE 19. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO  
OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR  
HOT WATER SUPPLIED TO FIXTURES.  
FIGURE 9  
FIGURE 10  
13  
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acceptable for the purpose in locating gas leaks. DO NOT USE  
MATCHES, CANDLES, FLAME OR OTHER SOURCES OF  
IGNITION FOR THIS PURPOSE.  
GAS CONNECTIONS  
WARNING  
THE INLET GAS PRESSURE MUST NOT EXCEED THE VALUE  
SPECIFIED BY THE MANUFACTURER ON THE RATING PLATE  
(10.5" W.C. - NATURAL GAS, 13.0" W.C. - PROPANE GAS).  
EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE  
DAMAGE TO THE GAS VALVE WHICH COULD RESULT IN FIRE  
OR EXPLOSION. IF OVERPRESSURE HAS OCCURRED SUCH  
AS THROUGH IMPROPER TESTING OF GAS LINES OR  
EMERGENCY MALFUNCTION OF THE SUPPLY SYSTEM, THE  
GAS VALVE MUST BE CHECKED FOR SAFE OPERATION. MAKE  
SURE THAT THE OUTSIDE VENTS ON THE SUPPLY  
REGULATORS AND THE SAFETY VENT VALVES ARE  
PROTECTED AGAINST BLOCKAGE. THESE ARE PARTS OF  
THE GAS SUPPLY SYSTEM, NOT THE HEATER. VENT  
BLOCKAGE MAY OCCUR DURING ICE STORMS.  
DISCONNECTTHE HEATERAND ITS MANUALGAS SHUTOFF  
VALVE FROM THE GAS SUPPLY PIPING SYSTEM DURING  
ANY PRESSURE TESTING OF THAT SYSTEM AT TEST  
PRESSURES IN EXCESS OF 1/2 PSIG. THE GAS SUPPLY  
LINE MUST BE CAPPED WHEN NOT CONNECTED TO  
HEATER.  
THE HEATER MUST BE ISOLATED FROM THE GAS SUPPLY  
PIPING SYSTEM BY CLOSING ITS MANUAL GAS SHUTOFF  
VALVE DURING ANY PRESSURE TESTING OF THE GAS  
SUPPLY PIPING SYSTEM AT TEST PRESSURES EQUAL TO  
OR LESS THAN 1/2 PSIG (3.44kPa).  
CORRECT GAS  
IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING  
FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING  
MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.  
MAKE SURE the gas on which the heater will operate is the same  
as that specified on the heater model and rating plate. Do not  
install the heater if equipped for a different type gas - contact the  
heater supplier.  
IF COPPER SUPPLY LINES ARE USED THEY MUST BE  
INTERNALLY TINNED AND CERTIFIED FOR GAS SERVICE.  
SIZING GAS SUPPLY LINE  
BEFOREATTACHING THE GAS LINE BE SURE THATALLGAS  
PIPE IS CLEAN ON THE INSIDE.  
The iron pipe or equivalent pipe sizes in Table 6 are derived from  
Table C-3 in the NATIONAL FUEL GAS CODE. The pipe sizes  
are based on a supply line gas pressure drop of 0.3 inches of  
water column from the gas meter to the point of installation of the  
heater(s). For natural gas, a heating value of 1050 Btu/ft3 and a  
specific gravity of 0.60 has been assumed. A heating value of  
2500 Btu/ft3 and a specific gravity of 1.53 has been assumed for  
L.P. (propane) gas.  
TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS  
SUPPLY LINE, A DIRT LEG (SOMETIMES CALLED SEDIMENT  
TRAP OR DRIP LEG), MUST BE INCORPORATED IN THE  
PIPING. SEE PIPING DIAGRAMS. THE DIRT LEG MUST BE  
READILY ACCESSIBLE AND NOT SUBJECT TO FREEZING  
CONDITIONS.  
INSTALL IN ACCORDANCE WITH  
RECOMMENDATIONS OF SERVING GAS SUPPLIERS. IN THE  
UNITED STATES REFER TO ANSI Z223.1-1999 OR MOST  
RECENT EDITION OF THE NATIONAL FUEL GAS CODE. IN  
CANADA, THE CANADIAN INSTALLATION CODE CAN/CGA  
B 149 (LATEST EDITION).  
Where it is necessary to use an excess number of pipe fittings,  
i.e., elbows, tees and valves, in the gas supply line, use pipe at  
least one size larger than that recommended in Table 2 to  
compensate for the increased pressure drop.  
If the service pressure is 4.5 inches W.C. (1.12kPa) (11 inches  
(1.74kPa) for L.P. gas) of water column or less, use pipe size  
larger than specified in Table 6 to minimize pressure drop in the  
line.  
To prevent damage, care must be taken not to apply too much  
torque when attaching gas supply pipe to gas valve gas inlet.  
Fittings and unions in the gas line must be 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.  
GAS METER SIZE - City Gases Only  
Be sure that the gas meter has sufficient capacity to supply the  
full rated gas input of the heater as well as the requirements of all  
other gas fired equipment supplied by the meter. If gas meter is  
BEFORE PLACING THE HEATER IN OPERATION, CHECK FOR too small, ask the gas company to install a larger meter having  
GAS LEAKAGE. Use soap and water solution or other material adequate capacity.  
TABLE 6  
GAS SUPPLY PIPE SIZES (IN INCHES)  
NATURAL GAS (1050 Btu/ft3)  
PROPANE GAS (2500 Btu/ft3)  
Distance To Heater  
From Meter (FT./M) HW-120M  
HW-160M  
3/4  
HW-200M  
3/4  
HW-225M HW-120M  
HW-160M  
HW-200M  
10 (3M)  
30 (9.1M)  
1/2  
3/4  
3/4  
1
3/4  
1
1
1 1/4  
1 1/4  
1 1/4  
1 1/2  
1/2  
1/2  
3/4  
3/4  
3/4  
1
1/2  
3/4  
3/4  
1
1
1
1/2  
3/4  
1
1
1
3/4  
1
1
1 1/4  
1 1/4  
1 1/4  
1
1
50 (15.2M)  
80 (24.4M)  
100 (30.5M)  
150 (45.7M)  
200 (61M)  
1 1/4  
1 1/4  
1 1/4  
1 1/4  
1
1
1 1/4  
1 1/4  
1 1/4  
1
1 1/4  
14  
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Aminimum gas supply pressure of 4.5" W.C. (1.12kPa) for natural  
gas and 11" W.C. (1.74kPa) for propane gas is required for  
purposes of input adjustment.  
Figures 11 and 12 show the heater mounted controls as they are  
wired when the heater leaves the factory. Using the individual  
wiring diagrams on the installation diagrams, the installer connects  
his wiring to terminals in the heater(s) mounted junction box as  
shown.  
ELECTRICAL INFORMATION  
All wiring should be done such that the heater(s) will operate in  
the following manner:  
ALL ELECTRICAL WORK MUST BE INSTALLED IN  
ACCORDANCE WITH THE NATIONAL ELECTRICAL CODE IN  
THE UNITED STATES AND IN CANADA MUST CONFORM TO  
LOCAL REGULATIONS OR THE CANADIAN ELECTRICAL  
CODE CSA C22.  
1. When the tank temperature control calls for heat:  
The circulating pump starts to operate. Once the safety flow  
switch contacts close, intermittent ignition device is powered  
and sequence through steps as described for I.I.D. Control  
Module on Page 5.  
The electrical connections must be made so that both the circulator  
and intermittent ignition device operate simultaneously when the  
storage tank temperature control calls for heat.  
The appliance, when installed, must be electrically grounded in  
accordance with local codes or, in the absence of local codes, in  
the United States with the NATIONALELECTRICAL CODE,ANSI/  
NFPA 70. In Canada with the CANADIAN ELECTRIC CODE,  
CSA C22.  
2. When the tank temperature control is satisfied:  
The main burners should stop firing, but the circulating pump  
should continue to operate for about 2 minutes when equipped  
with a thermal balancer.  
A screw is provided in the heater junction box for a ground  
connection.  
3. When the automatic gas shutoff control or coil protector switch  
operate (break electric circuit):  
All piping diagrams include an electrical wiring diagram to assist  
the installer in properly wiring of the additional components  
required to assure correct system operation.  
The main burners should stop firing. Circulating pump should  
continue to operate.  
ELECTRICAL WIRING DIAGRAMS FOR THE HW-120M, 160M, 200M AND 225M WATER HEATERS  
I.I.D. SYSTEM (NATURAL)  
FIGURE 11  
15  
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ELECTRICAL WIRING DIAGRAMS FOR THE HW-120M, 160M, AND 200M WATER HEATERS  
I.I.D. SYSTEM (PROPANE)  
FIGURE 12  
NOTES:  
16  
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OPERATION  
CAUTION  
PURGING SHOULD BE PERFORMED BY PERSONS  
EXPERIENCED IN THIS TYPE GAS SERVICE. TOAVOID RISK  
OF FIRE OR EXPLOSION, PURGE DISCHARGE MUST NOT  
ENTER CONFINED AREAS OR SPACES WHERE IGNITION  
CAN OCCUR. THE AREA MUST BE WELL VENTILATED AND  
ALL SOURCES OF IGNITION MUST BE INACTIVATED OR  
REMOVED.  
IMPORTANT  
Only qualified personnel shall perform the initial firing of the heater.  
At this time the user should not hesitate to ask the start-up  
technician any questions regarding the operation and  
maintenance of the unit.  
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.  
BEFORE PLACING THE WATER HEATER IN OPERATION,  
CHECK FOR GAS LEAKAGE. USE A SOAP AND WATER  
SOLUTION OR OTHER MATERIAL ACCEPTABLE FOR THE  
PURPOSE OF LOCATING GAS LEAKS. DO NOT USE  
MATCHES, CANDLES, FLAME OR OTHER SOURCES OF  
IGNITION FOR THIS PURPOSE.  
GENERAL  
Never operate the water heater without first making sure the water  
heater and system are filled with water, in addition:  
CAUTION  
BEFORE PROCEEDING WITH THE OPERATION OF THE UNIT,  
MAKE SURE HEATERAND SYSTEMARE FILLED WITH WATER  
AND ALL AIR IS EXPELLED FROM HEATER AND PIPING.  
Make sure a temperature and pressure relief valve is installed  
at the water heater and if used, the storage tank. Also check  
for leaks.  
THE MAIN MANUAL GAS SHUTOFF VALVE AND THE PILOT  
ADJUSTING VALVE (WHEN APPLICABLE) MUST HAVE BEEN  
CLOSED FOR AT LEAST FIVE (5) MINUTES. 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 THIS 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. SEE THE FRONT PAGE FOR STEPS TO BE  
TAKEN.  
Also be sure to check the gas piping for leaks before beginning  
the initial firing of the boiler.  
FILLING  
1. Close the systems drain valve by turning handle clockwise.  
2. Open a nearby hot water faucet to permit the air in the system  
to escape.  
3. Fully open the cold water inlet pipe valve allowing the heater  
and piping to be filled.  
DO NOT USE THIS HEATER IF ANY PART HAS BEEN UNDER  
WATER. IMMEDIATELY CALL A QUALIFIED SERVICE  
TECHNICIAN TO INSPECT THE HEATER AND TO REPLACE  
ANY PART OF THE CONTROL SYSTEM AND ANY GAS  
CONTROL WHICH HAS BEEN UNDER WATER.  
4. Close the hot water faucet as water starts to flow.  
5. The heater is ready to be operated.  
PURGING OF GAS LINE  
Light the unit in accordance with the instructions on the lighting  
label attached to the boiler. These instructions are repeated in  
the following.  
Gas line purging is required with new piping or systems in which  
air has entered.  
17  
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OPERATING INSTRUCTIONS FOR I.I.D. MODELS  
The I.I.D. models have an automatic intermittent spark ignition system, figure 3, mounted on the jacket at the front of the heater which  
ignites the pilot gas whenever system controls call for heat.  
Start the unit in accordance with the instructions on the operating label attached to the heater. These instructions are repeated in the  
following.  
FOR YOUR SAFETY READ BEFORE OPERATING  
WARNING: IF YOU DO NOT FOLLOW THESE INSTRUCTIONS  
EXACTLY A FIRE OR EXPLOSION MAY RESULT CAUSING  
PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE.  
A.  
B.  
THIS APPLIANCE IS EQUIPPED WITH AN IGNITION C.  
DEVICE WHICH AUTOMATICALLY LIGHTS THE  
PILOT. DO NOT TRY TO LIGHT THE PILOT BY HAND.  
USE ONLY YOUR HAND TO TURN THE GAS  
CONTROL KNOB . NEVER USE TOOLS. IF THE KNOB  
WILL NOT TURN BY HAND, DON’T TRY TO REPAIR  
IT. CALL A QUALIFIED SERVICE TECHNICIAN.  
FORCE OR ATTEMPTED REPAIR MAY RESULT IN A  
FIRE OR EXPLOSION.  
BEFORE OPERATING SMELL ALL AROUND THE  
APPLIANCE AREA FOR GAS . BE SURE TO SMELL  
NEXT TO THE FLOOR BECAUSE SOME GAS IS  
HEAVIER THAN AIR AND WILL SETTLE ON THE  
FLOOR.  
D.  
DO NOT USE THIS APPLIANCE IF ANY PART HAS  
BEEN UNDER WATER. IMMEDIATELY CALL A  
QUALIFIED SERVICE TECHNICIAN TO INSPECT THE  
APPLIANCE AND TO REPLACE ANY PART OF THE  
CONTROL SYSTEM AND ANY GAS CONTROL  
WHICH HAS BEEN UNDER WATER.  
WHAT TO DO IF YOU SMELL GAS  
• DO NOT TRY TO LIGHT ANY APPLIANCE.  
• DO NOT TOUCH ANY ELECTRIC 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.  
E.  
DO NOT OPERATE APPLIANCE UNLESS UNIT IS  
FILLED WITH WATER AND INLET LINES AFTER  
FULLY OPEN.  
• IF YOU CANNOT REACH YOUR GAS SUPPLIER,  
CALL THE FIRE DEPARTMENT.  
HONEYWELL VR8304P GAS CONTROL  
OPERATING INSTRUCTIONS  
1.  
STOP! READ THE SAFETY INFORMATION  
ABOVE ON THIS LABEL.  
8.  
9.  
TURN ON ALL ELECTRICAL POWER TO THE  
APPLIANCE.  
2.  
3.  
SET THERMOSTAT TO LOWEST SETTING.  
SET THERMOSTAT TO DESIRED SETTING. PILOT  
WILL BE IGNITED BY ELECTRONIC SPARK. WHEN  
PILOT IGNITION IS SENSED, THE MAIN BURNERS  
WILL IGNITE.  
TURN OFF ALL ELECTRIC POWER TO THE  
APPLIANCE.  
4.  
5.  
6.  
THIS APPLIANCE IS EQUIPPED WITH AN IGNITION  
DEVICE WHICH AUTOMATICALLY LIGHTS THE  
PILOT. DO NOT TRY TO LIGHT THE PILOT BY HAND.  
10. IF MAIN BURNER FAILS TO IGNITE, REMOVE  
BURNER ACCESS DOOR AND FOLLOW SMALL  
METAL TUBE FROM GAS VALVE TO PILOT. REPEAT  
STEPS 2 THRU 9. MAKE SURE PILOT IS BURNING.  
IF PILOT FAILS TO IGNITE, CHECK FOR PILOT  
IGNITION SPARK.  
TURN GAS VALVE CONTROL KNOB CLOCKWISE  
TO “OFF” (FIG. A) A SLIGHT INDENT CAN BE FELT  
IN THE “OFF” POSITION.  
IF APPLIANCE WILL NOT OPERATE, FOLLOW THE  
INSTRUCTIONS “TO TURN OFF GAS TO  
APPLIANCE” AND CALL YOUR SERVICE  
TECHNICIAN OR GAS SUPPLIER.  
WAIT FIVE (5) MINUTES TO CLEAR OUT ANY GAS.  
THEN SMELL FOR GAS, INCLUDING NEAR THE  
FLOOR. IF YOU THEN SMELL GAS.  
STOP! FOLLOW “B” IN THE SAFETY  
INFORMATION ABOVE IN THIS LABEL.  
IF YOU DON’T SMELL GAS. GO TO NEXT  
STEP.  
7.  
TURN GAS CONTROL KNOB COUNTERCLOCKWISE  
TO “ON” (FIG. B) UNTIL KNOB SNAPS INTO “ON”  
POSITION.  
TO TURN OFF GAS TO APPLIANCE  
1. SET THE THERMOSTAT TO LOWEST SETTING.  
2. TURN OFF ALL ELECTRIC POWER TO THE APPLIANCE IF SERVICE IS TO BE PERFORMED.  
3. TURN GAS VALVE CONTROL KNOB CLOCKWISE  
ABOVE.  
TO “OFF”. REFER TO STEP 5 OF “OPERATING INSTRUCTIONS”  
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2. Attach a pressure gauge or a manometer to the outlet pressure  
tap, figure 14 and refer to table 3 for correct manifold pressure.  
3. Fire the heater by turning the gas valve control knob to “ON”.  
4. Use this formula to “clock” the meter. Be sure that other gas  
consuming appliances are not operating during this interval.  
DANGER  
HOT WATER TEMPERATURES REQUIRED FOR AUTOMATIC  
DISHWASHER AND LAUNDRY USE CAN CAUSE SCALD  
BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/  
OR DEATH. THE TEMPERATUREAT WHICH INJURY OCCURS  
VARIES WITH THE PERSON’SAGEAND 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  
ACHILD OR DISABLED PERSON UNATTENDED INABATHTUB  
OR SHOWER.  
3600  
T
x H = Btuh  
T = Time (in seconds) to burn one cubic foot of gas.  
H = Heating value of gas (in Btu’s per cubic foot of gas).  
Btuh = Actual heater input (in Btuh).  
EXAMPLE: (Using HW-120M heater)  
T = 31.5 seconds/ft3  
THE WATER HEATER SHOULD BE LOCATED IN AN AREA  
WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS  
TO SET TEMPERATURES.  
H = 1050 Btu/ft3  
Btuh = ?  
3600 x 1050 = 120,000 (compare with the ratings in  
31.5 Table 5).  
Should it be necessary to adjust the gas pressure to the burners  
to obtain the full input rate, the steps below should be followed.  
5. Remove the regulator adjustment sealing cap, fig. 14, and  
adjust the pressure by turning the adjusting screw with a  
screwdriver.  
It is recommended in domestic hot water applications that lower  
water temperature 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 boiler and minimize scale formation in the heat exchanger,  
thus prolonging the life of the boiler.  
• Clockwise  
to increase gas pressure and input rate.  
• Counterclockwise  
rate.  
to decrease gas pressure and input  
DO NOT turn the adjusting screw in past the point of little or no  
manifold pressure change or fully bottom the adjusting screw.  
SETTING THE WATER HEATER TEMPERATURE AT 120°F  
(49°C) WILL REDUCE THE RISK OF SCALDS. Some states  
require settings at specific lower temperatures. The table below  
shows the approximate time-to-burn relationship for normal adult  
skin.  
6. “Clock” the meter as in step 4 above.  
7. Repeat steps 5 and 6 until the specified input rate is achieved.  
8. Turn the gas valve control knob to “OFF”. Replace the regulator  
adjustment sealing cap and remove the pressure gauge or  
manometer from the outlet pressure tap. Using an allen  
wrench, replace the set screw in the outlet pressure tap.  
Temperature  
Setting  
Over 170°F (77°C)  
160°F (71°C)  
150°F (66°C)  
140°F (60°)  
Time to Produce 2nd & 3rd  
Degree Burns on Adult Skin  
Nearly instantaneous  
About 1/2 seconds  
9. Turn the gas valve control knob to “ON”.  
About 1-1/2 seconds  
Less than 5 seconds  
About 30 seconds  
If gas pressure regulator cannot be equipped to give the full input  
rating with sufficient gas pressure at the valve, re-orifice the main  
burners.  
130°F (54°)  
120°F (49°C) or less  
More than 5 minutes  
Table 7  
IMPORTANT  
UNDER NO CIRCUMSTANCES SHOULD THE GAS INPUT  
EXCEED THE INPUT SHOWN IN TABLE 2. OVERFIRING  
COULD RESULT IN DAMAGE OR SOOTING OF THE HEATER.  
USE ANTI-SCALD VALVE(S) in the hot water system to reduce  
the risks of scalding at points of use such as lavatories, sinks and  
bathing facilities.  
When the heater is operating at full capacity, or full gas input, it  
should consume 1 cu. ft. of gas in approximately the amount of  
time indicated in table 8.  
CAUTION  
IN THE EVENT OF ELECTRIC POWER FAILURE, DO NOT  
ATTEMPT TO OPERATE THE HEATER.  
TABLE 8 — TIME REQUIRED TO CONSUME 1 CUBIC FT. OF GAS  
(Heater operating at full input or full capacity.  
Does not apply to high altitude installations.)  
CHECKING AND ADJUSTING THE INPUT  
The maximum inlet gas pressure must not exceed the value  
specified by the manufacturer (10.5" W.C. - natural gas,  
13.0" W.C. - propane gas). The minimum value listed on the  
Rating Plate is for the purposes of input adjustment.  
Heating  
Value  
(Btu/  
Total Time Required (Seconds)  
MODEL  
Type of  
Gas  
Cu. Ft.)  
HW-120M  
HW-160M HW-200M HW-225M  
Natural  
1050  
2500  
31.5  
78.3  
23.6  
56.3  
19.0  
45.2  
16.8  
- - -  
Propane  
1. Turn the gas valve control knob to “OFF”, (See page 18).  
19  
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SERVICE INFORMATION  
The installer may be able to observe and correct certain problems  
which may arise when the unit is put into operation. HOWEVER,  
it is recommended that only qualified service personnel, using  
appropriate test equipment, be allowed to service the heater.  
5. Restore electrical power and gas supply to heater.  
Check for gas leaks and proper heater and vent operation.  
I.I.D. PILOT BURNER  
Any safety devices used in conjunction with this appliance should  
receive periodic (at least twice a year) inspection to assure proper  
operation. All relief valves should be inspected and manually  
operated every six months.  
Servicing of the pilot burner includes cleaning the burner head  
and the orifice of the pilot burner, fig. 15.  
The pilot flame should envelop 3/8 to 1/2 in. of the tip of the  
insulated rod on the igniter-sensor. If adjustment is required, it is  
necessary to establish pilot flame without main burner operation.  
For this to happen, perform the following steps.  
PILOT AND MAIN BURNER MAINTENANCE  
At least twice a year, check the pilot burner, fig. 15 and the main  
burners, fig 13, for proper operation.  
1. Follow “TO TURN OFF GAS TO APPLIANCE” steps in the  
“OPERATING INSTRUCTIONS FOR I.I.D. MODELS”.  
The burners should display the following characteristics:  
2. Carefully disconnect the wire terminal connected to the  
MV terminal of the S8600 module, fig. 3.  
Provide complete combustion of gas.  
Cause rapid ignition and carryover of flame across entire  
burner.  
Give reasonably quiet operation during ignition, burning and  
extinction.  
3. Turn gas valve control knob counterclockwise to “ON”.  
4. Turn on all electric power to the heater.  
Cause no excessive lifting of flame from burner ports.  
5. Set tank temperature control to call for heat. Pilot will operate  
without the main burners igniting.  
If the preceding burner characteristics are not evident, check for  
accumulation of lint or other foreign material that restricts or blocks  
the air openings to the burners or heater.  
6. Remove the pilot adjustment cover screw, fig. 14, and turn the  
inner adjustment screw clockwise  
to decrease or  
Also check for good flow of combustion and ventilating air to the  
unit. Maintain a clear area around the heater at all times.  
counterclockwise to increase the pilot flame. Be sure to  
replace cover screw after adjustment to prevent possible gas  
leakage.  
Qualified servicers should follow this procedure when the heater’s  
burners need cleaning.  
7. Repeat step 1.  
1. Turn off the electrical power and close the main manual gas  
shutoff valve.  
8. Carefully reconnect the MV wire terminal to the S8600 module.  
Be sure the terminal is securely connected.  
9. Follow “OPERATING INSTRUCTIONS FOR I.I.D. MODELS”  
to put heater back into operation.  
• Allow heater parts to cool before disassembly.  
2. Remove main burner manifold assembly from heater.  
If the pilot burner ignites but the main burner fails to light, check  
for gas flow to the main burner.  
Refer to parts list supplied with this manual for disassembly  
aid.  
Check for good terminal connections at the igniter-sensor  
connector (fig. 15) and at the S8600 module.  
3. Remove any loose foreign material such as dust or lint with a  
vacuum. Check all ports, orifices and air openings for blockage.  
Dislodge any foreign material causing blockage. Do not use  
sharp metal objects to clean blocked orifices as they will  
damage the soft brass orifice. Remove any soot or carbon  
deposits with a rag making sure to remove any lint left on burner  
by vacuuming again.  
For further assistance see Chart 2, “S8600 INTERMITTENT PILOT  
SYSTEM TROUBLESHOOTING”.  
MAIN BURNER FOR HW HEATERS  
FIGURE 13  
HONEYWELL GAS VALVE FOR I.I.D. SYSTEM (TOP VIEW)  
FIGURE 14  
4. Reinstall the burner manifold assembly on heater.  
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If control is out of calibration, replace control.  
AUTOMATIC GAS SHUTOFF CONTROL  
The automatic gas shutoff control, fig. 1, is an automatic device  
which is wired in series with the gas valve and intermittent ignition  
control module.  
The control settings are fixed at 1950F (90.5°C) cut-out and 1900F  
(87.7°C) cut-in. Reduced water flow due to lime scale  
accumulation is one cause of frequent automatic gas shutoff  
control operations. Refer to “PREVENTIVE MAINTENANCE”  
section for deliming instructions. If this non-adjustable control is  
out of calibration, replace control.  
PILOT BURNER USED ON I.I.D. SYSTEMS  
FIGURE 15  
THERMAL BALANCER  
PROTECTOR SWITCH  
(Coil High Limit - All Heaters)  
Figure 16 shows the internal wiring of the thermal balancer. The  
device may be tested after disconnecting the four leads from their  
respective terminals on the unit.  
If the protector switch, fig 2, should shut off unit, check for the  
following conditions:  
1. Apply a test light to the yellow and red leads:  
• The lamp should light as the contact in this circuit is normally  
closed when the resistor is cool.  
1. No water in heater.  
2. Restricted water flow through the heater.  
3. Excessive liming.  
4. Improper wiring (automatic gas shutoff control acting as primary  
control).  
5. Pump failure.  
2. Apply the light to the black and yellow leads.  
The lamp should not light as the contact in this circuit is  
normally open when the resistor is cool.  
3. Remove the test light.  
After correcting failure condition, remove the protector switch cover  
and depress reset button. Button will not reset until water  
temperature in heater coil is down to 2000F. Restart heater,  
following the “OPERATING INSTRUCTIONS FOR I.I.D.  
MODELS” , PAGE 18.  
4. Apply 120 volts to the white and red leads which power the  
1900 ohm resistor.  
After warming period, the contacts of the thermal balancer  
should change position.  
5. Remove the 120 volt power source.  
PROTECTOR SWITCH CONTINUITY TEST  
6. Apply the test light as described in steps 1 and 2.  
Do not depress the protector switch reset button prior to testing.  
The leads from the switch are removed at the point farthest from  
the switch.  
While the resistor is still warm, the lamp indications should  
be the opposite as described above. If this is not the case,  
replace the thermal balancer.  
Attach the leads from a test flashlight to the switch leads.  
The Model N22T test kit (combination flashlight and continuity  
tester) is manufactured by the Ray-O-Vac Company, Madison,  
WI and available through your local suppliers.  
With the flashlight turned on, the lamp should light. If the lamp  
lights, the protector switch circuit is closed and in proper working  
order. If the lamp does not light, the reasons could be:  
1. Protector switch contacts open.  
Depress reset button on switch (switch cannot be reset until  
water temperature in the heater coil drops below 2000F).  
Lamp should light.  
THERMAL BALANCER SCHEMATIC DIAGRAM  
FIGURE 16  
INSPECTING THE HEAT EXCHANGER  
AND VENTING SYSTEM  
2. Defective protector switch or bad leads.  
If lamp does not light when reset button is depressed, attach  
the test flashlight leads to the protector switch terminals. If  
Every 6 months, inspect the venting system (including the  
lamp does not light, switch is defective and must be replaced. chimney) for blockages which will retard free draft and points of  
flue gas leakage. Remove any obstructions and replace any  
damaged or deteriorated vent pipe.  
If lamp does not light, the leads are bad and must be repaired  
or replaced.  
Check the heat exchanger to be sure it is not blocked by dirt or  
soot. It is not sufficient to only look through the flue outlet with  
the draft hood removed. Examination should also be made using  
a mirror and light through the burner opening, viewing the entire  
bottom area of the exchanger.  
TANK TEMPERATURE CONTROL  
The tank temperature control is the primary operating control of  
the system. The sensing element is mounted on the hot water  
storage tank. A change of temperature lower than the control  
setting will cause the element to activate the electrical switch and  
start the heater.  
Qualified servicers should follow this procedure when the heater’s  
external heating surfaces need cleaning.  
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with sufficient gas pressure at the valve, replace with new gas  
valve.  
CAUTION  
DO NOT USEANYLON BRUSH OR OTHER STATIC CREATING  
MATERIAL TO CLEAN DUSTAND CARBON DEPOSITS FROM  
HEATING SURFACES AND VENT.  
RELIEF VALVE  
At least twice a year the system relief valves should be checked  
to ensure that they are in operating condition. To check a relief  
valve, lift the lever at the end of the valve several times. The  
valve should seat properly and operate freely.  
SUCH DEPOSITS ARE FLAMMABLE AND MAY BE IGNITED  
BY STATIC ELECTRICITY. USE AMETAL BRUSH TO MINIMIZE  
THE DANGER OF EXPLOSION.  
1. Turn off the electrical power and main manual gas shutoff valve.  
CAUTION  
Allow heater parts and vent to cool before disassembly.  
BEFORE MANUALLY OPERATING A RELIEF VALVE, MAKE  
SURE THAT A DRAIN LINE HAS BEEN ATTACHED TO THE  
VALVE TO DIRECT DISCHARGE TO AN OPEN DRAIN.  
FAILURE TO TAKE THIS PRECAUTION COULD MEAN  
CONTACT WITH EXTREMELY HOT WATER EXITING THE  
VALVE DURING THE CHECK OPERATION.  
2. Remove the heater draft diverter and vent pipe running to the  
chimney.  
Check parts and chimney for obstructions and clean as  
necessary.  
Replace any damaged or deteriorated parts of the venting  
system.  
If a relief valve discharges periodically or continuously, it may be  
due to thermal expansion of water in a closed water supply system,  
or, it may be due to a faulty relief valve.  
3. Remove burners from heater and other metal parts as required  
to clean and vacuum the heat exchangers and combustion  
coils.  
Thermal expansion is the normal response of water when it is  
heated. In a closed system, thermal expansion will cause the  
system pressure to build until the relief valve actuation pressure  
is equaled. Then the relief valve will open allowing some water to  
escape, slightly lowering the pressure.  
Refer to parts list supplied with this manual for disassembly  
aid.  
4. Reinstall the parts removed in steps 2 and 3.  
Be sure the vent pipe has a minimum upward pitch of one  
quarter inch per foot of length and is sealed as necessary. Installation of a properly sized thermal expansion tank will usually  
correct this problem. Contact your water supplier or local plumbing  
5. Restore electrical power and gas supply to heater.  
Check for gas leaks and proper heater and vent operation.  
inspector for information on how to best correct this situation.  
ABOVE ALL DO NOT PLUG ANY RELIEF VALVE. THIS IS NOT  
A SOLUTION AND CAN CREATE A HAZARDOUS SITUATION.  
Upon reassembly, a negative draft must be produced by the  
system. Check for proper draft by holding a lit match near the  
draft hood opening while the heater is operating. The flame should  
be drawn into the draft hood opening indicating proper draft.  
CIRCULATING PUMP  
The circulating pump may require occasional lubrication. Refer  
to circulator manufacturer’s instructions for lubrication procedures,  
and lubrication frequency.  
GAS PRESSURE REGULATOR  
The gas pressure regulator is included in the combination gas  
valve, fig.14, and is set to operate on the gas specified on the  
heater model and rating plate.  
ELECTRICAL SERVICE  
CAUTION  
Periodically check main burner, fig. 13, and pilot flame, fig. 15, for  
proper operation. This should be checked every six months.  
LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN  
SERVICING CONTROLS. WIRING ERRORS CAN CAUSE  
IMPROPER AND DANGEROUS OPERATION.  
Do not subject the gas valve to inlet gas pressure of more than  
10.5" W.C. - natural gas, 13.0" W.C. - propane gas. If higher gas  
pressures are encountered, a service regulator is necessary.  
VERIFY PROPER OPERATION AFTER SERVICING.  
REPLACEMENT PARTS  
Check for a minimum inlet gas pressure value shown on the Rating  
Plate before making any adjustment of the regulator.  
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 the A. O. Smith Water Products  
Company, 5621 West 115th Street, Alsip, IL 60803,  
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  
Attempts to adjust the regulator during periods of low gas supply  
pressure could result in overfiring of the heater when the gas  
supply pressure returns to normal.  
DO NOT INCREASE PRESSURE ABOVE THAT SPECIFIED AS  
OVERFIRING WILL RESULT IN DAMAGE TO THE HEATER  
.
If gas pressure regulator cannot be adjusted to correct pressure more information.  
PREVENTIVE MAINTENANCE  
The higher the water temperature or water usage, the more lime  
deposits are dropped out of the water. This is the lime scale  
which forms in pipes, heaters and on cooking utensils.  
RECOMMENDED PROCEDURE FOR PERIODIC  
REMOVAL OF LIME DEPOSITS FROM COIL  
TYPE COMMERCIAL WATER HEATERS  
Lime accumulation not only reduces the life of the equipment,  
but also reduces efficiency of the heater and increases fuel  
consumption.  
The amount of calcium carbonate (lime) released from water is in  
direct proportion to water temperature and usage, see fig. 17.  
22  
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The usage of water softening equipment greatly reduces the  
hardness of the water. However, this equipment does not always  
remove all of the hardness (lime). For this reason it is  
recommended that a regular schedule for deliming be maintained.  
The time between cleaning will vary from weeks to months  
depending upon water conditions and usage. A change of  
approximately 50F in the normal temperature rise through the  
heater is usually an indication that scale should be removed. For  
long life, copper or brass is recommended for all valves, pipe and  
fittings used between gate valves “A” and “B” and the heater, see  
fig. 18.  
Heater failure due to excessive lime build-up voids the warranty  
DELIMING THE HW WATER HEATER  
FIGURE 18  
6. Continue to fill until foaming action stops.  
7. When foaming action has stopped completely, allow 10 to 15  
minutes for UN•LIME to dissolve any remaining scale in the  
heater.  
8. Open the drain valve and drain all UN•LIME from the heater.  
9. Remove standpipe and drain hose assembly from tees. Install  
fittings originally removed into openings. Open valve “A”,  
allowing fresh water to flow through heater and out drain valve  
for 3 to 5 minutes.  
10.Close drain valve and open valve “B”. Heater is now ready for  
operation.  
HEAVY LIME DEPOSITS  
.
If the solvent does not readily pass through the clogged coils or  
heat exchanger, it will be necessary to use a deliming pump or  
contact a service agency for proper cleaning.  
FIGURE 17  
DELIMING SOLVENTS  
A. O. Smith part no. 4930 motorized deliming pump kit, complete  
with pump, hoses, fittings, container and instructions, is available  
from your dealer, distributor or A. O. Smith Water Products  
Company.  
A. O. Smith recommends the use of UN•LIME® for deliming.  
UN•LIME is a patented food grade acid which is safe to handle  
and does not create the harmful fumes which are associated with  
other products.  
A. O. Smith Form No. 4778, entitled “AllAbout Deliming Coil Type  
Water Heaters”, describes heater cleaning methods and  
equipment required. UN•LIME and the booklet may be obtained  
through your dealer, distributor or A. O. Smith Water Products  
Company.  
UN•LIME may be obtained from your dealer, distributor or the  
A. O. Smith Water Products Company. Order part no. 4763  
(1 gal.), packed 4 gallons per case, or part no. 4813 (5 gal.  
container).  
CAUTION  
Observe handling instructions on label of product being used.  
REMOVING LIGHT DEPOSITS  
1. Shut off electric and gas supply to the burner.  
2. Close gate valves “A” and “B”.  
3. Install drain hose assembly in upper deliming tee. Open drain  
cock and drain heater. Install standpipe in lower deliming tee  
or in tee from which pressure relief valve has been removed.  
4. Close drain valve.  
5. Slowly pour 3 gallons of UN•LIME into heater through  
standpipe. Direct solution into suitable container with a hose,  
see fig. 18.  
FIGURE 19  
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The part no. 4920 pump contained in the deliming kit is  
equipped with a titanium shaft. This shaft will not withstand  
ammonium bifluoride solutions and must be replaced with a  
stainless steel shaft, part no. 4926.  
REMOVING SILICATE  
Ammonium bifluoride flakes (NH4FlHF) are used in conjunction  
with A. O. Smith UN•LIME delimer and pump type deliming kit,  
part no. 4930, to delime and remove siliceous materials from  
copper coil water heaters.  
Ammonium bifluoride flakes should be purchased locally from  
chemical suppliers. Contact your dealer, distributor or  
A. O. Smith Water Products Company for additional information.  
CHECKOUT  
examined before using the checkout procedure. Be sure to refer  
to the correct piping - wiring diagram and checkout for the type of  
system that is installed.  
The checkout sequence should be used as an on-the-job trouble-  
shooting guide to identify the cause of incorrect system operation  
and suggest a remedy for its correction.  
The system should be filled with water, purged of air, valves  
properly set and utilities connected and ready to operate.  
Because improper piping and wiring can result in unsatisfactory  
system performance, it is suggested that the installation be  
CHART 1 - CER-TEMP 80 RECOVERY SYSTEM CHECKOUT PROCEDURE  
(Use this checkout for Cer-Temp 80 Recovery Systems)  
SYSTEM OPERATION  
Checkout Sequence  
Contact  
Incorrect  
Cause  
Remedy  
Set tank temperature  
control 20° (11°C) below  
tank water temperature  
Circulating pump  
and burner shut  
off.  
Pump and burner  
remain on.  
Tank temperature control  
differential wide.  
Reduce differential.  
With thermal  
Tank temperature control  
defective.  
Replace.  
balancer, pump off  
delay of approx-  
imately 2 minutes.  
System wiring is incorrect.  
Correct wiring.  
Correct wiring.  
Circulating pump  
on.  
Pump wired for continuous  
operation.  
Burner on.  
See intermittent pilot system troubleshooting chart 2.  
Gas valve stuck or defective.  
System wiring in incorrect.  
Correct or replace valve.  
Correct wiring.  
Set tank temperature  
control 20° (11°C) above  
tank water temperature.  
Circulating pump  
and burner on.  
Circulating pump  
on.  
Automatic gas shutoff  
control calibrated too low  
or differential too wide.  
Replace. (If problem  
proven to be at this  
control by applying  
jumper to terminals.)  
If system has been in  
extended use it may  
have lime build-up.  
See preventive  
maintenance.  
System wiring is incorrect.  
Correct wiring.  
Gas valve or wiring  
defective.  
Check wiring repair or  
replace valve.  
See intermittent pilot system trouble-shooting chart 2.  
Circulating pump  
and burner off.  
Tank temperature control  
differential too great.  
Reduce differential. A 5°  
differential is generally  
used.  
Power off or system wiring  
is incorrect.  
Check power supply and  
wiring.  
Tank temperature control  
defective.  
Replace.  
See intermittent pilot system trouble-shooting chart 2.  
System wiring is incorrect. Replace.  
See intermittent pilot system trouble-shooting chart 2.  
Burner on.  
Heater outlet water  
temperature exceeds  
210°F.  
Circulating pump  
on.  
Circulating pump  
and burner on.  
Automatic gas shutoff  
control defective.  
Replace.  
See intermittent pilot system trouble-shooting chart 2.  
Set tank temperature  
control for desired water  
temperature.  
System maintains.  
desired water  
temperature.  
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CHART 2  
S8600 (NATURAL GAS AND LP GAS)  
INTERMITTENT PILOT SYSTEM TROUBLESHOOTING  
NO SPARK AT PILOT BURNER  
Turn gas supply off.  
NO  
Replace ignition module.  
Is voltage (24 Vac) across the 24 V terminals on “Call for heat”?  
YES  
Is voltage (24 Vac) across the PV & MV/PV terminals on  
“call for heat”?  
NO  
NOTE: (FOR LP MODELS ONLY) Pilot valve will be de-energized  
if module goes into lockout condition. Reset system by turning  
electrical power off or by turning system controller to “OFF” or  
down below “Call for heat”. Wait one minute then turn system on.  
YES  
Turn on gas supply.  
turn on power supply.  
Turn off power supply.  
NO  
Is ignition cable firmly plugged into module?  
Securely connect cable  
and/or ground wire.  
Is green ground wire firmly attached to mounting screw  
and GND terminal on module?  
YES  
Ensure ground strap is the closest metal to the igniter/sensor  
rod (electrode) to prevent the spark from shorting out  
to other metal parts (pilot screen, pilot shield, etc.).  
NO  
NO  
Carefully bend downward  
top of ground strap  
to achieve 1/8”  
Ignition cable must not touch metal surfaces or  
current carrying wires.  
spark gap.  
Is there a 1/8” gap between ground strap and electrode?  
YES  
Are the ceramic insulators surrounding the electrode  
cracked or broken?  
Replace ignition  
module.  
YES  
Replace pilot burner assembly or bus bar.  
25  
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CHART 2  
S8600 (NATURAL GAS AND LP GAS)  
INTERMITTENT PILOT SYSTEM TROUBLESHOOTING  
SPARK AT PILOT BURNER BUT PILOT WILL NOT LIGHT  
Ensure all manual shutoff valves are fully open; All filters are  
clean; All gas connections are gas tight; Pilot tubing is not  
damaged, obstructed or kinked; and pilot orifice is unclogged.  
Check for air in gas line, purge (bleed) line if necessary.  
NO  
NO  
Are the wires securely attached to the pilot operator on the gas  
control and to the PV & MV/PV terminals on the ignition module?  
Attach wires firmly.  
YES  
Install a pressure gauge in the pilot tubing line between the gas  
control and the pilot burner assembly. Ensure that the pilot  
adjustment screw (under cap) is adjusted to a position that will  
permit gas to flow.  
Replace gas valve.  
Is pilot gas flowing during ignition attempt?  
YES  
Turn on power supply  
Turn off power supply.  
Is ignition cable firmly plugged into module?  
NO  
Securely connect  
cable and/or ground  
wire.  
Is green ground wire firmly attached to mounting screw  
and GND terminal on module?  
YES  
NO  
Replace pilot burner  
and/or ground wire.  
Is pilot burner ignition cable in good condition (not brittle, burnt, or cracked)?  
YES  
Ensure ground strap is the closest metal to the igniter/sensor  
rod (electrode) to prevent the spark from shorting out to  
other metal parts (pilot screen, pilot shield, etc.).  
NO  
Carefully bend down-  
wards top of ground  
strap to achieve  
Ignition cable must not touch metal surfaces or  
current carrying wires.  
1/8” spark gap.  
Is there a 1/8” gap between ground strap and electrode?  
YES  
NO  
Are the ceramic insulators surrounding the electrode in good  
Replace pilot burner.  
condition (not cracked or broken)?  
YES  
NO  
Replace ignition  
module.  
Is there excessive draft conditions that may cause pilot  
burner ignition problems?  
YES  
Correct draft problems in a manner that would ensure  
adequate combustion and ventilation air and proper  
pilot burner performance.  
26  
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CHART 2  
S8600 (NATURAL GAS AND LP GAS)  
INTERMITTENT PILOT SYSTEM TROUBLESHOOTING  
PILOT BURNER LIGHTS BUT MAIN BURNER DOES NOT LIGHT  
Correct the situation by consulting the  
installation or user’s manual on how to  
adjust pilot flame.  
NO  
NO  
Does the pilot flame cover 3/8” to 1/2”  
of igniter/sensor rod?  
YES  
Replace  
ignition  
module.  
NO  
NO  
Does spark stay on for more than 30 seconds  
after the pilot is “proven” (lit)?  
Is voltage (24 Vac) across terminals  
MV & MV/PV?  
Are the wires securely attached to the main  
valve operator on the gas control and to  
terminals MV & MV/PV on ignition module?  
Attach  
wires  
firmly.  
YES  
Replace main gas valve.  
NO  
NO  
Is the pilot burner ignition cable in good  
condition (not brittle, burnt, or cracked)?  
Replace pilot burner.  
Replace pilot burner.  
YES  
Are the ceramic insulators surrounding the  
igniter/sensor rod in good condition  
(not broken or cracked)?  
YES  
Are the igniter/sensor rod in good  
condition (not worn, corroded, sooted  
or damaged)?  
NO  
Clean rod or replace  
pilot burner if necessary.  
YES  
Replace ignition module.  
27  
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MODEL HW LIMITED WARRANTY  
A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this water heater.  
1. If within FIVE years after initial installation of this water heater, a heat exchanger, coil or gas burner 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.  
a.  
This warranty is extended to the owner for all other parts or portion during the FIRST year following initial installation of this water heater.  
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 water heater 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 temperature and pressure relief valve, certified by A.G.A. and  
approved by the American Society of Mechanical Engineers, must have been installed.  
a.  
This warranty shall apply only when the heater is:  
(1) used at temperatures not exceeding the maximum calibrated setting of its thermostat;  
(2) used at water pressure not exceeding the working pressure shown on the heater;  
(3) filled with potable water, free to circulate at all times and with the tank free of damaging water sediment or scale deposits;  
(4) used in a non-corrosive and non-contaminated atmosphere;  
(5) in its original installation location;  
(6) in the United States, its territories or possessions, and Canada;  
(7) sized in accordance with proper sizing techniques for commercial and/or residential water heaters;  
(8) bearing a rating plate which has not been altered, defaced or removed, except as required by the warrantor;  
(9) operated with properly installed dirt leg;  
(10) fired with the fuel for which it was factory built;  
(11) fired at the factory rated input;  
b.  
c.  
Any accident to the water heater, any misuse, abuse (including freezing) or alteration of it, any operation of it in a modified form, or any  
attempt to repair tank leaks will void this warranty.  
This warranty is void if a device acting as a backflow prevention device (check valves etc.) is installed in the cold water supply the heater  
is connected to, unless an effective method of controlling thermal expansion is also installed at the heater(s) and operational at all times.  
The relief valve installed on the heater is not an acceptable method.  
3. SERVICE AND REPAIR EXPENSES  
Under the limited warranty the warrantor will provide only a replacement water heater or part thereof. The owner is responsible for all other costs.  
Such costs may include but are not limited to:  
a.  
b.  
Labor charges for service removal, repair or reinstallation of the water heater or any component part;  
Shipping, delivery, handling, and administrative charges for forwarding the new heater or replacement part from the nearest distributor and  
returning the claimed defective heater or part to such distributor.  
c.  
All cost necessary or incidental for any material and/or permits required for installation of the replacement heater or part.  
4. LIMITATIONS ON IMPLIED WARRANTIES  
Implied warranties, including the warranty of merchantability imposed on the sale of this heater under state law are limited to one (1) year duration  
for the heater or any of its parts. Some states do not allow limitation 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 heater, 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  
A. O. Smith Enterprises Ltd.  
P. O. Box, 310 - 768 Erie Street  
Stratford, Ontario N5A 6T3  
a.  
b.  
The warrantor will only honor replacement with identical or similar water heater or parts thereof which are manufactured or distributed by  
the warrantor.  
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  
MERCHANTABILITY OF THE HEATER OR THE INSTALLATION, OPERATION, REPAIR OR REPLACEMENT OF THE HEATER. 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 IN TORT.  
a.  
Some states 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.  
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 heater’s  
rating plate.  
Model No.  
Dealer’s Name__________________________________________________________________________________________________________  
Dealer’s Address ________________________________________________________________ _ Phone No.____________________  
______ Serial No.  
________________________________ Date Installed ________________  
City and State_____________________________________________________________________________ Zip _________________________  
KEEP THIS WARRANTY POSTED ADJACENT TO THE HEATER FOR FUTURE REFERENCE.  
28  
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