A.O. Smith 160M User manual

1
PART NO. 212626-000
PRINTED IN U.S.A. 0905 SUPERSEDES PART NO. 192011-000 REV.4
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.)
A DIVISION OF A.O. SMITH CORPORATION
McBEE,SOUTHCAROLINA,USA
RENTON,WA, USA
STRATFORD,ONTARIO,CANADA
VELDHOVEN, THE NETHERLANDS
www.hotwater.com
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER
AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE
•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
•Do not try to light any appliance.
•Do not touch any electrical switch;
do not use any phone in your
building.
•Immediately call your gas supplier
from a neighbor’s phone. Follow
the gas supplier’s instructions.
•If you cannot reach your gas
supplier, call the fire department.
— Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
CAUTION
TEXT PRINTED OR OUTLINED IN RED CONTAINS
INFORMATION RELATIVE TOYOUR SAFETY. PLEASE READ
THOROUGHLY BEFORE USING APPLIANCE.

2
ROUGH-IN-DIMENSIONS
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.
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 - CAPACITYAND GAS AND ELECTRIC CHARACTERISTICS
Manifold Pressure Maximum Supply Pressure Electrical Characteristics
Model Type of Gas Inches W.C. kPa Inches W.C. kPa Volts/Hz Amperes
HW-120M thru 225M NATURAL 3.5 0.87 10.5 2.61 120/60 <5
HW-120M thru 200M PROPANE 10 2.49 13.0 3.23 120/60 <5
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.
Models HW-120M HW-160M HW-200M HW-200M
Dimensions Inches mm Inches mm Inches mm Inches mm
A49 3/8 1254 50 1/8 1273 53 1/4 1353 60 1524
B30 3/8 772 30 3/8 772 33 1/8 841 33 1/8 841
C23 5/8 600 23 5/8 600 27 1/8 689 27 1/8 689
D20 3/4 527 20 3/4 527 20 3/4 527 20 3/4 527
E5 1/2 140 5 1/2 140 5 1/2 140 5 1/2 140
F10 254 10 254 10 254 10 254
G11 13/16 300 11 13/16 300 11 13/16 300 11 13/16 300
H6 152 7 178 7 178 7 178
J26 11/16 678 26 11/16 678 26 11/16 678 26 11/16 678
K20 3/4 527 20 3/4 527 20 3/4 527 20 3/4 527
L1 1/4 NPT 1 1/4 NPT 1 1/4 NPT 1 1/4 NPT
M1 NPT 1 NPT 1 NPT 1 NPT
N1/2 NPT 1/2 NPT 1/2 NPT 1/2 NPT
W1 3/4 44 1 3/4 44 1 3/4 44 1 3/4 44
Approx.
Shipping 120 lbs. 54 Kg. 155 lbs. 70 Kg. 165 Lbs. 75 Kg. 175 lbs. 79 Kg.
Weight
TABLE 1 - ROUGH-IN DIMENSIONS
TABLE 2 - RECOVERY CAPACITIES U.S. Gallons/Hrs. and Litres/Hr. at TEMPERATURE RISE INDICATED
Input F° 20F° 30F° 36F° 40F° 50F° 54F° 60F° 70F° 72F° 80F° 90F° 100F° 108F° 110F° 120F° 126F° 130F° 140F°
Model Btuh 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 GPH 605 403 336 303 242 224 202 173 168 151 134 121 112 110 101 96 93 86
35 LPH 2290 1527 1272 1145 916 848 763 654 636 573 509 458 242 416 382 364 352 327
160,000 GPH 777 518 432 388 311 288 259 222 216 194 173 155 144 141 129 123 120 111
47 LPH 2941 1961 1634 1471 1176 1089 980 840 817 735 654 588 545 535 490 467 452 420
199,000 GPH 987 658 548 494 395 366 329 282 274 247 219 197 183 179 165 157 152 141
58 LPH 3737 2491 2076 1869 1495 1384 1246 1068 1038 934 830 747 692 679 623 593 575 534
225,000 GPH 1096 731 609 548 438 406 365 313 304 274 244 219 203 199 183 174 169 157
66 LPH 4149 2766 2305 2074 1659 1537 1383 1185 1152 1037 922 830 768 754 691 659 638 593
HW-120M
HW-160M
HW-200M
HW-2250M

3
FOREWORD
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.
Detailedinstallationdiagramsarein thismanual. These diagrams
will serve to provide the installer with a reference for the materials
and method of piping suggested. IT IS ESSENTIAL THAT ALL
WATERAND GAS PIPING AND THE ELECTRICAL WIRING BE
INSTALLEDANDCONNECTEDASSHOWN INTHEDIAGRAMS.
You should thoroughly read and understand this manual before
installation and operation of this unit.
CHECK THE DIAGRAMS THOROUGHLY BEFORE STARTING
INSTALLATION TO AVOID POSSIBLE ERRORS AND TO
MINIMIZE TIME AND MATERIALS COST.
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.
MAKE SURE THE GAS ON WHICH THE HEATER WILL
OPERATEISTHE SAMEASTHATSPECIFIEDONTHE HEATER
MODEL AND RATING PLATE.
Thefactory warrantywill bevoid ifthe unit(s)havebeenimproperly
installed or operated.
In addition to these instructions, the boiler(s) shall be installed in
accordance with those installation regulations in force in the local
areawherethe installationis tobemade. These shallbe carefully
followed in all cases. Authorities having jurisdiction should be
consulted before installations are made.
In absence of local codes, the installation must comply with the
latest editions.
In the United States:
The National Fuel Gas Code, ANSI Z223.1 and the National
Electric Code, NFPA 70.
In Canada:
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,
CanadianGasAssociationLaboratories,55 ScarsdaleRoad, Don
Mills, Ontario M3B 2R3, Canada.
TABLE OF CONTENTS
ROUGH-INDIMENSIONS .................................................................. 2
FOREWORD....................................................................................... 3
GENERAL SAFETY INFORMATION .................................................. 3
Precautions .................................................................................... 3-4
GroundingInstructions ................................................................... 4
Chemical Vapor Corrosion ............................................................. 4
Liquid Petroleum Models ................................................................ 4
High Altitude Installations ............................................................... 4
FEATURES ......................................................................................... 5
Automatic Gas Shutoff Control ....................................................... 5
Protector Switch (Coil High Limit)................................................... 5
Thermal Balancer........................................................................... 5
IntermittentIgnition Control Module ................................................ 5-6
Circulating Pump............................................................................ 6
Tank Temperature Control (Not Supplied) ...................................... 6
Safety Flow Switch (Not Supplied) ................................................. 6-7
Drain Valve (Not Supplied) ............................................................. 7
Thermometers (Not Supplied) ........................................................ 7
INSTALLATION INSTRUCTIONS ....................................................... 8
Important ........................................................................................ 8
RequiredAbility .............................................................................. 8
Location ......................................................................................... 8
InstallationClearances ................................................................... 8
Levelling......................................................................................... 8
Air Requirements ........................................................................... 8-9
Venting ........................................................................................... 9
Relief Valve .................................................................................... 9-10
Hard Water..................................................................................... 10
Closed Water System .................................................................... 10
Water Line Connections ................................................................ 10
Water (Potable) Heating ................................................................ 10
PIPING DIAGRAMS ............................................................................ 11-13
Gas Connections ........................................................................... 14-15
Electrical Information..................................................................... 15-16
OPERATION........................................................................................ 17
Important ....................................................................................... 17
General........................................................................................... 17
Filling.............................................................................................. 17
Purging Of Gas Line ...................................................................... 17
Operating Instructions For I.I.D Models. ....................................... 18
Checking And Adjusting The Input................................................. 19
SERVICE INFORMATION .................................................................. 20
PilotAnd Main Burner Maintenance ............................................... 20
I.I.D. Pilot Burner ........................................................................... 20-21
Protector Switch (Coil High Limit-All Heaters) ............................... 21
TankTemperatureControl .............................................................. 21
Automatic Gas Shutoff Control ..................................................... 21
ThermalBalancer ........................................................................... 21
Inspecting The Heat Exchanger And Venting System .................. 21-22
Gas Pressure Regulator ................................................................ 22
Relief Valve ................................................................................... 22
Circulating Pump............................................................................ 22
Electrical Service ........................................................................... 22
Replacement Parts ........................................................................ 22
PREVENTIVEMAINTENANCE ........................................................... 22
Recommended Procedure For Periodic Removal Of Lime
Deposits From Coil Type Commercial Water Heaters ................. 22-23
Deliming Solvents.......................................................................... 23
Removing Light Deposits .............................................................. 23
Heavy Lime Deposits ................................................................... 23-24
CHECKOUT ........................................................................................ 24-27
LIMITED WARRANTY ........................................................................ 28
PAGE
PAGE
GENERAL SAFETY INFORMATION
PRECAUTIONS
If the unit is exposed to the following, do not operate heater until
all corrective steps have been made by a qualified serviceman:
1. FLOODING TO LEVEL OF BURNER OR CONTROLS OR
HIGHER.
2. EXPOSURE TO FIRE.
3. IF DAMAGED.
4. FIRING WITHOUT WATER.
5. SOOTING.
KEEP THE HEATER AREA CLEAR AND FREE FROM
COMBUSTIBLE MATERIALS, GASOLINE AND OTHER
FLAMMABLEVAPORSANDLIQUIDS. AREAAROUNDHEATER
MUST NOT CONTAIN OBSTRUCTING MATERIAL TO THE
FLOW OF COMBUSTION AND VENTILATING AIR.

4
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL
TO SHUT OFF, TURN OFF THE MANUAL GAS CONTROL
VALVE TO THE APPLIANCE.
Heater must be protected from freezing downdrafts during
shutdown periods.
GROUNDING INSTRUCTIONS
This water heater must be grounded in accordance with the
NationalElectric Codeand/or localcodes. Thesemustbefollowed
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.
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.
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.)
LIQUID PETROLEUM MODELS
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.
At times you may not be able to smell an LP gas leak. One cause
is odor fade, which is a loss of the chemical odorant that gives LP
gas its distinctive smell. Another cause can be your physical
condition, such as having a cold or diminishing sense of smell
with age. For these reasons, the use of a propane gas detector
is recommended.
IF YOU EXPERIENCE AN OUT-OF-GAS SITUATION, DO NOT
TRY TO RELIGHT APPLIANCES YOURSELF. Only trained LP
professionals should conduct the required safety checks in
accordance with industry standards.
HIGHALTITUDE INSTALLATIONS
WARNING
INSTALLATIONSABOVE2000 FEETREQUIREREPLACEMENT
OF THE BURNER ORIFICE IN ACCORDANCE WITH SECTION
8.1.2OFTHENATIONALFUELGASCODE(ANSIZ223.1). 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
MONOXIDEGASIN EXCESSOF SAFELIMITSWHICH COULD
RESULT IN SERIOUS PERSONAL INJURY OR DEATH.
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
reducedat highaltitudesforsatisfactoryoperation withthe 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.
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).
CANADIAN REQUIREMENTS
Appliances with inputs up to and including 400,000 BTU (117.2
Kw)must befactoryequipped withorifices foroperation atspecific
elevations. Standard (sea level) orifices permit operation up to
2000’ (610m) elevation. For operation between 2000’ (610m)
and4500’(1370m) specify“HIGHALTITUDEOPERATION”when
orderingthe heater(s). Foroperation above4500’ (2370m)consult
factory before ordering.
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
themainburnerorifice. Todo this,the mainburnerorificesrequire
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.
Upon completion of derating of the heater, adjustment to the gas
pressureregulator maybe required. SeeCHECKING THEINPUT
section in this manual for inlet and manifold pressure
requirements.
Also due to the input rating reduction required at high altitudes,
the output rating of the appliance is reduced and should be
compensatedforin thesizing ofthe equipment forthe application.

5
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).
Shouldtheautomatic gasshutoffcontrolactivate duringaheating
cycle, the heater’s gas valve will close; extinguishing the main
burners. Thepilot burnerwill alsobe extinguished. Thecirculating
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.
AUTOMATIC GAS SHUTOFF CONTROL
FIGURE 1
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).
FIGURE 2
DO NOT RESET THIS SWITCH WITHOUT PERFORMING THE
SYSTEM CHECKS OUTLINED UNDER PROTECTOR SWITCH
INTHESERVICEINFORMATION SECTION. ALSO,SEECHART
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
efficiencyandbalances heatertemperature withtanktemperature
at shutdown.
INTERMITTENT IGNITION CONTROL MODULE
The Honeywell S-8600 control module contain the electronic
components of the system and also serve as a central wiring
systemfor thecontrols mountedontheheater. The controlmodule
performs the following functions:
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.
FEATURES
Control Device Factory Setting Field Adjustment
1950F (90.5°C) cut out temp.
Heater Automatic Gas Shutoff Control Fixed 1900F (87.7°C) cut in temp. Non-adjustable
2500F (121°C) cut out temp.
Heater Protector Switch Fixed 2000F (93.3°C) cut in temp. Non-adjustable
Tank Temperature Control Field Supplied and Installed Adjust to Requirements
Safety Flow Switch See Table 1 Field Adjustable
TABLE 4.

6
4. Discontinuesignition sparkwhenthe pilotflame isestablished.
The S-8600 control used on propane gas models provides
safety lockout if the pilot fails to ignite within the pilot flame
establishing period. The S-8600 control used on natural gas
modelscontinues trialfor ignitionuntil pilotflame isestablished.
5. After proof-of-pilot flame, opens the main valve.
6. On a power loss, shuts the heater down. When power is
restored it will begin a new ignition cycle.
7. On a loss of flame, shuts off main gas and starts trial for pilot
ignition.
INTERMITTENT IGNITION CONTROL MODULE (I.I.D.)
FIGURE 3
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.
Onlyall bronzecirculatorsareusedwith commercialwaterheaters.
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.
Thereafter, lubricate the three oil cups at least once every 4
months.
TYPICAL CIRCULATING PUMP
FIGURE 4
Use 2 or 3 teaspoonsful in bearing oil cups, and 10 or 12 drops in
the motor oil cups. Use no. 20 non-detergent motor oil.
Follow the same oiling procedure if a replacement circulator is
installed into the system.
TANK TEMPERATURE CONTROL
(Not Supplied)
DANGER
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
bathing facilities.
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
normaluse, thethermostat shouldbeadjustedtothe lowestsetting
whichproduces anacceptable hotwater supplytemperature. This
willalwaysgive themost energy efficient operation. Donot adjust
thethermostat toachieveastoragetemperature of190oF(87.7°C)
orabove. Thisactionmaycause theautomatic gasshutoffcontrol
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.
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.
An accessory package A.O.S. No. 211480 containing a safety
flow switch is available for this application.
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.
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
sideof theflow switch(i.e.donotlocate adjacenttovalves,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
adjusted or trimmed to the size of the pipe in which it will be
installed.

7
CAUTION
Any part of the paddle must not touch the pipe or any restrictions
in the pipe. Screw the flow switch in position so the flat of the
paddle is at right angles to the flow. The arrow on the side case
must point in the direction of the flow.
The safety flow switch may be field adjusted to obtain higher
minimum flow rates than those shown in Table 5.
To adjust the flow rate setting:
1. Remove the flow switch cover.
2. Forhigher flowrate—turnthe rangeadjusting screwclockwise.
3. For lower flow rate—turn the range adjusting screw
counterclockwise.
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.
4. Replace the flow switch cover.
TABLE 5 - SAFETY FLOW SWITCH SETTINGS
Minimum Flow Rate (GPM)
Contacts Close Contacts Close Pkg.
Model GPM LPM GPM LPM No.
HW-120M,160M 0.6 2.3 0.3 1.1 211480
HW-200M 4.2 15.9 2.5 9.5 211480
HW-225M 5.8 22.0 3.7 14.0 211480
Theinstaller iscautioned tofollowthe manufacturer’s instructions
exactlywhen insertingthis switchintoapipetee. This isnecessary
in order to assure positive action of the switch with water flow.
Once the minimum flow rate (Table 5) through the heater is
reached, the safety flow switch contacts close and consequently,
main burner operation is achieved.
DRAIN VALVE (Not Supplied)
A drain valve must be obtained and installed on each heater and
tank for draining purposes, see installation diagrams in this
manual.
THERMOMETERS (Not Supplied)
Thermometers should be obtained and field installed as shown
in the installation diagrams.
Thermometersareinstalled inthe systemas ameansofdetecting
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
differencebetweentheheaterinlet andoutlet watertemperatures.
An increase of 50F (3°C) above the recorded temperature rise
maysignify alimingconditioninthecoilsor heatexchanger. Refer
to PREVENTIVE MAINTENANCE section of this manual for
deliming instructions.
Record temperature rise at initial start-up for future reference.
CAUTION: The paddle must be trimmed at the dotted arc. It must not touch the pipe or any restrictions when installed.
FIGURE 5

8
INSTALLATION INSTRUCTIONS
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.
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.
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.
THEHEATERSHOULD NOTBE LOCATEDINANAREAWHERE
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.
WHENSUCH LOCATIONSCANNOT 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.
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
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 SUCHAREAS
IF THEYARE INSTALLED 18 INCHES OR MORE ABOVE THE
FLOOR. THISMAYREDUCE THERISK IFLOCATION INSUCH
AN AREA CANNOT BE AVOIDED.
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.
Forapplianceinstallation inlocations withelevationsabove 2,000
feet (600M), refer to HIGH ALTITUDE INSTALLATIONS section
of this manual for input reduction procedure.
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.
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.
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.
LEVELLING
Each unit should be checked after installation to be certain that it
is level.
If the unit is not level, obtain and insert metal shims under the
base ring of the unit to correct this condition.
AIR REQUIREMENTS
WARNING
FOR SAFE OPERATIONANAMPLE SUPPLYOF AIR MUSTBE
PROVIDED FOR PROPER COMBUSTIONAND VENTILATION.
AN INSUFFICIENT SUPPLY OF AIR WILL RESULT IN A
YELLOW/LUMINOUSBURNERFLAME,CAUSINGCARBONING
OR SOOTING OF THE FINNED HEAT EXCHANGER AND
CREATING A RISK OF ASPHYXIATION. DO NOT OBSTRUCT
THE FLOW OF COMBUSTION AND VENTILATION AIR.
UNCONFINED SPACE
In buildings of conventional frame, brick, or stone construction,
unconfined spaces may provide adequate air for combustion,
ventilation and draft hood dilution.
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 drafthood dilutionmustbeobtainedfrom outdoors.
The installation instructions for confined spaces in tightly
constructed buildings must be followed to ensure adequate air
supply.

9
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
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).
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.
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
INTOTHE ROOM THROUGHTHE CHIMNEY, CAUSING POOR
COMBUSTION. SOOTING MAY RESULT AND RISK OF
ASPHYXIATION WILL OCCUR.
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING THE
HEATER MUST BE FOLLOWED TO AVOID CHOKED
COMBUSTIONORRECIRCULATIONOF FLUEGASES. SUCH
CONDITIONS CAUSE SOOTING OR RISKS OF FIRE AND
ASPHYXIATION.
In the United States:
Vent sizing, installation and termination shall be in accordance
withthe NATIONALFUELGASCODE.ANSI Z223.1-1999or most
recent edition.
In Canada:
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.
PROPER VENT PIPE INSTALLATION
FIGURE 6
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.
2. Where a continuous or intermittent back draft is found to exist,
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 back draft cannot be corrected by the normalmethods
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.
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.
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.
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).
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
theStandard forReliefValvesandAutomatic 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.
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.

10
Your local code authority may have other specific relief valve
requirements not covered in this section.
THE PURPOSE OFARELIEF VALVE IS TOAVOID EXCESSIVE
PRESSURE OR TEMPERATURE INTO THE STEAM RANGE,
WHICH MAY CAUSE SCALDING AT FIXTURES, TANK
EXPLOSION, SYSTEM OR HEATER DAMAGE.
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
HEATERANDTHERELIEFVALVE ORTHE RELIEFVALVEAND
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
CONDITIONSMIGHT OCCUR. DONOTTHREADORCAP 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.
Recommended locations of relief valves are shown in the
installation diagrams.
HARD WATER
Wherehard waterconditions exist,watersofteningorthe 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.
CLOSED WATER SYSTEM
A closed system will exist if a back-flow prevention device (check
valve),pressurereducing valve,or othersimilardevice isinstalled
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.
WATER LINE CONNECTIONS
This manual provides detailed installation diagrams for typical
methods of application. See piping diagrams.
• Cer-Temp 80 Recovery System (for one temperature water).
Thesediagramswill serve toprovide the installerwitha 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.
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.
Check the diagrams thoroughly before starting installation to
avoid errors and minimize time and material costs.
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.
WATER (POTABLE) HEATING
1. All piping components connected to this unit for space
heating applications shall be suitable for use with potable
water.
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.

11
PIPING DIAGRAMS
(USE THIS DIAGRAM FOR STRAIGHT RECOVERY
SYSTEMS SUPPLYING HOT WATER AT ONE
TEMPERATURE ONLY)
FIGURE 7
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.

12
FIGURE 8
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATUREAT 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.

13
FIGURE 9
FIGURE 10
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.

14
GAS CONNECTIONS
WARNING
THE INLET GAS PRESSURE MUST NOTEXCEED THE VALUE
SPECIFIEDBYTHE MANUFACTURERONTHERATINGPLATE
(10.5" W.C. - NATURAL GAS, 13.0" W.C. - PROPANE GAS).
EXPOSURETOHIGHERGASSUPPLYPRESSURE MAYCAUSE
DAMAGETOTHEGASVALVEWHICHCOULD RESULTINFIRE
OREXPLOSION. IF OVERPRESSUREHASOCCURREDSUCH
AS THROUGH IMPROPER TESTING OF GAS LINES OR
EMERGENCYMALFUNCTIONOFTHE SUPPLYSYSTEM, THE
GASVALVEMUSTBECHECKEDFORSAFEOPERATION. 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.
IT IS IMPORTANT TO GUARD AGAINSTGAS VALVE FOULING
FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING
MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.
IF COPPER SUPPLY LINES ARE USED THEY MUST BE
INTERNALLY TINNED AND CERTIFIED FOR GAS SERVICE.
BEFOREATTACHING THE GAS LINE BE SURE THATALLGAS
PIPE IS CLEAN ON THE INSIDE.
TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS
SUPPLY LINE, ADIRT 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
RECOMMENDATIONSOFSERVING GASSUPPLIERS. INTHE
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).
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.
BEFOREPLACINGTHEHEATERIN OPERATION, CHECKFOR
GAS LEAKAGE. Use soap and water solution or other material
acceptable for the purpose in locating gas leaks. DO NOT USE
MATCHES, CANDLES, FLAME OR OTHER SOURCES OF
IGNITION FOR THIS PURPOSE.
DISCONNECTTHE HEATERAND ITSMANUALGASSHUTOFF
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
MAKESUREthe gason which theheater willoperateis thesame
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.
SIZING GAS SUPPLY LINE
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/ft3and a
specific gravity of 0.60 has been assumed. A heating value of
2500 Btu/ft3and a specific gravity of 1.53 has been assumed for
L.P. (propane) gas.
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.
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
too small, ask the gas company to install a larger meter having
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 HW-200M HW-225M HW-120M HW-160M HW-200M
10 (3M) 1/2 3/4 3/4 3/4 1/2 1/2 1/2
30 (9.1M) 3/4 3/4 1 1 1/2 3/4 3/4
50 (15.2M) 3/4 1 1 1 3/4 3/4 1
80 (24.4M) 1 1 1 1/4 1 1/4 3/4 1 1
100 (30.5M) 1 1 1/4 1 1/4 1 1/4 3/4 1 1
150 (45.7M) 1 1 1/4 1 1/4 1 1/4 1 1 1 1/4
200 (61M) 1 1/4 1 1/4 1 1/4 1 1/2 1 1 1/4 1 1/4

15
ELECTRICAL WIRING DIAGRAMS FOR THE HW-120M, 160M, 200M AND 225M WATER HEATERS
I.I.D. SYSTEM (NATURAL)
FIGURE 11
Aminimum gassupply pressureof4.5" W.C.(1.12kPa) fornatural
gas and 11" W.C. (1.74kPa) for propane gas is required for
purposes of input adjustment.
ELECTRICALINFORMATION
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.
Theelectrical connectionsmust bemadesothatboth thecirculator
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
theUnitedStateswiththeNATIONALELECTRICALCODE,ANSI/
NFPA 70. In Canada with the CANADIAN ELECTRIC CODE,
CSA C22.
A screw is provided in the heater junction box for a ground
connection.
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.
Figures 11 and 12 show the heater mounted controls as they are
wired when the heater leaves the factory. Using the individual
wiringdiagrams onthe installationdiagrams, theinstaller connects
his wiring to terminals in the heater(s) mounted junction box as
shown.
All wiring should be done such that the heater(s) will operate in
the following manner:
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.
2. When the tank temperature control is satisfied:
• The main burners should stop firing, but the circulating pump
shouldcontinueto operatefor about 2minutes whenequipped
with a thermal balancer.
3. When the automatic gas shutoff control or coil protector switch
operate (break electric circuit):
• The main burners should stop firing. Circulating pump should
continue to operate.

16
ELECTRICAL WIRING DIAGRAMS FOR THE HW-120M, 160M, AND 200M WATER HEATERS
I.I.D. SYSTEM (PROPANE)
FIGURE 12
NOTES:

17
OPERATION
IMPORTANT
Onlyqualified personnelshall performthe initialfiring ofthe 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.
LightingandOperating instructionsare included withthis manual.
By using these instructions, the user may be able to make minor
operational adjustments and save unnecessary service calls.
However the user should not attempt repairs, but should contact
a service technician or gas supplier.
GENERAL
Neveroperatethewaterheater withoutfirst makingsure thewater
heater and system are filled with water, in addition:
• Make sure a temperature and pressure relief valve is installed
at the water heater and if used, the storage tank. Also check
for leaks.
• Alsobesure tocheck thegaspiping forleaks 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.
4. Close the hot water faucet as water starts to flow.
5. The heater is ready to be operated.
PURGING OF GAS LINE
Gas line purging is required with new piping or systems in which
air has entered.
CAUTION
PURGING SHOULD BE PERFORMED BY PERSONS
EXPERIENCEDINTHISTYPE GAS SERVICE. TOAVOIDRISK
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.
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.
CAUTION
BEFOREPROCEEDINGWITH THEOPERATIONOF THEUNIT,
MAKESURE HEATERAND SYSTEMARE FILLEDWITHWATER
AND ALLAIR IS EXPELLED FROM HEATER AND PIPING.
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 HAVEACCUMULATED IN THE
COMBUSTION CHAMBER TO CLEAR. IF YOU DETECT GAS
AT THE END OF THIS PERIOD, DO NOT PROCEED WITH
LIGHTING. RECOGNIZETHATGAS ODOR,EVEN IFITSEEMS
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.
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.
Light the unit in accordance with the instructions on the lighting
label attached to the boiler. These instructions are repeated in
the following.

18
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.
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 VALVECONTROL KNOB CLOCKWISE TO “OFF”. REFER TO STEP5 OF “OPERATINGINSTRUCTIONS”
ABOVE.
A. THIS APPLIANCE IS EQUIPPED WITH AN IGNITION
DEVICE WHICH AUTOMATICALLY LIGHTS THE
PILOT. DO NOT TRY TO LIGHT THE PILOT BYHAND.
B. 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.
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.
• IF YOU CANNOT REACH YOUR GAS SUPPLIER,
CALL THE FIRE DEPARTMENT.
C. 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.
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.
E. DO NOT OPERATE APPLIANCE UNLESS UNIT IS
FILLED WITH WATER AND INLET LINES AFTER
FULLY OPEN.
WARNING: IF YOU DO NOT FOLLOW THESE INSTRUCTIONS
EXACTLY A FIRE OR EXPLOSION MAY RESULT CAUSING
PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE.
1. STOP! READ THE SAFETY INFORMATION
ABOVE ON THIS LABEL.
2. SET THERMOSTAT TO LOWEST SETTING.
3. TURN OFF ALL ELECTRIC POWER TO THE
APPLIANCE.
4. THIS APPLIANCE IS EQUIPPED WITH AN IGNITION
DEVICE WHICH AUTOMATICALLY LIGHTS THE
PILOT. DO NOT TRY TO LIGHT THE PILOT BYHAND.
5. TURN GAS VALVE CONTROL KNOB CLOCKWISE
TO “OFF” (FIG. A) A SLIGHT INDENT CAN BE FELT
IN THE “OFF” POSITION.
6. 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) UNTILKNOB SNAPS INTO “ON”
POSITION.
8. TURN ON ALL ELECTRICAL POWER TO THE
APPLIANCE.
9. SET THERMOSTAT TO DESIRED SETTING. PILOT
WILL BE IGNITED BY ELECTRONIC SPARK. WHEN
PILOT IGNITION IS SENSED, THE MAIN BURNERS
WILL IGNITE.
10. IF MAIN BURNER FAILS TO IGNITE, REMOVE
BURNER ACCESS DOOR AND FOLLOW SMALL
METALTUBE 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.
IF APPLIANCE WILL NOT OPERATE, FOLLOW THE
INSTRUCTIONS “TO TURN OFF GAS TO
APPLIANCE” AND CALL YOUR SERVICE
TECHNICIAN OR GAS SUPPLIER.
FOR YOUR SAFETY READ BEFORE OPERATING
TO TURN OFF GAS TO APPLIANCE
OPERATING INSTRUCTIONS
HONEYWELL VR8304P GAS CONTROL

19
DANGER
HOT WATER TEMPERATURES REQUIRED FOR AUTOMATIC
DISHWASHER AND LAUNDRY USE CAN CAUSE SCALD
BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/
ORDEATH. THETEMPERATUREATWHICH INJURY OCCURS
VARIESWITHTHEPERSON’SAGEAND TIMEOFEXPOSURE.
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 DRAWTHEIR OWN BATHWATER. NEVER LEAVE
ACHILD ORDISABLED PERSONUNATTENDED INABATHTUB
OR SHOWER.
THE WATER HEATER SHOULD BE LOCATED IN AN AREA
WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS
TO SET TEMPERATURES.
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 forthelowest temperaturewhich satisfiestheuser’shotwater
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.
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.
Temperature Time to Produce 2nd & 3rd
Setting Degree Burns on Adult Skin
Over 170°F (77°C) Nearly instantaneous
160°F (71°C) About 1/2 seconds
150°F (66°C) About 1-1/2 seconds
140°F (60°) Less than 5 seconds
130°F (54°) About 30 seconds
120°F (49°C) or less More than 5 minutes
Table 7
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.
CAUTION
IN THE EVENT OF ELECTRIC POWER FAILURE, DO NOT
ATTEMPT TO OPERATE THE HEATER.
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.
1. Turn the gas valve control knob to “OFF”, (See page 18).
2. Attachapressuregaugeor amanometer tothe outletpressure
tap,figure14 andrefer to table3 forcorrectmanifold 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.
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
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.
• Clockwise to increase gas pressure and input rate.
• Counterclockwise to decrease gas pressure and input
rate.
DO NOT turn the adjusting screw in past the point of little or no
manifold pressure change or fully bottom the adjusting screw.
6. “Clock” the meter as in step 4 above.
7. Repeat steps 5 and 6 until the specified input rate is achieved.
8. Turnthegasvalvecontrolknob to“OFF”. Replace theregulator
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.
9. Turn the gas valve control knob to “ON”.
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.
IMPORTANT
UNDER NO CIRCUMSTANCES SHOULD THE GAS INPUT
EXCEED THE INPUT SHOWN IN TABLE 2. OVERFIRING
COULD RESULT IN DAMAGE OR SOOTING OFTHE HEATER.
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.
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.)
Heating Total Time Required (Seconds)
Value MODEL
Type of (Btu/
Gas Cu. Ft.) HW-120M HW-160M HW-200M HW-225M
Natural 1050 31.5 23.6 19.0 16.8
Propane 2500 78.3 56.3 45.2 - - -

20
SERVICE INFORMATION
Theinstallermay beable to observeand correctcertainproblems
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.
Any safety devices used in conjunction with this appliance should
receiveperiodic(at leasttwice ayear)inspection toassure proper
operation. All relief valves should be inspected and manually
operated every six months.
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.
The burners should display the following characteristics:
• Provide complete combustion of gas.
• Cause rapid ignition and carryover of flame across entire
burner.
• Give reasonably quiet operation during ignition, burning and
extinction.
• Cause no excessive lifting of flame from burner ports.
If the preceding burner characteristics are not evident, check for
accumulationof lintor otherforeignmaterialthatrestrictsorblocks
the air openings to the burners or heater.
Also check for good flow of combustion and ventilating air to the
unit. Maintain a clear area around the heater at all times.
Qualifiedservicersshould followthis procedurewhen theheater’s
burners need cleaning.
1. Turn off the electrical power and close the main manual gas
shutoff valve.
• Allow heater parts to cool before disassembly.
2. Remove main burner manifold assembly from heater.
• Refer to parts list supplied with this manual for disassembly
aid.
3. Remove any loose foreign material such as dust or lint with a
vacuum. Checkall ports,orifices andairopeningsforblockage.
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
depositswith arag makingsure toremoveanylintleftonburner
by vacuuming again.
MAIN BURNER FOR HW HEATERS
FIGURE 13
4. Reinstall the burner manifold assembly on 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
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.
1. Follow “TO TURN OFF GAS TO APPLIANCE” steps in the
“OPERATING INSTRUCTIONS FOR I.I.D. MODELS”.
2. Carefully disconnect the wire terminal connected to the
MV terminal of the S8600 module, fig. 3.
3. Turn gas valve control knob counterclockwise to “ON”.
4. Turn on all electric power to the heater.
5. Set tank temperature control to call for heat. Pilot will operate
without the main burners igniting.
6. Remove the pilot adjustment cover screw, fig. 14, and turn the
inner adjustment screw clockwise to decrease or
counterclockwise to increase the pilot flame. Be sure to
replace cover screw after adjustment to prevent possible gas
leakage.
7. Repeat step 1.
8. Carefullyreconnectthe MVwire terminalto the S8600module.
Be sure the terminal is securely connected.
9. Follow “OPERATING INSTRUCTIONS FOR I.I.D. MODELS”
to put heater back into operation.
If the pilot burner ignites but the main burner fails to light, check
for gas flow to the main burner.
Check for good terminal connections at the igniter-sensor
connector (fig. 15) and at the S8600 module.
Forfurther assistanceseeChart 2,“S8600INTERMITTENTPILOT
SYSTEMTROUBLESHOOTING”.
HONEYWELL GAS VALVE FOR I.I.D. SYSTEM (TOP VIEW)
FIGURE 14