A.O. Smith SBD 30 150 User manual

1
MODELS SBD 30 150 AND SBD 30 199
COMMERCIAL GAS, GLASS-LINED, TANK-TYPE WATER HEATER
• INSTALLATION • OPERATION • MAINTENANCE • LIMITED WARRANTY
PLACETHESEINSTRUCTIONSADJACENTTOHEATER
ANDNOTIFYOWNERTOKEEPFORFUTUREREFERENCE.
Printed in U.S.A. 1004 PART NO. 196310-001
500LINDAHLPARKWAY
ASHLANDCITY,TN37015
www.statewaterheaters.com
CAUTION
TEXT IN BLACK BOLD TYPE OR UNDERLINED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE READ
THOROUGHLYBEFORE INSTALLING AND USING THIS
APPLIANCE.
Thank you for buying this energy efficient water heater from
A.O. Smith Water Products Company. We appreciate your
confidence in our products.

2
FOREWORD
These designs comply with ANSI Z21.10.3 as a Booster type
water heater.
Detailed installation diagrams are found in this manual. These
diagrams will serve to provide the installer with a reference for
the materials and methods of piping necessary. It is highly
essential that all water, gas piping and wiring be installed as
shown on the diagrams.
Particular attention should be given to the installation of
thermometers at the locations indicated on the diagrams as
these are necessary for checking the proper functioning of the
heater.
The heater is designed to operate on natural gas.
These heaters may be installed on combustible floors.
In addition to these instructions, the equipment 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.
The installation must conform to these instructions and the local
code authority having jurisdiction. In the absence of local codes,
the installation must comply with the latest editions of the
National Fuel Gas Code,ANSI Z223.1/NFPA54 and the National
Electrical Code, NFPA 70, documents are available from the
NationalFireProtectionAssociation, 1BatterymarchPark, Quincy,
MA02269.
ROUGH-IN-DIMENSIONS
FIGURE1
TABLE1- HEATERPERFORMANCE DATA
Input Approx. RECOVERYRATING CAPACITIES (GPH) AT TEMPERATURE RISE SHOWN
Rate Tank Approx. F 20°F 30°F 40°F 50°F 60°F 70°F 80°F 90°F 100°F 110°F 120°F 130°F 140°F
Model Btuh Cap. Eff. % C 11°C 17°C 22°C 28°C 33°C 39°C 44°C 50°C 56°C 61°C 67°C 72°C 78°C
SBD 30 150 150,000 NAT 32 Gal 80 GPH 727 485 364 291 242 208 182 162 145 132 121 112 104
44 kW/Hr. NAT 121 Litres LPH 2752 1836 1378 1102 916 787 689 613 549 500 458 424 394
SBD 30 150 150,000 LP 32 Gal 80 GPH 727 485 364 291 242 208 182 162 145 132 121 112 104
44kW/Hr. LP 121 Litres LPH 2752 1836 1378 1102 916 787 689 613 549 500 458 424 394
SBD 30 199 199,900 NAT 32 Gal 80 GPH 969 646 485 388 323 277 242 215 194 176 162 149 139
59 kW/Hr. NAT 121 Litres LPH 3668 2445 1836 1469 1223 1049 916 814 734 666 613 564 526
SBD 30 199 182,000 LP 32 Gal 80 GPH 882 588 441 353 294 252 221 196 177 160 147 136 126
53kW/Hr. LP 121 Litres LPH 3339 2226 1669 1336 1113 954 837 742 670 606 557 515 477

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GENERALSAFETYINFORMATION
PRECAUTIONS
DONOTUSETHISAPPLIANCEIFANYPARTHASBEENUNDER
WATER. Immediately calla qualified servicetechnician to inspect
the appliance and to replace any part of the control system and
any gas control which has been under water.
IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT
OPERATE HEATER UNTIL ALL CORRECTIVE STEPS HAVE
BEENMADEBY AQUALIFIED SERVICEMAN.
1. EXTERNALFIRE.
2. DAMAGE.
3. FIRINGWITHOUTWATER.
4. SOOTING
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, see
Figure 9.
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
FAILUREANDRISKOFASPHYXIATION.
Spray can propellants, cleaning solvents, refrigerator and air
conditioning refrigerants, swimming pool chemicals, calcium
and sodium chloride (water softener salt), waxes, and process
chemicalsand typical compounds whichare potentially corrosive.
Do not store products of this sort near the heater. Also, air which
is brought in contact with a 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.
IMPROPER COMBUSTION
WARNING
ATTICAND/OREXHAUSTFANSOPERATINGONTHEPREMISES
WITHAWATER HEATERCANRESULTINCARBONMONOXIDE
POISONINGANDDEATH.
TABLE OF CONTENTS
ROUGH-IN-DIMENSIONS ..................................................... 2
FOREWORD.......................................................................... 2
GENERALSAFETYINFORMATION ....................................... 3
Precautions ....................................................................... 3
Grounding Instructions...................................................... 3
Chemical Vapor Corrosion................................................ 3
Improper Combustion......................................................3-4
Extended Non-Use............................................................ 4
Insulation Blankets............................................................ 4
High Altitude Installation.................................................... 4
FEATURES ............................................................................ 4
Self-Cleaning Hydro-Cannon............................................ 4
High Limit Switch..............................................................4-5
Electronic Ignition Control ................................................. 5
Exhaust Inducer (Blower Assy.) ......................................... 5
Circulating Pump............................................................... 5
Dishwashing Machine Requirement ................................ 5
INSTALLATIONINSTRUCTIONS ........................................... 6
Required Ability.................................................................. 6
Uncrating ........................................................................... 6
Locating The Heater.......................................................... 6
Levelling ............................................................................ 6
Clearances........................................................................ 6
Air Requirements .............................................................6-7
Venting ..............................................................................7-8
Multiple Heater Manifold.................................................... 8
Water Line Connections ................................................... 8
Water (Potable) Heating and Space Heating.................... 8
Thermometers (Not Supplied).......................................... 8
Relief Valve ........................................................................ 8
Gas Piping......................................................................... 9
Gas Pressure Regulator................................................ 9-10
Heater Wiring.................................................................... 10
INSTALLATIONDIAGRAMS................................................11-17
OPERATION......................................................................... 18
General............................................................................ 18
SEQUENCEOF OPERATION.............................................. 18
Lighting and Operation.................................................... 19
Water Temperature Control............................................. 20
PREVENTIVEMAINTENANCE ............................................ 20
Check The Ignitor Assembly ........................................... 20
Ignitor Assembly .............................................................. 20
Main Burner ...................................................................20-21
Gas Valves ....................................................................... 21
Checking The Input ......................................................... 21
Venting System................................................................ 21
Remote Storage Tank Temperature Control ................... 21
Relief Valve ...................................................................... 22
Hot Water Odor ................................................................ 22
Anode Rod Inspection..................................................... 22
Flushing........................................................................... 22
Draining........................................................................... 22
Recommended Procedure For Periodic
Removal of Lime Deposits From Tank Type
Commercial Water Heaters ..........................................22-23
Deliming Solvents ........................................................... 23
Tank Cleanout Procedures ...........................................23-24
Ignition Module System ................................................... 24
System Diagnostics ........................................................ 24
SERVICE ............................................................................. 24
Electrical Servicing .......................................................... 24
Replacement Parts ......................................................... 24
Sequence of Operation Flow Chart................................. 25
Operational Checklist...................................................... 26
Limited Warranty ............................................................. 27
Page Page

4
OPERATION OF THESE FANS CAN PRODUCE A NEGATIVE
DRAFT IN THEAREA OF THE WATER HEATER PREVENTING
THE PRODUCTS OF COMBUSTION FROM EXHAUSTING
THROUGHTHE CHIMNEY OR VENT PIPE.
Theventing of the waterheater should be inspectedby a qualified
service technician at the time of installation and periodically
thereafter to ensure a down-draft condition does not exist.
DO NOT OBSTRUCT THE FLOW OF COMBUSTION AND
VENTILATING AIR. ADEQUATE AIR FOR COMBUSTION AND
VENTILATIONMUSTBEPROVIDED FORSAFE OPERATION.
EXTENDED NON-USE PERIODS
WARNING
HYDROGENGASCANBEPRODUCEDINAHOTWATERSYSTEM
SERVEDBYTHISHEATERTHAT HAS NOTBEEN USED FORA
LONGPERIODOFTIME(GENERALLYTWO WEEKS OR MORE).
HYDROGEN GAS IS EXTREMELY FLAMMABLE. Toreduce the
risk of injury under these conditions, it is recommended that the
hot water faucet be opened for several minutes at the kitchen
sink before using any electrical appliance connected to the hot
water system. If hydrogen is present, there will probably be an
unusual sound such as air escaping through the pipe as the
water begins to flow. THERE SHOULD BE NO SMOKING OR
OPENFLAMENEARTHE FAUCETATTHETIMEITIS OPEN.
INSULATION BLANKETS
Insulation blankets available to the general public for external
use on gas water heaters are not approved for use on your
State water heater. The purpose of an insulation blanket is to
reduce the standby heat loss encountered with storage tank
water heaters. Your State water heater meets or exceeds
the ASHRAE/IES 90.1-1999 standards with respect to
insulation and standby loss requirement making an insulation
blanket unnecessary.
WARNING
Shouldyouchoosetoapplyan insulation blanket to this heater,
you should follow these instructions. Failure to follow these
instructions can result in fire, asphyxiation, serious personal
injury or death.
•Do not apply insulation to the top of the water heater, as
this will interfere with safe operation of drafthood.
•Do not cover the temperature & pressure relief valve.
•Do not cover the instruction manual. Keep it on the side of
the water heater or nearby for future reference.
•Do obtain new labels from State Water Heaters for
placement on the blanket directly over the existing labels.
HIGH ALTITUDE INSTALLATIONS
WARNING
INSTALLATIONS ABOVE 2000 FEET (610 METERS) REQUIRE
REPLACEMENTOF THE BURNER ORIFICE IN ACCORDANCE
WITH SECTION 8.1.2 OF THE NATIONAL FUEL GAS CODE
(ANSIZ223.1).FAILURETOREPLACETHEORIFICEWILLRESULT
INIMPROPERANDINEFFICIENTOPERATIONOFTHEAPPLIANCE
RESULTING IN THE PRODUCTION OF INCREASED LEVELS OF
CARBONMONOXIDEGASINEXCESSOFSAFELIMITSWHICH
COULDRESULTINSERIOUSPERSONALINJURYORDEATH.
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 air. Therefore, the heater input rate should be
reduced at high altitudes for satisfactory operation with the
reduced oxygen supply. Failure to make this reduction would
result in an overfiring of the heater causing sooting, poor
combustion and/or unsatisfactory heater performance.
REQUIREMENTS
Ratings specified by manufacturers for most appliances apply
for elevations up to 2000 feet. For elevations above 2000 feet,
ratings must be reduced at the rate of 4% for each 1000 feet
above sea level. For example, if a heater is rated at
120,000 Btuh at sea level, to rate the heater at 4000 feet, you
subtract4 (once for each thousand feet) x.04(4% input reduction)
x120,000 Btuh(original rating) fromthe original rating. Therefore,
tocalculatethe inputrating at4,000 feet:4 x.04x 120,000=19,200
Btuh, 120,000 - 19,200 = 100,800 Btuh. At 6000 feet the correct
input rating should be 91,200 Btuh.
The input reduction is primarily achieved by reducing the size of
the main burner orifices. 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 State Water Heaters. 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
pressure regulator may be required. See CHECKING THE
INPUT 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 also reduced and should be
compensated for in the sizing of the equipment for application.
FEATURES
SELF-CLEANING HYDRO-CANNON
These units include a self-cleaning hydro-cannon installed in
the front water inlet. See figure 2. The hydro-cannon must be
oriented correctly for proper function. There is a marked range
on the pipe nipple portion of the hydro-cannon, that must be
aligned with the top of the inlet spud. A label above the jacket
hole has an arrow that will point to the marked portion of the
pipe nipple if the orientation is correct. If the arrow does not
point within the marked range on the pipe nipple, adjust the pipe
nipple to correct. Apipe union is supplied with the hydro-cannon
to reduce the probability of misaligning the hydro-cannon
accidentally while tightening the connection to the inlet water
supply line. Improper orientation of the hydro-canon can cause
poor performance of the heater and can significantly reduce
outlet water temperatures during heavy draws.
NOTE: The inlet may have 1, 2 or 7 cross- tubes.
FIGURE2
HIGH LIMIT SWITCH
The digital thermostat (Figure 3) contains the high limit (energy
cutoff) sensor. The high limit switch interrupts main burner gas
flow should the water temperature reach 203°F (195°C).

5
In the event of high limit switch operation, the appliance cannot
be restarted unless the water temperature is reduced to
approximately 120°F (49°C). The high limit reset button on the
front of the control then needs to be depressed.
Continued manual resetting of high limit control, preceded by
higher than usual water temperature is evidence of high limit
switch operation. The following is a possible reason for high
limit switch operation.
A malfunction in the thermostatic controls would allow the gas
valve to remain open causing water temperature to exceed the
thermostat setting. The water temperature would continue to
rise until high limit switch operation.
Contact your dealer or service agent if continued high limit
switch operation occurs.
FIGURE 3-DIGITALTHERMOSTAT
ELECTRONIC IGNITION CONTROL
Each heater is equipped with a ignition module. The solid state
ignition control (Figure 4), ignites the main burner by utilizing a
silicone nitride ignitor. The silicone nitride ignitor shuts off during
the heating cycle and the main burner flame is sensed through
a remote flame sensor integral to the silicone nitride ignitor
assembly. The ignition control will try to ignite the main burner
three times before lockout. Then it waits one hour before trying
again to ignite the main burners. This is a continuous cycle.
FIGURE4-IGNITIONCONTROLBOARD
EXHAUST INDUCER (BLOWER ASSEMBLY)
All units are equipped with a exhaust inducer. The inducer
assists in drawing in fresh air to the unit for combustion and
then assists in dispensing the combustion by-products into the
venting leading outside.
The exhaust inducer is equipped with a gravity controlled damper
to reduce the amount of heat loss through the flue, improving
efficiency.
FIGURE5-EXHAUSTINDUCER
CIRCULATING PUMP
A circulating pump is used when a system requires a circulating
loop or there is a storage tank used in conjunction with the
heater. Refer tothe pipingdiagrams atrear ofmanual forelectrical
hookup information and install in accordance with the latest
version of the National Electric Code ANSI/NFPA No. 70.
Only all bronze circulators are used with commercial water
heaters.
Although circulators are oiled and operated by the manufacturer
some circulators must be oiled again before operating. Please
refer to manufacturer’s instructions.
DISHWASHING MACHINE REQUIREMENT
These appliances meet the National Sanitation Foundation
Standard for sanitary installations when used with the following
leg kits, Part No’s. 6570-0 and 6570-7.
All dishwashing machines meeting the National Sanitation
Foundation requirements are designed to operate with water
flow pressures between 15 and 25 psi. Flow pressures above
25 psi, or below 15 psi, will result in improperly sanitized dishes.
Where pressures are high, a water pressure reducing or flow
regulating control valve should be used in 180°F (82°C) line to
the dishwashing machine, and should be adjusted to deliver
water between these limits.
The National Sanitation Foundation also recommends
circulation of 1800F water. Where this is done, the circulation
should be very gentle so that it does not cause any unnecessary
turbulence inside the water heater. The circulation should be
just enough to provide 1800F water at the point of take-off to the
dishwashing machine. Adjust flow by means of the plug cock in
the circulating line.

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INSTALLATIONINSTRUCTIONS
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,GASSUPPLYANDELECTRICALWORKARE
REQUIRED.
WARNING
FAILURETOFOLLOWTHESEINSTRUCTIONSCANRESULTIN
SERIOUSPERSONALINJURY ORDEATH.
UNCRATING
The heater is shipped with the inducer already installed. The
wiring conduit runs from the thermostat to the inducer. Before
turning unit on, check to make sure the wiring conduit is securely
plugged into the inducer.
LOCATING THE HEATER
WARNING
THEREISARISKINUSINGFUELBURNINGAPPLIANCESSUCH
AS GAS WATER HEATERS IN ROOMS, GARAGES OR OTHER
AREASWHEREGASOLINE,OTHERFLAMMABLELIQUIDSOR
ENGINE DRIVEN EQUIPMENT OR VEHICLES ARE STORED,
OPERATED OR REPAIRED. FLAMMABLEVAPORSARE HEAVY
ANDTRAVELALONGTHEFLOORANDMAYBEIGNITEDBYTHE
HEATER’SPILOTORMAINBURNERFLAMESCAUSINGFIREOR
EXPLOSION. SOME LOCAL CODES PERMIT OPERATION OF
GASAPPLIANCESINSUCHAREASIFTHEYAREINSTALLED18”
ORMOREABOVETHEFLOOR. THISMAYREDUCETHERISKIF
LOCATION IN SUCHANAREACANNOT BEAVOIDED.
DO NOT INSTALL THIS WATER HEATER DIRECTLY ON A
CARPETEDFLOOR. AFIRE HAZARD MAYRESULT. Insteadthe
water heater must be placed on a metal or wood panel extending
beyondthefull widthand depthby atleast3 inchesin anydirection.
If the heater is installed in a carpeted alcove, the entire floor
shall be covered by the panel. Also, see the DRAINING
requirements in MAINTENANCE Section.
THEHEATERSHALLBELOCATEDORPROTECTEDSOITISNOT
SUBJECTTOPHYSICALDAMAGE BYAMOVINGVEHICLE.
WARNING
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHERPOTENTIALFIREHAZARDOUSARTICLESMUSTNEVER
BE PLACED ON OR ADJACENT TO THE HEATER. OPEN
CONTAINERS OR FLAMMABLE MATERIALSHOULD NOT BE
STOREDOR USEDINTHESAMEROOMWITHTHEHEATER.
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 the piping system as possible.
THEHEATERMUST NOT BELOCATED INANAREAWHERE IT
WILLBESUBJECTTOFREEZING.
LOCATE IT NEARAFLOORDRAIN. THEHEATER SHOULD BE
LOCATEDINANAREAWHERELEAKAGEFROMTHEHEATEROR
CONNECTIONS WILL NOT RESULT IN DAMAGE TO THE
ADJACENTAREAORTOLOWERFLOORSOFTHESTRUCTURE.
WHENSUCH LOCATIONSCANNOTBEAVOIDED,ASUITABLE
DRAINPANSHOULDBEINSTALLEDUNDERTHEHEATER. Such
pans should be fabricated with sides at least 2" deep, with length
and width at least 2" greater than the diameter of the heater and
must be piped to an adequate drain. The pan must not restrict
combustion air flow.
For appliance installation locations with elevations above
2000 feet (610m), refer to HIGH ALTITUDE INSTALLATIONS
section of this manual for input reduction procedure.
LEVELING
If the unit is not level, insert the bolts which were used in crating
into the legs to correct this condition.
CLEARANCES
These heaters are approved for installation on combustible
flooring in an alcove when the minimum clearance from any
combustion construction are followed as indicated in figure 6.
Models SBD 30 150 and 30 199 are approved for installation on
non-cumbustible flooring or combustible flooring with leg kit
part no. 6570.
In all installations the minimum combustible clearances from
ventpiping shall be6". Ventpiping passingthrougha combustible
wall or ceiling must be a continuous run (no joints) and retain
the 6" clearance unless an approved reducing thimble is used.
Aservice clearance of 24"should be maintained from serviceable
parts, such as relief valves, flue baffles, thermostats, cleanout
openings or drain valves.
The units are approved for installation with side, rear and ceiling
clearances.
AIR REQUIREMENTS
REFER TO THE LATEST EDITION OF THE "NATIONAL FUEL
GASCODE"ANSI Z223.1/NFPA54.
KEEPAPPLIANCEAREACLEAR ANDFREEOFCOMBUSTIBLE
MATERIALS,GASOLINEANDOTHERFLAMMABLES,VAPORS
ANDLIQUIDS.
DO NOT OBSTRUCT THE FLOW OF COMBUSTION OR
VENTILATINGAIR.
WARNING
FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR
COMBUSTIONAND VENTILATION. AN INSUFFICIENTSUPPLY
OF AIR WILL CAUSE RECIRCULATION OF COMBUSTION
PRODUCTSRESULTINGINAIRCONTAMINATIONTHATMAYBE
HAZARDOUSTOLIFE. SUCHACONDITIONOFTENWILLRESULT
IN A YELLOW, LUMINOUS BURNER FLAME, CAUSING
CARBONINGORSOOTING OF THE COMBUSTION CHAMBER,
BURNERS AND FLUE TUBES AND CREATES A RISK OF
ASPHYXIATION.
Where an exhaust fan is supplied in the same room with a
heater, sufficient openings for air must be provided in the walls.
UNDERSIZEDOPENINGSWILLCAUSEAIR TOBEDRAWNINTO
THE ROOM THROUGH THE CHIMNEY, CAUSING POOR
COMBUSTION. SOOTINGMAYRESULTINSERIOUSDAMAGE
TOTHE HEATERAND RISKOFFIREOREXPLOSION.

7
UNCONFINEDSPACE
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 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.
CONFINEDSPACE
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 OF THE ENCLOSURE TOPAND ONE
IN OR WITHIN 12 INCHES OF THE ENCLOSURE BOTTOM.
Each opening shall have a free area of at least one square inch
per 1000 Btuh of the total input of all appliances in the enclosure,
but not less than 100 square inches.
If the confined space is within a building of tight construction, air
for combustion, ventilation, 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 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 of the total input of all appliances in the enclosure.
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING MUST
BE FOLLOWED TO AVOID CHOKED COMBUSTION OR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS
CAUSESOOTINGORRISKSOFFIREANDASPHYXIATION.
Heater must be protected from freezing downdrafts.
Remove all soot or other obstructions from the chimney that will
retard a free draft.
Type B venting is recommended with these heaters.
This water heater must be vented in compliance with all local
codes, the current revision of the National Fuel Gas Code
(ANSI-Z223.1) and with the Category I Venting Tables.
If any part of the vent system are exposed to ambient
temperatures below 40°F (4°C) it must be insulated to prevent
condensation.
The following steps shall be followed with each appliance
connected to the venting system placed in operation, while any
other appliances connected to the venting system are not in
operation.
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and horizontal
pitch, as required in the National Fuel Gas Code, ANSI
Z223.1. Determine that there is no blockage or restriction,
leakage, corrosion and other deficiencies which could cause
an unsafe condition.
3. So far as is practical, close all building doors and windows
and all doors between the space in which the water heater(s)
connected to the venting system are located and other
spaces of the building. Turn on all appliances not connected
to the venting system. Turn on all exhaust fans, such as
range hoods and bathroom exhausts, so they shall operate
at maximum speed. Close fireplace dampers.
4. Follow the lighting instruction. Place the water heater being
inspected in operation. Adjust thermostat so appliance shall
operate continuously.
5. After it has been determined that each appliance connected
to the venting system properly vents when tested as outlined
above, return doors, windows, exhaust fans, fireplace
dampers and any other gas burning appliance to their
previous conditions of use.
6. If improper venting is observed during any of the above tests,
the venting system must be corrected.
WARNING
FAILURE TO CORRECT BACK DRAFTS MAY CAUSE AIR
CONTAMINATIONANDUNSAFECONDITIONS.
• If the back draft cannot be corrected by the normal method or
if a suitable draft cannot be obtained, a blower type flue gas
exhauster must be employed to assure proper venting and
correct combustion.
• Do not connect the heater to a common vent 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.
FIGURE7
FIGURE6-ILLUSTRATIONOFMINIMUMCLEARANCESTOCOMBUSTIBLES

8
• Where a separate vent connection is not available and the
vent pipe from the heater must be connected to a common
vent with an oil burning furnace, the vent pipe should enter
the smaller common vent or chimney at a point above the
large vent pipe.
MULTIPLE HEATER MANIFOLD
When horizontally manifolding two or more heaters vent as
shown in Figure 8. Refer to NFPA 54/ANSI Z223.1 for venting
multiple heaters.
FIGURE8
WATER LINE CONNECTIONS
This manual provides detailed installation diagrams (see pages
12-17 of this manual) for typical methods of application for the
water heaters.
The water heater may be installed by itself, or with a separate
storage tank, on both single and two-temperature systems.
When used with a separate storage tank, the circulation may be
either by gravity or by means of a circulating pump. When a
circulating pump is used it is important to note that the flow rate
should be slow so that there will be a minimum of turbulence
inside the heater.
If a water heater is installed in a closed water system, contact
the water supplier or local plumbing inspector on how to control
this situation.
WATER (POTABLE) HEATING
AND SPACE 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.
4. When the system requires water for space heating at
temperatures higher than required for domestic water
purposes, a tempering valve must be installed. Please refer
to installation diagrams on pages 12 thru 17 of this manual
for suggested piping arrangements.
CAUTION
A closed system will exist if a check valve (without bypass),
pressure reducing valve (without bypass), or a water meter
(without bypass) is installed in the cold water line between
the water heater and street main (or well).
Excessive pressure may develop in such closed systems,
causing premature tank failure or intermittent relief valve
operation. This is not a warranty failure. An expansion tank
or a similar device may be required in the inlet supply line
between the appliance and the meter or valve to compensate
for the thermal expansion of the water.
SYSTEMCONNECTIONS
The system installation must conform to these instructions and
to the local code authority having jurisdiction. Good practice
requires that all heavy piping be supported.
THERMOMETERS (Not Supplied)
Thermometers should be obtained and field installed as shown
in the installation diagrams.
Thermometers are installed in the system as a means of
detecting the temperature of the outlet water supply.
RELIEF VALVE
This water heater is equipped with a combination
temperature-pressure relief valve that complies with the standard
for relief valves and automatic gas shutoff devices for hot water
supply system,ANSI Z21.22. FOR SAFE OPERATION OF THE
WATERHEATER,THERELIEFVALVE(S)MUSTNOTBEREMOVED
ORPLUGGED.
ASME ratings cover pressure relief capacities. A.G.A. ratings
cover release rate with temperature actuation.
In addition to the appliance relief valve, each remote storage
tank which may be used in conjunction with this appliance shall
also be installed with a properly sized, rated and approved
combination temperature (ANSI) and pressure (ASME) relief
valve(s).
WARNING
THE PURPOSE OF RELIEF VALVE IS TO AVOID EXCESSIVE
PRESSUREORTEMPERATUREINTOTHESTEAMRANGE,WHICH
MAY CAUSE SCALDING AT FIXTURES, TANK EXPLOSION,
SYSTEMOR HEATER DAMAGE. NO VALVE ISTOBE PLACED
BETWEENTHERELIEFVALVEANDTANK.
Your local code authority may have other specific relief valve
requirements.
ADRAINLINEMUSTBECONNECTEDTOTHERELIEFVALVETO
DIRECTDISCHARGETOASAFELOCATIONTOAVOIDSCALDING
ORWATERDAMAGE. THISLINEMUSTNOTBEREDUCEDFROM
THE SIZE OF THE VALVE OUTLET AND MUST NOT CONTAIN
VALVES, RESTRICTIONS NOR SHOULD IT BE LOCATED IN
FREEZINGAREAS. DONOTTHREADORCAPTHEENDOFTHIS
LINE. RESTRICTEDORBLOCKED DISCHARGE WILL DEFEAT
THE PURPOSE OF THE VALVEAND IS UNSAFE. DISCHARGE
LINESHALLBEINSTALLEDTOALLOWCOMPLETEDRAINAGE
OFBOTHTHEVALVEANDLINE.
See SERVICE INFORMATION section for procedure and
precautions.

9
GAS PIPING
Contact your local gas service company to ensure that adequate
gas service is available and to review applicable installation
codes for your area.
Size the main gas line in accordance with Table 2. The figures
shown are for straight lengths of pipe at 0.5 in. W.C. pressure
drop, which is considered normal for low pressure systems.
Note: Fittings such as elbows, tees and line regulators will add
to the pipe pressure drop. Also refer to the latest version of the
National Fuel Gas Code.
WARNING
THEHEATERIS NOT INTENDED FOR OPERATIONAT HIGHER
THAN14.0"W.C.(3.48kPa)-NATURALGAS,14.0"W.C.(3.48kPa)
EXPOSURE TO HIGHER SUPPLY PRESSURE MAY CAUSE
DAMAGETOTHEGASVALVE WHICH COULD RESULT IN FIRE
OREXPLOSION. IF OVERPRESSURE HAS OCCURRED SUCH
AS THROUGH IMPROPER TESTING OF GAS LINES OR
EMERGENCYMALFUNCTIONOFTHESUPPLYSYSTEM,THEGAS
VALVEMUSTBECHECKEDFORSAFEOPERATION. MAKESURE
THATTHEOUTSIDEVENTSONTHESUPPLYREGULATORSAND
THE SAFETY VENT VALVES ARE PROTECTED AGAINST
BLOCKAGE. THESEAREPARTSOFTHEGASSUPPLYSYSTEM,
NOTTHEHEATER. VENTBLOCKAGEMAYOCCURDURINGICE
STORMS.
TABLE2-GASSUPPLYLINESIZES(ININCHES)*
MAXIMUMCAPACITYOFPIPEINCUBICFEETPERHOUR
(Based upon a Pressure Drop of 0.5 inch Water Column and
0.6 specific Gravity Gas and max. gas pressure of 0.5 psig)
LENGTH NOMINAL IRON PIPE SIZES (INCHES)
INFEET 1/2" 3/4" 1" 1 1/4" 1 1/2" 2" 2 1/2" 3" 4"
10 175 360 680 1400 2100 3960 6300 11000 23000
20 120 250 465 950 1460 2750 4360 7700 15800
30 97 200 375 770 1180 2200 3520 6250 12800
40 82 170 320 660 990 1900 3000 5300 10900
50 73 151 285 580 900 1680 2650 4750 9700
60 66 138 260 530 810 1520 2400 4300 8800
70 61 125 240 490 750 1400 2250 3900 8100
80 57 118 220 460 690 1300 2050 3700 7500
90 53 110 205 430 650 1220 1950 3450 7200
100 50 103 195 400 620 1150 1850 3250 6700
125 44 93 175 360 550 1020 1650 2950 6000
150 40 84 160 325 500 950 1500 2650 5500
175 37 77 145 300 460 850 1370 2450 5000
200 35 72 135 280 430 800 1280 2280 4600
IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING
FROMCONTAMINANTSINTHEGASWAYS. SUCHFOULINGMAY
CAUSEIMPROPEROPERATION,FIREOREXPLOSION.
IF COPPER SUPPLY LINES ARE USED THEY MUST BE
INTERNALLYTINNEDANDCERTIFIEDFORGASSERVICE.BEFORE
ATTACHING THE GAS LINE, BE SURE THATALL GAS PIPE IS
CLEANONTHE INSIDE.
TOTRAPANYDIRTORFOREIGNMATERIALINTHEGASSUPPLY
LINE,A DIRT LEG (SOMETIMESCALLED SEDIMENT TRAP OR
DRIPLEG)MUSTBEINCORPORATED INTHEPIPING(SEEFIG.
9). THE DIRT LEG MUST BE READILYACCESSIBLEAND NOT
SUBJECT TO FREEZING CONDITIONS. INSTALL IN
ACCORDANCEWITHRECOMMENDATIONS OFSERVINGGAS
SUPPLIERS. REFERTOTHELATESTVERSIONOFTHENATIONAL
FUELGASCODE.
To prevent damage, care must be taken not to apply too much
torque when attaching gas supply pipe to gas valve inlet.
Apply joint compounds (pipe dope) sparingly and only to the
male threads of pipe joints. Do not apply compounds to the first
two threads. Use compounds resistant to the action of liquefied
petroleum gases.
BEFOREPLACINGTHEHEATERINOPERATION,CHECKFORGAS
LEAKAGE. Use soap and water solution or other material
acceptable for the purpose in locating the leaks. DO NOT USE
MATCHES,CANDLES,FLAMEOROTHERSOURCESOFIGNITION
FORTHISPURPOSE.
DISCONNECTTHE HEATERANDITSMANUALGASSHUTOFF
VALVEFROMTHEGASSUPPLYPIPINGSYSTEMDURINGANY
SUPPLY PRESSURE TESTING EXCEEDING 1/2 PSIG. GAS
SUPPLYLINEMUSTBECAPPEDWHEN DISCONNECTEDFROM
THEHEATERFORTESTPRESSURESOF1/2PSIGORLESS.THE
APPLIANCE NEED NOT BE DISCONNECTED, BUT MUST BE
ISOLATEDFROMTHESUPPLY PRESSURE TEST BYCLOSING
THEMANUALGASSHUTOFFVALVE.
GASPIPINGANDDIRTLEGINSTALLATION
FIGURE9
PURGING
Gas line purging is required with new piping or systems in which
air has entered.
CAUTION
PURGINGSHOULDBEPERFORMEDBYPERSONSEXPERIENCED
IN THIS TYPE GAS SERVICE. TO AVOID RISK OF FIRE OR
EXPLOSION,PURGEDISCHARGEMUSTNOTENTERCONFINED
AREASORSPACESWHEREIGNITIONCANOCCUR. THEAREA
MUSTBEWELLVENTILATEDANDALLSOURCESOFIGNITION
MUSTBEINACTIVATEDORREMOVED.
GASMETERSIZE—NATURALGASESONLY
Be sure the gas meter has sufficient capacity to supply the full
rated gas input of the water 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.
GAS PRESSURE REGULATOR
The gas pressure regulator is built into the gas valve and is
equipped to operate on the gas specified on model and rating

10
plate. The regulator is factory adjusted to deliver gas to burner at
correct water column pressure allowing for a nominal pressure
drop through the controls.
The minimum gas supply pressure for input adjustment must
not be less than 4.5" w.c. for natural gas.
Do not subject the combination gas valve to inlet gas
pressures of more than 14.0" W.C. - natural gas. A service
regulator is necessary if higher gas pressures are encountered.
Manifold gas pressure in inches of water column is 3.5.
The gas pressure specified refers to flow pressure taken at
pressure tap of automatic gas valve while heater is operating.
FIGURE10-SINGLEUNITWIRINGDIAGRAM
HEATER WIRING
All electrical work must be installed in accordance with the latest
version of the National Electrical CodeANSI/NFPA No. 70, must
conform to all local code authority having jurisdiction. AN
ELECTRICAL GROUND IS REQUIRED TO REDUCE RISK OF
ELECTRICALSHOCKORPOSSIBLEELECTROCUTION.
If any of the original wire as supplied with the appliance must be
replaced, use only type 105°C thermoplastic or equivalent.
250°C type F must be used for the flame sensor leads and the
spark ignition cable must be high voltage 250°C.
Figures shown are valid for 0-2000 ft. installations. See “HIGH
ALTITUDE INSTALLATIONS” for deration requirements over
2000 ft.

11
INSTALLATION DIAGRAMS
GENERAL
The type, size and location of the relief valves must be in
accordance with local codes. The locations of the relief valves
shown in the installation diagrams are typical. The heater has a
factory installed high temperature limit switch and temperature
and pressure relief valve.
Cold water lines to heater should be installed as shown in order
to minimize gravity circulation of hot water to building cold water
lines.
A listed temperature and pressure relief valve of adequate
capacity is installed on the heater. The locations shown in the
installation diagrams on the following pages are typical.
The discharge opening of the temperature and pressure relief
valve, located in front of the heater must be piped to an open
drain and should not be subject to freezing temperatures.
Install in accordance with all local codes.
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 20. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATERSUPPLIEDTOFIXTURES.

12
VERTICAL STORAGE TANK AND FORCED CIRCULATION
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATUREATFIXTURES. SEE WATER TEMPERATURECONTROL
WARNING ON PAGE 20. IF HIGHER PREHEAT TEMPERATURES ARE
NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN
ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.
HORIZONTAL STORAGE TANK AND FORCED CIRCULATION

13
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATUREATFIXTURES. SEE WATERTEMPERATURE CONTROL
WARNING ON PAGE 20. IF HIGHER PREHEAT TEMPERATURES ARE
NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN
ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.
TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE STORAGE
WITH RECIRCULATION OF SANITIZING LOOP
NOTE1: TOGGLESWITCHCONTROLS180°F (82°C)WATER
CIRCULATION. INSTALLON OR CLOSE TO DISHWASHING
MACHINE. TOGGLESWITCHMUSTBECLOSED(ON)DURING
THERINSEOPERATIONANDOPEN(OFF)WHENDISHWASHER
ISNOTOPERATINGORWHEN ONLONGSTANDBY.
NOTE2: INSTALLLINETEMPERATURECONTROLINANUNINSULATED
TEEBEYONDTHEDISHWASHINGMACHINETAKEOFFINTHE
SANITIZING LOOP. CONTROL SHOULD BE SET AT 185°F
(85°C).
NOTE3: ADJUSTPLUGCOCKSOTHESANITIZINGLOOPFLOWRATE
DOESNOTCAUSEUNNECESSARYTURBULENCEINTHETANK.
*TEMPEREDWATERLOOP,IFUSED,CONNECTTO
POINT “A”.
**PIPERELIEFVALVETOOPENDRAIN.
INSTALLINACCORDANCE WITHLOCALCODES.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACKFLOW
PREVENTER,CHECKVALVEORWATERMETERWITHCHECK
VALVE. PROVISIONSFORTHERMALEXPANSIONOFWATER
INTHEHOTWATERSYSTEMMUSTBE PROVIDED.

14
INSTALLATION DIAGRAMS-SIDE INLET/OUTLET USAGE
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATUREATFIXTURES. SEE WATERTEMPERATURE CONTROL
WARNING ON PAGE 20. IF HIGHER PREHEAT TEMPERATURES ARE
NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN
ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.
A listed temperature and pressure relief valve of adequate
capacity is installed on the heater. The locations shown in the
installation diagrams on the following pages are typical.
TWO TEMPERATURE - TWO HEATERS, ONE PRE-HEATER/ONE - BOOSTER HEATER
WITH OR WITHOUT BUILDING RECIRCULATION
The discharge opening of the temperature and pressure relief
valve must be piped to an open drain and should not be subject
to freezing conditions. DO NOT REDUCE, BLOCK OR PLUG
THEDISCHARGE OPENING OFTHE VALVE.
CIRCULATINGRETURN LINE CONNECTION
- FROMFIXTURELOOP,IFUSED,CONNECT
TOPRE-HEATERINLET.
- FROMBOOSTEDTEMPERATURELOOP,IF
USEDCONNECTTOBOOSTERINLET.
† AVAILABLE FROMA.O.SMITH.
* PIPERELIEFVALVETOOPENDRAIN.
INSTALLINACCORDANCEWITHLOCALCODES.

15
ONE OR TWO TEMPERATURE - ONE HEATERS,HIGH TEMPERATURE
STORAGE WITH OR WITHOUT RECIRCULATION
HEATER WITH OR WITHOUT MIXING VALVE
HEATER WITH MIXING VALVE AND RECIRCULATED SANITIZING LOOP
NOTE 1: TOGGLE SWITCH CONTROLS 180°F (82°C)
WATER CIRCULATION. INSTALLON ORCLOSE
TODISHWASHINGMACHINE. TOGGLE SWITCH
MUST BE CLOSED (ON) DURING THE RINSE
OPERATION AND OPEN (OFF) WHEN
DISHWASHER IS NOT OPERATING OR WHEN
ON LONG STANDBY.
NOTE 2: INSTALL LINE TEMPERATURE CONTROL
IN AN UNINSULATED TEE BEYOND THE
DISHWASHING MACHINE TAKEOFF IN
THE SANITIZING LOOP. CONTROL
SHOULD BE SETAT 185°F (85°C).
NOTE 3: ADJUST PLUGCOCK SOTHESANITIZING
LOOP FLOW RATE DOES NOT CAUSE
UNNECESSARY TURBULENCE IN THE
TANK.
* PIPE RELIEF VALVE TO OPEN DRAIN.
INSTALL IN ACCORDANCE WITH LOCAL
CODES.
CIRCULATING RETURN LINE CONNECTIONS.
- TEMPERED WATER LOOP, IF USED,
CONNECT TO POINT “R”.
- STORED TEMPERATURE WATER LOOP, IF
USED, CONNECT TO COLD WATER INLET.
DANGER
TEMPERATURE SETTING SHOULD NOT
EXCEED SAFE USE TEMPERATURE AT
FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 20. IF HIGHER
PREHEAT TEMPERATURESARE NECESSARY
TO OBTAIN ADEQUATE BOOSTER OUTPUT,
ADDANANTI-SCALD VALVE FOR HOT WATER
SUPPLIED TO FIXTURES.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACKFLOW
PREVENTER, CHECK VALVE OR WATER METER WITH CHECK VALVE.
PROVISIONSFORTHERMALEXPANSION OFWATERINTHEHOTWATER
SYSTEM MUST BE PROVIDED.

16
TWO TEMPERATURE - TWO PRE-HEATERS WITH MIXING VALVE OR BOOSTER
HEATER WITH OR WITHOUT BUILING RECIRCULATION
TWO PRE-HEATERS WITH MIXING VALVE
TWO PRE-HEATERS WITH BOOSTER HEATER
DANGER
TEMPERATURE SETTING SHOULD NOT
EXCEED SAFE USE TEMPERATURE AT
FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 20. IF HIGHER
PREHEAT TEMPERATURES ARENECESSARY
TO OBTAIN ADEQUATE BOOSTER OUTPUT,
ADDANANTI-SCALD VALVE FOR HOT WATER
SUPPLIED TO FIXTURES.

17
MEDIUM TEMPERATURE - ONE HEATER WITH AUXILIARY STORAGE TANK FORCED
CIRCULATION WITH OR WITHOUT BUILDING RECIRCULATION
VERTICAL STORAGE TANK
HORIZONTAL STORAGE TANK
DANGER
TEMPERATURESETTING SHOULD NOTEXCEED SAFE USE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 20. IF HIGHER PREHEAT
TEMPERATURESARE NECESSARY TO OBTAINADEQUATE
BOOSTER OUTPUT, ADD ANANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TOFIXTURES.
* PIPE RELIEF VALVE TO OPEN DRAIN.
**WHEN USING AN A.O. SMITH T-140, -200,
-350 OR -400 STORAGE TANK, USE
LOWER 3/4” OPENING FOR TANK
TEMPERATURE CONTROL.
IF BUILDING CIRCULATING LOOP IS USED,
CONNECT TO AN OPENING NEAR THE
BOTTOM OFTHE TANK.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A
BACKFLOW PREVENTER, CHECK VALVE OR WATER
METER WITH CHECK VALVE. PROVISIONS FOR
THERMAL EXPANSION OF WATER IN THE HOT WATER
SYSTEM MUST BE PROVIDED.
*PIPE RELIEF VALVE TO OPEN DRAIN
INSTALL IN ACCORDANCE WITH LOCAL CODES.

18
OPERATION
IMPORTANT
A qualified person must perform the initial firing of the heater. At
this time the user should not hesitate to ask the individual any
questions which they may have in regard to the operation and
maintenance of the unit.
An Operational Checklist is included at the rear of this manual.
By using this checklist the user may be able to make minor
operational adjustments and avoid unnecessary service calls.
However, the user should not attempt repairs which are not listed
under the USER column.
GENERAL
NEVER OPERATE THE HEATER WITHOUT FIRST BEING
CERTAIN IT IS FILLED WITH WATER AND A TEMPERATURE
ANDPRESSURE RELIEFVALVEIS INSTALLEDINTHERELIEF
VALVEOPENING OF THEHEATER.
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL
TOSHUTOFF,TURNOFFTHE MANUALGASCONTROLVALVE
TOTHEAPPLIANCE.
CAUTION
Before proceeding with the operation of the unit make sure
the water heater and system are filled with water and all air is
expelled.
FILLING
1. Close the heater drain valve by turning handle clockwise.
2. Opena nearby hot water faucet topermit 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.
WARNING
THEGASVALVE MUST HAVE BEEN INTHEOFFPOSITIONFOR
AT LEAST 5 MINUTES. This waiting period is an important
safety step. Its purpose is to permit gas that may have
accumulated in the combustion chamber to clear. IF YOU
DETECT GAS ODOR AT THE END OF THIS PERIOD DO NOT
PROCEEDWITHLIGHTING. RECOGNIZETHAT GAS EVEN IF IT
SEEMSWEAK,MAYINDICATEPRESENCEOFACCUMULATED
GAS SOMEPLACE IN THE AREA WITH RISK OF FIRE OR
EXPLOSION. SEETHEFRONTPAGEFORSTEPSTOBE TAKEN.
All gas and water lines leak tested and open.
ReadSEQUENCE OF OPERATION sectionof thismanual priorto
lighting and operating this appliance.
With above conditions satisfied, start the unit in accordance with
the instructions on the Operating label attached to the heater. If
label instructions are not legible - determine which gas valve the
appliance is equipped with and use the applicable OPERATING
INSTRUCTIONS asfollows:
Each heater is equipped with an ignition control board. The
controller will try three times to light the main burner before going
into lockout. After the controller tries three times, it will wait one
hour before trying to light the unit again. This cycle will continue
until the main burners are ignited or the unit is shut down.
ADJUSTMENTS
ONINITIALSTARTUPSOMEADJUSTMENTSARE NECESSARY.
1. CHECKMANIFOLDANDINLETGASPRESSURES.
2. CYCLECHECK-CHECKATLEASTONEBURNEROPERATION
- WHEN THERMOSTAT IS SATISFIED, BURNER WILL SHUT
OFFAND INDUCER WILL STOP RUNNING. ON CALL FOR
HEAT - THE INDUCER WILL COME ON AND CLOSE THE
PRESSURE SWITCH AND THE IGNITION SEQUENCE
DESCRIBED ABOVE WILL BEGIN, SEE “SEQUENCE OF
OPERATION”.
SEQUENCE OF OPERATION
The following information will describe the Sequence of
Operation for this appliance.
1. Switch power on to unit.
2. Thermostat calls for heat.
3. Ignition Control Board performs diagnostic check on system
components.
4. On completion of diagnostics check, the Ignition Control
Board sends signal to Exhaust Inducer.
5. Exhaust Inducer begins drawing air through appliance
closing the Prover Switch.
6. On completion of Prover Switch engagement, the Ignition
Control Board begins the ignition cycle.
7. The Ignition Control Board provides power to the Silicon
Nitride Ignitor.
8. The Silicon Nitride Ignitor heats up for approximately 17 to
20 seconds.
9. At the end of Silicon Nitride Ignitor’s warm-up, the Ignition
Control Board opens the Gas Valve.
10. From the time the Gas Valve opens, the Ignition Control
Board waits 3 seconds and then shuts off power to the
Silicon Nitride Ignitor.
11. From the time the Silicon Nitride Ignitor’s power is shut off,
the Ignition Control Board waits 3 more seconds to monitor
the Flame Sensor.
12. If the Flame Sensor does not detect a strong enough flame,
the Ignition Control Board shuts off the Gas Valve and allows
the Exhaust Inducer to purge the unit for 20 seconds. At that
time, the Ignition Control Board restarts with step 7. It will try
and ignite the main burners 2 more times. If the unit does
not light, the Ignition Control Board will wait one hour and
then restart at step 3. This cycle will continue until the unit
lights or the power is shutoff to the unit.
13. If the Flame Sensor detects a strong flame, the Ignition
ControlBoard willallow theunit tooperate untilthe thermostat
is satisfied.
14. Once the unit is satisfied, the Ignition Control Board will
shut off the Gas Valve and the unit will be in standby mode
until another call for heat is initiated by the thermostat.
See the flow chart on page 25 for more information.

19
A. This appliance does not have a pilot. It is equipped
with an ignition device which automatically lights the
burner. Do not try to light the burner by hand.
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
telephone in your building.
• Immediately call your gas supplier from a neighbor’s
telephone. Follow the gas supplier’s instructions.
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 burner. Do not try to
light the burner by hand.
5. Push in gas control knob slightly and turn clockwise
to “OFF”.
6. Wait five (5) minutes to clear out any gas. If you
then smell gas, STOP! Follow “B” in the
safety information above on this label. If you
don’t smell gas, go on to the next step.
7. Turn gas control knob counterclockwise to “ON”.
8. Turn on all electric power to the appliance.
FORYOUR SAFETY READBEFOREOPERATING
OPERATING INSTRUCTIONS
WARNING
• If you cannot reach your gas supplier, call the fire
department.
C. Use only your hand to push in or turn the gas control
knob. Never use tools. If the knob will not push in or
turn by hand, don’t try to repair it, call a qualified
service technician. Force or attempted repair may
result in 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.
1. Set the thermostat to lowest setting.
2. Turn off all electric power to appliance if service is to be performed.
3. Push in gas control knob slightly and turn clockwise to “OFF”. Do not force.
FORYOURSAFETY READBEFOREOPERATING
9. Set thermostat to desired setting.
10. If the appliance will not operate, follow the
instructions “To Turn Off Gas To Appliance” and call
your service technician or gas supplier.

20
WATER TEMPERATURE CONTROL
DANGER
THIS WATER HEATER IS EQUIPPED WITHAN ADJUSTABLE
THERMOSTAT TO CONTROL WATER TEMPERATURE. HOT
WATER TEMPERATURES REQUIRED FOR AUTOMATIC
DISHWASHERANDLAUNDRYUSE CANCAUSESCALDBURNS
RESULTING IN SERIOUS PERSONALINJURYAND/OR DEATH.
THETEMPERATUREATWHICHINJURYOCCURS VARIES WITH
THEPERSON'SAGEANDTIMEOF EXPOSURE. THE SLOWER
RESPONSETIMEOFCHILDREN,AGEDORDISABLEDPERSONS
INCREASESTHEHAZARDSTOTHEM. NEVERALLOWSMALL
CHILDREN TO USEAHOT WATER TAP, OR TO DRAW THEIR
OWN BATH WATER. NEVER LEAVE A CHILD OR DISABLED
PERSONUNATTENDED INABATHTUBORSHOWER.
THE WATER HEATER SHOULD BE LOCATED IN AN AREA
WHERETHEGENERALPUBLICDOESNOTHAVEACCESSTO
SETTEMPERATURES.
SETTINGTHEWATERHEATER TEMPERATUREAT 120°F WILL
REDUCE THE RISK OF SCALDS. Some states or provinces
require settings at specific lower temperatures.
Below you will find listed the approximate time-to-burn
relationship for normal adult skin. Short repeated heating cycles
caused by small hot water uses can cause temperatures at the
pointof use to exceedthe thermostat setting by up to 20°F . If you
experience this type of use, you should consider using lower
temperature settings to reduce scald hazards.
Temperature Time to Produce 2nd & 3rd
Setting Degree Burns on Adult Skin
185°F Nearly instantaneous
180°F Nearly instantaneous
170°F Nearly instantaneous
160°F About 1/2 second
150°F About 1-1/2 seconds
140°F Less than 5 seconds
130°F About 30 seconds
120°F More than 5 minutes
Valves for reducing point-of-use temperature by mixing cold and
hot water are available. Also available are inexpensive devices
that attach to faucets to limit hot water temperatures. Contact a
licensed plumber or the local plumbing authority.
The water temperature is controlled by a thermostat, see
Figure 3, which has two sensing elements. One sensor is
located near the top of the tank and the other is near the center.
The thermostat is set in the lowest position before the heater
leaves the factory.
The thermostat temperature dial, see Figure 3, is accessible by
removing the control cover. The dial is adjustable and may be
set for 120° to 180°F water temperature, but 120°F is the
recommended starting point. It is suggested the dial be placed
on the lowest setting which produces an acceptable hot water
supply. This will always give the most energy efficient operation.
The temperature control has a 4°F fixed differential.
PREVENTIVE MAINTENANCE
CHECK THE IGNITOR ASSEMBLY
At least once a year, check the ignitor assembly, see Figure 11,
and the main burner, see Figure 12, for proper operation. Refer
to the following ignitor assembly and main burner sections.
IGNITOR ASSEMBLY
For access to ignitor assembly, unfasten two screws to burner
cover and remove. Locate the burner with the ignitor assembly
and remove screw holding burner to manifold. Slide burner out
to access ignitor assembly.
Servicing of the ignitor assembly includes keeping the ignitor
free of lint, scale or any other foreign debris.
FIGURE11
MAIN BURNER
The main burner, see Figure 12, should display the following
characteristics:
• Cause rapid ignition and carry across entire burner.
• Give reasonably quiet operation during ignition, burning, and
extinction.
• Cause no excessive lifting of flame from burner ports.
FIGURE12
If the preceding burner characteristics are not evident, check for
accumulation of lint, scale or other foreign debris that restricts or
blocks the air openings to the burner or heater.