A.O. Smith BT-100-LP User manual

1
Instruction Manual
100276483_2000538796
KEEP THIS MANUAL IN THE POCKET ON HEATER FOR FUTURE REFERENCE
WHENEVER MAINTENANCE ADJUSTMENT OR SERVICE IS REQUIRED.
COMMERCIAL GAS WATER HEATERS
INSTALLATION - OPERATION -
SERVICE - MAINTENANCE
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.
Read and understand this instruction
manual and the safety messages
herein before installing, operating or
servicing this water heater.
Failure to follow these instructions and
safety messages could result in death
or serious injury.
This manual must remain with the
water heater.
WARNING: If the information in these
instructions is not followed exactly, a fire
or explosion may result causing property
damage, personal injury or death.
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS:
Do not try to light any appliance.
Do not touch any electrical switch; do
not use any phone in your building.
Immediately call your gas supplier
from a neighbor’s phone. Follow the
gas supplier’s instructions.
If you cannot reach your gas supplier,
call the fire department.
Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
•
•
•
•
Low Lead Content
• For Your Safety •
AN ODORANT IS ADDED TO THE GAS USED
BY THIS WATER HEATER.

2
TABLE OF CONTENTS
SAFE INSTALLATION, USE AND SERVICE..................3
APPROVALS ..................................................................3
GENERAL SAFETY INFORMATION..............................4
INTRODUCTION............................................................5
Abbreviations Used ................................................... 5
Qualied Installer or Service Agency......................... 5
Preparing for The Installation .................................... 5
INSTALLATION CONSIDERATIONS .............................6
Rough-In Dimensions ................................................ 6
Thermometers (Not Supplied) ................................... 7
Facts to Consider About the Location........................ 7
High Altitude .............................................................. 9
Adjusting Air Shutter for Higher Altitudes................... 9
Clearances ............................................................... 10
Insulation Blankets ................................................... 10
Hard Water ............................................................... 11
Circulation Pumps .................................................... 11
INSTALLATION REQUIREMENTS ..............................12
Gas Supply Systems ................................................ 12
Gas Pressure Requirements ................................... 12
Supply Gas Regulator .............................................. 12
Mixing Valves............................................................ 12
Water Piping ............................................................. 13
Temperature-Pressure Relief Valve.......................... 14
Filling the Water Heater ............................................ 15
Air Requirements...................................................... 16
Unconned Space .................................................... 16
Conned Space ........................................................ 16
Fresh Air Openings For Conned Spaces ................ 17
Outdoor Air Through Two Openings ......................... 17
Outdoor Air Through One Opening........................... 17
Outdoor Air Through Two Horizontal Ducts .............. 18
Outdoor Air Through Two Vertical Ducts................... 18
Air From Other Indoor Spaces.................................. 18
Venting...................................................................... 19
Gas Piping ................................................................ 20
Sediment Traps ........................................................ 22
TEMPERATURE REGULATION ..................................24
FOR YOUR INFORMATION.........................................25
Start-UP CONDITIONS ............................................ 25
Operational Conditions ............................................. 26
PERIODIC MAINTENANCE.........................................27
Venting System Inspection ....................................... 27
Burner Inspection ..................................................... 27
Burner Cleaning........................................................ 27
Air Shutter Adjustment.............................................. 28
Housekeeping........................................................... 28
Anode Rod Inspection .............................................. 28
Temperature-Pressure Relief Valve Test .................. 28
Periodic Removal of Lime Deposits From Tank Type
Commercial Water Heaters ...................................... 30
Deliming Solvents..................................................... 30
Tank Cleanout Procedure ......................................... 30
Deliming Using Flo-Jug Method ............................... 31
Draining and Flushing............................................... 32
Service...................................................................... 32
LEAKAGE TEST POINTS ............................................33
Removing and Replacing the Gas Control Valve/
Thermostat .............................................................. 34
WATER PIPING DIAGRAMS........................................39
COMMERCIAL WATER HEATER LIMITED
WARRANTY .................................................................46

3
SAFE INSTALLATION, USE AND SERVICE
The proper installation, use and servicing of this water heater is extremely important to your safety and the safety of
others.
Many safety-related messages and instructions have been provided in this manual and on your own water heater to
warn you and others of a potential injury hazard. Read and obey all safety messages and instructions throughout this
manual. It is very important that the meaning of each safety message is understood by you and others who install,
use, or service this water heater.
All safety messages will generally tell you about the type of hazard, what can happen if you do not follow the safety
message, and how to avoid the risk of injury.
DANGER indicates an imminently
hazardous situation which, if not avoided,
will result in injury or death.
This is the safety alert symbol. It is used to alert you to
potential personal injury hazards. Obey all safety
messages that follow this symbol to avoid possible
injury or death.
WARNING indicates a potentially hazardous
situation which, if not avoided, could result
in injury or death.
CAUTION indicates a potentially hazardous
situation which, if not avoided, could result in
minor or moderate injury.
CAUTION used without the safety alert
symbol indicates a potentially hazardous
situation which, if not avoided, could result in
property damage.
WARNING
CAUTION
CAUTION
DANGER
APPROVALS
Low Lead Content

4
GENERAL SAFETY INFORMATION
Improper installation, use and service may
result in property damage.
CAUTION
• Do not operate water heater if any part has been
exposed to flooding or water damage.
• Inspect anode rods regularly, replace when significantly depleted.
• Install in location with drainage.
•
Fill tank with water before operation.
• Properly sized thermal expansion tanks are required on all
closed water systems.
Refer to this manual for installation and service.

5
Thank You for purchasing this water heater. Properly
installed and maintained, it should give you years of
trouble free service.
ABBREVIATIONS USED
Abbreviations Found In This Instruction Manual:
• UL - Underwriters Laboratories Inc.
• ANSI - American National Standards Institute
• NFPA - National Fire Protection Association
• ASME - American Society of Mechanical Engineers
• AHRI - Air-Conditioning, Heating and Refrigeration
Institute
• CAN - Canada
• EPACT - Energy Policy Act
• CSA - Canadian Standards Association
This gas-red water heater is design certied by
Underwriters Laboratories Inc. under the American
National Standard/CSA Standard for Gas Water Heaters
ANSI Z21.10.3 • CSA 4.3 (current edition).
QUALIFIED INSTALLER OR SERVICE AGENCY
Installation and service of this water heater requires
ability equivalent to that of a Qualied Agency (as dened
by ANSI below) in the eld involved. Installation skills
such as plumbing, air supply, venting, gas supply and
electrical supply are required in addition to electrical
testing skills when performing service.
ANSI Z223.1 2006 Sec. 3.3.83: “Qualied Agency” - “Any
individual, rm, corporation or company that either in
person or through a representative is engaged in and is
responsible for (a) the installation, testing or replacement
of gas piping or (b) the connection, installation, testing,
repair or servicing of appliances and equipment; that
is experienced in such work; that is familiar with all
precautions required; and that has complied with all the
requirements of the authority having jurisdiction.”
If you are not qualied (as dened by ANSI above) and
licensed or certied as required by the authority having
jurisdiction to perform a given task do not attempt to
perform any of the procedures described in this manual.
If you do not understand the instructions given in this
manual do not attempt to perform any procedures
outlined in this manual.
PREPARING FOR THE INSTALLATION
1. Read the “General Safety” section, page 4 of this
manual rst and then the entire manual carefully. If you
don’t follow the safety rules, the water heater will not
operate properly. It could cause DEATH, SERIOUS
BODILY INJURY AND/OR PROPERTY DAMAGE.
This manual contains instructions for the installation,
operation, and maintenance of the gas-red water
heater. It also contains warnings throughout the manual
that you must read and be aware of. All warnings and
all instructions are essential to the proper operation of
the water heater and your safety. Since we cannot put
everything on the rst few pages, READ THE ENTIRE
MANUAL BEFORE ATTEMPTING TO INSTALL OR
OPERATE THE WATER HEATER.
2. The installation must conform with these instructions
and the local code authority having jurisdiction. In the
absence of local codes, the installation must comply
with the current editions of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 or CAN/CSA-B149.1 the Natural
Gas and Propane Installation Code. All documents are
available from the Canadian Standards Association,
8501 East Pleasant Valley Road, Cleveland, OH
44131. NFPA documents are also available from the
National Fire Protection Association, 1 Batterymarch
Park, Quincy, MA 02269.
3. If after reading this manual you have any questions or
do not understand any portion of the instructions, call
the local gas utility or the manufacturer whose name
appears on the rating plate.
4. Carefully plan the place where you are going to put
the water heater. Correct combustion, vent action, and
vent pipe installation are very important in preventing
death from possible carbon monoxide poisoning and
res, see Figure 8 (page 10) and Figure 12 (page
14).
Examine the location to ensure the water heater is
consistent with the requirements described in Facts to
Consider About the Location (page 7).
5. For California installation this water heater must be
braced, anchored, or strapped to avoid falling or
moving during an earthquake. See instructions for
correct installation procedures. Instructions may be
obtained from California Ofce of the State Architect,
400 P Street, Sacramento, CA 95814.
6. Massachusetts Code requires this water heater to be
installed in accordance with Massachusetts 248-CMR
2.00: State Plumbing Code, and 248-CMR 5.00.
INTRODUCTION

6
ROUGH-IN DIMENSIONS
TABLE 1. DIMENSIONS AND RECOVERY RATINGS DIMENSIONS
Model Units A B C D E F G H J K L M
75
Natural & LP
Inches
CM
61 7/8
157.2
59 3/8
150.8
29 15/16
76
26 1/2
67.3
14 3/16
36
4
10.2
14 7/8
39.4
16
40.6
1 7/8
4.8
1
NPT
1/2
NPT
12.0
30.5
100
Natural & LP
Inches
CM
69 7/8
177.5
67 3/8
171.1
31 1/2
80.0
27 3/4
70.5
14 1/8
35.9
4
10.2
15 5/8
39.7
16
40.6
1 7/8
4.8
1 1/4
NPT
1/2
NPT
11 15/16
30.3
TABLE 2. RECOVERY RATINGS
Model
Input Approx.
Gal.
Cap.
Approx.
Liter
Cap.
Temp.
Rise
C° 17 22 28 33 39 44 50 56 61 67 72 78
Rating
Btu/Hr
Rating
kW F° 30 40 50 60 70 80 90 100 110 120 130 140
75 75,100 22 74 280 GPH 243 182 146 121 104 91 81 73 66 61 56 52
LPH 916 686 550 456 392 343 305 275 249 230 211 196
100 75,100 22 98 371 GPH 243 182 146 121 104 91 81 73 66 61 56 52
LPH 916 686 550 456 392 343 305 275 249 230 211 196
Recovery ratings based on 80% thermal efciency.
INSTALLATION CONSIDERATIONS
FIGURE 1. ROUGH-IN DIMENSIONS

7
THERMOMETERS (NOT SUPPLIED)
Thermometers should be obtained and eld installed.
Thermometers are installed in the system as a means of
detecting the temperature of the outlet water supply.
This Water Heater has been design certied as
complying with ANSI Z21.10.3-CSA 4.3 current edition for
water heaters and is considered suitable for:
• Water (Potable) Heating and Space Heating*: All
models are considered suitable for water (potable)
heating and space heating.
*These water heaters cannot be used in space heating
applications only.
HOTTER WATER CAN SCALD:
Water heaters are intended to produce hot water.
Water heated to a temperature which will satisfy space
heating, clothes washing, dish washing, and other
sanitizing needs can scald and permanently injure
you upon contact. Some people are more likely to be
permanently injured by hot water than others. These
include the elderly, children, the inrm, or physically/
mentally handicapped. If anyone using hot water in your
home ts into one of these groups or if there is a local
code requiring a certain temperature water at the hot
water tap, then you must take special precautions. In
addition to using the lowest possible temperature setting
that satises your hot water needs, a means such as a
*Mixing Valve should be used at the hot water taps used
by these people or at the water heater. See Figure 11
(page 13).Mixing valves are available at plumbing
supply or hardware stores. Consult a qualied installer
or service agency. Follow mixing valve manufacturer’s
instructions for installation of valves. Before changing
the factory setting on the thermostat, see Temperature
Regulation (page 24).
FACTS TO CONSIDER ABOUT THE LOCATION
Carefully choose an indoor location for the new water
heater, because the placement is a very important
consideration for the safety of the occupants in the
building and for the most economical use of the water
heater. This water heater is not for use in manufactured
(mobile) homes or outdoor installation.
Whether replacing an old water heater or putting the
water heater in a new location, the following critical points
must be observed:
1. Select a location indoors as close as practical to the
gas vent or chimney to which the water heater vent
is going to be connected, and as centralized with the
water piping system as possible.
2. Selected location must provide adequate clearances
for servicing and proper operation of the water heater.
Installation of water heater must be accomplished in
such a manner that if the tank or any connections should
leak, ow will not cause damage to the structure. For
this reason, it is not advisable to install water heater in
an attic or upper oor. When such locations cannot be
avoided, a suitable metal drain pan should be installed
under the water heater. Metal Drain pans are available
at your local hardware store. Such a metal drain pan
must have a minimum length and width of at least 2” (51
mm) greater than water heater dimensions and must be
piped to an adequate drain. The pan must not restrict
combustion air ow.
Water heater life depends upon water quality, water
pressure and the environment in which the water heater
is installed. Water heaters are sometimes installed in
locations where leakage may result in property damage,
even with the use of a drain pan piped to a drain.
However, unanticipated damage can be reduced or
prevented by a leak detector or water shut-off device
used in conjunction with a piped drain pan. These
devices are available from some plumbing supply
wholesalers and retailers, and detect and react to
leakage in various ways:

8
• Sensors mounted in the drain pan that trigger an
alarm or turn off the incoming water to the water
heater when leakage is detected.
• Sensors mounted in the drain pan that turn off the
water supply to the entire home when water is
detected in the drain pan.
• Water supply shut-off devices that activate based on
the water pressure differential between the cold water
and hot water pipes connected to the water heater.
• Devices that will turn off the gas supply to a gas water
heater while at the same time shutting off its water
supply.
INSTALLATIONS IN AREAS WHERE FLAMMABLE
LIQUIDS (VAPORS) ARE LIKELY TO BE PRESENT OR
STORED (GARAGES, STORAGE AND UTILITY AREAS,
ETC.): Flammable liquids (such as gasoline, solvents,
propane [LP or butane, etc.] and other substances such
as adhesives, etc.) emit ammable vapors which can be
ignited by a gas water heater’s pilot light or main burner.
The resulting ashback and re can cause death or
serious burns to anyone in the area, as well as property
damage. If installation in such areas is your only option,
then installation must be accomplished in a way that
the pilot ame and main burner ame are elevated from
oor at least 18 inches. While this may reduce chances
of ammable vapors, from a oor spill being ignited,
gasoline and other ammable substances should never
be stored or used in the same room or area containing a
gas water heater or other open ame or spark producing
appliance.
NOTE: Flammable vapors may be drawn by air currents
from other areas of the structure to the appliance.
Also, the water heater must be located and/or protected
so it is not subject to physical damage by a moving
vehicle.
This water heater must not be installed directly on
carpeting. Carpeting must be protected by metal or wood
panel beneath the water heater extending beyond the full
width and depth of the water heater by at least 3” (76.2
mm) in any direction, or if the water heater is installed in
an alcove or closet, the entire oor must be covered by
the panel. Failure to heed this warning may result in a re
hazard.

9
HIGH ALTITUDE
Water heaters covered in this manual have been tested
and approved for installation at elevations up to 7,700
feet (2,347 m) above sea level. For installation above
7,700 feet (2,347 m), the water heater’s Btu input should
be reduced at the rate of 4 percent for each 1,000 feet
(305 m) above sea level which requires replacement of
the burner orice in accordance with the National Fuel
Gas Code ANSI Z223.1/NFPA 54 or the Natural Gas and
Propane Installation Code CAN/CSA B149.1. Contact
your local gas supplier for further information.
Failure to replace the standard orice with the proper
high altitude orice when installed at elevations above
7,700 feet (2,347 m) could result in improper and
inefcient operation of the water heater, producing
carbon monoxide gas in excess of the safe limits. This
could result in serious injury or death. Contact your
local gas supplier for any specic changes that may be
required in your area.
ADJUSTING AIR SHUTTER FOR HIGHER ALTI-
TUDES
The air shutter is preset with the air shutter in the open
position and for most applications changing the air
shutter is not required.
FIGURE 2. AIR SHUTTER OPEN
A correctly set burner should have a stable quiet ame.
The ame will be blue with a well dened blue inner
ame, Some yellow tipping is normal with LP gas. See
Figure 3.
FIGURE 3. NORMAL FLAMES
If ames are seen to lift from the burner ports, gradually
close the air shutter until a stable ame is achieved. See
Figure 4.
FIGURE 4. FLAME LIFTING
See Figure 5 for the appearance of the half-closed and
full-closed air shutter. Normally, this ame lifting occurs
only at altitudes above 5,400 feet.
FIGURE 5. HALF-CLOSED AND CLOSED AIR SHUTTER
If the air shutter is closed too far, the ame will look hazy
and not have dened cones. See the example in Figure
6(page 10). In this case, the air shutter will need to be
opened. See Figure 2.

10
FIGURE 6. UNSTABLE FLAME
CLEARANCES
Minimum clearances between the water heater and
combustible construction are 0 inch at the sides and
rear, 4” (102 mm) at the front, and 6” (153 mm) from the
vent pipe. Clearance from the top of the jacket is 12”
(305 mm).
FIGURE 7. CLEARANCES
A gas water heater cannot operate properly without the
correct amount of air for combustion. Do not install in a
conned area such as a closet, unless you provide air
as described in Air Requirements (page 16). Never
obstruct the ow of ventilation air. If you have any doubts
or questions at all, call your gas supplier. Failure to
provide the proper amount of combustion air can result
in a re or explosion and cause death, serious bodily
injury, or property damage.
FIGURE 8. VENTILATION CLEARANCES
If this water heater will be used in beauty shops,
barber shops, cleaning establishments, or self-service
laundries with dry cleaning equipment, it is imperative
that the water heater or water heaters be installed
so that combustion and ventilation air be taken from
outside these areas.
Propellants of aerosol sprays and volatile compounds,
(cleaners, chlorine based chemicals, refrigerants, etc.)
in addition to being highly ammable in many cases,
will also change to corrosive hydrochloric acid when
exposed to the combustion products of the water
heater. The results can be hazardous, and also cause
product failure.
INSULATION BLANKETS
Do not obstruct water heater air intake
with insulating blanket.
Gas and carbon monoxide detectors
are available.
Install water heater in accordance with
the instruction manual.
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
Breathing Hazard - Carbon Monoxide Gas
Insulation blankets are available to the general public
for external use on gas water heaters but are not
necessary with these products. The purpose of an
insulation blanket is to reduce the standby heat loss
encountered with storage tank heaters. The water
heaters covered by this manual meet or exceed the
Energy Policy Act standards with respect to insulation
and standby heat loss requirements, making an
insulation blanket unnecessary.
Should you choose to apply an insulation blanket to
this heater, you should follow these instructions. See
Leakage Test Points (page 33) for identication of
components mentioned below. Failure to follow these
instructions can restrict the air ow required for proper
combustion, potentially resulting in re, asphyxiation,
serious personal injury or death.

11
• DO NOT apply insulation to the top of the water
heater, as this will interfere with safe operation of the
draft hood. See Figure 18 (page 20).
• DO NOT cover the thermostat or the temperature-
pressure relief valve.
• DO NOT allow the insulation to come within 2 inches
(5 cm) of the oor to prevent blockage of combustion
air ow to the burner.
• DO NOT cover the instruction manual. Keep it on the
side of the water heater or nearby for future reference.
• DO obtain new warning and instruction labels from
the manufacturer for placement on the blanket directly
over the existing labels.
• DO inspect the insulation blanket frequently to make
certain it does not sag, thereby obstructing the
combustion air ow.
HARD WATER
Where hard water conditions exist, water softening or the
threshold type of water treatment is recommended. This
will protect the dishwashers, coffee urns, water heaters,
water piping and other equipment. See the Periodic
Removal of Lime Deposits From Tank Type Commercial
Water Heaters (page 30) for sediment and lime scale
removal procedures.
CIRCULATION PUMPS
A circulating pump is used when a system requires
a circulating loop or there is a storage tank used in
conjunction with the water heater. See Water Piping
(page 13) and Water Piping Diagrams (page 39) for
installation location of circulating pumps.
See the circulation pump wiring diagrams (Figure 9
and Figure 10) for electrical hookup information. Install
in accordance with the current edition of the National
Electrical Code, NFPA 70 or the Canadian Electrical Code,
CSA C22.1.
All bronze or stainless steel circulating pumps are
recommended for use with commercial water heaters.
Some circulating pumps are manufactured with sealed
bearings and do not require further lubrication. Some
circulating pumps must be periodically oiled. Refer to
the pump manufacturer’s instructions for lubrication
requirements.
CIRCULATING PUMP WIRING DIAGRAM
STORAGE TANK OR BUILDING RECIRCULATION
FIELD SUPPLIED TEMPERATURE CONTROL
INSTALLED IN THE STORAGE TANK
OR CIRCULATING LOOP RETURN LINE
CIRC
PUMP
MOTOR
L1 HOT
L2 NEUTRAL
120 VAC
POWER
NOTE: USE SEPARATE 120 VAC POWER
SUPPLY FOR PUMP CIRCUIT. DO NOT
SHARE POWER WITH APPLIANCE AS THIS
MAY CAUSE ELECTRICAL LINE NOISE AND
LEAD TO ERRATIC CONTROL SYSTEM
OPERATION.
FIGURE 9. STORAGE TANK/BUILDING RECIRCULATION
CIRCULATING PUMP WIRING DIAGRAM
DISHWASHER LOOP WITH TOGGLE SWITCH
FIELD SUPPLIED TEMPERATURE
CONTROL INSTALLED IN THE
CIRCULATING LOOP RETURN LINE
DISHWASHER
TOGGLE
SWITCH
CIRC
PUMP
MOTOR
L1 HOT
L2 NEUTRAL
120 VAC
POWER
NOTE: USE SEPARATE 120 VAC POWER
SUPPLY FOR PUMP CIRCUIT. DO NOT
SHARE POWER WITH APPLIANCE AS THIS
MAY CAUSE ELECTRICAL LINE NOISE AND
LEAD TO ERRATIC CONTROL SYSTEM
OPERATION.
FIGURE 10. DISHWASHER LOOP WITH TOGGLE SWITCH

12
GAS SUPPLY SYSTEMS
Low pressure building gas supply systems are dened
as those systems that cannot under any circumstances
exceed 14” W.C. (1/2 PSI Gauge). These systems do
not require pressure regulation. Measurements should
be taken to insure that gas pressures are stable and fall
within the requirements stated on the water heater rating
plate. Readings should be taken with all gas burning
equipment off (static pressure) and with all gas burning
equipment running at maximum rate (dynamic pressure).
The gas supply pressure must be stable within 1.5”
W.C. from static to dynamic pressure to provide good
performance. Pressure drops that exceed 1.5” W.C.
may cause rough starting, noisy combustion or nuisance
outages. Increases or spikes in static pressure during
off cycles may cause failure to ignite or in severe cases
damage to appliance gas valves. If your low pressure
system does not meet these requirements, the installer is
responsible for the corrections.
High Pressure building supply systems use pressures
that exceed 14” W.C. (1/2 PSI Gauge). These systems
must use eld supplied regulators to lower the gas
pressure to less than 14” W.C. (1/2 PSI Gauge).
Appliances require gas regulators that are properly
sized for the water heater input and deliver the rating
plate specied pressures. Gas supply systems where
pressure exceeds 5 PSI often require multiple regulators
to achieve desired pressures. Systems in excess of 5
PSI building pressure should be designed by gas delivery
professionals for best performance. Water heaters
connected to gas supply systems that exceed 14” W.C.
(1/2 PSI Gauge) at any time must be equipped with a gas
supply regulator.
GAS PRESSURE REQUIREMENTS
Natural gas models require a minimum gas supply
pressure of 5.0” W.C. (1.24 kPa). Propane gas models
require a minimum gas supply pressure of 11” W.C. (2.74
kPa). The minimum supply pressure is measured while
gas is owing (dynamic pressure). The supply pressure
(dynamic) should never fall below the specied minimum
supply pressure. The supply pressure should be
measured with all gas red appliances connected to the
common main ring at full capacity. If the supply pressure
drops more than 1.5” W.C. (0.37 kPa) as gas begins
to ow to the water heater then the supply gas system
including the gas line and/or the gas regulator may be
restricted or undersized. See Water Piping Diagrams
(page 39) and Gas Piping (page 20). The gas valve
on all models has a maximum gas supply pressure limit
of 14” W.C. (3.48 kPa) The maximum supply pressure is
measured while gas is not owing (static pressure).
SUPPLY GAS REGULATOR
The maximum allowable gas supply pressure for this
water heater is 14.0 inches W.C. (3.48 kPa). Install a
positive lock-up gas pressure regulator in the gas supply
line if inlet gas pressure can exceed 14.0 inches W.C.
(3.48 kPa) at any time. Regulators must be sized/used
according to manufacturer’s specications.
If a positive lock-up regulator is required follow these
instructions:
1. Positive lock-up gas pressure regulators must be rated
at or above the input Btu/hr rating of the water heater
they supply.
2. Positive lock-up gas pressure regulator(s) should be
installed no closer than 3 feet (1 meter) and no farther
than 8 feet (2.4 meters) of equivalent length from the
water heater’s inlet gas connection.
3. After installing the positive lock-up gas pressure
regulator(s), and while the water heater is operating,
an initial nominal supply pressure setting of 7.0” W.C.
is recommended and will generally provide good
water heater operation. Some addition adjustment
maybe required later to maintain a steady gas supply
pressure.
4. When installing multiple water heaters in the same
gas supply system it is recommended that individual
positive lock-up gas pressure regulators be installed at
each unit.
MIXING VALVES
Water temperature over 125°F (52°C)
can cause severe burns instantly
resulting in severe injury or death.
Children, the elderly and the physically
or mentally disabled are at highest risk
for scald injury.
Feel water before bathing or showering.
Temperature limiting devices such as
mixing valves must be installed when
required by codes and to ensure safe
temperatures at fixtures.
Water heated to a temperature which will satisfy clothes
washing, dish washing, and other sanitizing needs can
scald and cause permanent injury upon contact. Short
repeated heating cycles caused by small hot water uses
can cause temperatures at the point of use to exceed the
water heater’s temperature setting by up to 20°F (11°C).
Some people are more likely to be permanently injured
by hot water than others. These include the elderly,
children, the inrm and the physically/mentally disabled.
INSTALLATION REQUIREMENTS

13
Table 3 shows the approximate time-to-burn relationship
for normal adult skin. If anyone using hot water provided
by the water heater being installed ts into one of these
groups or if there is a local code or state law requiring a
certain water temperature at the point of use, then special
precautions must be taken.
In addition to using the lowest possible temperature
setting that satises demand of the application, a mixing
valve should be installed at the water heater or at hot
water taps to further reduce system water temperature.
See Figure 11 (page 13).
Mixing valves are available at plumbing supply stores.
Consult a Qualied Installer or Service Agency. Follow
mixing valve manufacturer’s instructions for installation of
the valves.
TABLE 3. APPROXIMATE TIME-TO-BURN
Water
Temperature °F
Time for
1st Degree Burn
(Less Severe Burns)
Time for Permanent Burns
2nd & 3rd Degree
(Most Severe Burns)
110 (normal shower temp.)
116 (pain threshold)
116 35 minutes 45 minutes
122 1 minute 5 minutes
131 5 seconds 25 seconds
140 2 seconds 5 seconds
149 1 second 2 seconds
154 instantaneous 1 second
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15,1978)
HOT WATER
OUTLET
TO TANK
INLET
CHECK
VALVE
MIXING
VALVE
COLD
WATER
INLET
TEMPERED WATER
OUTLET
12” TO 15”
(30-38 cm)
CHECK
VALVE
FIGURE 11. MIXING VALVE
WATER PIPING
WATER (POTABLE) HEATING AND SPACE HEATING
This water heater shall not be connected to any heating
systems or component(s) used with a non-potable water
heating appliance.
All piping components connected to this unit for space
heating applications shall be suitable for use with potable
water. Toxic chemicals, such as those used for boiler
treatment shall not be introduced into this system.
When the system requires water for space heating at
temperatures higher than required for domestic water
purposes, a mixing valve must be installed. See Figure 11
(page 13) for suggested piping arrangement.
These water heaters cannot be used in space heating
applications only.
CLOSED WATER SYSTEMS
Water supply systems may, because of code
requirements or such conditions as high line pressure,
among others, have installed devices such as pressure
reducing valves, check valves, and back ow preventers.
Devices such as these cause the water system to be a
closed system.
THERMAL EXPANSION
As water is heated, it expands (thermal expansion). In
a closed system the volume of water will grow when it
is heated. As the volume of water grows there will be a
corresponding increase in water pressure due to thermal
expansion. Thermal expansion can cause premature tank
failure (leakage). This type of failure is not covered under
the limited warranty. Thermal expansion can also cause
intermittent temperature-pressure relief valve operation:
water discharged from the valve due to excessive
pressure build up. This condition is not covered under the
limited warranty. The temperature-pressure relief valve is
not intended for the constant relief of thermal expansion.
A properly sized thermal expansion tank must be installed
on all closed systems to control the harmful effects of
thermal expansion. Contact a local plumbing service
technician to have a thermal expansion tank installed.

14
FIGURE 12. TYPICAL PIPING ARRANGEMENT
Note: To protect against untimely corrosion of hot and
cold water ttings, it is strongly recommended that
dielectric unions or couplings be installed on this water
heater when connected to copper pipe.
Figure 12 shows the typical attachment of the water
piping to the water heater. The water heater is equipped
with 1” NPT threaded nipple (75 gallon models) or
1.25” NPT threaded nipple (100 gallon models) water
connections.
TEMPERATURE-PRESSURE RELIEF VALVE
Explosion Hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.
This water heater is provided with a properly rated/
sized and certied combination temperature-pressure
relief valve (T&P valve) by the manufacturer. The valve
is certied by a nationally recognized testing laboratory
that maintains periodic inspection of production of listed
equipment of materials as meeting the requirements for
relief valves for hot water supply systems, ANSI Z21.22 •
CSA 4.4, and the code requirements of ASME. If replaced,
the new T&P valve must meet the requirements of local
codes, but not less than a combination temperature-
pressure relief valve rated/sized and certied as indicated
in the above paragraph. The new valve must be marked
with a maximum set pressure not to exceed the marked
hydrostatic working pressure of the water heater (150
psi = 1,035 kPa) and a discharge capacity not less than
the water heater Btu/hr or kW input rate as shown on the
water heater’s model rating label.
Note: In addition to the factory installed
temperature-pressure relief valve on the water heater,
each remote storage tank that may be installed and
piped to a water heating appliance must also have its
own properly sized, rated, and approved temperature-
pressure relief valve installed. Call the toll free technical
support phone number listed on the back cover of this
manual for technical assistance in sizing a temperature-
pressure relief valve for remote storage tanks.
For safe operation of the water heater, the temperature-
pressure relief valve must not be removed from its
designated opening nor plugged. The temperature-
pressure relief valve must be installed directly into the
tting of the water heater designed for the relief valve.
Install discharge piping so that any discharge will exit
the pipe within 6 inches (15.2 cm) above an adequate
oor drain, or external to the building. In cold climates
it is recommended that it be terminated at an adequate
drain inside the building. Be certain that no contact is
made with any live electrical part. The discharge opening
must not be blocked or reduced in size under any
circumstances. Excessive length, over 30 feet (9.14 m),
or the use of more than four elbows can cause restriction
and reduce the discharge capacity of the valve.

15
No valve or other obstruction is to be placed between the
temperature-pressure relief valve and the tank. Do not
connect discharge piping directly to the drain unless a
6” (15.2 cm) air gap is provided. To prevent bodily injury,
hazard to life, or property damage, the relief valve must
be allowed to discharge water in adequate quantities
should circumstances demand. If the discharge pipe is
not connected to a drain or other suitable means, the
water ow may cause property damage.
Water Damage Hazard
• Temperature-Pressure Relief Valve discharge
pipe must terminate at adequate drain.
CAUTION
T&P Valve Discharge Pipe Requirements:
• Shall not be smaller in size than the outlet pipe size
of the valve, or have any reducing couplings or other
restrictions.
• Shall not be plugged or blocked.
• Shall not be exposed to freezing temperatures.
• Shall be of material listed for hot water distribution.
• Shall be installed so as to allow complete drainage
of both the temperature-pressure relief valve and the
discharge pipe.
• Must terminate a maximum of six inches above a
oor drain or external to building. In cold climates, it is
recommended that discharge pipe be terminated at an
adequate drain inside building.
• Shall not have any valve or other obstruction between
the relief valve and the drain.
Burn hazard.
Hot water discharge.
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.
The temperature-pressure relief valve must be manually
operated at least twice a year. Caution should be taken to
ensure the following:
1. No one is in front of or around the outlet of the
temperature-pressure relief valve discharge line.
2. The water manually discharged will not cause any
bodily injury or property damage because the water
may be extremely hot.
If, after manually operating the valve, it fails to completely
reset and continues to release water, immediately close
the cold water inlet to the water heater, follow the draining
instructions in this manual, and replace the temperature-
pressure relief valve with a properly rated/sized new one.
Note: The purpose of a temperature-pressure relief valve
is to prevent excessive temperatures and pressures in
the storage tank. The T&P valve is not intended for the
constant relief of thermal expansion. A properly sized
thermal expansion tank must be installed on all closed
systems to control thermal expansion, see Figure 12
(page 13).
If you do not understand these instructions or have any
questions regarding the temperature-pressure relief valve
call the toll free number listed on the back cover of this
manual for technical assistance.
FILLING THE WATER HEATER
Never use this water heater unless it is completely full
of water. To prevent damage to the tank, the tank must
be lled with water. Water must ow from the hot water
faucet before turning on the gas to the water heater.
To ll the water heater with water:
1. Close the water heater drain valve by turning the
handle to the right (clockwise). The drain valve is on
the lower front of the water heater.
2. Open the cold water supply valve to the water heater.
NOTE: The cold water supply valve must be left open
when the water heater is in use.
3. To insure complete lling of the tank, allow air to exit
by opening the nearest hot water faucet. Allow water
to run until a constant ow is obtained. This will let air
out of the water heater and the piping.
4. Check all water piping and connections for leaks.
Repair as needed.

16
AIR REQUIREMENTS
Breathing Hazard - Carbon Monoxide Gas
Install water heater in accordance with
the Instruction Manual and NFPA 54 or
CAN/CSA-B149.1.
To avoid injury, combustion and ventilation
air must be taken from outdoors.
Do not place chemical vapor emitting
products near water heater.
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
For safe operation, an adequate supply of fresh
uncontaminated air for combustion and ventilation must
be provided.
An insufcient supply of air can cause recirculation of
combustion products resulting in contamination that may
be hazardous to life. Such a condition often will result
in a yellow, luminous burner ame, causing sooting of
the combustion chamber, burners, and ue tubes, and
creates a risk of asphyxiation.
Do not install the water heater in a conned space unless
an adequate supply of air for combustion and ventilation
is brought in to that space using the methods described
in Conned Space (page 16) that follows later in this
manual.
Never obstruct the ow of ventilation air. If you have any
doubts or questions at all, call your gas supplier. Failure
to provide the proper amount of combustion air can result
in a re or explosion and cause property damage, serious
bodily injury or death.
UNCONFINED SPACE
An unconned space is one in which the volume is not
less than 50 cubic feet per 1,000 Btu/hr (4.8 cubic meters
per kW) of the total input rating of all appliances installed
in the space. Rooms communicating directly with the
space in which the appliances are installed, through
openings not furnished with doors, are considered a part
of the unconned space.
Makeup air requirements for the operation of exhaust
fans, kitchen ventilation systems, clothes dryers and
replaces shall also be considered in determining the
adequacy of a space to provide combustion, ventilation
and dilution air.
UNUSUALLY TIGHT CONSTRUCTION
In unconned spaces in buildings, inltration may be
adequate to provide air for combustion, ventilation and
dilution of ue gases. However, in buildings of unusually
tight construction (for example, weather stripping, heavily
insulated, caulked, vapor barrier, etc.) additional air must
be provided using the methods described in that follows.
CONFINED SPACE
A conned space is one in which the volume is less than
50 cubic feet per 1,000 Btu/hr (4.8 cubic meters per kW)
of the total input rating of all appliances installed in the
space.
Openings must be installed to provide fresh air for
combustion, ventilation and dilution in conned spaces.
The required size for the openings is dependent on the
method used to provide fresh air to the conned space
and the total Btu/hr input rating of all appliances installed
in the space.
DIRECT VENT APPLIANCES
Appliances installed in a direct-vent conguration
that derives all air for combustion from the outdoor
atmosphere through sealed intake air piping are not
factored in the total appliance input Btu/hr calculations
used to determine the size of openings providing fresh air
into conned spaces.
EXHAUST FANS
Where exhaust fans are installed, additional air shall be
provided to replace the exhausted air. When an exhaust
fan is installed in the same space with a water heater,
sufcient openings to provide fresh air must be provided
that accommodate the requirements for all appliances
in the room and the exhaust fan. Undersized openings
will cause air to be drawn into the room through the
water heater’s vent system causing poor combustion.
Sooting, serious damage to the water heater and the risk
of re or explosion may result. It can also create a risk of
asphyxiation.
LOUVERS AND GRILLES
The free areas of the fresh air openings in the
instructions that follow do not take in to account the
presence of louvers, grilles or screens in the openings.
The required size of openings for combustion, ventilation
and dilution air shall be based on the “net free area” of
each opening. Where the free area through a design
of louver or grille or screen is known, it shall be used in
calculating the size of opening required to provide the
free area specied. Where the louver and grille design

17
and free area are not known, it shall be assumed that
wood louvers will have 25% free area and metal louvers
and grilles will have 75% free area. Non motorized
louvers and grilles shall be xed in the open position.
FRESH AIR OPENINGS FOR CONFINED SPACES
The following instructions shall be used to calculate the
size, number and placement of openings providing fresh
air for combustion, ventilation and dilution in conned
spaces. The illustrations shown in this section of the
manual are a reference for the openings that provide
fresh air into conned spaces only. Do not refer to these
illustrations for the purpose of vent installation. See
Venting (page 19) for complete venting instructions.
OUTDOOR AIR THROUGH TWO OPENINGS
FIGURE 13. FRESH AIR FROM TWO OPENINGS
The conned space shall be provided with two permanent
openings, one commencing within 12 inches (300 mm)
of the top and one commencing within 12 inches (300
mm) of the bottom of the enclosure. The openings shall
communicate directly with the outdoors. See Figure 13 .
Each opening shall have a minimum free area of 1
square inch per 4,000 Btu/hr (550 mm2 per kW) of the
aggregate input rating of all appliances installed in the
enclosure. Each opening shall not be less than 100
square inches (645 cm2).
OUTDOOR AIR THROUGH ONE OPENING
FIGURE 14. FRESH AIR FROM ONE OPENING
Alternatively a single permanent opening, commencing
within 12 inches (300 mm) of the top of the enclosure,
shall be provided. See Figure 14.
The water heater shall have clearances of at least 1 inch
(25 mm) from the sides and back and 6 inches (150 mm)
from the front of the appliance. The opening shall directly
communicate with the outdoors or shall communicate
through a vertical or horizontal duct to the outdoors or
spaces that freely communicate with the outdoors and
shall have a minimum free area of the following:
1. One square inch per 3000 Btu/hr (733 mm2 per kW)
of the total input rating of all appliances located in the
enclosure, and
2. Not less than the sum of the areas of all vent
connectors in the space.

18
OUTDOOR AIR THROUGH TWO HORIZONTAL
DUCTS
FIGURE 15. FRESH AIR FROM TWO HORIZONTAL DUCTS
The conned space shall be provided with two permanent
horizontal ducts, one commencing within 12 inches (300
mm) of the top and one commencing within 12 inches
(300 mm) of the bottom of the enclosure. The horizontal
ducts shall communicate directly with the outdoors. See
Figure 15.
Each duct opening shall have a minimum free area of 1
square inch per 2,000 Btu/hr (1100 mm2 per kW) of the
aggregate input rating of all appliances installed in the
enclosure.
When ducts are used, they shall be of the same cross
sectional area as the free area of the openings to which
they connect. The minimum dimension of rectangular air
ducts shall be not less than 3 inches.
OUTDOOR AIR THROUGH TWO VERTICAL DUCTS
The illustrations shown in this section of the manual are
a reference for the openings that provide fresh air into
conned spaces only.
DO NOT refer to these illustrations for the purpose of
vent installation. See Venting (page 19) for complete
venting instructions.
FIGURE 16. FRESH AIR FROM TWO VERTICAL DUCTS
The conned space shall be provided with two permanent
vertical ducts, one commencing within 12 inches (300
mm) of the top and one commencing within 12 inches
(300 mm) of the bottom of the enclosure. The vertical
ducts shall communicate directly with the outdoors. See
Figure 16.
Each duct opening shall have a minimum free area of 1
square inch per 4,000 Btu/hr (550 mm2 per kW) of the
aggregate input rating of all appliances installed in the
enclosure.
When ducts are used, they shall be of the same cross
sectional area as the free area of the openings to which
they connect. The minimum dimension of rectangular air
ducts shall be not less than 3 inches.
AIR FROM OTHER INDOOR SPACES
FIGURE 17. AIR FROM INDOOR SPACES

19
The conned space shall be provided with two permanent
openings, one commencing within 12 inches (300 mm) of
the top and one commencing within 12 inches (300 mm)
of the bottom of the enclosure. See Figure 17.
Each opening shall communicate directly with an
additional room(s) of sufcient volume so that the
combined volume of all spaces meets the criteria for an
unconned space.
Each opening shall have a minimum free area of 1
square inch per 1,000 Btu/hr (2200 mm2 per kW) of the
aggregate input rating of all appliances installed in the
enclosure. Each opening shall not be less than 100
square inches (645 cm2).
VENTING
Water heaters covered by these instructions are Category
I, Natural Draft appliances.
If the water heater is being installed as a replacement
for an existing heater in pre-existing venting, a thorough
inspection of existing venting system must be performed
prior to any installation work.
VENT DAMPERS - Any vent damper, whether it is
operated thermally or otherwise must be removed if its
use inhibits proper drafting of the water heater.
Thermally Operated Vent Dampers: this gas-red water
heater has a thermal efciency at or above 80% which
may produce a relatively low ue gas temperature.
Such temperatures may not be high enough to properly
open thermally operated vent dampers. This would
cause spillage of the ue gases and may cause carbon
monoxide poisoning. Vent dampers must bear evidence
of certication as complying with the current edition of
the American National Standard ANSI Z21.66 CGA 6.14
(covering electrically and mechanically actuated vent
dampers). Before installation of any vent damper, consult
the local gas utility for further information.
To insure proper venting of this gas-red water heater,
the correct vent pipe diameter must be utilized. Any
additions or deletions of other gas appliances on a
common vent with this water heater may adversely affect
the operation of the water heater. Consult your gas
supplier if any such changes are planned.
For proper venting in certain installations, a larger
diameter vent pipe may be necessary. Consult your gas
supplier to aid you in determining the proper venting
for your water heater from the vent tables in the current
edition of the National Fuel Gas Code ANSI Z223.1/NFPA 54
or the Natural Gas and Propane Installation Code CAN\CSA
B 149.1.
Periodically check the venting system for signs of
obstruction or deterioration and replace if needed.
The combustion and ventilation air ow must not be
obstructed.
The water heater with draft hood installed must be
connected to a chimney or listed vent pipe system,
which terminates to the outdoors. Never operate the
water heater unless it is vented to the outdoors and has
adequate air supply to avoid risks of improper operation,
explosion or asphyxiation.
• For proper draft hood attachment, the draft hood legs
may be angled slightly inward.
• Place the draft hood legs in the receiving holes on the
top of the water heater. The legs will snap in the holes
to give a tight t. Secure draft hood with the supplied
brackets.
• Place the vent pipe over the draft hood. With the vent
pipe in position, drill a small hole through both the
vent pipe and draft hood. Secure them together with a
sheet metal screw. See Figure 18 (page 20).
Obstructed or deteriorated vent systems may present
serious health risk or asphyxiation.

20
Draft Hood
Draft Hood
Top of Heater
Screw
Vent to outdoors
or chimney
Screw
Vent
FIGURE 18. DRAFT HOOD ATTACHMENT
The vent pipe from the water heater must be no less
than the diameter of the draft hood outlet on the water
heater and must slope upward at least 1/4 inch per
linear foot (21 mm per meter). See Figure 19 (page
20).
All vent gases must be completely vented to the
outdoors of the structure (dwelling). Install only the draft
hood provided with the new water heater and no other
draft hood.
Vent pipes must be secured at each joint with sheet
metal screws.
FIGURE 19. VENT PIPE MINIMUM UPWARD SLOPE
There must be a minimum of 6” (153 mm) clearance
between single wall vent pipe and any combustible
material. Fill and seal any clearance between single
wall vent pipe and combustible material with mortar
mix, cement, or other noncombustible substance. For
other than single wall, follow vent pipe manufacturer’s
clearance specications. To insure a tight t of the vent
pipe in a brick chimney, seal around the vent pipe with
mortar mix cement.
Failure to have required clearances between vent piping
and combustible material will result in a re hazard.
Be sure vent pipe is properly connected to prevent
escape of dangerous ue gases which could cause
deadly asphyxiation.
Chemical vapor corrosion of the ue and vent system
may occur if air for combustion contains certain chemical
vapors. Spray can propellants, cleaning solvents,
refrigerator and air conditioner refrigerants, swimming
pool chemicals, calcium and sodium chloride, waxes,
bleach and process chemicals are typical compounds
which are potentially corrosive.
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 4 and