A.O. Smith 100 Series Manual

1
A DIVISION OF A.O. SMITH CORPORATION
Mc BEE, SOUTH CAROLINA
PLACE THESE INSTRUCTIONSADJACENT TO HEATERAND
NOTIFYOWNER TOKEEP FORFUTURE REFERENCE.
PRINTEDINU.S.A. 0307 PART NO. 197727-000
CYCLONE Xi Model BTH 120-250(A)
SERIES 100AND 101
COMMERCIAL GAS WATER HEATER
GAS-FIREDPOWERBURNER
FOR DOMESTIC HOT WATER
Thank you for buying this energy efficient water heater from
A.O. Smith Water Products Company. We appreciate your
confidenceinourproducts.
CAUTION
TEXT PRINTED OR UNDERLINED IN RED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE
READ THOROUGHLYBEFORE INSTALLING AND USING
THISAPPLIANCE.
•INSTALLATION • OPERATION • SERVICE • MAINTENANCE • LIMITED WARRANTY
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.
• Ifyoucannot reachyour gassupplier,
call the fire department.
– Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.

2
These designs comply with the current edition of the American National
Standard for Gas Water Heaters, Volume III,ANSI Z21.10.3 / CSA 4.3 as an
automatic circulating tank water heater, and automatic storage water
heaters.
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.
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.
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 and the
NationalElectricalCode,NFPA70 or CAN/CSA-B149.1,theNaturalGasand
PropaneInstallationCodeandCSAC22.1,theCanadianElectricalCode.All
documents are available from the Canadian Standards Association, 8501
EastPleasantValley Road, Cleveland, OH 44131. NFPAdocumentsarealso
available from the National Fire Protection Association, 1 Batterymarch
Park, Quincy, MA 02269.
FOREWORD
CYCLONE Xi BTH 120 - 250A ROUGH-IN-DIMENSIONS
Table 1. RECOVERYCAPACITIES - NATURALGAS/L.P.
Approx.
Input Gas Gallon TEMPERATURE RISE - DEGREES °F - GALLONS PER HOUR
Model BTU/Hr. Usage Capacity 30 40 50 60 70 80 90 100 110 120 130 140
BTH 120 120,000 nat/lp 60 461 345 276 230 197 173 154 138 126 115 106 99
BTH 150 150,000 nat/lp 100 576 432 345 288 247 216 192 173 157 144 133 123
BTH 199 199,900 nat/lp 100 767 575 460 384 329 288 256 230 209 192 177 164
BTH 250 250,000 nat/lp 100 960 720 576 480 411 360 320 288 262 240 221 206
Approx.
Gas Liter TEMPERATURE RISE - DEGREES C - Liters PER HOUR
Model kW-Hr Usage Capacity 17 22 28 33 39 44 50 56 61 67 72 78
BTH 120 35 nat/lp 227 1744 1308 1046 872 747 654 581 523 476 436 402 374
BTH 150 44 nat/lp 379 2179 1635 1308 1090 934 817 726 654 594 545 503 467
BTH 199 58 nat/lp 379 2904 2178 1743 1452 1245 1089 968 871 792 726 670 622
BTH 250 73 nat/lp 379 3632 2724 2179 1816 1557 1362 1211 1090 991 908 838 778
Recovery capacities are based on 95% thermal efficiency.
GASVALVEPIPING
BTH-120, 199 & 250 1/2" NPT
BTH-150 3/4" NPT

3
DANGER
THISWATERHEATERISEQUIPPEDWITHANADJUSTABLETHERMOSTAT
TO CONTROL WATER TEMPERATURE. HOT WATER TEMPERATURES
REQUIRED FOR AUTOMATIC DISHWASHER AND LAUNDRY USE CAN
CAUSESCALDBURNSRESULTINGIN SERIOUSPERSONALINJURYAND/
OR DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS VARIES
WITHTHEPERSON’SAGEANDTHETIMEOFTHEEXPOSURE.THESLOWER
RESPONSE TIME OF CHILDREN, AGED OR DISABLED PERSONS
INCREASESTHE HAZARDSTOTHEM.NEVERALLOWSMALLCHILDREN
TO USE A HOT WATER TAP, OR TO DRAW THEIR OWN BATH WATER.
NEVERLEAVEACHILDORDISABLEDPERSONUNATTENDEDINABATHTUB
ORSHOWER.
THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE THE
GENERALPUBLICDOESNOTHAVEACCESSTOSETTEMPERATURES.
The water temperature is controlled using the Temperature Control Button
on the Display at the front of the unit (See Figure 1). This control utilizes
two temperature probes to determine the tank temperature. The primary
temperature probe is located at the top of the tank and the other is near the
water inlet.
The temperature may be adjusted from 90°F/32°C to 180°F/82°C. The
thermostat was adjusted to 120°F/49°C before the heater was shipped
from the factory. It is recommended that lower water temperature be used
to avoid the risk of scalding. It is further recommended, in all cases, that the
FEATURES
IMPORTANT
ITISREQUIREDTHATAQUALIFIEDSERVICETECHNICIANPERFORMTHE
INITIALFIRINGOFTHE HEATER. ATTHIS TIMETHE USERSHOULDNOT
HESITATETOASK THETECHNICIANANY QUESTIONS WHICH HE MAY
HAVEINREGARDTOTHE OPERATIONANDMAINTENANCEOFTHEUNIT.
ACHECKLISTAND SERVICEINFORMATIONsectionareincludedat therear
of this manual. By using this checklist the user may be able to make minor
operational adjustments and save himself unnecessary service calls.
However, the user should not attempt repairs which are not listed in this
section.
WATERTEMPERATURECONTROL
TABLE OF CONTENTS
ROUGH-INDIMENSIONS ................................................................... 2
FOREWORD ...................................................................................... 2
FEATURES ........................................................................................ 3,4
Water Temperature Control.......................................................... 3
High Limit Switch (E.C.O.) ............................................................ 4
Dishwashing Machine Requirement ............................................ 4
CirculatingPump........................................................................... 5
INSTALLATIONINSTRUCTIONS ........................................................ 4-12
RequiredAbility ............................................................................ 6
Insulation Blankets ....................................................................... 6
Locating The Heater..................................................................... 5
Clearances ................................................................................... 5
Hard Water ................................................................................... 6
Air Requirements ......................................................................... 6
Mechanical Exhausting of Room Air ............................................ 6
Unconfined Space........................................................................ 6
Confined Space............................................................................ 6
Chemical Vapor Corrosion ........................................................... 6
Venting ......................................................................................... 6
Vent Pipe Termination ................................................................... 6-10
Installation Requirements for the
Commonwealth of Massachusetts...................................... 7
Direct Venting............................................................................... 10
Direct Vent Terminal Installation (Sidewall) ................................. 10
Installation Sequence................................................................... 10
Vertical Vent Terminal Installation ................................................ 11
Installation Sequence................................................................... 11
Installation of Vent System .......................................................... 12
Vent Pipe Preparation................................................................... 12
CONTROLANDSWITCHES .............................................................. 13
Blower Prover Switch ................................................................. 13
Blocked Outlet Prover Switch...................................................... 13
Blocked Inlet Prover Switch......................................................... 13
Low Gas Pressure Switch.......................................................... 13
On/Off Switch.............................................................................. 13
Hot Surface Igniter ....................................................................... 13
GASPIPING....................................................................................... 13
Connection of Gas Pipe ............................................................... 14
Purging ......................................................................................... 15
Gas Meter Size - City Gases Only .............................................. 15
Gas Pressure Regulation............................................................. 15
Gas Valves................................................................................... 15
SYSTEMCONNECTIONS .................................................................. 15
Thermometers .............................................................................. 15
Relief Valve .................................................................................. 15
Water Line Connections ............................................................. 15
Heater Wiring .............................................................................. 16
USINGTHEELECTRONICCONTROLLER......................................... 17
Overview .................................................................................... 17
Operating States ......................................................................... 17
Adjusting the Operating Set Point ............................................... 18
Changing the Display Units ......................................................... 19
Fault and Warning Conditions ..................................................... 19
Access to the Current Fault or Warning .................................... 19
Viewing the Fault History ........................................................... 20
PRIORTOSTART-UP ....................................................................... 20
RequiredAbility ........................................................................... 20
OPERATIINGINSTRUCTIONS ........................................................... 21
Adjustment Procedure (Initial Start-Up) 120 and 150 Models .... 21
Adjustment Procedure (Initial Start-Up) 199 and 250 Models .... 21
Cathodic Protection ..................................................................... 22
Precautions ................................................................................. 22
GENERALINFORMATION ................................................................ 22
Power Burner ............................................................................. 22
HighLimit ..................................................................................... 22
High Altitude Installations ............................................................ 22
MAINTENANCE ................................................................................ 22
General........................................................................................ 22
Maintenance Schedule ............................................................... 22
Flushing ....................................................................................... 26
Draining ....................................................................................... 26
SedimentRemoval....................................................................... 26
LimeScaleRemoval .................................................................... 26
Anode Inspection and Replacement........................................... 26,27
Drain Valve and Access Panels ................................................. 27
Relief Valve ................................................................................. 27
CirculatingPump.......................................................................... 27
Vent System ................................................................................ 27
INSTALLATIONDIAGRAMS ............................................................. 28-32
Manifold Kits................................................................................ 33
CHECKLISTANDSERVICEINFORMATION ...................................... 34
TROUBLE-SHOOTING...................................................................... 34,35
LIMITEDWARRANTY....................................................................... 36
PAGE PAGE

4
water temperature be set for the lowest temperature which satisfies your
hot water needs. This will also provide the most energy efficient operation
of the water heater and minimize scale formation.
SETTINGTHEWATERHEATERTEMPERATUREAT120°F/49°CWILLREDUCE
THE RISK OF SCALDS. Some states require settings at specific lower
temperatures.
Figure 1 shows 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 point of use to exceed the thermostat setting by
up to 20°F/11°C. 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
180°F / 82°C Nearly instantaneous
170°F / 77°C Nearly instantaneous
160°F / 71°C About 1/2 second
150°F / 66°C About 1-1/2 seconds
140°F / 60°C Less than 5 seconds
130°F / 54°C About 30 seconds
120°F / 49°C More than 5 minutes
FIGURE1.
Valves for reducing point-of-use temperature by mixing cold and hot water
are available (see Figure 2). Also available are inexpensive devices that
attach to faucets to limit hot water temperatures. Contact a licensed plumber
or the local plumbing authority.
FIGURE2.
HIGH LIMIT SWITCH (E.C.O.)
The top immersion well of the dual bulb controller also contains the high limit
(energy cutoff) sensor. The high limit switch interrupts the main burner
gas flow should the water temperature reach approximately 202°F/94°C.
Should the high limit switch activate, the control system will automatically
reset the unit once the water temperature in the tank falls below 140°F/
60°C. If the unit is manually shut down and restarted, as long as the
temperature in the tank is lower than 160°F/71°C, the unit will reset and
initiate operation.
High limit switch operation is the likely cause when higher than normal
water temperatures occur with a recurring need to restart the water heater.
This could be due to a malfunctioning thermostat allowing the gas valve to
remain open and the burner to continue firing even after water temperature
in the tank has already reached the set point. Contact your dealer or
servicer if continued high limit switch operation occurs.
DISHWASHINGMACHINEREQUIREMENT
All dishwashing machines meeting the National Sanitation Foundation
requirements are designed to operate with water flow pressures between
15 and 25 pounds per square inch (103 Kpa and 173 Kpa). Flow pressures
above 25 pounds per square inch (173 Kpa), or below 15 pounds per
square inch (103 Kpa), will result in improperly sanitized dishes. Where
pressures are high, a water pressure reducing or flow regulating control
valve should be used in the 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 180°F
(82°C) 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 180°F (82°C) water at the
point of take-off to the dishwashing machine. Adjust flow by means of the
plug cock in the circulating line. (See installation diagrams.)
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 to the piping diagrams at rear of manual for electrical hookup
information and install in accordance with the current edition of the
National Electrical Code, NFPA70 or the Canadian Electrical Code,
CSAC22.1.
All bronze circulators are recommended for used with commercial
water heaters.
Although circulators are oiled and operated by the manufacturer
some circulators must be oiled again before operated. Please
refer to manufacturer's instructions.
INSTALLATION INSTRUCTIONS
REQUIREDABILITY
INSTALLATIONORSERVICEOFTHIS WATERHEATER REQUIRESABILITY
EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD
INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPLY AND
ELECTRICALWORKAREREQUIRED.
INSULATIONBLANKETS
Insulation blankets available to the general public for external use on gas
water heaters are not approved for use on your A.O. Smith water heater.
The purpose of an insulation blanket is to reduce the standby heat loss
encountered with storage tank water heaters. Your A.O. Smith water
heater meets or exceeds the ASHRAE/IES 90.1 1999 standards with
respect to insulation and standby loss requirements, making an insulation
blanket unnecessary.
WARNING
Should you choose to apply an 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, or the upper 15" (38 cm) of the water
heater, as this will interfere with safe operation.
• 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 A.O. Smith for placement on the blanket
directly over the existing labels.

5
LOCATINGTHEHEATER
WARNING
THEREISARISKINUSINGFUELBURNINGAPPLIANCESSUCHASGAS
WATER HEATERS IN ROOMS, GARAGES OR OTHER AREAS WHERE
GASOLINE,OTHERFLAMMABLELIQUIDSORENGINEDRIVENEQUIPMENT
ORVEHICLESARESTORED,OPERATEDORREPAIRED. FLAMMABLE
VAPORS ARE HEAVYAND TRAVELALONG THE FLOOR AND MAY BE
IGNITEDBYTHEHEATER’SIGNITERORMAINBURNERFLAMESCAUSING
FIREOREXPLOSION.SOMELOCALCODESPERMITOPERATIONOFGAS
APPLIANCESIFINSTALLED 18 INCHES (46cm)ORMOREABOVETHE
FLOOR.THISMAYREDUCETHE RISK IF LOCATIONINSUCHANAREA
CANNOTBEAVOIDED.
THEHEATERSHALLBELOCATEDORPROTECTEDSOITISNOTSUBJECT
TOPHYSICALDAMAGEBYAMOVINGVEHICLE.
DONOTLOCATETHEHEATERWHERENOISEFROMTHEEXHAUSTOR
INTAKEWILLBEOBJECTIONABLE.THISINCLUDESLOCATIONSCLOSETO
ORACROSSFROMWINDOWSANDDOORS.AVOIDANCHORINGTHEVENT
ANDINTAKEPIPESDIRECTLYTOFRAMEDWALLS,FLOORSOFCEILINGS
UNLESSRUBBERISOLATIONPIPEHANGERSAREUSED.THISPREVENTS
ANYVIBRATIONSFROMBEINGTRANSMITTEDINTOTHELIVINGSPACES.
WARNING
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY OTHER
POTENTIALFIREHAZARDOUSARTICLESMUSTNEVERBEPLACEDON
ORADJACENTTO THE HEATER.OPENCONTAINERS OF FLAMMABLE
MATERIALSHOULDNOTBESTOREDORUSEDINTHESAMEROOMWITH
THEHEATER.
When installing the heater, consideration must be given to proper location.
Locationselected should be as closetotheintake and exhaust termination
points as practicable, with adequate air supply and as centralized with the
piping system as possible.
THEHEATER MUSTNOTBELOCATEDINANAREAWHEREITWILLBE
SUBJECTTOFREEZING.
LOCATEITNEARAFLOORDRAIN.THEHEATERSHOULDBELOCATEDIN
ANAREAWHERELEAKAGEFROMTHEHEATERORCONNECTIONSWILL
NOTRESULTINDAMAGETOTHEADJACENTAREAORTOLOWERFLOORS
OFTHESTRUCTURE.
When such locations cannot be avoided, it is recommended that a suitable
drain pan, adequately drained, be installed under the appliance.
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:
• 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.
WARNING
THISWATER HEATER ISACONDENSING UNITAND REQUIRESADRAIN
TO BE LOCATED IN CLOSE PROXIMITY TOALLOW THE CONDENSATE
TODRAINSAFELY.THECONDENSATE DRAINS FROMTHEUNITATTHE
EXHAUSTELBOW LOCATEDATTHEBOTTOM OFTHEUNIT. NOTE: ITIS
IMPORTANTTHATTHE CONDENSATE HOSE NOTBE ELEVATEDABOVE
THE EXHAUST ELBOW (SEE FIGURE 3). THE CONDENSATE BUILD-UP
WILLBLOCK THE EXHAUST OUTLET, WHICH WILLCAUSE IMPROPER
OPERATION.
FIGURE3.
WARNING
DONOTUSETHISAPPLIANCEIFANYPARTHAS BEEN UNDER WATER.
IMMEDIATELYCALLAQUALIFIEDSERVICETECHNICIANTOINSPECTTHE
APPLIANCEANDTOREPLACEANYPARTOFTHECONTROLSYSTEMAND
ANYGASCONTROLWHICHHASBEENUNDERWATER.
CLEARANCES
These heaters are approved for installation on combustible flooring in an
alcove when the minimum clearances from any combustion construction
are followed as indicated in Figure 4.
In all installations the minimum combustible clearances from any vent piping
shall be 0". Vent piping passing through a combustible wall or ceiling must
be a continuous run (no joints).
A service clearance of 24" (61 cm) should be maintained from serviceable
parts such as relief valves, flue baffles, flue damper devices, thermostats,
cleanout openings or drain valves.
Always disconnect electrical power before servicing the unit.
FIGURE4.
*ILLUSTRATION OF MINIMUM COMBUSTIBLE CLEARANCES IN AN
ALCOVE.

6
Iftheconfinedspace iswithinabuildingof tightconstruction,airforcombustion
andventilationmustbe obtainedfromoutdoors. Whendirectlycommunicating
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 (6.5 cm²) 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 (6.5 cm²) per
2000 Btuh of the total input of all appliances in the enclosure.
CHEMICALVAPORCORROSION
WARNING
CORROSIONOFTHEFLUEWAYSANDVENTSYSTEMMAYOCCURIFAIR
FOR COMBUSTION CONTAINS CERTAIN CHEMICAL VAPORS. SUCH
CORROSIONMAYRESULTINFAILUREANDRISKOFASPHYXIATION.
Spray can propellants, cleaning solvents, refrigerator and air conditioning
refrigerants,swimmingpoolchemicals,calciumandsodiumchloride,waxes,
and process chemicals are typical compounds which are potentially
corrosive.
PRODUCTSOFTHISSORTSHOULDNOTBESTOREDNEARTHEHEATER.
ALSO, AIR WHICH IS BROUGHT IN CONTACT WITH THE HEATER
SHOULD NOT CONTAINANY OF THESE CHEMICALS. IF NECESSARY,
UNCONTAMINATEDAIRSHOULDBEOBTAINEDFROMREMOTEOROUTSIDE
SOURCES.
VENTING
WARNING
THEINSTRUCTIONSINTHISSECTIONONVENTINGMUSTBEFOLLOWED
TOAVOIDCHOKEDCOMBUSTIONORRECIRCULATIONOFFLUEGASES.
SUCH CONDITIONS CAUSE SOOTING OR RISKS OF FIRE AND
ASPHYXIATION.
Heater must be protected from freezing downdrafts during shutdown periods.
WARNING
NEVEROPERATETHEHEATERUNLESSITISVENTEDTOTHEOUTDOORS
AND HAS ADEQUATE AIR SUPPLY TO AVOID RISKS OF IMPROPER
OPERATION,FIRE,EXPLOSIONORASPHYXIATION.
VENTPIPETERMINATION
NOTE: Before installing venting, determine place of vent pipe termination.
See Figures 5a & b and 6a & b before proceeding.
CAUTION
DONOTTERMINATETHEVENTINGWHERENOISEFROMTHEEXHAUSTOR
INTAKEWILLBEOBJECTIONABLE.THISINCLUDESLOCATIONSCLOSETO
ORACROSSFROMWINDOWSANDDOORS.AVOIDANCHORINGTHEVENT
ANDINTAKEPIPESDIRECTLYTOFRAMEDWALLS,FLOORSORCEILINGS
UNLESSRUBBERISOLATIONPIPEHANGERSAREUSED.THISPREVENTS
ANYVIBRATIONSFROMBEINGTRANSMITTEDINTOTHELIVINGSPACES.
HARDWATER
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 MAINTENANCE section for details of tank cleanout procedure.
AIRREQUIREMENTS
KEEPAPPLIANCEAREACLEARANDFREEOFCOMBUSTIBLEMATERIALS,
GASOLINEANDOTHERFLAMMABLE VAPORSANDLIQUIDS.
DONOTOBSTRUCTTHEFLOWOFCOMBUSTIONANDVENTILATINGAIR.
WARNING
FORSAFEOPERATIONPROVIDEADEQUATEAIRFORCOMBUSTIONAND
VENTILATION. AN INSUFFICIENT SUPPLY OF AIR WILL CAUSE
RECIRCULATION OF COMBUSTION PRODUCTS RESULTING IN
CONTAMINATIONTHATMAYBEHAZARDOUSTOLIFE. SUCHACONDITION
OFTENWILLRESULTINAYELLOW,LUMINOUSBURNERFLAME,CAUSING
CARBONINGORSOOTING OFTHECOMBUSTIONCHAMBER, BURNERS
ANDFLUETUBESAND CREATESARISKOFASPHYXIATION.
MECHANICALEXHAUSTINGOF ROOM AIR
Where an exhaust fan is installed in the same room with a heater, sufficient
openings for air must be provided in the walls. UNDERSIZED OPENINGS
WILLCAUSEAIRTOBEDRAWNINTOTHEROOMTHROUGHTHEHEATER’S
VENTINGSYSTEM,CAUSINGPOORCOMBUSTION. SOOTINGMAYRESULT
INSERIOUSDAMAGETOTHEHEATERANDRISKOFFIREOREXPLOSION.
ITCANALSO CREATEARISKOFASPHYXIATION.
UNCONFINEDSPACE
In buildings of conventional frame, brick or stone construction, unconfined
spaces may provide adequate air for combustion and ventilation.
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 and ventilation 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 air from inside a conventionally constructed
building to a confined space, such a space shall be provided with two
permanentopenings,ONEIN ORWITHIN12" (31cm) OFTHEENCLOSURE
TOPAND ONE INORWITHIN12"(31cm)OFTHEENCLOSUREBOTTOM.
Each opening shall have a free area of at least one square inch (6.5 cm²)
per 1000 Btuh appliances in the enclosure, but not less than 100 square
inches (645 cm²).

7
For all side wall terminated, horizontally vented power vent, direct vent, and power direct vent gas fueled water heaters
installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or
operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished
grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:
INSTALLATION OF CARBON MONOXIDE DETECTORS Atthe timeof installationofthe sidewall horizontalventedgas fueled
equipment, the installing plumber or gasfitter shall observe that a hard wired carbon monoxide detector with an alarm and
battery back-up is installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or
gasfitter shall observe that a battery operated or hard wired carbon monoxide detector with an alarm is installed on each
additional level of the dwelling, building or structure served by the sidewall horizontal vented gas fueled equipment. It shall
be the responsibility of the property owner to secure the services of qualified licensed professionals for the installation of
hard wired carbon monoxide detectors.
In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl space or an attic, the hard wired
carbon monoxide detector with alarm and battery back-up may be installed on the next adjacent floor level.
In the event that the requirements of this subdivision can not be met at the time of completion of installation, the owner shall
have a period of thirty (30) days to comply with the above requirements provided that during said thirty (30) day period, a
battery operated carbon monoxide detector with an alarm shall be installed.
APPROVED CARBON MONOXIDE DETECTORS Each carbon monoxide detector as required in accordance with the above
provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and CSA certified.
SIGNAGE A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum
height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating
appliance or equipment. The sign shall read, in print size no less than one-half (1/2) inch in size, “GAS VENT DIRECTLY
BELOW.KEEPCLEAROFALLOBSTRUCTIONS.”
INSPECTION The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the
installation unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accor-
dance with the provisions of 248 CMR 5.08(2)(a) 1 through 4.
EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled “Equipment Not Required To Be Vented” in the most current edition of NFPA 54
as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room or structure separate from the
dwelling, building, or structure used in whole or in part for residential purposes.
MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM PROVIDED Whenthemanufacturer ofProduct
Approved side wall horizontally vented gas equipment provides a venting system design or venting system components with
the equipment, the instructions provided by the manufacturer for installation of the equipment and the venting system shall
include:
1. Detailed instructions for the installation of the venting system design or the venting system components; and
2. A complete parts list for the venting system design or venting system.
MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED When the manufacturer of a
ProductApproved side wall horizontally vented gas fueled equipment does not provide the parts for venting the flue gases, but
identifies “special venting systems,” the following requirements shall be satisfied by the manufacturer:
1. The referenced “special venting system” instructions shall be included with the appliance or equipment installation
instructions; and
2. The “special venting systems” shall be Product Approved by the Board, and the instructions for that system shall include
a parts list and detailed installation instructions.
A copy of all installation instructions for all Product Approved side wall horizontally vented gas fueled equipment, all venting
instructions, all parts lists for venting instructions, and/or all venting design instructions shall remain with the appliance or
equipment at the completion of the installation.
INSTALLATION REQUIREMENTSFORTHECOMMONWEALTHOF MASSACHUSETTS

8
FIGURE 5a.
U.S. POWER VENT
CANADIANPOWER VENT
FIGURE 5b.
CAUTION
TOPREVENTEXHAUSTINGPRODUCTS FROM CIRCULATING TOTHEAIR INTAKE
INWINDY/COLDAREAS,THE MAXIMUM PRACTICALDISTANCEBETWEEN
THESETWOTERMINALS IS RECOMMENDED.

9
FIGURE 6a.
U.S. DIRECT VENT
CANADIANDIRECT VENT
FIGURE 6b.
CAUTION
TOPREVENT EXHAUSTING PRODUCTSFROMCIRCULATING TOTHEAIRINTAKE
INWINDY/COLDAREAS,THE MAXIMUM PRACTICALDISTANCE BETWEEN
THESETWOTERMINALS IS RECOMMENDED.

10
IMPORTANT
The vent system must terminate so that proper clearances are maintained
as cited in local codes or the current editions of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 or the Natural Gas and Propane Installation Code,
CAN/CSA-B149.1.
Do not terminate the exhaust vent terminal over public area where
condensate or vapor can cause nuisance or hazard.
Plan the vent system layout so that proper clearances are maintained from
plumbing and wiring.
Vent pipes serving power vented appliances are classified by building
codes as "vent connectors". Required clearances from combustible
materials must be provided in accordance with information in this manual
under LOCATION OF HEATER and CLEARANCES, and with National Fuel
Gas Code and local Codes.
IMPORTANT
Plan the layout of the vent system backwards from the vent termination to
the appliance.
WARNING
USEONLYTHEVENTTERMINALSSUPPLIEDWITHTHISUNIT.TERMINATION
OFAVENTSYSTEMWITHADEVICEOTHERTHANTHESUPPLIED VENT
TERMINATIONSWILLAFFECTSYSTEMPERFORMANCEANDRESULTINA
SAFETY HAZARD.
DIRECT VENTING
The air intake provided on the unit contains a mesh screen (see Figure 7)
to prevent large particles from entering the unit.
FIGURE 7.
WARNING
WHENTHEUNITISTOBESETUPASADIRECTVENT,THEMESHSCREEN
MUSTBEREMOVED.THEINLETVENTPIPEMAYTHENBEGLUEDTOTHE
AIRINTAKE (seeFigure8)PROVIDEDONTHEUNIT.
DIRECTVENTTERMINAL INSTALLATION
IMPORTANT
THIS UNIT CONSISTS OF TWO VENT TERMINALS - AN INTAKE VENT
TERMINAL AND AN EXHAUST VENT TERMINAL. THE INTAKE VENT
TERMINALISA3"45°PVCELBOWWITHADOMEMESHWIRESCREENAND
THE EXHAUST VENTTERMINALISA 3" 45°PVC ELBOW WITHAMESH
WIRESCREEN.
NOTE:TO PREVENTEXHAUSTING PRODUCTSFROMCIRCULATINGTO
THE AIR INTAKE IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL
DISTANCEBETWEENTHESETWOTERMINALSISRECOMMENDED.
FIGURE 8.
IMPORTANT
WHEN LOCATING THE TERMINALS ONASIDEWALL, THE FOLLOWING
SPECIFICATIONS PERTAINING TO TERMINAL LOCATION MUST BE
FOLLOWED.
1. The intake vent terminal and the exhaust vent terminal must terminate on
the same exterior wall and must be located at a minimum of 24" (61cm)
from the vertical centerline of the exhaust vent terminal (see Figure 9).
In colder climates increasing the 24" (61cm) minimum will reduce
possibility of frost over from side winds blowing exhaust vapors to the
air intake of the direct vent.
2. The horizontal centerline of the intake vent terminal may not be located
lower than the horizontal centerline of the exhaust vent terminal
(see Figure 9).
INSTALLATIONSEQUENCE
For installations in the City of LosAngeles, California Category IV PVC Pipe
such as that manufactured by Brownline Pipe Company, must be used as
vent pipe material
CAUTION
Vent terminals supplied with the heater must be used.
NOTE: BEFOREBEGINNINGINSTALLATIONOFANYVENTPIPEREADTHE
VENTPIPEMANUFACTURER'SINSTALLATIONINSTRUCTIONS.
1. After the points of termination have been determined, use the cover
plates as templates to mark the holes for the vent pipes to be inserted
throughthewall. BEWAREOFCONCEALEDWIRINGANDPIPINGINSIDE
OF WALL.
2. If the vent terminals are being installed on the outside of a finished wall,
it may be easier to mark both the inside and outside wall.Align the holes
by drilling a hole through the center of the template from the inside
through to the outside. The template can now be positioned on the
outside wall using the drilled holes as a centering point for the template.
3. A) MASONRY SIDE WALLS
Chisel an opening approximately 1/2" (1.3 cm) larger than the marked
circle.
B)WOODENSIDEWALLS
Drill a pilot hole approximately one quarter inch outside of the marked
circle. This pilot hole is used as a starting point for a saws-all or sabre
saw blade. Cut around the marked circle staying approximately one
quarter inch outside of the line. (This will allow the vent pipe to easily
slide through the opening. The resulting gap will be covered by the vent
terminal cover plates.) Repeat this step on the inside wall if necessary.
4. Cut a length of 3" PVC pipe about 3.5" (8.9 cm) longer than the wall
thickness at the opening.
FORALL
MODELS

11
5. Glue the intake vent terminal to the section of the pipe.
6. Slide the wall plate over the pipe to stop against intake vent terminal.
7. Place a bead of caulking (not supplied) around the gap between the
pipe and the wall. Place some of the caulking on the back of the plate to
hold it against the wall after installation.
8. If the vent pipe is installed up to the wall, with a coupling on the end
against the wall opening, the pipe with the vent terminal can be
prepared for gluing before inserting through the wall. Slide the pipe
through the wall and insert into coupling on the other side of the wall,
making sure that the vent terminal ends up pointed in the correct position
(See Figure 9).
FIGURE9.
FIGURE10.
VERTICAL VENT TERMINAL INSTALLATION
IMPORTANT
WHENTERMINATINGTHROUGHAROOF,THEFOLLOWINGSPECIFICATIONS
PERTAININGTOTERMINALLOCATIONMUSTBEFOLLOWED.
1. Proper support must be provided for all pipe protruding through the
roof.
2. The vertical roof terminations should be sealed with a plumbing roof
boot or equivalent flashing.
3. The intake vent termination and the exhaust vent termination must
penetrate the same side of roof.
4. The center line of the intake vent termination and the center line of the
exhaust vent termination must be no closer than 24" (61cm).
5. The intake vent terminal and the exhaust vent terminal must be oriented
facing downward and the same direction.
The specifications are displayed in Figure 10 & 11.
NOTE: Exhaust vent terminal is installed using the same procedure.
INSTALLATIONSEQUENCE
NOTE: BEFOREBEGINNINGINSTALLATION OFANYVENTPIPE, READ
“VENTPIPEPREPARATION”SECTIONONPAGE12.
1. After the points of termination have been determined, use the cover
plates as templates to mark the holes for the vent pipes to be inserted
through the roof.
2. Drill a pilot hole approximately 1/4" (6 mm) outside of the marked circle.
This pilot hole is used as a starting point for a saws-all or sabre saw
blade. Cut around the marked circle staying approximately one quarter
inch outside the line. (This will allow the vent pipe to easily slide through
the opening). The resulting gap will be covered by the roof
boot/flashing.
3. Suspend the pipe through the center of the hole using proper support.
4. Slide roof boot or equivalent flashing over pipe and secure roof boot
equivalent flashing to roof.
5. Seal around flashing.
6. Terminate intake terminal and exhaust vent terminal facing down as
shown in Figure 11.
FIGURE11.

12
NOTE: for Water Heaters in locations with high ambient temperatures
(above 100°F or 38°C) and/or insufficient dilution air, it is recommended that
CPVCorABS pipe and fittings(MUSTUSESUPPLIEDVENTTERMINAL) be
used.
4. It is important that condensate not be allowed to buildup in the exhaust
vent pipe. To prevent this from happening the pipe should be installed
with a slight, 1/8" (3mm) per 5' (152 cm) of pipe maximum downward
slope.
5. The vent system should be supported every 5' (152 cm) of vertical run
and every 3' (91cm) of horizontal run of vent pipe length.
NOTE: Stress levels in the pipe and fittings can be significantly increased
by improper installation. If rigid pipe clamps are used to hold the pipe in
place, or if the pipe cannot move freely through a wall penetration, the pipe
may be directly stressed, or high thermal stresses may be formed when
thepipeheatsupandexpands.Installaccordinglytominimizesuchstresses.
VENTPIPEPREPARATION
1. INITIALPREPARATION
A. Make sure the solvent cement you are planning to use is designed
for the specific application you are attempting.
B. Know the physical and chemical characteristics and limitations of
the PVC, PVC cellular core, ABS or CPVC piping materials that you
are about to use.
C. Know the reputation of your pipe and cement manufacturer and
their products.
D. Know your own qualifications or those of your contractor. The
solvent welding technique of joining PVC, PVC cellular core, ABS or
CPVCpipeisaspecializedskilljustasanyotherpipefittingtechnique.
E. Closely supervise the installation and inspect the finished job before
start-up.
F. Contact the manufacturer, supplier, or competent consulting agency
if you have any questions about the application or installation of
PVC, PVC cellular core,ABS or CPVC pipe.
G. Take the time and effort to do a professional job. Shortcuts will only
cause you problems and delays in start-up. The majority of failures
in these systems are the result of shortcuts and/or improper joining
techniques.
2. SELECTIONOFMATERIALS
PRIMER
It is recommended that Tetrahydrofuran (THF) be used to prepare the
surfaces of pipe and fittings for solvent welding. Do not use water, rags,
gasoline or any other substitutes for cleaning PVC cellular core, ABS or
CPVC surfaces. A chemical cleaner such as MEK may be used.
CEMENT
The cement should be a bodied cement of approximately 500 to 1600
centipoise viscosity containing 10-20% (by weight) virgin PVC material
solvated with tetrahydrofuran (THF). Small quantities of dimethyl formamide
(DMF) may be included to act as a retarding agent to extend curing time.
Selecttheproper cement; Schedule 40 cement should be used for Schedule
40 pipe. Never use all-purpose cements, commercial glues and adhesives
or ABS cement to join PVC or CPVC pipe and fittings.
SAFETY PRECAUTION: PRIMERS AND CEMENTS ARE EXTREMELY
FLAMMABLE AND MUST NOT BE STORED OR USED NEAR HEAT OR
OPENFLAME. ALSO,USEONLYINAWELL-VENTILATEDAREA.
INSTALLATION OF VENT SYSTEM
WARNING
THEOPTIONALINTAKE VENTINGARRANGEMENTAND THEEXHAUST
VENTINGARRANGEMENTMUSTBEINSTALLEDTORUNDIRECTLYTOTHE
OUTDOORSANDNOTINANYWAYBECONNECTEDTOANOTHERVENTING
SYSTEM(I.E.FURNACE,DRYERSORSPACE HEATERS). ITISCRUCIAL
THATTHEVENTINGARRANGEMENTBE KEPTSEPARATEFROMOTHER
VENTINGSYSTEMS.IFTHISWARNINGISIGNORED,ANDTHESYSTEMIS
VENTEDINCORRECTLY,ITMAYCAUSE IMPROPEROPERATION,FIRE,
EXPLOSION,ORASPHYXIATION.
1. Plan the route of the vent system from the vent termination to the planned
locationoftheappliance.Layoutthetotalvent system to use the minimum
of vent pipe and elbows possible.
2. The installer may add up to a MAXIMUM OF FIFTY (50) EQUIVALENT
FEET (15.2m)of pipe to the exhaust venting arrangement. This addition
of FIFTY (50) EQUIVALENT FEET (15.2 m) of pipe on both the intake
venting arrangement and exhaust venting arrangement must include
any 3" PVC elbows which equals (5) EQUIVALENT FEET (1.5 m) of
pipe.
Table 2. VENT LENGTH TABLE
Number 3" 3" 4"
of 90° Minimum Maximum Maximum
Elbows Pipe (Ft./M.) Pipe (Ft./M.) Pipe (Ft./M.)
ONE (1) 7/2 45/13.7 115/35
TWO (2) 7/2 40/12.2 110/33.5
THREE(3) 7/2 35/10.7 105/32
FOUR (4) 7/2 30/9.1 100/30.5
FIVE (5) 7/2 --- 95/29
SIX (6) 7/2 --- 90/27.4
4" PVC may be used for a MAXIMUM intake of ONE HUNDRED TWENTY
(120) EQUIVALENT FEET (36.6m) and a MAXIMUM exhaust of ONE
HUNDRED TWENTY (120) EQUIVALENT FEET (36.6m). The maximum
number of 90° elbows with the 4" venting is six (6) on the intake and six (6)
on the exhaust. A 90° elbow is equal to five (5) equivalent feet (1.5m) of
pipe. One (1) 90° elbow is equal to two (2) 45° elbows. Any venting
configuration using less than 50 equivalent feet should use 3" venting. See
Table 2.
The 3" venting terminals (provided) must be used with the
3" vent pipe. Two, approved 4" vent terminals (not provided) must be used
with 4" vent pipe. See replacement parts list for terminals.
IMPORTANT
When multiple units are direct vented through a wall (3" or 4" venting), all
intake vent terminals should be no lower than the highest exhaust vent
terminal.
NOTE: This unit can be vented using only PVC (Class 160, ASTM D-2241
Schedule 40, ASTM D-1785 ; or Cellular Core Schedule 40 DWV, ASTM
F-891) , Schedule 40 CPVC (ASTM F-411), or ABS (ASTM D-2661) pipe.
The fittings, other than the TERMINATIONS should be equivalent to PVC-
DWV fittings meeting ASTM D-2665 (Use CPVC fittings, ASTM F-438 for
CPVC pipe and ABS fittings,ASTM D-2661/3311 for ABS pipe. If CPVC or
ABS pipe and fittings are used, then the proper cement must be used for all
joints, including joining the pipe to the Termination (PVC Material). PVC
Materials should use ASTM D-2564 Grade Cement; CPVC Materials should
use ASTM F-493 Grade Cement and ; ABS Materials should use ASTM
D-2235 Grade Cement.

13
LOW GAS PRESSURE SWITCH
(SEEFIGURE12)
The Low Gas Switch (LGS) is a single-pole, normally open pressure switch
that will close its contacts when a rising pressure of 5.0 in. (1.25Kpa) W.C.
is encountered. The contacts will open when the pressure falls below the
fixed set point of 4.8"WC (1.18Kpa) for natural gas models and 8.5"WC
(2.08Kpa) for propane models. The LGS monitors the gas supply pressure
to the heater. If the gas supply falls below 4.8"WC (1.18Kpa), the main
burner is extinguished (if heater is running) or the heater will not start up.
ON/OFF SWITCH
The ON/OFF Switch is a single-pole, single-throw rocker switch. This
switch provides 120V from the line source to the heater.
CAUTION
THE WATER HEATER IS POLARITY SENSITIVE. BEFORE APPLYING
ELECTRICITYTOTHISHEATERBECERTAINTHATSUPPLYNEUTRALWIRE
TOGROUNDCHECKINDICATESZEROVOLTAGE.
HOTSURFACE IGNITER
The Hot Surface Igniter is a device that ignites the main burner by high
temperature (>1800°F or >982°C). When 120VAC is applied to the igniter,
sufficientheatisgeneratedtoignitethemainburner.Although improvements
have been made to strengthen the igniter, it is still fragile and care must be
taken when handling the igniter to prevent breakage.
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 3. The figures shown are
for straight lengths of pipe at 0.5" (125Pa) W.C. pressure drop, which is
considered normal for low pressure systems Note that fittings such as
elbows and tees will add to the pipe pressure drop.
CAUTION
DONOTUSEFLEXIBLEGASPIPING.
TABLE 3. MAXIMUM CAPACITY OF PIPE IN CUBIC FEET
OFGASPER HOUR
(Based upon a Pressure Drop of 0.5") Water Column and 0.6
Specific Gravity Gas and max. gas pressure of 0.5 psig)
CONTROLS AND SWITCHES
All BTH models are provided with four pressure switches. These switches
are essential to the safe and proper operation of the unit. All switches are
wired in series. The controller is set up to shut the unit down whenever
there is a failure of any of the switches. It is important to understand the
purpose of each switch.
FIGURE12.
BLOWERPROVERSWITCH
(SEEFIGURE12)
The Blower Prover Switch is provided on the heater to verify that the fan is
operating. It is a positive pressure switch whose electrical contacts are
normally open. When the fan increases the pressure in the burner, the
pressure switch will allow the electrical contacts to close. The pressure
switch is connected to the burner tap by a piece of tygon tubing. This
tubing must be connected in order for the switch to change the electrical
contacts. The controller requires that the electrical contacts on this air flow
switch be open before it will allow the blower to come on.
BLOCKEDOUTLETPROVER SWITCH
(SEEFIGURE12)
The Blocked Outlet Prover Switch is set up to shut the unit off when a build-
up of positive pressure in the exhaust vent pipe occurs. This switch is a
positive pressure switch that requires an increase in pressure to change
the electrical contacts from normally closed to open. When this switch
prevents the unit from igniting, most likely the exhaust is blocked by some
means Check to see if the condensate is allowed to flow freely from the
exhaust elbow and for obstructions in the exhaust venting and exhaust
vent terminal. Also verify that there is no more than fifty equivalent feet
(15.2 m) of three inch PVC vent pipe on the exhaust.
BLOCKEDINLETPROVER SWITCH
(SEEFIGURE12)
The Blocked Inlet Prover Switch is set up to shut the unit off when a build-
up of negative pressure in the intake vent pipe occurs. This switch is a
negative pressure switch that requires an increase in negative pressure to
change the electrical contacts from normally closed to open. The switch is
connected to the pressure tap on the PVC flange connected to the inlet of
the blower. When this switch prevents the unit from igniting, most likely the
intake is blocked by some means. Check to see if there is no more than fifty
equivalent feet (15.2 m) of three inch PVC vent pipe on the intake. Also
verify that the intake and intake vent terminal is free of obstructions that
may prevent air from entering the unit.
LENGTH NORMAL IRON PIPE SIZES (INCHES)
IN INPUT IN THOUSANDS BTU/HR
FEET 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
20 120 250 485 950 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
LENGTH NORMAL IRON PIPE SIZES (INCHES)
IN INPUT IN KW
METERS 1/2" 3/4" 1" 1 1/4" 1 1/2" 2" 2 1/2" 3" 4"
3.0 51 105 199 410 615 1160 1845 3221 6735
6.1 35 73 142 278 428 805 1277 2255 4626
9.1 28 59 110 225 346 644 1031 1830 3748
12.2 24 50 94 193 290 556 878 1552 3192
15.2 21 44 83 170 264 492 776 1391 2840
18.3 19 40 76 155 237 445 703 1259 2577
21.3 18 37 70 143 220 410 659 1142 2372
24.4 17 35 64 135 202 381 600 1083 2196
27.4 16 32 60 126 190 357 571 1010 2108
30.5 15 30 57 117 182 337 542 952 1962
38.1 13 27 51 105 161 299 483 864 1757
45.7 12 25 47 95 146 278 439 776 1610
53.3 11 23 42 88 135 249 401 717 1464
61.0 10 21 40 82 126 234 375 688 1347

14
WARNING
THEHEATERIS NOT INTENDEDFOROPERATIONATHIGHERTHAN10.5"
(2.59 KPa) WATER COLUMN SUPPLY GAS PRESSURE. HIGHER GAS
SUPPLY PRESSURES REQUIRE SUPPLEMENTALREDUCINGSERVICE
REGULATION.EXPOSURETOHIGHERGASSUPPLYPRESSUREMAYCAUSE
DAMAGE TO THE GAS CONTROLS WHICH COULD RESULTIN FIRE OR
EXPLOSION.IFOVERPRESSUREHAS OCCURRED SUCHASTHROUGH
IMPROPERTESTINGOFGASLINESOREMERGENCYMALFUNCTIONOF
THESUPPLYSYSTEMTHEGASVALVE MUST BECHECKEDFORSAFE
OPERATION. MAKE SURETHATTHE OUTSIDE VENTS ON THE SUPPLY
REGULATORSANDTHESAFETYVENTVALVESAREPROTECTEDAGAINST
BLOCKAGE.THESEAREPARTS OFTHEGASSUPPLY SYSTEM,NOTTHE
HEATER.VENTBLOCKAGEMAYOCCUR DURINGICESTORMS.
IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING FROM
CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY CAUSE
IMPROPEROPERATION,FIREOREXPLOSION.
IFCOPPERSUPPLYLINESAREUSEDTHEYMUSTBEINTERNALLYTINNED
ANDCERTIFIEDFORGASSERVICE.
BEFOREATTACHINGTHEGASLINEBESURETHATALLGASPIPEISCLEAN
ONTHEINSIDE.
TOTRAPANYDIRTORFOREIGNMATERIALINTHEGAS SUPPLYLINE,A
DIRTLEG(SOMETIMESCALLEDASEDIMENTTRAPORDRIPLEG)MUSTBE
INCORPORATEDINTHEPIPING(SEEFIGURE13).THEDIRTLEGMUSTBE
READILYACCESSIBLEANDNOTSUBJECTTOFREEZING CONDITIONS.
INSTALLINACCORDANCEWITHRECOMMENDATIONSOFSERVINGGAS
SUPPLIERS.REFERTOTHE NATIONALFUELGASCODE.
FIGURE13.
CONNECTION OF GAS PIPE
1. When connecting gas pipe to unit, apply wrench to flange only. Note:
Do not use wrench on gas valve or gas bracket. See Figure 14a, b, c.
2. PERFORMTHE GASLEAKTESTANYTIMEWORKIS DONEONAGAS
SYSTEMTOAVOIDTHEPOSSIBILITYOFFIREOREXPLOSION WITH
PROPERTYDAMAGE,PERSONALINJURYORLOSS OFLIFE.
FIGURE 14a. BTH 199/250 Models Only
FIGURE 14b. BTH 150 Models Only
FIGURE 14c. BTH 120 Models Only
TheGasLeakTestisperformedasfollows: Paintpipeconnectionsupstream
of gas control with a rich soap and water solution to test for leaks before
operating main burner. Bubbles indicate gas leak. To stop leak, tighten pipe
connections. After piping connections are checked, turn on main burner.
With main burner in operation, paint pipe joints (including flanges), pilot gas
tubing connections and control inlet and outlet with rich soap and water
solution. Bubbles indicate gas leak. To stop leak, tighten flange screws,
joints and pipe connections. Replace part if leak can’t be stopped.
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
ofpipejoints.Donotapply compound to thefirsttwothreads.Usecompounds
resistant to the action of liquefied petroleum gases.

15
DISCONNECTTHEAPPLIANCEAND ITS MANUALGASSHUTOFFVALVE
FROMTHEGASSUPPLYPIPINGSYSTEMDURINGANYSUPPLYPRESSURE
TESTING EXCEEDING 1/2 PSIG (3.45Kpa). GAS SUPPLY LINE MUSTBE
CAPPEDWHENDISCONNECTEDFROMTHEHEATER.FORTESTPRESSURES
OF 1/2 PSIG (3.45Kpa) OR LESS, THE APPLIANCE NEED NOT BE
DISCONNECTED,BUTMUSTBEISOLATEDFROMTHESUPPLYPRESSURE
TESTBYCLOSINGTHEMANUALGASSHUTOFFVALVE.
BEFOREPLACINGTHEHEATERINOPERATION,CHECKFORGASLEAKAGE.
USESOAPAND WATERSOLUTIONOROTHERMATERIALACCEPTABLE
FORTHE PURPOSEOF LOCATINGGASLEAKS. DONOTUSE MATCHES,
CANDLES,FLAMEOROTHERSOURCESOFIGNITIONFORTHISPURPOSE.
PURGING
Gas line purging is required with new piping or systems in which air has
entered.
CAUTION
PURGINGSHOULDBEPERFORMEDBYPERSONSEXPERIENCEDINTHIS
TYPEOFGASSERVICE.TOAVOIDRISKOFFIREOREXPLOSION,PURGE
DISCHARGEMUSTNOTENTER CONFINEDAREASORSPACES WHERE
IGNITIONCANOCCUR.THEAREAMUST BEWELLVENTILATEDANDALL
SOURCESOFIGNITIONMUSTBEINACTIVATEDORREMOVED.
GAS METER SIZE - CITY GASES ONLY
Be sure that 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 the gas meter is too small, ask the
gas company to install a larger meter having adequate capacity.
GASPRESSURE REGULATION
Main line gas pressure to the water heater should be between a maximum
10.5" (2.59Kpa) W.C. (14.0"/3.45Kpa for propane) and a minimum as shown
in Table 4: that is, for Natural Gas, 4.8" (1.18Kpa) W.C. and 8.5" (2.08Kpa)
for Propane Gas. The inlet gas pressure must not exceed the maximum
value. A service regulator must be installed within 10' (305 cm) of unit.
WARNING
FAILURETOINSTALLAPRESSUREREGULATORWITHIN10FEETOFTHE
WATER HEATERCAN RESULT IN LEAKAGE OFFLUEGASESINTOTHE
SURROUNDINGROOM.SERIOUSPERSONALINJURYORDEATHCOULD
RESULTFROMINHALATIONOFCARBONMONOXIDEGAS.
GASVALVES
WARNING
SHOULDOVERHEATINGOCCURORTHEGASSUPPLYFAILTOSHUTOFF,
TURNOFFTHE MANUALGASCONTROLVALVETOTHEAPPLIANCE.
SYSTEM CONNECTIONS
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(NotSupplied)
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.
RELIEFVALVE
This heater is equipped with an approved temperature and pressure relief
valve. ASME ratings cover pressure relief. CSA ratings cover release rate
with temperature actuation.
FORSAFEOPERATION OFTHEWATERHEATER,THERELIEFVALVE(S)
MUSTNOTBEREMOVEDORPLUGGED.
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 temperature (ANSI) and pressure
(ASME) relief valve(s). This relief valve shall comply with the standard for
relief valves for hot water supply systems. ANSI Z21.22-CSA 4.4.
Your local code authority may have other specific relief valve requirements.
WARNING
THEPURPOSEOFARELIEFVALVEISTOAVOIDEXCESSIVE PRESSURE
OR TEMPERATURE INTO THE STEAM RANGE, WHICH MAY CAUSE
SCALDINGATFIXTURES,TANKEXPLOSION,SYSTEMORHEATERDAMAGE.
NO VALVE IS TO BE PLACED BETWEEN THE RELIEF VALVE AND THE
TANK.
ADRAIN LINE MUSTBECONNECTEDTOTHE RELIEFVALVETO DIRECT
DISCHARGE TO A SAFE LOCATION TO AVOID SCALDING OR WATER
DAMAGE.THISLINEMUSTNOTBEREDUCEDFROMTHESIZEOFTHE
VALVE OUTLETANDMUSTNOTCONTAIN VALVES OR RESTRICTIONS,
NORSHOULDITBELOCATEDINFREEZINGAREAS.DONOTTHREADOR
CAPTHEENDOFTHISLINE.RESTRICTEDORBLOCKED DISCHARGEWILL
DEFEATTHEPURPOSEOFTHEVALVEANDISUNSAFE.THEDISCHARGE
LINESHALLBE INSTALLEDTOALLOWCOMPLETEDRAINAGEOFBOTH
THEVALVEAND LINE.
WATERLINE CONNECTIONS
This manual provides detailed installation diagrams (see back section 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.
CLOSEDSYSTEM
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 causing premature tank failure or
intermittent relief valve operation. This type of failure is not covered by the
limited warranty. 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 water under supply pressure.
If a water heater is installed in a closed water system, check local codes
or contact the water supplier or local plumbing inspector on how to control
this situation.
WATER (POTABLE) HEATINGAND 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.

16
CONDITIONERMUSTBE INSTALLED IFTHEABOVE CONDITIONS EXIST.
MALFUNCTIONS CAUSED BYA POOR ELECTRICALSUPPLYARE NOT
COVERED UNDER YOUR WARRANTY.
The controller is wired to the heater as shown in Figure 15. The model
and rating plate provides the electrical information needed to size the
complete heater branch supply.
All electrical work must be installed in accordance with the National
Electrical Code, NFPA 70 or the Canadian Electrical Code, CSAC22.1 and
local requirements.
When installed, the appliance must be electrically grounded in
accordance with local codes or, in the absence of local codes,
with the National Electrical Code,ANSI/NFPA70 or the Canadian
Electrical Code, CSA C22.1.
DONOTENERGIZETHEBRANCHCIRCUITBEFORETHEHEATERTANK
IS FILLED WITH WATER.
NOTE: This controller is Polarity Sensitive. If the Hot and Neutral Supply
Voltage is reversed, the controller will not sense flame. Verify polarity
before connecting the unit.
3. This unit may never be connected to any existing heating system or
component(s) previously used with 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 23
through 28 in back of manual for suggested piping arrangements.
HEATER WIRING
IFANY OF THE ORIGINALWIREAS SUPPLIED WITHTHEAPPLIANCE
MUST BE REPLACED, IT MUST BE REPLACED WITH 105°C OR ITS
EQUIVALENT, EXCEPT IN THE BURNER HOUSING. INTHIS CASE USE
200°CWIRE.
THECOMPUTER CONTROLREQUIRESASOURCEOF STABLECLEAN
ELECTRICITYFORPROPEROPERATION. INSTALLINGTHE HEATERON
ABRANCH CIRCUITTHATHAS ELECTRONIC NOISE, IS SUBJECTTO
FLUCTUATIONS IN VOLTAGE LEVEL OR HASAN APPLIANCE WHICH
GENERATES EMF OF RFI INTERFERENCE CAN CAUSE THE
CONTROLLER TO MALFUNCTION. A HIGH QUALITY POWER
FIGURE15.

17
USING THE ELECTRONIC CONTROLLER
1.Overview
Interaction with the water heater controller is done through an up, a down, and three operation buttons. These buttons are illustrated to the
right. Operation of the three lower buttons is defined immediately above them on the screen. The [UP] and [DN] buttons are used to navigate
through the menus and make adjustments to the water heater.
While the water heater is operating, the user interface will display the desktop screen (if there are no active faults or warnings). An example
of this screen is shown to the right. The first temperature on this screen is the temperature of the water inside the tank. The second
temperature on this screen is the Operating Set Point. The Operating Set Point is the temperature at which the water heater will maintain the
water inside the tank. The third line on the screen is a text description of the Operational State of the water heater (please see Operating States
for more details).
The following status icons describe graphically operational details of the heater. The legend of all the status icons is listed below.

18
3. Adjusting the Operating Set Point
The Operating Set Point of this water heater determines the regulated
temperature for the water in the tank. This parameter is adjusted in the
Temperature menu. Items in this menu allow you to monitor different
temperature readings in the tank along with adjusting the Operating Set
Point and Differential.
ACTION:
From the desktop screen, press Menu.
DISPLAY:
ACTION:
From the Main Menu, press Select to enter the "Temperatures" screen.
DISPLAY:
2. Operating States
In the main desktop screen, there are some specific Operating States that
are indicated on the status line. These are summarized below:
ACTION:
Press Change then use the UP and DOWN buttons to change the Set
Point.
Note: This procedure can also be used to change the Differential. The
Tank, Upper and Lower Temperatures are not user changeable. They
are determined by the temperature probes on the heater.
DISPLAY:
ACTION:
Press Update to accept the change or Cancel to reset it.
DISPLAY:

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4. Changing the Display Units
The display interface to the heater has the option of selecting between
degrees Fahrenheit and degrees Celsius for temperature displays. This
can be found in the “Display Settings” menu. Also in this menu, you may
adjust how the backlight operates and the contrast of the LCD screen.
ACTION:
From the Main Menu, press the DOWN button to highlight "Display
Settings" then press Select.
DISPLAY:
ACTION:
Use the UP and DOWN buttons to highlight the desired setting. Then
press Change. Again, use the UP and DOWN buttons to scroll through
the options for that setting.
DISPLAY:
ACTION:
Press Update to accept the change or Cancel to reject it.
DISPLAY:
5. Fault and Warning Conditions
This water heater is equipped with electronic controls that have the ability
to monitor almost all aspects of the water heater operation. In the case that
there is an undesirable or unsafe condition that occurs, the water heater
controls will detect this condition and determine the appropriate action.
Part of this is displaying the information on the LCD in plain text that accu-
rately describes the condition and diagnostics information that can be used
to correct the issue.
There are two types of conditions that can occur during operation. These
are Warnings and Faults:
• Warnings: This is a non-safety related condition that the control has
detected that may cause the water heater to operate in a less than optimal
condition, but does not pose a safety concern.
NOTE: When these conditions occur, continued heating cycles will con-
tinue and the heater will attempt to regulate the water in the tank to the
Operating Set Point.
Example of a Warning:
• Faults: This is a safety related condition that has been detected by the
heater.
NOTE: When these conditions occur, the water heater will not continue
any further heating cycles and the water will no longer be heated until the
condition is corrected and, in most cases, power has been cycled.
Example of a Fault:
Advanced Diagnostics Information
When a fault or warning has been declared, advanced information can be
found in the control. By pressing theAdvanced button, detailed information
can be found regarding diagnosing and resolving the problem.
WARNING: Usage of the Advanced information requires ability
equivalent to that of a licensed tradesmen in the field involved.
6. Access to the Current Fault or Warning
When a fault or warning has been detected by the control, it will automati-
cally be displayed on the screen and the back light will blink. If you choose
to leave the current fault or warning by pressing the Back key, you can
always return to the fault screen through the menu.

20
ACTION:
To get to the current fault information screen, press Menu.
DISPLAY:
ACTION:
Press the DOWN button to highlight "current Fault" and press Select.
DISPLAY:
ACTION:
Press the DOWN button for more information.
DISPLAY:
7. Viewing the Fault History
The controller for this water heater will store a history of ten of the last
Fault and Warning conditions that occurred. This is stored in the Fault
History. Along with all the information about the fault, including a estimate
time of when the fault occurred, information regarding the advanced
diagnostics for that fault can be accessed at any time.
ACTION:
Press the DOWN button for more information.
DISPLAY:
ACTION:
Press the DOWN key to scroll through the fault history. If you select a
specific fault or warning, you may press the VIEW button to view details
regarding this fault.
DISPLAY:
8. Viewing Information About the Heater
The electronic control for this water heater monitors many different as-
pects of the water to ensure safe and optimal operation. Much of the
information monitored is available to view in two areas of the control. The
first is the "Heater Status" and; the second is "Heater Information." These
items can be selected through the main menu in the same fashion as
described above. In these menus, detailed information about the water
heater and the current status of specific conditions can be found.
INSTALLATIONORSERVICEOFTHIS WATERHEATERREQUIRESABILITY
EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD
INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPLY AND
ELECTRICALWORKAREREQUIRED.
Before attempting start-up, thoroughly study and familiarize yourself with
the exact sequence of operation and all other details on the specific heater
being used.
The power burner is equipped with an ignition system which automatically
sequences prepurge and ignition, senses and ignites main burner flame
and sequences burner operation. Heater is equipped with an ignition control
which locks out after three unsuccessful ignition attempts. Familiarize
yourself with the sequence of operation of this unit prior to start-up.
Be certain that the water heater is full of water, that air is purged from all
lines, there are no leaks (gas and water), and all inlet water lines are open.
The following test equipment should be on hand (all test equipment must be
acclimated to ambient temperature before calibration and use.)
– Two U-tube manometers or calibrated pressure gages that can read
0-10" (0-2.5Kpa) and 0-35" (0-8.7Kpa) W.C. pressure gauges.
• Attach a gas pressure gauge or manometer to the upstream side of
main gas cock and a gas pressure gauge or manometer to the manifold
pressure tap (see Figure 15).
• You are now ready to begin the burner start-up procedure.
PRIOR TO START UP
REQUIREDABILITY