A.O. Smith BTH 120-250(A) Manual

1
A DIVISION OF A.O. SMITH CORPORATION
Mc BEE, SOUTH CAROLINA
PLACE THESE INSTRUCTIONS ADJACENT TO HEATERAND
NOTIFYOWNER TOKEEP FORFUTURE REFERENCE.
PRINTEDINU.S.A. 1104 PART NO. 196145-001
CYCLONE XHE®Model BTH 120-250(A)
SERIES 970 AND 973
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
TEXTIN BLACKBOLD TYPEOR UNDERLINEDCONTAINS
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE
READ THOROUGHLYBEFORE INSTALLINGAND USING
THISAPPLIANCE.
•INSTALLATION • OPERATION • SERVICE • MAINTENANCE•LIMITEDWARRANTY
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 latest version of the American National
Standard for Gas Water Heaters, Volume III,ANSI Z21.10.3 / CSA 4.3 M 98
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 latest
editions of the National Fuel Gas Code, ANSI Z223.1/NFPA 54 and the
NationalElectricCode,NFPA70CAN/CSA149.1or.2andCSA2C22.1.The
former is available from the CSA International, 8501 East Pleasant Valley
Road, Cleveland, OH 44131, and both documents are available from the
NationalFireProtectionAssociation,1BatterymarchPark,Quincy,MA02269.
FOREWORD
CYCLONE XHE BTH 120 - 250 ROUGH-IN-DIMENSIONS
TEMPERATURE RISE-DEGREES °C -LITERSPER HOUR
Approx.
Input Liter
Model kW Capacity 17°C 22°C 28°C 33°C 39°C 44°C 50°C 56°C 61°C 67°C 72°C 78°C
BTH - 120 37 Nat. 227 1798 1348 1079 898 768 674 598 538 488 450 416 386
BTH - 120 35 L.P. 227 1726 1295 1037 863 738 647 575 519 469 432 397 371
BTH - 150 44 Nat. 379 2158 1616 1295 1079 924 810 719 647 587 538 500 462
BTH - 150 44 L.P. 379 2158 1616 1295 1079 924 810 719 647 587 538 500 462
BTH - 199 58 Nat. 379 2873 2154 1726 1438 1230 1079 958 863 784 719 662 617
BTH - 199 54 L.P. 379 2661 1995 1597 1329 1139 996 886 799 727 666 613 572
BTH - 250 70 Nat. 379 3452 2589 2071 1726 1480 1295 1151 1037 939 863 795 738
Recovery capacities are based on heater performance at 94% thermal efficiency.
Table 1. RECOVERYCAPACITIES - NATURAL GAS / L.P.
TEMPERATURE RISE-DEGREES °F -GALLONSPER HOUR
Approx.
Input Gallon
Model BTU/Hr. Capacity 30 40 50 60 70 80 90 100 110 120 130 140
BTH - 120 125,000 Nat. 60 475 356 285 237 203 178 158 142 129 119 110 102
BTH - 120 120,000 L.P. 60 456 342 274 228 195 171 152 137 124 114 105 98
BTH - 150 150,000 Nat. 100 570 427 342 285 244 214 190 171 155 142 132 122
BTH - 150 150,000 L.P. 100 570 427 342 285 244 214 190 171 155 142 132 122
BTH - 199 199,900 Nat. 100 759 569 456 380 325 285 253 228 207 190 175 163
BTH - 199 185,000 L.P. 100 703 527 422 351 301 263 234 211 192 176 162 151
BTH - 250 240,000 Nat. 100 912 684 547 456 391 342 304 274 248 228 210 195
GASVALVEPIPING
BTH-120 1/2" NPT
BTH-150,
199 & 250 3/4" NPT

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DANGER
THISWATERHEATERISEQUIPPEDWITHANADJUSTABLETHERMOSTAT
TO CONTROL WATER TEMPERATURE. HOT WATER TEMPERATURES
REQUIRED FOR AUTOMATIC DISHWASHER AND LAUNDRYUSE CAN
CAUSESCALD BURNSRESULTINGINSERIOUSPERSONALINJURYAND/
OR DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS VARIES
WITH THE PERSON’S AGE AND THE TIME OF THE EXPOSURE. THE
SLOWERRESPONSETIMEOFCHILDREN,AGEDORDISABLEDPERSONS
INCREASESTHE HAZARDSTOTHEM.NEVERALLOWSMALLCHILDREN
TO USE A HOT WATER TAP, OR TO DRAW THEIR OWN BATH WATER.
NEVER LEAVE A CHILD OR DISABLED PERSON UNATTENDED IN A
BATHTUBORSHOWER.
THE WATER HEATER SHOULD BE LOCATED IN ANAREA WHERE THE
GENERALPUBLIC DOES NOTHAVEACCESS TOSETTEMPERATURES.
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 80°F/27°C to 185°F/85°C. The
thermostat was adjusted to 120°F/49°C before the heater was shipped
from the factory. It is recommended that lower water temperatures be
used to avoid the risk of scalding. It is further recommended, in all cases,
FEATURES
IMPORTANT
ITISREQUIREDTHATAQUALIFIEDSERVICETECHNICIANPERFORMTHE
INITIALFIRINGOFTHE HEATER. ATTHISTIMETHEUSERSHOULDNOT
HESITATETOASK THETECHNICIANANYQUESTIONS WHICH HE MAY
HAVEINREGARDTOTHEOPERATIONAND MAINTENANCEOFTHEUNIT.
ACHECKLISTANDSERVICEINFORMATIONsectionareincluded attherear
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........................................................................... 4
INSTALLATIONINSTRUCTIONS ........................................................ 4-13
Required Ability ............................................................................ 4
Insulation Blankets ....................................................................... 4,5
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 PipeTermination ................................................................... 6-8
Direct Venting............................................................................... 8
Direct Vent Terminal Installation (Sidewall) ................................. 8
Installation Sequence................................................................... 9
Vertical Vent Terminal Installation ................................................ 10
Installation Sequence................................................................... 10
Installation of Vent System .......................................................... 10 ,11
Vent Pipe Preparation................................................................... 11
CONTROLANDSWITCHES .............................................................. 11,12
Blower Prover Switch ................................................................. 11
Blocked Outlet Prover Switch...................................................... 12
Blocked Inlet Prover Switch......................................................... 12
Low Gas Pressure Switch.......................................................... 12
On/Off Switch.............................................................................. 12
Hot Surface Igniter ....................................................................... 12
GASPIPING....................................................................................... 12
Connection of Gas Pipe ............................................................... 13
Purging ......................................................................................... 13
Gas Meter Size - City Gases Only .............................................. 13
Gas Pressure Regulation............................................................. 13
Gas Valves................................................................................... 13
SYSTEMCONNECTIONS .................................................................. 13
Thermometers .............................................................................. 13
Relief Valve .................................................................................. 13
Water Line Connections ............................................................. 14
Heater Wiring .............................................................................. 14
OPERATION ...................................................................................... 15
Sequence of Operation .............................................................. 15
Self Diagnostic Controller ........................................................... 15
Gas Value LEDs Flashing ........................................................... 15
Error Codes ................................................................................. 16
Fault Conditions ........................................................................... 16
No Incoming Line Voltage............................................................ 16
No Low Voltage .......................................................................... 16
Temperature Probe Fault............................................................. 16
E.C.O. Switch Open .................................................................... 17
Control Bad.................................................................................. 17
Combustion Air Blockage............................................................ 17
PRIORTOSTART-UP ....................................................................... 18
Required Ability ........................................................................... 18
OPERATIINGINSTRUCTIONS ........................................................... 18
Adjustment Procedure (Initial Start-Up) ...................................... 18
Lighting Instructions .................................................................... 19
Cathodic Protection ..................................................................... 20
Precautions ................................................................................. 20
GENERALINFORMATION ................................................................ 20
Power Burner ............................................................................. 20
HighLimit ..................................................................................... 20
High Altitude Installations ............................................................ 20
MAINTENANCE ................................................................................ 20
General........................................................................................ 20
Maintenance Schedule ............................................................... 20
Flushing ....................................................................................... 21
Draining ....................................................................................... 21
SedimentRemoval....................................................................... 21
LimeScaleRemoval .................................................................... 21
Anode Inspection and Replacement........................................... 21,22
Drain Valve and Access Panels ................................................. 22
Relief Valve ................................................................................. 22
CirculatingPump.......................................................................... 22
Vent System ................................................................................ 22
INSTALLATION DIAGRAMS ............................................................. 23 - 27
Manifold Kits................................................................................ 28
CHECKLISTANDSERVICEINFORMATION ...................................... 29
TROUBLE-SHOOTING...................................................................... 29,30
REPLACEMENTPARTS .................................................................... 30
LIMITEDWARRANTY....................................................................... 31
PAGE PAGE

4
that the 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.
SETTING THE WATER HEATER TEMPERATURE AT 120°F/49°C WILL
REDUCE 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.
Shouldthehighlimit switch activate, it must be manually reset by depressing
the TemperatureAdjustment Button/Reset Button on the display board. The
water temperature must drop below 160°F/71°C before the controller can
be reset.
Continued manual resetting of high limit control, preceded by higher than
usual water temperature is evidence of high limit switch operation. The
following are possible reasons for high limit switch operation.
• A malfunction in the thermostatic controls would allow the gas valve to
remainopencausingwatertemperaturetoexceedthethermostatsetting.
The water temperature would continue to rise until high limit switch
operation.
Contact your dealer or servicer if continued high limit switch operation
occurs.
DISHWASHING MACHINEREQUIREMENT
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 latest version of the National Electric Code
NFPA70 or Canadian 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
INSTALLATIONOR SERVICEOFTHISWATERHEATERREQUIRESABILITY
EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD
INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPLY AND
ELECTRICALWORKAREREQUIRED.
INSULATION BLANKETS
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.

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•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.
LOCATING THEHEATER
WARNING
THEREISARISKINUSINGFUEL BURNINGAPPLIANCESSUCHASGAS
WATER HEATERS IN ROOMS, GARAGES OR OTHER AREAS WHERE
GASOLINE, OTHER FLAMMABLE LIQUIDS OR ENGINE DRIVEN
EQUIPMENTORVEHICLESARE STORED,OPERATEDORREPAIRED.
FLAMMABLEVAPORSAREHEAVYANDTRAVELALONGTHEFLOOR
AND MAYBE IGNITED BY THE HEATER’S IGNITER OR MAIN BURNER
FLAMESCAUSING FIREOREXPLOSION.SOMELOCALCODESPERMIT
OPERATION OF GASAPPLIANCES IF INSTALLED 18 INCHES (46 cm)
ORMOREABOVETHEFLOOR.THISMAYREDUCETHERISKIFLOCATION
INSUCHANAREACANNOTBEAVOIDED.
THE HEATER SHALL BE LOCATED OR PROTECTED SO IT IS NOT
SUBJECTTOPHYSICALDAMAGEBYAMOVINGVEHICLE.
DONOTLOCATETHE HEATER WHERENOISEFROMTHEEXHAUST OR
INTAKEWILLBEOBJECTIONABLE.THISINCLUDESLOCATIONSCLOSE
TO ORACROSS FROM WINDOWS AND DOORS.AVOID ANCHORING
THEVENTAND INTAKE PIPESDIRECTLYTO FRAMEDWALLS,FLOORS
OFCEILINGSUNLESSRUBBERISOLATIONPIPEHANGERSARE USED.
THISPREVENTSANYVIBRATIONS FROM BEING TRANSMITTEDINTO
THELIVINGSPACES.
WARNING
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY OTHER
POTENTIAL FIRE HAZARDOUS ARTICLES MUST NEVER BE PLACED
ON OR ADJACENT TO THE HEATER. OPEN CONTAINERS OF
FLAMMABLE MATERIAL SHOULD NOT BE STORED OR USED IN THE
SAMEROOMWITH THE HEATER.
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.
THEHEATERMUSTNOTBE LOCATEDINANAREAWHERE IT WILLBE
SUBJECTTO FREEZING.
LOCATE ITNEARAFLOOR DRAIN.THEHEATER SHOULD BELOCATED
INAN AREAWHERE LEAKAGE FROM THE HEATER OR CONNECTIONS
WILLNOTRESULTIN DAMAGETOTHEADJACENT AREAORTOLOWER
FLOORSOFTHE STRUCTURE.
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 UNITANDREQUIRESADRAIN
TO BE LOCATED IN CLOSE PROXIMITY TO ALLOW THE
CONDENSATE TO DRAIN SAFELY. THE CONDENSATE DRAINS FROM
THE UNIT AT THE EXHAUST ELBOW LOCATEDAT THE BOTTOM OF
THE UNIT. NOTE: IT IS IMPORTANT THAT THE CONDENSATE HOSE
NOT BE ELEVATED ABOVE THE EXHAUST ELBOW (SEE FIGURE 3).
THE CONDENSATE BUILD-UP WILLBLOCK THE EXHAUST OUTLET,
WHICH WILL CAUSE IMPROPER OPERATION.
FIGURE3
WARNING
DONOTUSETHIS APPLIANCE IFANYPART HAS BEENUNDERWATER.
IMMEDIATELY CALLAQUALIFIED SERVICE TECHNICIAN TO INSPECT
THE APPLIANCE AND TO REPLACE ANY PART OF THE CONTROL
SYSTEMANDANY GAS CONTROL WHICH HAS BEEN UNDER WATER.
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

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less than 100 square inches (645 cm²).
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.
CHEMICALVAPOR CORROSION
WARNING
CORROSION OF THE FLUE WAYS AND VENT SYSTEM MAY OCCUR IF
AIRFORCOMBUSTION CONTAINSCERTAINCHEMICALVAPORS. SUCH
CORROSION MAY RESULT IN FAILUREAND RISK OF ASPHYXIATION.
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 CONTAIN ANY OF THESE CHEMICALS. IF NECESSARY,
UNCONTAMINATED AIR SHOULD BE OBTAINED FROM REMOTE OR
OUTSIDESOURCES.
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING MUST BE
FOLLOWEDTOAVOIDCHOKEDCOMBUSTIONOR RECIRCULATION OF
FLUEGASES. SUCHCONDITIONSCAUSE SOOTING ORRISKSOF FIRE
ANDASPHYXIATION.
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 Figure 6 before proceeding.
CAUTION
DONOTTERMINATETHEVENTING WHERENOISEFROM THEEXHAUST
OR INTAKE WILL BE OBJECTIONABLE. THIS INCLUDES LOCATIONS
CLOSE TO OR ACROSS FROM WINDOWS AND DOORS. AVOID
ANCHORING THE VENT AND INTAKE PIPES DIRECTLY TO FRAMED
WALLS, FLOORS OR CEILINGS UNLESS RUBBER ISOLATION PIPE
HANGERSAREUSED.THISPREVENTSANYVIBRATIONS FROM BEING
ALCOVE
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
KEEP APPLIANCE AREA CLEAR AND FREE OF COMBUSTIBLE
MATERIALS, GASOLINE AND OTHER FLAMMABLE VAPORS AND
LIQUIDS.
DO NOT OBSTRUCT THE FLOW OF COMBUSTIONAND VENTILATING
AIR.
WARNING
FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR COMBUSTION
AND VENTILATION. AN INSUFFICIENT SUPPLY OF AIR WILL CAUSE
RECIRCULATION OF COMBUSTION PRODUCTS RESULTING IN
CONTAMINATION THAT MAY BE HAZARDOUS TO LIFE. SUCH A
CONDITION OFTEN WILL RESULT IN AYELLOW, LUMINOUS BURNER
FLAME, CAUSING CARBONING OR SOOTING OF THE COMBUSTION
CHAMBER, BURNERS AND FLUE TUBES AND CREATES A RISK OF
ASPHYXIATION.
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
WILL CAUSE AIR TO BE DRAWN INTO THE ROOM THROUGH THE
HEATER’SVENTINGSYSTEM,CAUSINGPOOR COMBUSTION. SOOTING
MAYRESULTINSERIOUSDAMAGE TOTHEHEATERAND RISK OFFIRE
OR EXPLOSION. IT CAN ALSO CREATEARISK OF ASPHYXIATION.
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
permanent openings, ONE IN OR WITHIN 12 INCHES (31 cm) OF THE
ENCLOSURE TOP AND ONE IN OR WITHIN 12 INCHES (31 cm) OF THE
ENCLOSUREBOTTOM. Eachopeningshallhaveafreeareaofatleastone
square inch (6.5 cm²) per 1000 Btuh appliances in the enclosure, but not

7
FIGURE 5
*NOTE: BTH 250 USES TEE ON
AIR INTAKE TERMINAL
DIRECTVENT
HORIZONTAL VENT
FIGURE 6
DO NOT TERMINATE EXHAUST
OVER PUBLIC AREA WHERE
CONDENSATE OR VAPOR CAN
CAUSENUISANCEORHAZARD.
ONDIRECTVENT INSTALLATIONS,EXHAUSTVENT
HOOD MUST BE LOCATED 1' (30.5cm) MINIMUM
FROMANYOPENINGIN BUILDING.
ONDIRECTVENTINSTALLATIONS,EXHAUSTVENT
HOOD MUST BE LOCATED 4' (122cm) MINIMUM
FROMANYOPENINGIN BUILDING.

8
TRANSMITTED INTO THE LIVING SPACES.
IMPORTANT
The vent system must terminate so that proper clearances are maintained
as cited in local codes or the latest edition of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 and for Canadian installations consult the Canadian
Installation Codes and CAN/CGA B149.1 and .2.
1. Do not terminate the exhaust vent terminal over public area where
condensate or vapor can cause nuisance or hazard.
2. For direct vent, the venting system shall terminate at least 1' (30.5 cm)
below, 1' (30.5 cm) horizontally from or 1' (30.5 cm) above any door,
window, or gravity air inlet into building.
3. For horizontal the venting system, using room for combustion, the vent
terminal shall terminate 4' (122 cm) below, 4' (122 cm) horizontally from
or 1' (30.5 cm) above any door, window, or gravity air inlet into building.
4. The manufacturer also recommends the vent system terminations not
be installed closer than 3' (91cm) from an inside corner of an L shaped
structure. And not less than 1' (30.5 cm) above grade or anticipated
snow level.
5. The vent termination shall not be mounted directly above or within 3'
(91cm) horizontally from an oil tank vent or gas meter to avoid potential
freeze-up from condensation.
6. The vent shall terminate a minimum of 12" (30.5 cm) above expected
snowfall level to prevent blockage of vent termination.
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
USE ONLY THE VENT TERMINALS SUPPLIED WITH THIS UNIT.
TERMINATION OF AVENT SYSTEM WITH ADEVICE OTHER THAN THE
SUPPLIED VENT TERMINATIONS WILL AFFECT SYSTEM
PERFORMANCEAND RESULT INA SAFETYHAZARD.
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
WHENTHE UNITISTOBESETUPASADIRECT VENT, THEMESH SCREEN
MUST BE REMOVED. THE INLET VENT PIPE MAY THEN BE GLUED TO
THE AIR INTAKE (see Figure 8) PROVIDED ON THE UNIT.
FIGURE 8
DIRECTVENTTERMINAL INSTALLATION
IMPORTANT
THIS UNIT CONSISTS OF TWO VENT TERMINALS - AN INTAKE VENT
TERMINAL AND AN EXHAUST VENT TERMINAL. THE INTAKE VENT
TERMINALISA3" 45°PVCELBOW(OR 3" PVCTEEFORBTH 250)WITHA
MESHWIRESCREENANDTHEEXHAUSTVENTTERMINALISA3" 45°PVC
ELBOWWITHAMESHWIRESCREEN.
NOTE:TOPREVENTEXHAUSTINGPRODUCTSFROMCIRCULATINGTO
THE AIR INTAKE IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL
DISTANCEBETWEENTHESETWOTERMINALSISRECOMMENDED.
3" (7.6cm) 45° PVC ELBOW WITH MESH SCREEN
BTH120
BTH150
&199
BTH250

9
FIGURE 9
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 the 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).
INSTALLATION SEQUENCE
For installations in the City of Los Angeles, 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.
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
(Figure 10).FIGURE10

10
FIGURE12
INSTALLATION OF VENT SYSTEM
WARNING
THE OPTIONAL INTAKE VENTINGARRANGEMENT AND THE EXHAUST
VENTINGARRANGEMENT MUST BE INSTALLED TO RUN DIRECTLY TO
THE OUTDOORSAND NOT IN ANYWAY BE CONNECTED TOANOTHER
VENTING SYSTEM (I.E. FURNACE, DRYERS OR SPACE HEATERS). IT IS
CRUCIAL THAT THE VENTING ARRANGEMENT BE KEPT SEPARATE
FROMOTHERVENTINGSYSTEMS. IF THISWARNING IS IGNORED,AND
THE SYSTEM IS VENTED INCORRECTLY, IT MAY CAUSE IMPROPER
OPERATION, FIRE,EXPLOSION,ORASPHYXIATION.
1. Plan the route of the vent system from the vent termination to the planned
locationoftheappliance.Layoutthetotalventsystemto 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.
FIGURE11
VERTICAL VENT TERMINAL INSTALLATION
IMPORTANT
WHEN TERMINATING THROUGH A ROOF, THE FOLLOWING
SPECIFICATIONS PERTAINING TO TERMINAL LOCATION MUST BE
FOLLOWED.
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 11 & 12.
NOTE: Exhaust vent terminal is installed using the same procedure.
INSTALLATION SEQUENCE
NOTE: BEFOREBEGINNING INSTALLATION OFANYVENT PIPE, READ
“VENT PIPE PREPARATION” SECTION ON PAGE 11.
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 12.

11
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
OPEN FLAME. ALSO, USE ONLY INA WELL-VENTILATED AREA.
CONTROLS AND SWITCHES
The BTH-120 and 250 are provided with four pressure switches. Both the
BTH 150 and 199 are provided with three 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.
FIGURE13
BLOWERPROVERSWITCH
(SEEFIGURE13)
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.
Table 2. VENT LENGTH TABLE
4-inchPVCmaybe usedforaMAXIMUMintake of ONEHUNDREDTWENTY
(120) EQUIVALENT FEET (36.6m) and a MAXIMUM exhaust of ONE
HUNDREDTWENTY(120)EQUIVALENTFEET (36.6m). Themaximumnumber
of 90° elbows with the 4-inch 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-inch venting. See Table 2.
The 3-inch venting terminals (provided) must be used with the
4-inch venting by adding 4x3 reducing couplings at the venting terminals. A
reducing coupling is also needed immediately after the condensate elbow
(exhaust) and immediately before the 3-inch blower adapter (intake) if
direct venting is installed. See Table 2.
IMPORTANT
When multiple units are direct vented through a wall (3-inch or 4-inch
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.
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
CPVCorABSpipeandfittings(MUSTUSE SUPPLIED VENTTERMINAL)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 inch (3mm) per 5 feet (152 cm) of pipe maximum
downward slope.
5. The vent system should be supported every 5 feet (152 cm) of vertical
run and every 3 feet (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.
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
NOTE: LOW GAS IS
LOCATED ON INLET
SIDE OF GAS VALVE.

12
BLOCKEDOUTLETPROVER SWITCH
(SEEFIGURE13)
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
(SEEFIGURE13)
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.
LOW GAS PRESSURE SWITCH
(SEEFIGURE13)
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 5.0 in. (1.25Kpa) W.C. The LGS monitors the gas supply
pressure to the heater. If the gas supply falls below 5.0 in. (1.25Kpa) W.C.,
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
ELECTRICITYTO THIS HEATER BE CERTAIN THAT SUPPLY NEUTRAL
WIRETOGROUND CHECK INDICATES ZERO VOLTAGE.
HOTSURFACEIGNITER
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 in. (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
DO NOT USE FLEXIBLE GAS PIPING.
TABLE 3
MAXIMUM CAPACITY OF PIPE IN CUBIC FEET OF GAS PER HOUR
(Based upon a Pressure Drop of 0.5 inch Water Column
and 0.6 Specific Gravity Gas and max. gas pressure of 0.5 psig)
WARNING
THEHEATER ISNOTINTENDED FOROPERATIONATHIGHER THAN14.0"
WATER COLUMN (1/2 POUND or 3.45Kpa PER SQUARE INCH) SUPPLY
GAS PRESSURE. HIGHER GAS SUPPLY PRESSURES REQUIRE
SUPPLEMENTAL REDUCING SERVICE REGULATION. EXPOSURE TO
HIGHER GAS SUPPLY PRESSURE MAY CAUSE DAMAGE TO THE GAS
CONTROLS WHICH COULD RESULT IN FIRE OR EXPLOSION. IF
OVERPRESSURE HAS OCCURRED SUCH AS THROUGH IMPROPER
TESTING OF GAS LINES OR EMERGENCY MALFUNCTION OF THE
SUPPLY SYSTEM THE GAS VALVE MUST BE CHECKED FOR SAFE
OPERATION. MAKE SURE THAT THE OUTSIDE VENTS ON THE SUPPLY
REGULATORS AND THE SAFETY VENT VALVES ARE PROTECTED
AGAINST BLOCKAGE. THESE ARE PARTS OF THE GAS SUPPLY
SYSTEM, NOT THE HEATER. VENT BLOCKAGE MAY OCCUR DURING
ICE STORMS.
IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING FROM
CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY CAUSE
IMPROPEROPERATION, FIRE OREXPLOSION.
IF COPPER SUPPLY LINES ARE USED THEY MUST BE INTERNALLY
TINNEDANDCERTIFIED FOR GASSERVICE.
BEFORE ATTACHING THE GAS LINE BE SURE THAT ALL GAS PIPE IS
CLEANONTHE INSIDE.
TO TRAPANY DIRT OR FOREIGN MATERIAL IN THE GAS SUPPLY LINE,
A DIRT LEG (SOMETIMES CALLED A SEDIMENT TRAP OR DRIP LEG)
MUST BE INCORPORATED IN THE PIPING (SEE FIG. 14). THE DIRT LEG
MUST BE READILY ACCESSIBLE AND NOT SUBJECT TO FREEZING
CONDITIONS. INSTALL INACCORDANCE WITH RECOMMENDATIONS
OF SERVING GAS SUPPLIERS. REFER TO THE NATIONAL FUEL GAS
CODE.
FIGURE14
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

13
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 15.
2. PERFORM THE GAS LEAK TEST ANY TIME WORK IS DONE ON A
GASSYSTEMTOAVOIDTHEPOSSIBILITYOF FIREOREXPLOSION
WITHPROPERTYDAMAGE,PERSONAL INJURY OR LOSSOFLIFE.
FIGURE15
TheGasLeakTest is performed as follows: Paint pipeconnectionsupstream
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.
DISCONNECTTHEAPPLIANCE ANDITSMANUALGAS SHUTOFFVALVE
FROM THE GAS SUPPLY PIPING SYSTEM DURING ANY SUPPLY
PRESSURETESTINGEXCEEDING 1/2PSIG(3.45Kpa). GASSUPPLYLINE
MUST BE CAPPED WHEN DISCONNECTED FROM THE HEATER. FOR
TEST PRESSURES OF 1/2 PSIG (3.45Kpa) OR LESS, THE APPLIANCE
NEED NOT BE DISCONNECTED, BUT MUST BE ISOLATED FROM THE
SUPPLY PRESSURE TEST BY CLOSING THE MANUALGAS SHUTOFF
VALVE.
BEFORE PLACING THE HEATER IN OPERATION, CHECK FOR GAS
LEAKAGE. USE SOAP AND WATER SOLUTION OR OTHER MATERIAL
ACCEPTABLE FORTHEPURPOSE OF LOCATINGGAS LEAKS.DONOT
USE MATCHES, CANDLES, FLAME OR OTHER SOURCES OF IGNITION
FORTHISPURPOSE.
PURGING
Gas line purging is required with new piping or systems in which air has
entered.
CAUTION
PURGING SHOULDBEPERFORMEDBYPERSONSEXPERIENCEDINTHIS
TYPEOF GASSERVICE.TOAVOIDRISKOF FIREOR EXPLOSION,PURGE
DISCHARGEMUSTNOT ENTER CONFINEDAREAS OR SPACES WHERE
IGNITION CAN OCCUR. THE AREAMUST BE WELL VENTILATED AND
ALL SOURCES OF IGNITION MUST BE INACTIVATED OR REMOVED.
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
14.0" (3.45Kpa) W.C. and a minimum as shown in Table 4: that is, for
Natural Gas, 5.0" (1.25Kpa) W.C. for BTH 120 & 250 or 4.5" (1.12Kpa) W.C.
for BTH 150 & 199 or; for L.P. Gas, 11.0" (2.74Kpa) W.C. The inlet gas
pressure must not exceed the maximum value. Aservice regulator must be
installed within 10' (305 cm) of unit.
WARNING
FAILURE TO INSTALLA PRESSURE REGULATOR WITHIN 10 FEET OF
THE WATER HEATER CAN RESULT IN LEAKAGE OF FLUE GASES INTO
THE SURROUNDING ROOM. SERIOUS PERSONAL INJURY OR DEATH
COULD RESULT FROM INHALATION OF CARBON MONOXIDE GAS.
GASVALVES
WARNING
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT
OFF, TURN OFF THE MANUAL GAS CONTROL VALVE TO THE
APPLIANCE.
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 OFTHEWATER HEATER, THE RELIEFVALVE(S)
MUST NOT BE REMOVED OR PLUGGED.
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
Your local code authority may have other specific relief valve requirements.
WARNING
THEPURPOSEOFARELIEF VALVEISTOAVOIDEXCESSIVEPRESSURE
OR TEMPERATURE INTO THE STEAM RANGE, WHICH MAY CAUSE
SCALDING AT FIXTURES, TANK EXPLOSION, SYSTEM OR HEATER
DAMAGE. NO VALVE IS TO BE PLACED BETWEEN THE RELIEF VALVE
ANDTHETANK.
ADRAINLINEMUSTBECONNECTEDTOTHERELIEFVALVETO DIRECT
DISCHARGE TO A SAFE LOCATION TO AVOID SCALDING OR WATER
DAMAGE.THISLINEMUSTNOTBEREDUCEDFROMTHESIZEOFTHE
VALVE OUTLETANDMUSTNOTCONTAIN VALVES OR RESTRICTIONS,
NORSHOULDITBELOCATEDINFREEZINGAREAS.DO NOTTHREADOR
CAPTHEENDOFTHISLINE.RESTRICTEDORBLOCKED DISCHARGEWILL
DEFEATTHEPURPOSEOFTHEVALVEANDISUNSAFE.THEDISCHARGE
LINESHALLBEINSTALLEDTOALLOWCOMPLETEDRAINAGEOF BOTH
THEVALVEANDLINE.

14
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
IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE APPLIANCE
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 STABLE CLEAN
ELECTRICITYFORPROPEROPERATION. INSTALLING THE HEATER ON
ABRANCH CIRCUIT THAT HAS ELECTRONIC NOISE, IS SUBJECTTO
FLUCTUATIONS IN VOLTAGE LEVEL OR HASANAPPLIANCE WHICH
GENERATES EMF OF RFI INTERFERENCE CAN CAUSE THE
CONTROLLER TO MALFUNCTION. A HIGH QUALITY POWER
CONDITIONERMUSTBE INSTALLEDIFTHEABOVE CONDITIONSEXIST.
MALFUNCTIONS CAUSED BYAPOOR ELECTRICAL SUPPLYARE NOT
COVERED UNDER YOUR WARRANTY.
The controller is wired to the heater as shown in figures 16 & 17. 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 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/NFPA 70 and/or the
CSA C22.1 Electrical Code.
DONOTENERGIZETHE BRANCH CIRCUITBEFORETHE HEATER TANK
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.
WATER LINECONNECTIONS
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.
3. This unit may never be connected to any existing heating system or
component(s) previously used with non-potable water heating
appliance.
FIGURE16
WHC1202 INTEGRATED WATER HEATER CONTROL CONNECTION DIAGRAM

15
OPERATION
SEQUENCEOF OPERATION
Typical Control/Appliance Operating Sequence
1. When the control is initially powered, it enters a test mode and will
display the current software revision (example "104") for approximately
2 seconds, then "88.8" and all the LED's will illuminate for approximately
2 seconds. At this point, the control is in the idle mode and will display
the actual tank temperature.
2. If the control determines the actual water temperature inside the tank is
belowtheprogrammedtemperaturesetpointlessonehalfthedifferential,
a call for heat is activated.
3. The control then performs selected system diagnostic checks. This
includes confirming the proper state of the air switch, ignitor, gas valve,
flame sense rod, and ECO limit device.
4. If all checks are successfully passed, the combustion blower is energized
for the pre-purge cycle.
5. When the pre-purge cycle is complete, power is applied to the ignitor
element for the ignitor warm-up period (blower should continue to run).
6. During the ignitor warm-up period, the control will sense ignitor current.
If ignitor current is within the specified range, the controller will energize
(open) the gas valve at the end of the ignitor warm-up period, allowing
gas to enter the burner chamber. If ignitor current is not within the
specified range, the control will not energize the gas valve, and the
control will return to Step 2 of the process. (See section below:Appliance
IgnitionFailure).
7. After energizing the gas valve, the control will keep the ignitor on for a
short predetermined time period, then remove power to the ignitor.
8. After an additional 1 second, the control will monitor the flame sense
probe to confirm a flame is present. If a flame is not verified within this
time period, the controller will immediately de-energize (close) the gas
valve, and return to step two of the process. (See section below:
Appliance Ignition Failure).
9. If a flame is confirmed, the control will enter the heating mode where it
will continue heating the tank water until the setpoint temperature plus
one half the differential is reached. At this point, the gas valve is closed
and the control enters the post-purge cycle.
10.The combustion blower will run for the duration of the post purge cycle
to purge the system of all combustion gases. When the post purge
cycle is complete, the blower is de-energized and will coast to a stop.
11.The control will now enter the idle state while continuing to monitor the
internal tank water temperature and the internal state of the controller. If
the temperature drops below the setpoint value less one half the
differential, the control will automatically return to Step 2 and repeat the
entire operating cycle.
SELF DIAGNOSTIC CONTROLLER
A green LED is mounted on the Main Control Board to indicate line voltage
polarity is properly connected. The green LED is mounted next to connector
CN1 (Line input connection). When 120 VAC input power is properly
connected to the Main Control Board, the green LED will illuminate. If an
error is made when connecting 120 VAC input power, this LED will not light.
Improperly connecting the input power may result in a false sensor failure.
The 24 VAC circuitry is protected with a 3 amp auto fuse. If the fuse opens,
the LED display and discrete LED's on the Display Board assembly will not
illuminate. The recommended fuse replacement part is Littlefuse p/n 257003
automotive fuse. Repeated failure of the fuse is an indication of possible
damage to the Main Control Board. If repeated fuse failure occurs, return
the Control Board for service.
Under normal operating conditions, should the ignitor current fall out of
specification or the gas fail to light at the burner during the first trial for
ignition, the control will perform two (2) more ignition trials prior to entering
a lockout state. Note that each subsequent ignition trial will not occur
immediately. After a failed trial for ignition, the controller will remove all
power from the blower, gas valve, and ignitor and return to the call for heat
state. If a call for heat is activated, the controller will energize the combustion
blower for the pre-purge cycle, and again activate the ignitor to complete its
warm-up period. After the warm-up period, the gas valve is opened, ignitor
power removed, and the control will again check for flame.
If ignition is sensed during any one of these trials, normal operation will
resume. If ignitor current should fall out of specification or flame is not
sensed after the third ignition trial, the control will automatically enter a
lockout state ("Loc" displayed on the Display Board) and the ignitor or gas
valve LED on the Display Board will flash. The lockout state is manually
reset by momentarily pressing the push-button on the Display Board. If a
manual reset does not occur within a one hour time period, the controller
will automatically reset the lockout condition and provided the call for heat
still exists, will attempt another ignition sequence.
FIGURE18
FIGURE17
14. Tubing-Pressure
15. Tubing-Pressure
17. Switch-On/Off
18. Low Gas Pressure Switch
(BTH 120 and 250 Only).
19. Bocked Inlet Switch
20. Wire Assembly-Air
Flow Switch
ITEMDESCRIPTION
1. Transformer
2. Control Board & Cable Ass'y
3. E.C.O./Temperature Probe
4. Blower Proving Air Switch
5. Low Voltage Cable Assembly
6. Line Voltage Cable Assembly
7. Blower/Motor Assembly
8. Igniter Assembly
10. Control Display Board
11. Blocked Outlet Exhaust Switch
12. Lower Temperature Probe
13. Wire Assembly-Gas Pressure
Switch

16
NO LOW VOLTAGE (Figure 20)
24V AC LED Off
NO LOW VOLTAGE, 24V AC LED Off
FIGURE20
TEMPERATURE PROBE FAULT (Figure 21)
Water Temp LED Flashing
TEMPERATUREPROBEFAULT,WaterTempLEDFlashing
FIGURE21
This condition accommodates multiple failure modes. To more accurately
determine the cause of failure, press the pushbutton on the display board.
FAULT CONDITIONS
The controller is set up to provide additional status indicators under Fault
Conditons. The following figures are possible Fault Conditions.
NO INCOMING LINE VOLTAGE (Figure 19) Line LED Off
PossibleCause Remedy
1. Burner ground wire broken 1. Check wire and connection
or corroded at burner
2. Connectors unplugged 2. Check connections
3. Igniter broken 3. Replace igniter
4. Flame probe faulty 4. Replace flame probe
5. Gas shut off 5. Turn on gas supply
6. Clogged gas valve 6. Replace gas valve
7. Faulty gas valve 7. Replace gas valve
8. Defective control 8. Replace control
9. Burner improperly adjusted 9. Adjust burner
10. Dirty burner 10. Clean burner
GASVALVE LEDFLASHING
This condition results from a failure to establish burner ignition after three
successive trials. In such cases:
1. Investigate the possible cause and remedy any observations.
2. Momentarily depress the button on the display panel to reset the lockout
condition.
3. Confirm proper appliance operation.
NOINCOMINGLINEVOLTAGE, LineLEDOff
FIGURE19
PossibleCause Remedy
1. No Input Power 1. Apply Power
2. Wiring Disconnected 2. Check all wiring
3. One or more wiring receptacles 3. Reconnect plugs on control,
disconnected from control confirm all are fully seated
4. LED burned out 4. Ignore or replace control
PossibleCause Remedy
1.Blower 24 VAC Fuse 1. Replace 24 VAC 3a Fuse
(Littlefuse 257003 automotive fuse).
2.Defective Transformer 2. Replace Transformer
3.LED burned out 3. Ignore or replace control

17
Display Flashes “05” when button is pressed:
Display Flashes “15” when button is pressed:
Display Flashes “25” when button is pressed:
ECO SWITCH OPEN (Figure 22)
ECOLEDFlashing:
ECOSWITCHOPEN,ECOLEDFlashing
FIGURE22
CONTROL BAD (Figure 23)
All LEDs Flashing:
PossibleCause Remedy
1. This indicates the control has 1. Press button on the
failed on of its internal display board to reset
diagnostic self-tests. control. If this error
occurs repeatedly,
replace control.
CONTROLBAD,AllLEDsFlashing
FIGURE23
COMBUSTION AIR BLOCKAGE (Figure 24)
Pressure Switch LED Flashing:
COMBUSTIONAIRBLOCKAGE,PressureSwitchLEDFlashing
FIGURE24
PossibleCause Remedy
1. Temperature Probe wiring 1. Repair Wiring
open
2. Defective probe 2. Replace probe
PossibleCause Remedy
1. No water in tank and tank 1. The symptom does not
in freezing conditions reflect a control problem
2. Water in tank above freezing 2. Temperature probe out of
tolerance, replace temp.
probe
PossibleCause Remedy
1. Water in tank is low, probe 1. Filltank
immersed in steam
2. Probe wiring shorted 2. Repair wiring
3. Defective probe 3. Replace probe
PossibleCause Remedy
1. Temp. Probe unplugged 1. Check connectors
2. Temp. probe wiring damaged 2. Repair wiring
3. Water in tank too hot 3. Normal condition when
water temperature
exceeds safety limit.
Allow water to cool or
admit water into tank and
manuallyresetthecontrol.
Determine cause for
overtemp condition.
PossibleCause Remedy
1. Combustion air blocked 1. Check exhaust piping and
flue for obstructions
2. Blower not operating: 2. a. Repair wiring
a. Check blower wiring b. Replace blower motor
b. Check blower motor
3. Defective air switch 3. Replace air switch
4. Pressure switch jumped out 4. This controller must sense
an open contact on the
blower proving airflow
switch before the blower
comes on. Check to see if
blower proving airflow
switch is still connected to
the unit.

18
ADJUSTMENT PROCEDURE
INITIALSTART-UP
A minimum gas supply pressure of 5.0" (1.25 kPa) W.C. (4.5" or 1.12 kPa)
on BTH 150 and 199) for natural gas (11.0" or 2.74 kPa W.C. for L.P. Gas)
is required before making any adjustment to the gas control pressure
regulator Attempts to adjust the regulator during periods of low gas supply
pressure could result in overfiring of the heater when the gas supply
pressure returns to normal.
1. Check gas line pressure with a manometer.
2. Check manifold pressure (see Table 4, page 20) using a pressure
gauge (manometer) connected to the manifold pressure tap on the
gas control valve, (Figure15).
If full rate adjustment is required, remove cover screw from top of the
gas control valve, (Figure 15).
Using a small screwdriver, turn adjusting screw clockwise to increase
or counterclockwise to decrease gas pressure to obtain 4.0" (1 kPa)
on BTH 120 and 250 (3.5" or .87 kPa on BTH 150 and 199) for natural gas
(10.0" or 2.5 kPa W.C. for L.P. Gas) Water Column.
3. Cycle the burner on and off several times to check its operation.
4. Check the operation of the limit and operating controls.
5. Check the vent system seams and joints and ensure that there is no
discharge of flue products into the room.
6. Check the input rate:
For appliance installation locations with elevations above 2000 feet
(610m)refer toHIGHALTITUDE INSTALLATIONS section of this manual.
a. Attach a pressure gauge (manometer) to the manifold pressure tap
(Figure 16) and refer to Table 4, page 20 for correct pressure.
b. Use this formula to “clock” the meter. Be sure other gas consuming
appliances are not operating during this interval.
3600 X H = Btuh
T
Should it be necessary to adjust the gas pressure to the burner, to obtain
the full input rate, the steps below should be followed:
T = Time in seconds to burn 1 cubic foot of gas. (With a stopwatch read
the gas meter and measure the amount of time required for the
heater to consume 1 cubic foot of gas.)
H = Heating value of gas (in Btu’s per cubic foot of gas).
Btuh = Actual heater input rate, in Btuh.
EXAMPLE: (Using BTH-199 heater)
T = 18.9 seconds
H = 1050 Btu/ft.3
BTUH=?
For high altitude installations, compare result to the derated input required
for the elevation at the installation location.
c. Remove the pressure regulator cover screw (Figure 16) and adjust
the pressure by turning the adjusting screw with a small
screwdriver. Do not exceed 4.0" (1 kPa) on BTH 120 and 250
(3.5" (.87 kPa) on BTH 150 and 199) Water Column.
Clockwise to increase gas pressure and input rate.
Counterclockwise to decrease gas pressure and input rate.
d. “Clock” the meter as in step (b) above.
e. Repeat steps (c) and (d) until the specified input rate is achieved.
f. Turn the manual gas valve to “OFF”. Replace the pressure regulator
cover screw. Remove the pressure gauge or manometer from the
manifold pressure tap. Replace the set screw in the manifold pressure
tap. If the gas pressure regulator cannot be adjusted to give the full
input rating with sufficient gas pressure at the valve, check to ensure
the unit is equipped with the correct orifice.
PRIOR TO START UP
REQUIREDABILITY
INSTALLATIONOR SERVICEOFTHISWATERHEATERREQUIRESABILITY
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 calibration 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.
OPERATING INSTRUCTIONS
IMPORTANT
IT IS RECOMMENDED THAT A QUALIFIED SERVICE TECHNICIAN
PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME THE
USERSHOULDASKTHE TECHNICIAN ANYQUESTIONSIN REGARD TO
THEOPERATIONAND MAINTENANCE OF THEUNIT.
CAUTION
BEFOREPROCEEDING WITHTHE OPERATION OFTHE UNIT,MAKE SURE
HEATER AND SYSTEM ARE FILLED WITH WATER AND ALL AIR IS
EXPELLEDFROMHEATERAND PIPING.
NEVEROPERATETHEHEATERWITHOUTFIRSTBEINGCERTAINITISFILLED
WITHWATERANDATEMPERATUREANDAPRESSURE RELIEFVALVEIS
INSTALLED IN THE RELIEF VALVEOPENING OF THE HEATER. DO NOT
ATTEMPTTOOPERATEHEATERWITHCOLDWATERINLETVALVECLOSED.
FILLING:
1. Close the heater drain valve.
2. Open a nearby hot water faucet to permit the air in the system to
escape.
3. Fully open the cold water inlet pipe valve allowing the heater and
piping to be filled.
4. Close the hot water faucet as water starts to flow.
5. The heater is ready to be operated.
THE MAIN MANUAL GAS SHUTOFF VALVE MUST HAVE BEEN CLOSED
FOR AT LEAST FIVE (5) MINUTES. THIS WAITING PERIOD IS AN
IMPORTANT SAFETY STEP. ITS PURPOSE IS TO PERMIT GAS THAT
MIGHT HAVE ACCUMULATED IN THE COMBUSTION CHAMBER TO
CLEAR. IF YOU DETECT GAS AT THE END OF THIS PERIOD, DO NOT
PROCEED WITH LIGHTING. RECOGNIZE THAT GAS ODOR, EVEN IF IT
SEEMSWEAK,MAYINDICATE THEPRESENCEOFACCUMULATED GAS
SOMEPLACE IN THE AREA WITH A RISK OF FIRE OR EXPLOSION. SEE
THEFRONTPAGEFORSTEPS TO BE TAKEN.
DO NOT USE THIS HEATER IF ANY PART HAS BEEN UNDER WATER.
IMMEDIATELY CALLAQUALIFIED SERVICE TECHNICIAN TO INSPECT
THE HEATERAND TO REPLACE ANYPART OF THE CONTROL SYSTEM
ANDANYGASCONTROLWHICH HASBEENUNDERWATER.
LIGHT THE UNIT IN ACCORDANCE WITH THE OPERATING
INSTRUCTIONS LABELATTACHED TO THE HEATER.
THESE INSTRUCTIONS ARE REPEATED IN THE LIGHTING AND
OPERATING LABEL ILLUSTRATION ON PAGE 20 IN THIS MANUAL.
3600 X 1050 = 199,900 Btuh (59 Kw)
18.9

19
FORYOUR SAFETYREAD BEFOREOPERATING
WARNING: If you do not follow these instructions exactly, a fire or
explosion may result causing property damage, personal injury or loss of life.

20
WARNING
UNDERNOCIRCUMSTANCES SHOULD THE INPUTEXCEEDTHERATE
SHOWNONTHE HEATER RATING PLATE. OVERFIRINGCOULDRESULT
IN DAMAGE OR SOOTING OF THE HEATER.
CATHODIC PROTECTION
CAUTION
HYDROGENGASCANBEPRODUCEDINAHOTWATERSYSTEMSERVED
BYTHIS HEATER THATHAS NOT BEEN USEDFORALONG PERIOD OF
TIME (GENERALLY TWO WEEKS OR MORE). HYDROGEN GAS IS
EXTREMELYFLAMMABLE. To reduce the risk of injury under these
conditions, it is recommended that a hot water faucet be opened for several
minutes before using any electrical appliance connected to the hot water
system. If hydrogen is present, there will probably be an unusual sound
such as air escaping through the pipe as the water begins to flow. There
should be no smoking or open flame near the faucet at the time it is open.
PRECAUTIONS
IFTHEUNITISEXPOSEDTOTHEFOLLOWING,DONOTOPERATEHEATER
UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE BYA QUALIFIED
SERVICEMAN.
1. FLOODINGTOORABOVETHELEVELOFTHEBURNERORCONTROLS
2. EXTERNALFIRING
3. DAMAGE
4. FIRINGWITHOUTWATER
5. SOOTING
NEVER OPERATE THE HEATER WITHOUT FIRST BEING CERTAIN IT IS
FILLED WITH WATERAND ATEMPERATUREAND PRESSURE RELIEF
VALVE IS INSTALLED INTHERELIEF VALVE OPENING OFTHEHEATER.
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT
OFF, TURN OFF THE MANUAL GAS CONTROL VALVE TO THE
APPLIANCE.
GENERAL INFORMATION
POWERBURNER
The initial start-up procedure of the unit is provided on page 18.
The sequence of operation of the unit is provided on page 15.
It is important to note that the controller has a reset button on the control
box, Figure 1. The reset button is a safety device and would not normally
be used.
HIGH LIMIT
The high limit (not adjustable) is factory set to cutout at 202°F (94°C). The
controller must be manually reset by depressing the reset button on front
of the control when water temperature drops to below 160°F (71°C).
HIGHALTITUDE INSTALLATIONS
WARNING
BTHHEATERSARE CERTIFIED FORUSEWITHOUTMODIFICATIONFOR
ALTITUDES UP TO 6500 FEET. INSTALLATIONSABOVE 6500 FEET MAY
REQUIRE REPLACEMENT OF THE BURNER ORIFICE. CALL THE
TECHNICAL CENTER @ [phone] FOR REQUIREMENTS.
Some gas utility companies derate their gas for altitude, making it
unneccessary to install high altitude orifices. Call the local gas or utlity
company to verify BTU content.
Due to the input rating reduction at high altitudes, the output rating of the
appliance is also reduced and should be compensated for in the sizing of
the equipment for applications.
MAINTENANCE
GENERAL
KEEP APPLIANCE AREA CLEAR AND FREE FROM COMBUSTIBLE
MATERIALS,GASOLINEANDOTHERFLAMMABLEVAPORSANDLIQUIDS.
(SEEWARNING ONPAGE5,LOCATINGTHEHEATER).
Water heater maintenance includes periodic tank flushing and cleaning,
and removal of lime scale. The unit should be inspected and adjusted to
maintainpropercombustion.Refertothefollowingtable.Aperiodicinspection
of the venting system should be made. Where used, the water circulating
pump should be oiled.
MAINTENANCESCHEDULE
Following are the instructions for performing some of the recommended
maintenance. Unit inspection and adjustment should be performed by a
competent technician.
COMPONENT OPERATION INTERVAL REQUIRED
Tank Sediment Monthly Flushing
Removal
Tank LimeScale Semi UN-LIME®
Removal Annually Delimer
Anode Inspect Semi Replace as
Rods Annually Required
Relief Valve Inspect Semi
Annually
SAE No. 20
Circulating Oiling Four Months non-detergent
Pump(1) motoroil
CleanInlet
Blower Screen and As Required Soft Brush
Blower Wheel
Vent System Inspect Every 3 Joints should
Months be sealed
(1) If furnished with oiling provision.
TABLE 4
GASSUPPLYSPECIFICATIONS NaturalGas NaturalGas L.P.Gas
Max. Gas Supply Pressure W.C. 12.0 12.0 14.0
(3 kPa) (3 kPa) (3.45 kPa)
Nominal Gas Supply Press. W.C 7.0 7.0 11.0
(1.74 kPa) (1.74 kPa) (2.74 kPa)
Minimal Gas Supply Press. W.C. 5.0 4.5 11.0
(1.25 kPa) (1.12 kPa) (2.74 kPa)
Manifold Press. W.C. 4.0 3.5 10.0
(1 kPa) (872 kPa) (2.5 kPa)
BTH 120 BTH 150 BTH 120,
& 250 &199 150 & 199