A.O. Smith 101, 100 User Manual

CYCLONE Xi Model BTH 120-250(A)

SERIES 100 AND 101

COMMERCIAL GAS WATER HEATER

GAS-FIRED POWER BURNER

FOR DOMESTIC HOT W A TER

• INST ALLATION • OPERA TION • SER VICE • MAINTENANCE • LIMITED W ARRANTY

WARNING: If the information in these
instructions is not followed exactly , a fire
or explosion may result causing property
damage, personal injury or death.

– Do not store or use gasoline or other

flammable vapors and liquids in the
vicinity of this or any other appliance.

– WHAT TO DO IF YOU SMELL GAS:

• Do not try to light any appliance.

• Do not touch any electrical switch;
do not use any phone in your
building.

• Immediately call your gas supplier
from a neighbor's phone. Follow the
gas supplier's instructions.

• If you cannot reach your gas supplier,
call the fire department.

– Installation and service must be

performed by a qualified installer,
service agency or the gas supplier .

Thank you for buying this energy efficient water heater from
A.O. Smith Water Products Company. We appreciate your
confidence in our products.

CAUTION

TEXT PRINTED OR UNDERLINED IN RED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE
READ THOROUGHLY BEFORE INSTALLING AND USING
THIS APPLIANCE.

PLACE THESE INSTRUCTIONS ADJACENT TO HEA TER AND

NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.

PRINTED IN U.S.A. 0307 PART NO. 197727-000

1

A DIVISION OF A.O. SMITH CORPORATION

Mc BEE, SOUTH CAROLINA

CYCLONE Xi BTH 120 - 250A ROUGH-IN-DIMENSIONS

GAS VAL VE PIPING

BTH-120, 199 & 250 1/2" NPT
BTH-150 3/4" NPT

T able 1. RECOVERY CAP ACITIES - NA TURAL GAS / L.P.

Approx.

Input Gas Gallon TEMPERA TURE 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 4 4 nat/lp 379 2179 1635 1308 1090 934 817 726 654 594 545 503 467
BTH 199 5 8 nat/lp 379 2904 2178 1743 1452 1245 1089 968 871 792 726 670 622
BTH 250 7 3 nat/lp 379 3632 2724 2179 1816 1557 1362 1211 1090 991 908 838 778

Recovery capacities are based on 95% thermal efficiency.

FOREWORD

These designs comply with the current edition of the American National
Standard for Gas W ater Heaters, V olume 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
National Electrical Code, NFP A 70 or CAN/CSA-B149.1, the Natural Gas and
Propane Installation Code and CSA C22.1, the Canadian Electrical Code. All
documents are available from the Canadian Standards Association, 8501
East Pleasant V alley Road, Cleveland, OH 44131. NFP A document s are also
available from the National Fire Protection Association, 1 Batterymarch

Park, Quincy, MA 02269.

2

TABLE OF CONTENTS

PAGE PAGE

ROUGH-IN DIMENSIONS ................................................................... 2

FOREWORD...................................................................................... 2

FEATURES ........................................................................................ 3,4

Water Temperature Control .......................................................... 3

High Limit Switch (E.C.O.) ............................................................ 4

Dishwashing Machine Requirement ............................................ 4

Circulating Pump........................................................................... 5

INSTALLA TION INSTRUCTIONS ........................................................ 4-12

Required Ability ............................................................................ 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

CONTROL AND SWITCHES .............................................................. 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

GAS PIPING....................................................................................... 13

Connection of Gas Pipe ............................................................... 14

Purging ......................................................................................... 15

Gas Meter Size - City Gases Only .............................................. 15

Gas Pressure Regulation............................................................. 15

Gas Valves................................................................................... 15

SYSTEM CONNECTIONS .................................................................. 15

Thermometers .............................................................................. 15

Relief Valve .................................................................................. 15

Water Line Connections ............................................................. 15

Heater Wiring .............................................................................. 16

USING THE ELECTRONIC CONTROLLER......................................... 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

PRIOR TO START -UP ....................................................................... 20

Required Ability ........................................................................... 20

OPERATIING INSTRUCTIONS ........................................................... 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

GENERAL INFORMA TION ................................................................ 22

Power Burner ............................................................................. 22

High Limit ..................................................................................... 22

High Altitude Installations ............................................................ 22

MAINTENANCE ................................................................................ 22

General........................................................................................ 22

Maintenance Schedule ............................................................... 22

Flushing ....................................................................................... 26

Draining ....................................................................................... 26

Sediment Removal....................................................................... 26

Lime Scale Removal .................................................................... 26

Anode Inspection and Replacement........................................... 26,27

Drain Valve and Access Panels ................................................. 27

Relief Valve ................................................................................. 27

Circulating Pump.......................................................................... 27

Vent System ................................................................................ 27

INSTALLA TION DIAGRAMS............................................................. 28-32

Manifold Kits................................................................................ 33

CHECKLIST AND SERVICE INFORMATION ...................................... 34

TROUBLE-SHOOTING...................................................................... 34,35

LIMITED WARRANTY....................................................................... 36

FEATURES

IMPORT ANT

IT IS REQUIRED THA T A QUALIFIED SER VICE TECHNICIAN PERFORM THE
INITIAL FIRING OF THE HEA TER. A T THIS TIME THE USER SHOULD NOT
HESITATE TO ASK THE TECHNICIAN ANY QUESTIONS WHICH HE MA Y
HAVE IN REGARD TO THE OPERATION AND MAINTENANCE OF THE UNIT.

A CHECKLIST AND SERVICE INFORMA TION section are included at the rear
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.

WA TER TEMPERA TURE CONTROL

DANGER

THIS WA TER HEATER IS EQUIPPED WITH A N ADJUST ABLE THERMOSTA T
TO CONTROL WATER TEMPERATURE. HOT WATER TEMPERATURES
REQUIRED FOR AUTOMATIC DISHWASHER AND LAUNDRY USE CAN
CAUSE SCALD BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/
OR DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS VARIES
WITH THE PERSON’S AGE AND THE TIME OF THE EXPOSURE. THE SLOWER
RESPONSE TIME OF CHILDREN, AGED OR DISABLED PERSONS
INCREASES THE HAZARDS TO THEM. NEVER ALLOW SMALL CHILDREN
TO USE A HOT WATER TAP, OR TO DRAW THEIR OWN BATH WATER.
NEVER LEAVE A CHILD OR DISABLED PERSON UNATTENDED IN A BATHTUB
OR SHOWER.

THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE THE
GENERAL PUBLIC DOES NOT H AVE ACCESS TO SET TEMPERATURES.

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

3

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 HEA TER TEMPERA TURE A T 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

FIGURE 1.

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.

DISHWASHING MACHINE REQUIREMENT

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.)

CIRCULA TING 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, NFP A 70 or the Canadian Electrical Code,
CSA C22.1.

All bronze circulators are recommended for used with commercial
water heaters.

FIGURE 2.

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.

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

REQUIRED ABILITY

INST ALLATION OR SERVICE OF THIS WA TER HEATER REQUIRES ABILITY
EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD
INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPLY AND
ELECTRICAL WORK ARE REQUIRED.

INSULA TION 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.

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.

WARNING

4

LOCA TING THE HEATER

WARNING

THERE IS A RISK IN USING FUEL BURNING APPLIANCES SUCH AS GAS
WATER HEATERS IN ROOMS, GARAGES OR OTHER AREAS WHERE
GASOLINE, OTHER FLAMMABLE LIQUIDS OR ENGINE DRIVEN EQUIPMENT
OR VEHICLES ARE STORED, OPERA TED OR REP AIRED. FLAMMABLE
VAPORS ARE HEA VY AND TRA V EL ALONG THE FLOOR AND MAY BE
IGNITED BY THE HEA TER’S IGNITER OR MAIN BURNER FLAMES CAUSING
FIRE OR EXPLOSION. SOME LOCAL CODES PERMIT OPERA TION OF GAS
APPLIANCES IF INST ALLED 18 INCHES (46 cm) OR MORE ABOVE THE
FLOOR. THIS MA Y REDUCE THE RISK IF LOCA TION IN SUCH AN AREA
CANNOT BE A VOIDED.

THE HEATER SHALL BE LOCATED OR PROTECTED SO IT IS NOT SUBJECT
TO PHYSICAL DAMAGE BY A MOVING VEHICLE.

DO NOT LOCATE THE HEATER WHERE NOISE FROM THE EXHAUST OR
INTAKE WILL BE OBJECTIONABLE. THIS INCLUDES LOCA TIONS CLOSE TO
OR ACROSS FROM WINDOWS AND DOORS. AVOID ANCHORING THE VENT
AND INTAKE PIPES DIRECTL Y T O FRAMED WALLS, FLOORS OF CEILINGS
UNLESS RUBBER ISOLATION PIPE HANGERS ARE USED. THIS PREVENTS
ANY VIBRATIONS FROM BEING TRANSMITTED INTO THE LIVING SP ACES.

WARNING

FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY OTHER
POTENTIAL FIRE HAZARDOUS ARTICLES MUST NEVER BE PLACED ON
OR ADJACENT TO THE HEA TER. OPEN CONT AINERS OF FLAMMABLE
MATERIAL SHOULD NOT BE STORED OR USED IN THE SAME ROOM WITH
THE HEATER.

When installing the heater , consideration must be given to proper location.
Location selected should be as close to the intake and exhaust termination
points as practicable, with adequate air supply and as centralized with the
piping system as possible.

THE HEATER MUST NOT BE LOCA TED IN AN AREA WHERE IT WILL BE
SUBJECT TO FREEZING .

LOCA TE IT NEAR A FLOOR DRAIN. THE HEA TER SHOULD BE LOCA TED IN
AN AREA WHERE LEAKAGE FROM THE HEA TER OR CONNECTIONS WILL
NOT RESULT IN DAMAGE TO THE ADJACENT AREA OR TO LOWER FLOORS
OF THE STRUCTURE.

WARNING

THIS WA TER HEA TER IS A CONDENSING UNIT AND REQUIRES A DRAIN
TO BE LOCATED IN CLOSE PROXIMITY TO ALLOW THE CONDENSATE
TO DRAIN SAFEL Y. THE CONDENSATE DRAINS FROM THE UNIT A T THE
EXHAUST ELBOW LOCATED A T THE BOTT OM OF THE UNIT. NOTE: IT IS
IMPORT ANT THA T THE CONDENSATE HOSE NOT BE ELEV A TED ABOVE
THE EXHAUST ELBOW (SEE FIGURE 3). THE CONDENSA TE BUILD-UP
WILL BLOCK THE EXHAUST OUTLET , WHICH WILL CAUSE IMPROPER
OPERATION.

FIGURE 3.

WARNING

DO NOT USE THIS APPLIANCE IF ANY PA RT HAS BEEN UNDER WA TER.
IMMEDIATEL Y CALL A QUALIFIED SERVICE TECHNICIAN TO INSPECT THE
APPLIANCE AND TO REPLACE ANY PA RT OF THE CONTROL SYSTEM AND
ANY GAS CONTROL WHICH HAS BEEN UNDER W ATER.

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).

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.

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.

FIGURE 4.

*ILLUSTRATION OF MINIMUM COMBUSTIBLE CLEARANCES IN AN
ALCOVE.

5

HARD WA TER

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.

AIR REQUIREMENTS

KEEP APPLIANCE AREA CLEAR AND FREE OF COMBUSTIBLE MA TERIALS,
GASOLINE AND OTHER FLAMMABLE V APORS AND LIQUIDS.

DO NOT OBSTRUCT THE FLOW OF COMBUSTION AND VENTILA TING AIR.

WARNING

FOR SAFE OPERA TION PROVIDE ADEQUA TE AIR FOR COMBUSTION AND
VENTILATION. AN INSUFFICIENT SUPPLY OF AIR WILL CAUSE
RECIRCULATION OF COMBUSTION PRODUCTS RESULTING IN
CONT AMINATION THA T MAY BE HAZARDOUS TO LIFE. SUCH A CONDITION
OFTEN WILL RESUL T IN A YELLOW , LUMINOUS BURNER FLAME, CAUSING
CARBONING OR SOOTING OF THE COMBUSTION CHAMBER, BURNERS
AND FLUE TUBES AND CREATES A RISK OF ASPHYXIA TION.

MECHANICAL EXHAUSTING OF 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 DRA WN INTO THE ROOM THROUGH THE HEATER’S
VENTING SYSTEM, CAUSING POOR COMBUSTION. SOOTING MAY RESUL T
IN SERIOUS DAMAGE TO THE HEA TER AND RISK OF FIRE OR EXPLOSION.
IT CAN ALSO CREA TE A RISK OF ASPHYXIA TION.

UNCONFINED SP ACE

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.

CONFINED SPACE

If the confined space is within a building of tight construction, air for combustion
and ventilation must be obtained from outdoors. When directly communicating
with the outdoors through vertical ducts, two permanent openings, located
in the above manner, shall be provided. Each opening shall have a free area
of not less than one square inch (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.

CHEMICAL V APOR CORROSION

WARNING

CORROSION OF THE FLUE WA YS AND VENT SYSTEM MA Y OCCUR IF AIR
FOR COMBUSTION CONTAINS CERTAIN CHEMICAL VAPORS. SUCH
CORROSION MAY RESULT IN F AILURE AND RISK OF ASPHYXIA TION.

Spray can propellants, cleaning solvents, refrigerator and air conditioning
refrigerants, swimming pool chemicals, calcium and sodium chloride, waxes,
and process chemicals are typical compounds which are potentially
corrosive.

PRODUCTS OF THIS SORT SHOULD NOT BE ST ORED NEAR THE HEA TER.
ALSO, AIR WHICH IS BROUGHT IN CONTACT WITH THE HEATER
SHOULD NOT CONT AIN ANY OF THESE CHEMICALS. IF NECESSARY,
UNCONT AMINATED AIR SHOULD BE OBTAINED FROM REMOTE OR OUTSIDE
SOURCES.

VENTING

WARNING

THE INSTRUCTIONS IN THIS SECTION ON VENTING MUST BE FOLLOWED
TO A VOID CHOKED COMBUSTION OR RECIRCULA TION OF FLUE GASES.
SUCH CONDITIONS CAUSE SOOTING OR RISKS OF FIRE AND
ASPHYXIATION.

Heater must be protected from freezing downdrafts during shutdown periods.

WARNING

NEVER OPERATE THE HEA TER UNLESS IT IS VENTED TO THE OUTDOORS
AND HAS ADEQUATE AIR SUPPLY TO AVOID RISKS OF IMPROPER
OPERA TION, FIRE, EXPLOSION OR ASPHYXIA TION.

VENT PIPE TERMINATION

NOTE: Before installing venting, determine place of vent pipe termination.
See Figures 5a & b and 6a & b before proceeding.

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" (31 cm) OF THE ENCLOSURE
TOP AND ONE IN OR WITHIN 12" (31 cm) OF THE ENCLOSURE BOTTOM.
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).

CAUTION

DO NOT TERMINA TE THE VENTING WHERE NOISE FROM THE EXHAUST OR
INTAKE WILL BE OBJECTIONABLE. THIS INCLUDES LOCATIONS CLOSE T O
OR ACROSS FROM WINDOWS AND DOORS. A VOID ANCHORING THE VENT
AND INTAKE PIPES DIRECTL Y TO FRAMED WALLS, FLOORS OR CEILINGS
UNLESS RUBBER ISOLA TION PIPE HANGERS ARE USED. THIS PREVENTS
ANY VIBRATIONS FROM BEING TRANSMITTED INTO THE LIVING SP ACES.

6

INST ALLA TION REQUIREMENTS FOR THE COMMONWEAL TH OF MASSACHUSETTS

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:

INST ALLA TION OF CARBON MONOXIDE DETECTORS At the time of installation of the side wall horizontal vented gas 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. KEEP CLEAR OF ALL OBSTRUCTIONS.”
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 accor­dance 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 NFP A 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 When the manufacturer of Product
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

Product Approved side wall horizontally vented gas fueled equipment does not provide the p art s 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.

7

U.S. POWER VENT

FIGURE 5a.

CAUTION

TO PREVENT EXHAUSTING PRODUCTS FROM CIRCULA TING TO THE AIR INT AKE

IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL DISTANCE BETWEEN

THESE TWO TERMINALS IS RECOMMENDED.

CANADIAN POWER VENT

FIGURE 5b.

8

U.S. DIRECT VENT

FIGURE 6a.

CAUTION

TO PREVENT EXHAUSTING PRODUCTS FROM CIRCULA TING TO THE AIR INT AKE

IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL DIST ANCE BETWEEN

THESE TWO TERMINALS IS RECOMMENDED.

CANADIAN DIRECT VENT

FIGURE 6b.

9

IMPORT ANT

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.

FOR ALL
MODELS

FIGURE 8.

IMPORT ANT

IMPORT ANT

Plan the layout of the vent system backwards from the vent termination to
the appliance.

WARNING

USE ONL Y THE VENT TERMINALS SUPPLIED WITH THIS UNIT. TERMINA TION
OF A VENT SYSTEM WITH A DEVICE OTHER THAN THE SUPPLIED VENT
TERMINATIONS WILL AFFECT SYSTEM PERFORMANCE AND RESUL T IN A
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

WHEN THE UNIT IS T O BE SETUP AS A DIRECT VENT , THE MESH SCREEN
MUST BE REMOVED. THE INLET VENT PIPE MA Y THEN BE GLUED TO THE
AIR INTAKE (see Figure 8) PROVIDED ON THE UNIT .

DIRECT VENT TERMINAL INST ALLATION

IMPORT ANT

THIS UNIT CONSISTS OF TWO VENT TERMINALS - AN INTAKE VENT
TERMINAL AND AN EXHAUST VENT TERMINAL. THE INTAKE VENT
TERMINAL IS A 3" 45° PVC ELBOW WITH A DOME MESH WIRE SCREEN AND
THE EXHAUST VENT TERMINAL IS A 3" 45°PVC ELBOW WITH A MESH
WIRE SCREEN.

NOTE: TO PREVENT EXHAUSTING PRODUCTS FROM CIRCULA TING T O
THE AIR INTAKE IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL

DISTANCE BETWEEN THESE TWO TERMINALS IS RECOMMENDED.

WHEN LOCA TING THE TERMINALS ON A SIDEW ALL, 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).

INST ALLATION 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: BEFORE BEGINNING INST ALLATION OF ANY VENT PIPE READ THE
VENT PIPE MANUFACTURER'S INST ALLA TION INSTRUCTIONS.

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 wall. BEWARE OF CONCEALED WIRING AND PIPING INSIDE
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) WOODEN SIDE WALLS
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.

10

5. Glue the intake vent terminal to the section of the pipe.

VERTICAL VENT TERMINAL INST ALLA TION

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).

IMPORT ANT

WHEN TERMINA TING THROUGH A ROOF , THE FOLLOWING SPECIFICATIONS
PERT AINING 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 10 & 11.

NOTE: Exhaust vent terminal is installed using the same procedure.

INST ALLATION SEQUENCE

NOTE: BEFORE BEGINNING INSTALLA TION OF ANY VENT PIPE, READ
“VENT PIPE PREPARA TION” SECTION ON P AGE 12.

FIGURE 9.

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.

FIGURE 10.

FIGURE 11.

11

INST ALLA TION OF VENT SYSTEM

WARNING

THE OPTIONAL INT AKE VENTING ARRANGEMENT AND THE EXHAUST
VENTING ARRANGEMENT MUST BE INST ALLED TO RUN DIRECTL Y TO THE
OUTDOORS AND NOT IN ANY WA Y BE CONNECTED TO ANOTHER VENTING
SYSTEM (I.E. FURNACE, DRYERS OR SPACE HEA TERS). IT IS CRUCIAL
THAT THE VENTING ARRANGEMENT BE KEPT SEPA RATE FROM OTHER
VENTING SYSTEMS. IF THIS WARNING IS IGNORED, AND THE SYSTEM IS
VENTED INCORRECTL Y , I T MA Y CAUSE IMPROPER OPERA TION, FIRE,
EXPLOSION, OR ASPHYXIA TION

1. Plan the route of the vent system from the vent termination to the planned
location of the appliance. Layout the total vent 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 (15.2 m) 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
T able 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 PVC­DWV 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
CPVC or ABS pipe and fittings (MUST USE SUPPLIED VENT TERMINAL) 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
the pipe heats up and expands. Install accordingly to minimize such stresses.

VENT PIPE PREP ARATION

1. INITIAL PREPARA TION
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
CPVC pipe is a specialized skill just as any other pipe fitting technique.

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. SELECTION OF MATERIALS

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.
Select the proper 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 ONL Y IN A WELL-VENTILA TED AREA.

12

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.

LOW GAS PRESSURE SWITCH

(SEE FIGURE 12)

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.

FIGURE 12.

BLOWER PROVER SWITCH

(SEE FIGURE 12)

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.

BLOCKED OUTLET PROVER SWITCH

(SEE FIGURE 12)

The Blocked Outlet Prover Switch is set up to shut the unit off when a build­up 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.

BLOCKED INLET PROVER SWITCH

(SEE FIGURE 12)

The Blocked Inlet Prover Switch is set up to shut the unit off when a build­up 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.

THE WATER HEATER IS POLARITY SENSITIVE. BEFORE APPLYING

CAUTION

ELECTRICITY TO THIS HEATER BE CERT AIN THA T SUPPLY NEUTRAL WIRE
TO GROUND CHECK INDICA TES ZERO VOLT AGE.

HOT SURFACE 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,
sufficient heat is generated to ignite the main burner . 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.

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") Water Column and 0.6
Specific Gravity Gas and max. gas pressure of 0.5 psig)

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 11 80 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 1 15 0 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

CAUTION

13

THE HEA TER IS NOT INTENDED FOR OPERA TION A T HIGHER THAN 10.5"
(2.59 KPa) WATER COLUMN SUPPLY GAS PRESSURE. HIGHER GAS
SUPPL Y PRESSURES REQUIRE SUPPLEMENT AL REDUCING SERVICE
REGULATION. EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE
DAMAGE TO THE GAS CONTROLS WHICH COULD RESUL T 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 V AL VE MUST BE CHECKED FOR SAFE
OPERATION. MAKE SURE T HAT THE OUTSIDE VENTS ON THE SUPPL Y
REGULAT ORS AND THE SAFETY VENT V ALVES ARE PROTECTED AGAINST
BLOCKAGE. THESE ARE P ARTS OF THE GAS SUPPL Y SYSTEM, NOT THE
HEATER. VENT BLOCKAGE MA Y OCCUR DURING ICE STORMS.

IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING FROM
CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY CAUSE
IMPROPER OPERATION, FIRE OR EXPLOSION.

IF COPPER SUPPLY LINES ARE USED THEY MUST BE INTERNALLY TINNED
AND CERTIFIED FOR GAS SERVICE.

BEFORE A TT ACHING THE GAS LINE BE SURE THA T ALL GAS PIPE IS CLEAN
ON THE INSIDE.

TO TRAP ANY DIRT OR FOREIGN MA TERIAL IN THE GAS SUPPLY LINE, A
DIRT LEG (SOMETIMES CALLED A SEDIMENT TRAP OR DRIP LEG) MUST BE
INCORPORA TED IN THE PIPING (SEE FIGURE 13). THE DIRT LEG MUST BE
READILY ACCESSIBLE AND NOT SUBJECT TO FREEZING CONDITIONS.
INST ALL IN ACCORDANCE WITH RECOMMENDATIONS OF SER VING GAS
SUPPLIERS. REFER TO THE NA TIONAL FUEL GAS CODE.

WARNING

FIGURE 14b. BTH 150 Models Only

FIGURE 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 14a, b, c.

2. PERFORM THE GAS LEAK TEST ANY TIME WORK IS DONE ON A GAS
SYSTEM TO A VOID THE POSSIBILITY OF FIRE OR EXPLOSION WITH
PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE.

FIGURE 14c. BTH 120 Models Only

The Gas Leak T est is performed as follows: Paint pipe connections upstream
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.

FIGURE 14a. BTH 199/250 Models Only

Apply joint compounds (pipe dope) sparingly and only to the male threads
of pipe joints. Do not apply compound to the first two threads. Use compounds
resistant to the action of liquefied petroleum gases.

14

DISCONNECT THE APPLIANCE AND ITS MANUAL GAS SHUT OFF V AL VE
FROM THE GAS SUPPL Y PIPING SYSTEM DURING ANY SUPPLY PRESSURE
TESTING EXCEEDING 1/2 PSIG (3.45Kpa). GAS SUPPL Y LINE MUST BE
CAPPED WHEN DISCONNECTED FROM THE HEA TER. FOR TEST PRESSURES
OF 1/2 PSIG (3.45Kpa) OR LESS, THE APPLIANCE NEED NOT BE
DISCONNECTED, BUT MUST BE ISOLA TED FROM THE SUPPL Y PRESSURE
TEST BY CLOSING THE MANUAL GAS SHUTOFF V AL VE.

BEFORE PLACING THE HEA TER IN OPERA TION, CHECK FOR GAS LEAKAGE.
USE SOAP AND WA TER SOLUTION OR OTHER MA TERIAL ACCEPT ABLE
FOR THE PURPOSE OF LOCATING GAS LEAKS. DO NOT USE MA TCHES,
CANDLES, FLAME OR OTHER SOURCES OF IGNITION FOR THIS PURPOSE.

PURGING

Gas line purging is required with new piping or systems in which air has
entered.

CAUTION

PURGING SHOULD BE PERFORMED BY PERSONS EXPERIENCED IN THIS
TYPE OF GAS SERVICE. T O A VOID RISK OF FIRE OR EXPLOSION, PURGE
DISCHARGE MUST NOT ENTER CONFINED AREAS OR SP ACES WHERE
IGNITION CAN OCCUR. THE AREA MUST BE WELL VENTILATED AND ALL
SOURCES OF IGNITION MUST BE INACTIV ATED OR REMOVED.

GAS METER SIZE - CITY GASES ONL Y

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.

GAS PRESSURE REGULATION

RELIEF V ALVE

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.

FOR SAFE OPERATION OF THE WA TER HEA TER, THE RELIEF V AL VE(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-CSA 4.4.

Your local code authority may have other specific relief valve requirements.

WARNING

THE PURPOSE OF A RELIEF V ALVE IS TO A VOID EXCESSIVE PRESSURE
OR TEMPERATURE INTO THE STEAM RANGE, WHICH MAY CAUSE
SCALDING A T FIXTURES, T ANK EXPLOSION, SYSTEM OR HEATER DAMAGE.
NO VALVE IS TO BE PLACED BETWEEN THE RELIEF VALVE AND THE
TANK.

A DRAIN LINE MUST BE CONNECTED TO THE RELIEF V AL VE TO DIRECT
DISCHARGE TO A SAFE LOCATION TO AVOID SCALDING OR WATER
DAMAGE. THIS LINE MUST NOT BE REDUCED FROM THE SIZE OF THE
VAL VE OUTLET AND MUST NOT CONT AIN V ALVES OR RESTRICTIONS,
NOR SHOULD IT BE LOCA TED IN FREEZING AREAS. DO NOT THREAD OR
CAP THE END OF THIS LINE. RESTRICTED OR BLOCKED DISCHARGE WILL
DEFEAT THE PURPOSE OF THE V AL VE AND IS UNSAFE. THE DISCHARGE
LINE SHALL BE INST ALLED T O ALLOW COMPLETE DRAINAGE OF BOTH
THE VA LVE AND LINE.

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

FAILURE TO INST ALL A PRESSURE REGULA TOR WITHIN 10 FEET OF THE
WA TER HEA TER CAN RESUL T IN LEAKAGE OF FLUE GASES INT O THE
SURROUNDING ROOM. SERIOUS PERSONAL INJURY OR DEATH COULD
RESULT FROM INHALA TION OF CARBON MONOXIDE GAS.

GAS VAL VES

WARNING

SHOULD OVERHEA TING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF ,
TURN OFF THE MANUAL GAS CONTROL V AL VE 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 (Not Supplied)

WA TER LINE 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.

CLOSED SYSTEM

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) HEA TING AND SP ACE HEA TING

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.

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.

15

3. This unit may never be connected to any existing heating system or
component(s) previously used with non-potable water heating
appliance.

CONDITIONER MUST BE INSTALLED IF THE ABOVE CONDITIONS EXIST .
MALFUNCTIONS CAUSED BY A POOR ELECTRICAL SUPPL Y ARE NOT
COVERED UNDER YOUR WARRANTY.

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.

HEA TER 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 . IN THIS CASE USE
200°C WIRE.

THE COMPUTER CONTROL REQUIRES A SOURCE OF ST ABLE CLEAN
ELECTRICITY FOR PROPER OPERATION. INST ALLING THE HEATER ON
A BRANCH CIRCUIT THA T HAS ELECTRONIC NOISE, IS SUBJECT TO
FLUCTUA TIONS IN VOL TAGE LEVEL OR HAS AN APPLIANCE WHICH
GENERATES EMF OF RFI INTERFERENCE CAN CAUSE THE
CONTROLLER TO MALFUNCTION. A HIGH QUALITY POWER

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, CSA C22.1 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/NFPA 70 or the Canadian
Electrical Code, CSA C22.1.

DO NOT ENERGIZE THE BRANCH CIRCUIT BEFORE THE HEA TER T ANK
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.

FIGURE 15.

16

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.

17

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:

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:

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:

18

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:

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 con­tinue and the heater will attempt to regulate the water in the tank to the
Operating Set Point.

Example of a Warning:

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:

• 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 the Advanced button, det ailed 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.

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 accu­rately describes the condition and diagnostics information that can be used
to correct the issue.

6. Access to the Current Fault or Warning

When a fault or warning has been detected by the control, it will automati­cally 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.

19

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:

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:

ACTION:
Press the DOWN button for more information.

DISPLAY:

PRIOR TO START UP

REQUIRED ABILITY

INSTALLA TION OR SERVICE OF THIS W A TER HEATER REQUIRES ABILITY
EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD
INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPLY AND
ELECTRICAL WORK ARE REQUIRED.

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.

8. Viewing Information About the Heater

The electronic control for this water heater monitors many different as­pects 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.

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.

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.

• 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.

20

OPERATING INSTRUCTIONS

IT IS RECOMMENDED THA T A QUALIFIED SERVICE TECHNICIAN PERFORM
THE INITIAL FIRING OF THE HEA TER. AT THIS TIME THE USER SHOULD ASK
THE TECHNICIAN ANY QUESTIONS IN REGARD TO THE OPERA TION AND
MAINTENANCE OF THE UNIT .

BEFORE PROCEEDING WITH THE OPERA TION OF THE UNIT , MAKE SURE
HEATER AND SYSTEM ARE FILLED WITH W ATER AND ALL AIR IS EXPELLED
FROM HEATER AND PIPING .

NEVER OPERATE THE HEA TER WITHOUT FIRST BEING CERTAIN IT IS FILLED
WITH WA TER AND A TEMPERA TURE AND A PRESSURE RELIEF V AL VE IS
INSTALLED IN THE RELIEF V ALVE OPENING OF THE HEATER. DO NOT
ATTEMPT TO OPERA TE HEATER WITH COLD W ATER INLET V AL VE CLOSED.

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 V ALVE MUST HAVE BEEN CLOSED
FOR A T LEAST FIVE (5) MINUTES. THIS WAITING PERIOD IS AN IMPORT ANT
SAFETY STEP. ITS PURPOSE IS TO PERMIT GAS THAT MIGHT HAVE
ACCUMULATED IN THE COMBUSTION CHAMBER TO CLEAR. IF YOU DETECT
GAS A T THE END OF THIS PERIOD, DO NOT PROCEED WITH LIGHTING .
RECOGNIZE THA T GAS ODOR, EVEN IF IT SEEMS WEAK, MA Y INDICA TE
THE PRESENCE OF ACCUMULA TED GAS SOMEPLACE IN THE AREA WITH
A RISK OF FIRE OR EXPLOSION. SEE THE FRONT PAGE FOR STEPS TO BE
TAKEN.

DO NOT USE THIS HEATER IF ANY PART HAS BEEN UNDER WATER.
IMMEDIA TELY CALL A QUALIFIED SERVICE TECHNICIAN TO INSPECT THE
HEATER AND TO REPLACE ANY PART OF THE CONTROL SYSTEM AND
ANY GAS CONTROL WHICH HAS BEEN UNDER W ATER.

LIGHT THE UNIT IN ACCORDANCE WITH THE OPERATING INSTRUCTIONS
LABEL A TT ACHED TO THE HEA TER.

THESE INSTRUCTIONS ARE REPEA TED IN THE LIGHTING AND OPERATING
LABEL ILLUSTRA TION ON P AGE 20 IN THIS MANUAL.

IMPORTANT

CAUTION

ADJUSTMENT PROCEDURE

INITIAL ST ART -UP - 120 AND 150 MODELS

Main line gas pressure to the water heater for natural gas should be
between a maximum of 10.5" (2.59Kpa for natural gas) 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 the unit.

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)

for natural gas and 10.0" W.C. (2.5 Kpa) for L.P. Gas.

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 6500 feet
(1982 meters) refer to HIGH ALTITUDE 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-150 heater)
T = 25.25 seconds

H = 1050 Btu/ft.
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) natural gas models and

10.0" W.C. (2.5Kpa) on the propane models.
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.

3

3600

X 1050 = 150,000 Btuh (44 Kw)

25.25

ADJUSTMENT PROCEDURE

INITIAL ST ART -UP - 199 AND 250 MODELS

Main line gas pressure to the water heater for natural gas should be
between a maximum of 10.5" (2.59Kpa for natural gas) W.C. (14.0"/3.45Kpa
for propane) and a minimum as shown in Table 4: that is, for Natural Gas 4"
(.98Kpa) W.C. and 9.0" (1.97Kpa) for Propane Gas. The inlet gas pressure
must not exceed the maximum value. A service regulator must be installed
within 10' (305 cm) of the unit.

The BTH 199 and 250 models incorporate a new gas control, which operates
at 0"W.C. (0kPa) for both natural and propane gas. These models are
configured prior to being shipped from the factory and no adjustments are
necessary prior to startup. The controller monitors the air-flow and makes
adjustments to the fan speed which in effect controls the amount of gas
flow. Therefore, the unit will self-adjust to acquire the correct amount of
input.

Once the unit is installed and filled with water and the inlet pressures
confirmed, simply turn the switch "on" and observe operation. Cycle the

unit "off" and "on" several times to ensure proper operation.

21

UNDER NO CIRCUMST ANCES SHOULD THE INPUT EXCEED THE RA TE
SHOWN ON THE HEA TER RATING PLA TE. OVER FIRING COULD RESUL T IN
DAMAGE OR SOOTING OF THE HEA TER.

WARNING

CA THODIC PROTECTION

CAUTION

HYDROGEN GAS CAN BE PRODUCED IN A HOT W ATER SYSTEM SERVED
BY THIS HEA TER THA T HAS NOT BEEN USED FOR A LONG PERIOD OF
TIME (GENERALLY TWO WEEKS OR MORE). HYDROGEN GAS IS
EXTREMELY FLAMMABLE. 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

HIGH AL TITUDE INSTALLA TIONS

WARNING

THE 199 AND 250 HEATERS ARE CERTIFIED FOR USE WITHOUT
MODIFICATION FOR AL TITUDES UP TO 10,100 FT. (3078 METERS). THE 120
AND 150 HEATERS ARE CERTIFIED FOR USE WITHOUT MODIFICATION FOR
ALTITUDES UP TO 7,700 FT . (2347 METERS). INSTALLA TIONS ABOVE THESE
ALTITUDES MA Y REQUIRE REPLACEMENT OF THE BURNER ORIFICE. CALL
THE TECHNICAL CENTER A T [phone] FOR REQUIREMENTS.

Some gas utility companies derate their gas for altitude, making it
unnecessary to install high altitude orifices. Call the local gas or utility
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.

IF THE UNIT IS EXPOSED TO THE FOLLOWING , DO NOT OPERA TE HEA TER
UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE BY A QUALIFIED
SERVICEMAN.

1. FLOODING TO OR ABOVE THE LEVEL OF THE BURNER OR CONTROLS

2. EXTERNAL FIRING

3. DAMAGE

4. FIRING WITHOUT WATER

5. SOOTING

NEVER OPERATE THE HEA TER WITHOUT FIRST BEING CERT AIN IT IS FILLED
WITH WATER AND A TEMPERATURE AND PRESSURE RELIEF V AL VE IS
INSTALLED IN THE RELIEF VAL VE OPENING OF THE HEA TER.

SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY F AIL TO SHUT OFF ,
TURN OFF THE MANUAL GAS CONTROL V AL VE TO THE APPLIANCE.

GENERAL INFORMATION

POWER BURNER

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

MAINTENANCE

GENERAL

KEEP APPLIANCE AREA CLEAR AND FREE FROM COMBUSTIBLE
MATERIALS, GASOLINE AND OTHER FLAMMABLE V APORS AND LIQUIDS.
(SEE WARNING ON P AGE 5, LOCA TING THE HEA TER).

Water heater maintenance includes periodic tank flushing and cleaning,
and removal of lime scale. The unit should be inspected and adjusted to
maintain proper combustion. Refer to the following table. A periodic inspection
of the venting system should be made. Where used, the water circulating
pump should be oiled.

MAINTENANCE SCHEDULE

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

T ank Lime Scale Semi UN-LIME

Removal Annually Delimer

®

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).

TABLE 4

Relief Valve Inspect Semi

Annually

Clean Inlet

Blower Screen and As Required Soft Brush

Blower Wheel

Vent System Inspect Every 3 Joints should

Months be sealed

22

FOR YOUR SAFETY READ BEFORE OPERA TING

WARNING:

explosion may result causing property damage, personal injury or loss of life.

If you do not follow these instructions exactly, a fire or

BTH 120 MODELS ONL Y.

23

FOR YOUR SAFETY READ BEFORE OPERA TING

WARNING:

may result causing property damage, personal injury or loss of life.

If you do not follow these instructions exactly , a fire or explosion

OPERA TING INSTRUCTIONS

TURN OFF GAS TO APPLIANCE

BTH 150 MODELS ONL Y.

24

FOR YOUR SAFETY READ BEFORE OPERA TING

WARNING:

explosion may result causing property damage, personal injury or loss of life.

If you do not follow these instructions exactly, a fire or

OPERA TING INSTRUCTIONS

OPERA TING INSTRUCTIONS

TURN OFF GAS TO APPLIANCE

TURN OFF GAS TO APPLIANCE

BTH 199/250 MODELS ONL Y.

25

FLUSHING

1. Turn off the heater electrical disconnect switch.

2. Open the drain valve and allow water to flow until it runs clean.

3. Close the drain valve when finished flushing.

4. Turn on the heater electrical disconnect switch.

DRAINING

The heater must be drained if it is to be shut down and exposed to
freezing temperatures. Maintenance and service procedures may also
require draining the heater.

1. Turn off the heater electrical disconnect switch.

2. Close the cold water inlet valve to heater.

3. Open a nearby hot water faucet to vent the system.

4. Open the heater drain valve.

FIGURE 16.

To dissolve and remove the more stubborn mineral deposits, A.O. Smith
UN•LIME® Professional Delimer should be used.

5. If the heater is being drained for an extended shutdown, it is suggested
the drain valve be left open during this period.

• Follow FILLING instructions when restoring hot water service.

SEDIMENT REMOV AL

Waterborne impurities consist of the particles of soil and sand which
settle out and form a layer of sediment on the bottom of the tank.

For convenience, sediment removal and lime scale removal should be
performed at the same time.

LIME SCALE REMOV AL

The amount of calcium carbonate (lime) released from water is in direct
proportion to water temperature and usage. The higher the water
temperature or water usage, the more lime deposits are dropped out of
the water. This is the lime scale which forms in pipes, heaters and on
cooking utensils.

Lime accumulation not only reduces the life of the equipment but also
reduces efficiency of the heater and increases fuel consumption.

The usage of water softening equipment greatly reduces the hardness
of the water. However, this equipment does not always remove all of the
hardness (lime). For this reason it is recommended that a regular schedule
for deliming be maintained.

The depth of lime buildup should be measured periodically. Heaters will
have about 3" (7.6cm) of lime buildup when the level of lime has reached
the bottom of the cleanout opening or about 1" (2.5cm) of lime buildup if it
has reached the drain valve opening. A schedule for deliming should be
set up, based on the amount of time it would take for a 1" (2.5cm) buildup
of lime.

A.O. Smith UN•LIME® Professional Delimer is an easy to handle patented
food grade acid formulated specifically for lime scale removal from all
types of water using equipment. Available in 1 gallon (3.8L)
(part no. 4763) and 5 gallon (19L) (part no. 4813) sizes. Hydrochloric
base acids are not recommended for use on glass-lined tanks.

A.O. Smith Form No. 4800, entitled “Why, When and How”, describes tank
cleaning methods and materials. UN•LIME and the booklet may be obtained
through your A.O. Smith dealer or distributor.

The cleanout opening is shown in Figure 16. To clean heater through
cleanout opening, proceed as follow:

1. Turn off water inlet valve, the heater electrical disconnect switch and
open drain valve.

2. Remove outer cover plate from lower side of heater jacket.

3. Remove cover from cleanout opening.

4. Remove lime, scale or sediment using care not to damage the
glass-lining.

5. Inspect cleanout plate gasket: If new gasket is required, replace with
A. O. Smith part no. 99038.

6. Install cleanout plate. Be sure to draw plate up tight by tightening
screws securely.

7. Close drain valve, open water inlet line and turn on the power burner
electrical disconnect switch.

Example 1:

Initial inspection shows 1/2" (1.3cm) of lime accumulation. Therefore,
the heater can be delimed once a year.

Example 2 :

Initial inspection shows 2" (5cm) of lime accumulation. Therefore, the
heater should be delimed every 3 months.

Sediment and lime scale removal may be accomplished through the
cleanout opening furnished on the heater, see Figure 25. The heater must
be drained, see DRAINING, before removing cleanout cover on tank.

8. Check for water leakage.

9. Replace outer jacket cover plate.

POWERED ANODE SYSTEM

The BTH 120-250 are factory equipped with a powered anode system.
The anodes are of a permanent design and do not need replacing unless
damaged.

26

DRAIN V AL VE AND ACCESS P ANELS

The heaters are equipped with a 3/4" drain valve.

build until the relief valve actuation pressure is equaled. Then, the relief
valve will open, allowing some water to escape, slightly lowering the
pressure.

An access panel covers the cleanout opening in the tank which is sealed
by a gasket and cover, figure 25.

RELIEF VAL VE

At least twice a year, the temperature and pressure relief valve should be
checked to ensure that it is in operating condition. To check the relief valve,
lift the lever at the end of the valve several times. The valve should seat
properly and operate freely.

If water does not flow, remove and inspect for obstructions or corrosion.
Replace with a new valve of the recommended size as necessary.
Inspection of the valve should be performed at least every three years. Do
not attempt to repair the valve, as this could result in improper operation
and a tank explosion. In areas with poor water conditions, it may be
necessary to inspect the T&P valve more often than every three years.

CAUTION

BEFORE MANUALLY OPERA TING THE VAL VE, MAKE SURE THA T A DRAIN
LINE HAS BEEN ATT ACHED TO THE V ALVE TO DIRECT THE DISCHARGE TO
AN OPEN DRAIN. FAILURE TO T AKE THIS PRECAUTION COULD MEAN
CONTACT WITH EXTREMELY HOT WATER PASSING OUT THE VALVE
DURING THIS CHECKING OPERA TION.

If the temperature and pressure relief valve on the heater discharges
periodically or continuously, it may be due to thermal expansion of water in
a closed water supply system, or, it may be due to a faulty relief valve.

Thermal expansion is the normal response of water when it is heated. In
a closed system, thermal expansion will cause the system pressure to

Contact your water supplier or local plumbing inspector on how to control
this situation.

Two common corrections are listed in the Checklist and Service Information
which appears later in this manual.

ABOVE ALL, DO NOT PLUG THE TEMPERA TURE AND PRESSURE RELIEF
VALVE. THIS IS NOT A SOLUTION AND CAN CREATE A HAZARDOUS
SITUATION.

CIRCULA TING PUMP

The water heating system may include a circulating pump. Where used, it
should be lubricated as directed by the circulator manufacturer.

VENT SYSTEM

Examine the vent system every 3 months. Points of inspection are as
follows:

1. Check for obstructions and/or deterioration of vent piping and vent
hood. Replace immediately where needed.

2. Vent pipe and vent hood screen should be cleaned of foreign material
and soot. The screen is located inside the vent hood outlet and is
accessible from the outside of the hood. Do not reach inside the vent
hood when the heater is in operation.

3. Check all vent system connections for leakage and reseal as required
using Hi Temp Silicone sealer or equivalent.

27

ONE TEMPERA TURE - ONE HEA TER VERTICAL STORAGE T ANK FORCED CIRCULA TION

CAUTION: IF THE PLUMBING

REQUIRES THE USE OF PIPES
WITH DISSIMILAR MA TERIAL (FOR
EXAMPLE, STEEL AND COPPER),
USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALVANIC
ACTION BETWEEN THE PIPING
COMPONENTS WITH DISSIMILAR
MATERIALS.

INST ALLA TION DIAGRAMS

WITH OR WITHOUT BUILDING RECIRCULA TION

CAUTION: IF BUILDING COLD

WATER SUPPLY HAS A BACK­FLOW PREVENTER, CHECK
VAL VE OR WA TER METER WITH
CHECK VALVE PROVISIONS
FOR THERMAL EXPANSION OF
WATER IN THE HOT WATER
SYSTEM MUST BE PROVIDED

NOTE: CONNECT RETURN
LINE FROM HOT WATER
CIRCULA TING LOOP (IF USED)
TO COLD WATER INLET LINE.

* PIPE TO OPEN DRAIN

INSTALL IN ACCORDANCE WITH
LOCAL CODES

ONE TEMPERA TURE - ONE HEA TER HORIZONT AL STORAGE T ANK

FORCED CIRCULATION WITH OR WITHOUT BUILDING RECIRCULA TION

DANGER

TEMPERATURE SETTING SHOULD NOT EXCEED
SAFE TEMPERATURE AT FIXTURES. SEE WATER
TEMPERATURE CONTROL WARNING ON PAGE 4.
IF HIGHER PREHEAT TEMPERATURES ARE
NECESSARY TO OBTAIN ADEQUATE BOOSTER
OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WA TER SUPPLIED T O FIXTURES.

*PIPE TO OPEN DRAIN

INSTALL IN ACCORDANCE
WITH LOCAL CODES

CAUTION: IF THE PLUMBING
REQUIRES THE USE OF PIPES
WITH DISSIMILAR MATERIAL (FOR
EXAMPLE, STEEL AND COPPER),
USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALV ANIC
ACTION BETWEEN THE PIPING
COMPONENTS WITH DISSIMILAR
MATERIALS.

28

TWO TEMPERA TURE - ONE HEATER HIGH TEMPERA TURE

WITH OR WITHOUT BUILDING RECIRCULA TION

DANGER

TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
TEMPERATURE AT FIXTURES. SEE WATER
TEMPERATURE CONTROL WARNING ON PAGE 4. IF
HIGHER PREHEAT TEMPERATURES ARE NECESSARY
TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN
ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO
FIXTURES.

CAUTION: IF BUILDING COLD WATER SUPPLY HAS A
BACK-FLOW PREVENTER, CHECK VALVE OR WATER
METER WITH CHECK VAL VE PROVISIONS FOR THERMAL
EXPANSION OF WATER IN THE HOT WATER SYSTEM
MUST BE PROVIDED.

PIPE RELIEF VALVE TO OPEN DRAIN.

*

NOTE: IF TEMPERED WATER IS
RECIRCULA TED, RETURN LINE SHOULD BE
CONNECTED AT POINT “A”.

INSTALL IN ACCORDANCE WITH LOCAL
CODES.

CAUTION: IF THE PLUMBING
REQUIRES THE USE OF PIPES
WITH DISSIMILAR MATERIAL (FOR
EXAMPLE, STEEL AND COPPER),
USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALV ANIC
ACTION BETWEEN THE PIPING
COMPONENTS WITH DISSIMILAR
MATERIALS.

29

CAUTION: IF THE PLUMBING
REQUIRES THE USE OF PIPES
WITH DISSIMILAR MATERIAL (FOR
EXAMPLE, STEEL AND COPPER),
USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALV ANIC
ACTION BETWEEN THE PIPING
COMPONENTS WITH DISSIMILAR
MATERIALS.

TWO TEMPERATURE - TWO HEA TERS HIGH TEMPERA TURE

WITH OR WITHOUT BUILDING RECIRCULA TION

TWO TEMPERA TURE - THREE HEATERS (TWO PRE-HEATERS/ONE BOOSTER HEATER)

WITH OR WITHOUT BUILDING RECIRCULA TION

CAUTION: IF THE PLUMBING

REQUIRES THE USE OF PIPES
WITH DISSIMILAR MATERIAL (FOR
EXAMPLE, STEEL AND COPPER),
USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALVANIC
ACTION BETWEEN THE PIPING

MUST BE IDENTICAL HEA TERS

COMPONENTS WITH DISSIMILAR
MATERIALS.

FOR MULTIPLE HEATER INSTALLATION SEE MANIFOLD KIT
SPECIFICATIONS, P AGE 33.

CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACK-FLOW
PREVENTER, CHECK VALVE OR WATER METER WITH CHECK VALVE
PROVISIONS FOR THERMAL EXP ANSION OF W A TER IN THE HOT WA TER
SYSTEM MUST BE PROVIDED.

DANGER

TEMPERA TURE SETTING SHOULD NOT EXCEED SAFE TEMPERA TURE A T
FIXTURES. SEE WA TER TEMPERA TURE CONTROL W ARNING ON PAGE 4. IF
HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBT AIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER
SUPPLIED TO FIXTURES.

30

TWO TEMPERA TURE - TWO HEATERS (ONE PRE-HEA TER/ONE BOOSTER HEA TER)

WITH OR WITHOUT BUILDING RECIRCULA TION

DANGER

TEMPERA TURE SETTING SHOULD NOT EXCEED SAFE TEMPERA TURE A T
FIXTURES. SEE WA TER TEMPERA TURE CONTROL W ARNING ON P AGE 4.
IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN
ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WA TER SUPPLIED TO FIXTURES.

* PIPE RELIEF VAL VE TO OPEN DRAIN
** 140°F (60°C) TO 150°F (66°C) SHOULD BE MAXIMUM WATER

TEMPERATURE MAINT AINED IN THE PRE-HEA TERS.
120°F (49°C) SHOULD BE THE MINIMUM TEMPERA TURE OF WA TER

IN THE PRE- HEA TERS.
CONNECT CIRCULA TING LINE FROM FIXTURES, IF USED, TO COLD

WA TER SUPPLY LINE OF PRE-HEA TER.
CONNECT CIRCULA TING LINE OF 180°F (82°C) OR BOOSTED WA TER,

IF USED, TO INLET W ATER LINE TO BOOSTER.
INSTALL IN ACCORDANCE WITH LOCAL CODES.

CAUTION: IF THE PLUMBING REQUIRES
THE USE OF PIPES WITH DISSIMILAR
MATERIAL (FOR EXAMPLE, STEEL AND
COPPER), USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALV ANIC ACTION
BETWEEN THE PIPING COMPONENTS WITH
DISSIMILAR MATERIALS.

31

TWO TEMPERA TURE - ONE HEATER HIGH TEMPERA TURE

WITH RECIRCULATION OF SANITIZING LOOP

CAUTION: IF THE PLUMBING REQUIRES

THE USE OF PIPES WITH DISSIMILAR
MATERIAL (FOR EXAMPLE, STEEL AND
COPPER), USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALV ANIC ACTION
BETWEEN THE PIPING COMPONENTS WITH
DISSIMILAR MATERIALS.

DANGER

TEMPERA TURE SETTING SHOULD NOT EXCEED SAFE TEMPERA TURE AT
FIXTURES. SEE WA TER TEMPERA TURE CONTROL WARNING ON P AGE 5.
IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN
ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WA TER SUPPLIED TO FIXTURES.

CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACK-FLOW
PREVENTER, CHECK VALVE OR WATER METER WITH CHECK VALVE
PROVISIONS FOR THERMAL EXP ANSION OF WA TER IN THE HOT WATER
SYSTEM MUST BE PROVIDED.

*PIPE RELIEF VAL VE TO OPEN DRAIN

INSTALL IN ACCORDANCE WITH LOCAL CODES

NOTE 1: TOGGLE SWITCH CONTROLS 180°F (82°C) WA TER CIRCULATION.
INST ALL ON OR CLOSE TO DISHW ASHER. TOGGLE SWITCH MUST BE
CLOSED (ON) DURING THE RINSE OPERA TION AND OPEN (OFF) WHEN
DISHWASHER IS NOT OPERA TING OR WHEN ON LONG ST ANDBY .

NOTE 2: INSTALL LINE TEMPERATURE CONTROL IN AN UNINSULA TED
TEE BEYOND THE DISHWASHER TAKEOFF IN THE SANITIZING LOOP.
CONTROL SHOULD BE SET A T 185°F (85°C).

NOTE 3: ADJUST PLUG COCK SO THE SANITIZING LOOP FLOW RATE
DOES NOT CAUSE UNNECESSARY TURBULENCE IN THE T ANK.

NOTE 4: IF TEMPERED WA TER IS RECIRCULATED, RETURN LINE SHOULD
BE CONNECTED A T POINT A.

32

MANIFOLD KITS

Precision cut type “L” all copper A.O. Smith manifold kits assure water flow balance of all units. Without this balance, the full water
heating and storage potential of the system cannot be achieved. Plus, the units with the higher water flow may have a shortened life.

Dimensions shown are for minimum space occupied by the water heaters assemblies.
Space for the venting system and unit servicing must be added.

CAUTION: IF THE PLUMBING REQUIRES
THE USE OF PIPES WITH DISSIMILAR
MATERIAL (FOR EXAMPLE, STEEL AND
COPPER), USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALV ANIC ACTION
BETWEEN THE PIPING COMPONENTS WITH
DISSIMILAR MATERIALS.

33

CHECKLIST AND SERVICE INFORMATION

IMPORTANT

The installer may be able to observe and correct certain problems which
might arise when the unit is put into operation or when it is re-fired after a
prolonged shutdown. HOWEVER, it is recommended that only qualified
servicemen, using appropriate test equipment, be allowed to service the
heater.

BE SURE TO TURN OFF THE ELECTRICITY WHENEVER POSSIBLE OR
APPROPRIATE WHILE CHECKING EQUIPMENT .

2. Some of the electrical components of the water heater make sounds
which are normal.

• Contacts click or snap as the heater starts and stops.

• Transformers often hum.

WA TER LEAKAGE IS SUSPECTED

1. Check to see if the water heater drain valve is tightly closed. Also
check the cleanout opening for leakage.

2. The apparent leakage may be condensation which forms on cool
surfaces of the heater and piping.

FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN SERIOUS

W ARNING

PERSONAL INJURY OR DEATH.
CAUTION: LABEL A LL WIRES PRIOR TO DISCONNECTION WHEN SERVICING

CONTROLS. WIRING ERRORS CAN CAUSE IMPROPER AND DANGEROUS
OPERATION.

VERIFY PROPER OPERA TION AFTER SERVICING .

BURNER OPERA TIONAL PROBLEMS

1. Refer to TROUBLESHOOTING.

NOT ENOUGH OR NO HOT WATER

1. Be certain the electrical disconnect switch serving the water heater
is in the ON position.

2. Check the fuses.

• The electrical disconnect switch usually contains fuses.

3. The capacity of the heater may have been exceeded by a large
demand for hot water.

• Large demands require a recovery period to restore water

temperature.

4. Colder incoming water temperature will lengthen the time required to
heat water to the desired temperature.

• If the heater was installed when incoming water temperature was

warm, colder water creates the effect of less hot water.

5. Look for hot water wastage and leaking or open hot water faucets.

6. Sediment or lime scale may be affecting water heater operation. Refer
to MAINTENANCE for details.

7. Burner may not be firing at proper rate.

• Check gas pressure. Adjust to obtain required manifold pressure.

8. Burner fan wheel may be dirty.

• Clean fan wheel with a stiff brush.

9. Condensate hose may be blocked where it connects to the exhaust
elbow.

• Verify the condensate drains from the unit without restriction.

3. If the outlet of the relief valve is leaking it may represent:

• Excessive water pressure.

• Excessive water temperature.

• Faulty relief valve.

Excessive water pressure is the most common cause of relief valve
leakage. It is often caused by a “closed system”. If a check valve is in the
inlet system it will not permit the expanded hot water volume to equalize
pressure with the main. The relief valve must release this water or the
water heater or plumbing system will be damaged. Refer to MAINTENANCE­RELIEF VALVE section in this manual.

When such a condition is encountered, local codes or inspection agency
should be consulted to determine which system is acceptable in your area.
See CLOSED SYSTEM section in this manual also.

TROUBLE-SHOOTING

1. Verify that the allowable vent length has not been exceeded and that
the blower inlet screen has been removed if direct venting.

2. Verify that the condensation, which WILL be present in the heater and
exhaust vent, will drain.

3. Check supply wire polarity - hot to hot and neutral to neutral and no
"stray" current in neutral.

4. Heater is properly grounded.

Checking these four (4) items first will often result in a timely solution to the
service call.

WARNING

JUMPING OUT COMPONENTS AND/OR CIRCUITS DURING
TROUBLESHOOTING CAN CAUSE SERIOUS PROBLEMS WITH THE UNIT’S
OPERATING SEQUENCE AND IGNITION SAFETY . IF YOU DO NOT HA VE THE
PROPER TEST EQUIPMENT , I.E. A VOLT-OHM METER AND A MICROAMMETER,
DO NOT A TTEMPT T O TROUBLESHOOT OR REP AIR A.O. SMITH EQUIPMENT.

ALTERING THE CONTROLLER AND/OR CONTROLLER WIRING IN ANY WA Y
COULD RESULT IN INTERNAL DAMAGE TO THE MODULE CIRCUITS,
POSSIBLY AL TERING THE IGNITION SEQUENCE ALLOWING GAS V ALVES
TO OPEN BEFORE THE HOT SURFACE IGNITER IS UP TO IGNITION
TEMPERATURE.

NOTE: ANY BYPASS OR ALTERATION OF THE UNITS SAFETIES WILL
RESULT IN VOIDING THE APPLIANCE WARRANTY.

Before performing any troubleshooting familiarize yourself with the particular
appliance.

WATER IS TOO HOT

1. Refer to WATER TEMPERA TURE CONTROL.

WA TER HEA TER MAKES SOUNDS

1. Sediment or lime scale accumulations cause rumbling and pounding
noises when the heater is operating.

• The sounds are normal, however, the tank bottom should be
cleaned. Refer to MAINTENANCE for details.

Refer to the SEQUENCE OF OPERATION and the connection diagram located
on page 15 before continuing.

Make sure the appliance is connected to a 120V AC power supply, manual
gas valve is in the ON position, and all electrical connections are secure
before continuing to troubleshoot this appliance.

CAUTION

THE WATER HEATER IS POLARITY SENSITIVE. BEFORE APPLYING
ELECTRICITY TO THIS HEA TER BE CERT AIN THA T SUPPL Y HEA TED WIRE
TO GROUND CHECK INDICATES ZERO VOL T AGE.

34

MOTOR WILL NOT RUN

1. Confirm 120V AC to the controller. Also, to verify correct polarity, check
for 120 V AC between hot supply and ground.

If there is no voltage, check for a loose connection where it connects to
the controller.

2. If there is 120 volts to the controller, check for loose connections or a
locked rotor. If the rotor cannot be freed the motor and blower assembly
must be replaced.

MOTOR RUNS, PREPURGE TIME ELAPSES BUT MAIN

FLAME NOT ESTABLISHED.

1. Check to see if main manual gas valve is open.

2. Check for a loose connection at the transformer, or a defective
transformer.

3. Check for a loose connection at the gas valve.

4. Check for open pressure switches or open reset button. Check for
blockage in the intake and exhaust venting or at the vent hoods. If no
blockage is found, check vinyl tubing for cuts or crimps. If this tubing is
damaged it must be replaced. If these steps do not eliminate the problem,
replace the pressure switches.

MOTOR RUNS, BURNER LIGHTS MOMENT ARIL Y ,

THEN LOCKS OUT

1. Reset the appliance two more times to ensure that all of the air has been
purged from the gas line.

2. If the burner lights momentarily but does not sustain ignition, verify that
the inlet pressure is not greater than 10.5""WC (2.59 kPa) for natural
gas and 14.0"WC (3.45 kPa) for propane gas or lower than the minimal
supply pressure which is 4.0"WC (.09kPa) for natural gas and 11.0"WC
(2.74 kPa) for propane gas. Also, verify that the manifold pressure is
correct, that is, 4.0"WC (.98kPa) for natural gas and 10.0"WC (2.46kPa)
for propane gas for the 120 and 150 models and 0"WC (0kPa) for both
natural and propane gas 199 and 250 models. If the manifold pressure
is not correct then adjust accordingly. See "ADJUSTMENT PROCEDURE"
in "OPERATING INSTRUCTIONS" sections for manifold pressure
adjustment procedure.

3. Check for the reversed polarity in the supply wiring. This controller is
polarity sensitive. If the hot and neutral supply wires are reversed, the
controller will not sense flame. Reverse the supply wires and try to fire
the unit.

NOTE: Always turn off and disconnect main supply wiring before servicing
the unit.

4. Check connecting wire to the flame sensor. Verify that the flame sensor
has not been damaged in any way.

5. Check to see if there is resistance across the igniter terminal with an
OHM meter. If there is no continuity, the igniter is broken and should be
replaced.

If the igniter appears to function properly, then verify that the inlet
pressure is within the range shown in Table 4. The gas valve supplied
on the appliance is not designed to open against a higher inlet pressure
of 10.5"WC (2.59kPa) for natural gas and 14.0"WC (3.45kPa) for propane
gas. At this time, also check to make sure the inlet pressure is not lower
than 4.0"WC (.98kPa) for natural gas and 11.0"WC (2.74kPa) for propane
gas. If the inlet pressure is not within these limits then adjust the supply
pressure accordingly.

If the inlet pressure falls within the allowable limits, then verify that the
manifold pressure, when the gas is fully open, with the heater running,
is as called out in Table 4: that is, 4.0"WC (.98kPa) for natural gas and

10.0"WC (2.46kPa) for propane gas for the 120 and 150 models and
0"WC (0kPa) for both natural and propane gas 199 and 250 models. If
the manifold pressure is not correct then adjust accordingly. See
"ADJUSTMENT PROCEDURE" in "OPERA TING INSTRUCTIONS" sections
for manifold pressure adjustment procedure.

6. If the inlet and manifold pressures are within the limits specified in step
5, then reset the appliance. Verify 24V AC at the gas valve during the
three (3) second ignition trial, after the igniter reaches operating
temperature. If 24V AC at the gas valve is not seen during this period,
the controller must be replaced.

If there is 24V AC at the gas valve during the four second ignition trial
and the manifold pressure does not increase above 0" W.C. then verify
that the manual gas control valve is in the “ON” position (see page 20).
If the valve is in the “ON” position and the previous voltage and gas
pressure conditions are met, then the gas valve is defective and must
be replaced.

Note that a positive manifold pressure reading of approximately

1.5" (.38 kPa) W.C. is normal during the prepurge portion of the ignition
cycle due to the location of the gas orifice.

5. Verify that the air supply is adequate. The air inlet screen or blower
wheel may be restricted. Also, check the installation for proper ventilation.
See AIR REQUIREMENTS.

6. Check the venting system for the correct sizing, excess or insufficient.
See VENTING.

7. Check for maximum inlet pressure of 10.5"WC (2.59 kPa) for natural
gas and 14.0"WC (3.45 kPa) for propane gas and the manifold pressure
which is 4.0"WC (.98 kPa) for natural gas and 10.0"WC (2.46 kPa) for
propane gas for the 120 and 150 models and 0"WC (o kPa) for both
natural and propane gas 199 and 250 models. Please note that the
manifold pressure listed is the maximum value for the manifold pressure.
Do not set the manifold pressure higher than the value show in Table 4.
OVER FIRING the heater will result in a rough ignition and/or noisy
operation.

8. Confirm that the air inlet screen (see Figures 7 & 8) is free of obstructions.

Do not reach into the burner housing or combustion chamber if the heater
is still hot. Allow the heater to cool and always use gloves as the combustion
chamber and the burner sleeve and housing can become very hot after
operation. OVER FIRING is a dangerous condition that must be corrected
immediately.

CAUTION

GAS FAILS T O SHUT OFF

Check for defective gas valve or thermostat. If operation is incorrect,
replace.

REPLACEMENT P ARTS

Replacement parts may be ordered through A.O. Smith dealers, authorized
servicers or distributors. Refer to the Yellow Pages for where to call or
contact the A.O. Smith Water Products Company, 500 Tennessee Waltz
Parkway, Ashland City, TN 37015, 1-800-433-2515. When ordering parts
be sure to state the quantity, part number and description of the items
including the complete model and serial number as it appears on the product.
Refer to the parts list for more information.

35

Model BTH Limited Warranty

A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this water heater.

1. THE TANK
If the glass-lined tank in this water heater shall prove upon examination by the warrantor to have leaked due to natural corrosion from potable water
therein, during the first THREE years after initial installation, the warrantor will supply a replacement tank less burner and controls or a complete new
A.O. Smith water heater of equivalent size and current model at the warrantor's option. Some government agencies are requiring energy efficient
standards for water heaters. In the event regulations prohibit sale of a model of equivalent size and construction, A.O. Smith will provide a model
which complies with the regulations of your area, in which case the consumer will be charged the difference in price between the like replacement
and the energy efficient model required. The warranty on the replacement water heater will be limited to the unexpired term of the original warranty.

2. ALL OTHER P ARTS
If within ONE year after initial installation of this water heater, any part or portion shall prove upon examination by the warrantor to be defective in
material or workmanship, the warrantor will repair or replace such part or portion at its option.

3. CONDITIONS AND EXCEPTIONS
This warranty shall apply only when the water heater is installed in accordance with local plumbing and building codes, ordinances and regulations,
the printed instructions provided with it and good industry practices. In addition, a temperature and pressure relief valve, certified by AGA/CGA and
approved by the American Society of Mechanical Engineers, must have been installed.

a. This warranty shall apply only when the heater is used:

(1 ) used at temperatures not exceeding the maximum setting of its thermostat;
(2 ) used at water pressure not exceeding the working pressure shown on the heater;
(3) when operated free of the damaging effects of uncontrolled water hammer;
(4 ) filled with potable water, free to circulate at all times and with the tank free of damaging water sediment or scale deposits;
(5 ) used in a non-corrosive and non-contaminated atmosphere;
(6 ) used with factory approved anode(s) installed;
(7) in its original installation location;
(8 ) in the United States, its territories or possessions, and Canada;
(9 ) sized in accordance with proper sizing techniques for commercial and/or residential water heaters;
(10) bearing a rating plate which has not been altered, defaced or removed, except as required by the warrantor;
(11) operated with properly installed dirt leg;
(12) fired with the fuel for which it was factory built;
(13) fired at the factory rated input;
(14) operated with the inner and outer combustion chamber doors in place.

b. Any accident to the water heater, any misuse, abuse (including freezing) or alteration of it, any operation of it in a modified form, or any attempt

to repair tank leaks will void this warranty.

c. This warranty is void if a device acting as a backflow prevention device (check valves etc.) is installed in the cold water supply the heater is

connected to, unless an effective method of controlling thermal expansion is also installed at the heater(s) and operational at all times. The relief
valve installed on the heater is not an acceptable method.

4. SERVICE AND REPAIR EXPENSES
Under the limited warranty the warrantor will provide only a replacement water heater or part thereof. The owner is responsible for all other costs.
Such costs may include but are not limited to:
a. Labor charges for service removal, repair or reinstallation of the water heater or any component part;
b. Shipping, delivery, handling, and administrative charges for forwarding the new heater or replacement part from the nearest distributor and

returning the claimed defective heater or part to such distributor.

c. All cost necessary or incidental for any material and/or permits required for installation of the replacement.

5. LIMIT A TIONS ON IMPLIED W ARRANTIES
Implied warranties, including the warranty of merchantability imposed on the sale of this heater under state law are limited to one (1) year duration
for the heater or any of its parts. Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply
to you.

6. CLAIM PROCEDURE
Any claim under the warranty should be initiated with the dealer who sold the boiler, or with any other dealer handling the warrantor’s products. If
this is not practicable, the owner should contact:

a. The warrantor will only honor replacement with identical or similar water heater or parts thereof which are manufactured or distributed by the

warrantor.

b. Dealer replacements are made subject to in-warranty validation by warrantor.

7. DISCLAIMERS
NO OTHER EXPRESS WARRANTY HAS BEEN OR WILL BE MADE IN BEHALF OF THE WARRANTOR WITH RESPECT TO THE MERCHANT ABILITY OF
HEA TER OR THE INST ALLA TION, OPERATION, REP AIR OR REPLACEMENT OF THE BOILER. THE WARRANTOR SHALL NOT BE RESPONSIBLE FOR
WA TER DAMAGE, LOSS OF USE OF THE UNIT , INCONVENIENCE, LOSS OR DAMAGE TO PERSONAL PROPERTY OR OTHER CONSEQUENTIAL
DAMAGE. THE W ARRANTOR SHALL NOT BE LIABLE BY VIRTUE OF THIS W ARRANTY OR OTHER WISE FOR DAMAGE T O ANY PERSONS OR
PROPERTY , WHETHER DIRECT OR INDIRECT, AND WHETHER ARISING IN CONTRACT OR TOR T .
a. Some states do not allow the exclusion or limitation of the incidental or consequential damage, so the above limitations or exclusions may not

apply to you.

b. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

Fill in the following for your own reference. Keep it. Registration is not a condition of warranty. The model and serial number are found on the heater’s
rating plate.

Date Installed________________________Model No.__________________________________________Serial No.__________________________________________________
Dealer’s Name
Dealer’s Address__________________________________________________City and State___________________________________________Zip Code

__________________________________________________________________________Phone No.___________________________________________________

U.S. Customers Canadian Customers
A. O. Smith Corporation A. O. Smith Enterprises Ltd.
500 Tennessee Waltz Parkway P. O. Box, 310 - 768 Erie Street
Ashland City, TN 37015 Stratford, Ontario N5A 6T3
Telephone: [phone] Telephone: [phone]

_________________

FILL IN WARRANTY AND KEEP FOR FUTURE REFERENCE.

36

NOTES:

37

NOTES:

38

NOTES:

39

A.O. SMITH WATER PRODUCTS COMPANY

500 TENNESSEE WAL TZ PARKW AY

ASHLAND CITY, TN 37015

PHONE: [phone] FAX: [phone]

ww w.aosmithwaterheaters.com / email: [e-mail]

40