A.O. Smith 650A, 740A User Manual

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MODELS BTP(V)-540A,650A AND 740A

COMMERCIAL GAS, GLASS-LINED,TANK-TYPELOW NOx

WATER HEATER

• INSTALLATION • OPERATION • MAINTENANCE • LIMITED WARRANTY

CONSERVATIONIST®

CAUTION

TEXT PRINTED OR OUTLINED IN RED CONTAINS IN-

FORMATION RELATIVE TO YOUR SAFETY. PLEASE

READTHOROUGHLYBEFOREINSTALLINGANDUSING

THIS APPLIANCE.

A DIVISION OF A.O.SMITH CORPORATION

MCBEE, SOUTH CAROLINA

www.aosmithwaterheaters.com

PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND

NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.

PRINTED IN U.S.A. 1004

PART NO. 195033-000

1

ROUGH-INDIMENSIONS

STANDARD BAROMETRIC DRAFT CONTROL

HORIZONTAL & DIRECT VENTING

BTP MODELS

BTPV MODELS

MAXIMUM TOTAL 75 EQUIVALENT

FEET INTAKE AND EXHAUST

ALLOWED.

ALL DIMENSIONS IN INCHES (MILLIMETERS)

 

 

 

 

 

 

 

 

 

 

Gas

Approx.

Models

A

B

C

D

E

F

G

H

I

Conn.

Ship. Wt.

BTP(V)-540A

80 3/4

73

32 1/4

9

6

26 1/2

93

29 1/2

48 1/2

1*

950

2,051

1,854

819

229

152

673

2,362

749

1,232

25.4

431 kg

 

BTP(V)-650A

80 3/4

73

32 1/4

9

8

26 1/2

93

29 1/2

48 1/2

1*

950

2,051

1,854

819

229

203

673

2,362

749

1,232

25.4

431 kg

 

BTP(V)-740A

80 3/4

73

32 1/4

9

8

26 1/2

93

29 1/2

48 1/2

1*

950

2,051

1,854

819

229

203

673

2,362

749

1,232

25.4

431 kg

 

*Minimum gas supply pipe is 1 1/4”, reference Table 7 for gas supply pipe size.

 

Storage

Input Rating

Recovery Rating

Recovery Rating

Current Draw

 

Capacity

BTU/HR.

GPH

GPH

120V

Models

U.S. Gals. (Litres)

Nat.

100°F Rise

140°F Rise

60Hz 1 Phase

BTP(V)-540A

85

(261)

540,000

523.6

374

 

BTP(V)-650A

85

(261)

650,000

630

450

6.0 Amps

BTP(V)-740A

85

(261)

740,000

718

512

 

 

 

 

 

 

 

 

Based on 80% thermal efficiency obtained in A. O. Smith engineering laboratories.

NOTE: To compensate for the effects of high altitude areas above 2000 feet, recovery ratings should be reduced approximately 4% for every 1000 feet above sea level.

FOREWORD

The design of the BTP 540A through 740A models complies with ANSI Z21.10.3/CSA 4.3 as an automatic circulating tank and an automatic instantaneous type heater. The BTPV 540A through 740A models are designed for sidewall venting and direct venting applications and are certified under UL 795.

Detailed installation diagrams are found in this manual. These diagrams will serve to provide the installer with a reference for the materials and methods of piping necessary. It is highly essential that all water, gas piping and wiring be installed as shown on the diagrams.

Particular attention should be given to the installation of thermometers at the locations indicated on the diagrams, as these are necessary for checking the proper functioning of the heater.

THE HEATER IS DESIGNED TO OPERATE ONLY ON NATURAL GAS.

THESE HEATERS MUST NOT BE INSTALLED ON COMBUSTIBLE FLOORS.

2

In addition to these instructions, the equipment shall be installed in accordance with those installation regulations 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 conform with the instructions as outlined in the latest publication of National Fuel Gas Code (NFPA-54/ANSIZ223.1) and National Electric Code(NFPA-70).These manuals can be purchased from the Canadian Standards Association Laboratories, 8501 East Pleasant Valley Road, Cleveland, OH 44131, National Fire Protection Association, 1 Batterymarch Park, Quincy MA 02269.

TABLE OF CONTENTS

 

 

PAGE

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

2

FOREWORD .......................................................................................

2,3

TABLE OF CONTENTS ...........................................................................

3

GENERAL SAFETY INFORMATION .......................................................

3

Precautions ...................................................................................

3

Liquid Petroleum Models ................................................................

3

Chemical Vapor Corrosion ........................................................

3,4

Improper Combustion ....................................................................

4

EXTENDEDNON-USEPERIODS .............................................................

4

Cathodic Protection .......................................................................

4

Insulation Blankets .........................................................................

4

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

4

FEATURES .............................................................................................

4

Low Emmission Control .................................................................

4

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

4,5

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

5

INSTALLATION INSTRUCTIONS .............................................................

5

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

5

Uncrating .......................................................................................

5

Locating the Heater ...................................................................

5,6

Hard Water ....................................................................................

6

Clearances ....................................................................................

6

Air Requirements ...........................................................................

6

Venting .......................................................................................

6,7

Vertical Venting - For BTP Models ................................................

7

Horizontal (Side-wall)Venting - For BTPV Models ..................

7,8

Direct Venting - For BTPV Models ..........................................

9-11

Gas Piping .............................................................................

11-12

Gas Meter Size ............................................................................

12

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

12

Gas Valves ............................................................................

12,13

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

13

Thermometers .............................................................................

13

Relief Valve .................................................................................

13

INSTALLATION DIAGRAMS ...........................................................

14-17

Manifold Kits ................................................................................

18

 

PAGE

Heater Wiring ...............................................................................

19

START UP ............................................................................................

19

Important ......................................................................................

19

Filling ............................................................................................

19

Purging .........................................................................................

19

Wiring Diagram ......................................................................

20,21

Lighting and Operating Label ......................................................

22

Sequence of Operation ...............................................................

23

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

23

Adjustment Procedure (Initial Start-Up) ................................

23,24

Adjustment Procedure for Fire-Rate,Low Nox and

 

High Elevation (Fine-Tune) ....................................................

24-26

GENERAL INFORMATION ....................................................................

27

Power Burner ..............................................................................

27

Thermostat ..................................................................................

27

High Limit ......................................................................................

27

MAINTENANCE ....................................................................................

27

General ........................................................................................

27

Maintenance Schedule ................................................................

27

Electrical Servicing ......................................................................

27

Flushing .......................................................................................

27

Draining ........................................................................................

28

Sediment Removal .......................................................................

28

Lime Scale ...................................................................................

28

Relief Valve ...........................................................................

28,29

Circulating Pump ..........................................................................

29

Low Emission Power Burner ......................................................

29

Cleaning Flues .............................................................................

29

Barometric Draft Control .............................................................

29

Vent System ................................................................................

29

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

29-30

TROUBLESHOOTING .....................................................................

30-32

Replacement Parts ......................................................................

32

WARRANTY ........................................................................................

33

NOTES ...........................................................................................

34,35

GENERAL SAFETY INFORMATION

PRECAUTIONS

DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN UNDER WATER. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control which has been under water.

IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT OPERATE HEATER UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE BY A QUALIFIED SERVICEMAN.

1.EXTERNAL FIRE.

2.DAMAGE.

3.FIRING WITHOUT WATER.

4.SOOTING.

LIQUID PETROLEUM MODELS

WARNING

Water heaters for propane or liquefied petroleum gas (LPG)

are different from natural gas models. A natural gas heater will not function safely on LP gas and no attempt should be made to convert a heater from natural gas to LP gas.

BTP(V)-540A,650A & 740A models are not available for use with Liquefied Petroleum or LP gas. If you have obtained aBTP(V)-540A,650A or 740A model with the intent to use it with Liquefied Petroleum, LP gas - STOP! Immediately contact your dealer to obtain a correct model.

CHEMICAL VAPOR CORROSION

WARNING

CORROSION OF THE FLUEWAYS AND VENT SYSTEM MAY OCCUR IF AIR FOR COMBUSTION CONTAINS CERTAIN CHEMICAL VAPORS. SUCH CORROSION MAY RESULT IN FAILURE AND RISK OF ASPHYXIATION.

Spray can propellants, cleaning solvents, refrigerator and air conditioning refrigerants, swimming pool chemicals, calcium

3

and sodium chloride (water softener salt), waxes, and process chemicals are typical compounds which are potentially corrosive. Do not store products of this sort near the heater. Also, air which is brought in contact with the heater should no contain any of these chemicals. If necessary, uncontaminated air should be obtained from remote or outside sources. The limited warranty is voided when failure of water heater is due to a corrosive atmosphere. (Refer to the limited warranty for complete terms and conditions).

2.INSULATION BLANKETS CAN RESTRICT THE AIR FLOW NEEDED FOR PROPER OPERATION OF THE COMBUSTION SYSTEM AND COULD RESULT IN FIRE, ASPHYXIATION, SERIOUS PERSONAL INJURY OR DEATH.

WARNING

FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN SERIOUS PERSONAL INJURY OR DEATH.

IMPROPER COMBUSTION

WARNING

ATTIC AND OR EXHAUST FANS OPERATING ON THE PREMISES WITH A WATER HEATER CAN RESULT IN CARBON MONOXIDE POISONING AND DEATH.

OPERATIONOFTHESEFANSCANPRODUCEANEGATIVEDRAFT IN THE AREA OF THE WATER HEATER PREVENTING THE PRODUCTS OF COMBUSTION FROM EXHAUSTING THROUGH THE CHIMNEY OR VENT PIPE.

The venting of the water heater should be inspected by a qualified service technician at the time of installation and periodically thereafter to ensure a down-draftcondition does not exist.

DO NOT OBSTRUCT THE FLOW OF COMBUSTION AND VENTILATION AIR, ADEQUATE AIR FOR COMBUSTION AND VENTILATION MUST BE PROVIDED FOR SAFE OPERATION.

EXTENDED NON-USEPERIODS

CATHODIC PROTECTION

CAUTION

HYDROGENGASCANBEPRODUCEDINAHOTWATERSYSTEM SERVED BY THIS HEATER THAT 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 not smoking or open flame near the faucet at the time it is open.

INSULATION BLANKETS

WARNING

INSULATION BLANKET 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 TANKWATERHEATER. YOURA.O.SMITHWATERHEATERMEETS OR EXCEEDS THE ASHRAE/IES 90.1B 2001 STANDARDS WITH RESPECT TO INSULATION AND STANDBY LOSS REQUIREMENTS, MAKING AN INSULATION BLANKET UNNECESSARY. THE USE OF INSULATION BLANKETS IN CONJUNCTION WITH AN A.O. SMITH WATER HEATER WILL ALSO VOID THE SMITH WARRANTY FOR THE FOLLOWING REASONS:

1.INSULATION BLANKETS COVER IMPORTANT OPERATING INSTRUCTIONS AND SAFETY LABELS.

HIGH ALTITUDE INSTALLATIONS

Your A.O. Smith water heater has been designed to operate at altitudes below 2000 Ft. (609.6 m), for appliance installation locations with elevations above 2000 Ft. (609.6 m), special considerations need to be taken. Adjustments for high altitude can only be made by an A.O. Smith authorized BTP Start-upAgent. To ensure your water heater operates properly at high elevation, an A.O. Smith authorized BTPStart-upAgent will readjust theair-intakedamper setting and the gas manifold pressure (if required).

NOTE: Some gas utility companies derate the heating value of the supplied gas at high elevation. Your authorized start-upagent must adjust for actual heating value of the gas at the time of start up.

FEATURES

LOW EMISSION CONTROL

Your A.O. Smith water heater has been designed to comply with standards established by California South Coast Air Quality Management District (SCAQMD), the most stringent emissions control agency in the nation. To ensure compliance with SCAQMD Rule 1146.2, your heater is equipped with an internal recirculation premix power burner, and must be started/adjusted by an A.O. Smith Authorized BTP Start-UpAgent.

HIGH LIMIT SWITCH (E.C.O.)

The dual bulb controller also contains the high limit (energy cutoff) sensor. The high limit switch interrupts main burner gas flow should the water temperature reach 205°F (96°C).

In the event of high limit switch operation, the appliance cannot be restarted unless the water temperature is reduced by 20°F (11°C) approx. and the high limit reset button on front of limit control is depressed, see Figure 1.

FIGURE 1.

4

Continued manual resetting of high limit control, preceded by higher than usual water temperature is evidence of high limit switch operation. The following are possible reasons for high limit switch operation.

A malfunction in the thermostatic controls would allow the gas valve to remain open causing water temperature to exceed the thermostat setting. The water temperature would continue to rise until high limit switch operation.

An improper thermostat setting for a short repetitive usage pattern may lead to a stacking effect. This causes a temperature gradient increasing from the bottom to the top of the tank. It is possible that the water at the high limit switch sensor could reach its maximum temperature before the water temperature at the thermostat reaches the dial setting, causing the high limit switch to activate.

A warming of ambient conditions associated with seasonal change could magnify the stacking process described above to the point where high limit switch operation would occur.

Contact your dealer or servicer if continued high limit switch operation occurs.

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. Flow pressures above 25 pounds per square inch, or below 15 pounds per square inch, will result in improperly sanitized dishes. Where pressures are high, a water pressure reducing or flow regulating control valve should be used in 180°F (82°C) line to the dishwashing machine, and should be adjusted to deliver water between these limits.

The National Sanitation Foundation also recommends circulation of 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-offto the dishwashing machine. Adjust flow by means of the plug cock in the circulating line.

INSTALLATION INSTRUCTIONS

REQUIRED ABILITY

INSTALLATION OR SERVICE OF THIS WATER HEATER REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPLY AND ELECTRICAL WORK ARE REQUIRED. NOTE: AUTHORIZED START-UP IS REQUIRED.

UNCRATING

The heater is shipped in standard form for vertical venting with a barometric draft control assembly in a separate carton.

Optional horizontal vent models are shipped with one (1) exhaust vent hood and one (1) flue reducer in a separate carton. Optional direct vent models are shipped with two (2) vent hoods in separate cartons. The exhaust vent hood carton contains one (1) exhaust vent hood and one (1) flue reducer. The intake vent hood carton contains one (1) intake vent hood and one (1) inlet adapter. All parts should be installed as received without alteration.

LOCATING THE HEATER

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

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, OPERATED OR REPAIRED. FLAMMABLE VAPORS ARE HEAVY AND TRAVEL ALONG THE FLOOR AND MAY BE IGNITED BY THE HEATER’S IGNITER OR MAIN BURNER FLAMES CAUSING FIRE OR EXPLOSION. SOME LOCAL CODES PERMIT OPERATION OF GAS APPLIANCES IF INSTALLED 18 INCHES OR MORE ABOVE THEFLOOR. THISMAYREDUCETHERISKIFLOCATIONINSUCH AN AREA CANNOT BE AVOIDED.

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

WARNING

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

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

LOCATE IT NEAR A FLOOR DRAIN. THE HEATER SHOULD BE LOCATED IN AN AREA WHERE LEAKAGE FROM THE HEATER OR CONNECTIONS WILL NOT RESULT IN DAMAGE TO THE ADJACENT AREA OR TO LOWER FLOORS OF THE STRUCTURE.

WHEN SUCH LOCATIONS CANNOT BE AVOIDED, A SUITABLE DRAIN PAN SHOULD BE INSTALLED UNDER THE HEATER. Such pans should be fabricated with sides at least 2” (50.8 mm) deep, with length and width at least 2” (50,8 mm) greater than the diameter of the heater and must be piped to an adequate drain. THE PAN MUST NOT RESTRICT COMBUSTION AIRFLOW.

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-offdevice 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-offdevices 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.

5

Units, which are to be installed on combustible flooring, must be supported by a full layer of hollow concrete blocks, from 8” (203.2 mm) to 12” (304.8 mm) thick and extending 12” (304.8 mm) minimum beyond the heater in all directions. The concrete blocks must provide an unbroken concrete surface under the heater with the hollows running continuously and horizontally. A 3/16-inchsteel plate must cover the concrete blocks, see Figure 2.

NOTE: If electrical conduits run under the floor of the proposed heater location, insulate the floor as recommended above.

For appliances installation locations with elevations above 2000 feet (609.6 m), refer to HIGH ALTITUDE INSTALLATIONS section.

PROPER INSTALLATION ON COMBUSTIBLE FLOORING

FIGURE 2.

HARD WATER

Where hard water conditions exist, water softening or the threshold type of water treatment is recommended. This will protect the dishwasher, Coffee urns, water heaters, water piping and other equipment.

See MAINTENANCE section for details of tank cleanout procedure.

CLEARANCES

These heaters are designed for installation on non-combustibleflooring in an alcove with clearances to combustible construction of 6” (152.4 mm) from the sides and rear, 24” (610 mm) from the top with a 6” (152.4 mm) minimum between vent pipe and ceiling. Minimum clearance from flue pipe to combustible material is 6” (152.4 mm), see Figure 3.

PROPER INSTALLATION CLEARANCES

FIGURE 3.

A clearance of 30” (762 mm) shall be maintained from serviceable parts, such as power burners, relief valves flue baffles, thermostats or drain valves.

AIR REQUIREMENTS

KEEP APPLIANCE AREA CLEAR AND FREE OF COMBUSTIBLE MATERIALS,GASOLINEANDOTHERFLAMMABLEVAPORSAND LIQUIDS.

DO NOT OBSTRUCT THE FLOW OF COMBUSTION OR VENTILATING AIR.

WARNING

FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR COMBUSTION AND VENTILATION. AN INSUFFICIENT SUPPLY OF AIR WILL CAUSE RECIRCULATION OF COMBUSTION PRODUCTS RESULTING IN AIR CONTAMINATION THAT MAY BE HAZARDOUSTOLIFE. SUCHACONDITIONOFTENWILLRESULT IN A YELLOW, LUMINOUS BURNER FLAME, CAUSING CARBONING OR SOOTING OF THE COMBUSTION CHAMBER, BURNERS AND FLUE TUBES AND CREATES A RISK OF ASPHYXIATION.

Where an exhaust fan is installed in the same room with a heater, sufficient openings for air must be provided in the walls.

UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN INTO THE ROOM THROUGH THE CHIMNEY, CAUSING POOR COMBUSTION. SOOTING MAY RESULT IN SERIOUS DAMAGE TO THE HEATER AND RISK OF FIRE OR EXPLOSION.

UNCONFINEDSPACE

In buildings of conventional frame, brick or stone construction, unconfined spaces may provide adequate air for combustion and ventilation.

If the unconfined space is within a building of tight construction, (building using the following construction: weather stripping, heavy insulation, caulking, vapor barrier, etc.), air for combustion and ventilation must be obtained from outdoors or spaces freely communicating with the outdoors. The installation instructions for confined spaces in tightly constructed buildings must be followed to ensure adequate air supply.

CONFINEDSPACE

When drawing combustion and dilution air from inside a conventionally constructed building to a confined space, such a space shall be provided with two permanent openings, ONE IN OR WITHIN 12 INCHES (304.8 mm) OF THE ENCLOSURE TOP AND ONE IN OR WITHIN 12 INCHES (304.8 mm) OF THE ENCLOSURE BOTTOM. Each opening shall have a free area of at least one square inch per 1000 Btuh of the total input of all appliances in the enclosure, but not less than 100 square inches.

If the confined space is within a building of tight construction, air for combustion and ventilation must be obtained from outdoors. When directly communication with the outdoors through vertical ducts, two permanent openings, located in the above manner, shall be provided. Each opening shall have a free area of not less than one square inch per 4000 Btuh of the total input of all appliances in the enclosure.

VENTING

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

6

Heater must be protected from freezing downdrafts during shutdown periods.

The BTP 540A, 650A and 750A water heater are classified as a category I appliance (non-positivevent pressure, noncondensing) when installed with the supplied barometric draft control assembly in a vertical vent installation.

The BTPV 540A through 740A heater is classified as a category III appliance (positive vent pressure, non-condensing)when installed with supplied sidewall vent kits or direct vent kit.

All regulations pertaining to the venting of these heaters must be followed.

The following vent installation instructions cover vertical, horizontal, and direct vent applications.

NOTE: A NEGATIVE DRAFT MUST BE MAINTAINED IN VENTING.

A negative draft of 0.02” to 0.04” w.c. Must be maintained in venting system. Measure draft at the location illustrated in Figure 4. Adjust the control counter-weightsif necessary as shown in the MAINTENANCE portion of this manual.

Where an existing chimney or vent is to be used, be sure that the chimney or vent has adequate capacity for the number and sizes of gas appliances being vented through it. Inspect the chimney or vent and remove all soot or other obstructions, which will retard free draft.

Vent connectors making horizontal runs must have a minimum upward slope toward the chimney or vent of ¼ inch per foot. Vent connector length should be kept as short as possible. Be sure that the vent pipe does not extend beyond the inside wall of a chimney, see Figure 4.

VERTICAL VENTING - FOR BTP MODELS

BAROMETRIC DRAFT CONTROL ASSEMBLY

A double-actingbarometric draft control assembly is provided with any unit intended for chimney venting. The purpose of this draft control is twofold. During downdrafts it acts as a pressure relief control to prevent the downdraft from blowing into the heater. It also allows for makeup air to enter the chimney without being drawn through the heater. In both cases the control prevents the heater performance from being adversely affected by conditions within the chimney.

The draft control assembly must be installed without alteration. This assembly is factory adjusted for horizontal application only and must be attached to the heater as shown in Figure 4. The direction in which the outlet to the draft controls assembly faces is arbitrary. The assembly must be fitted to the jacket cover such that it is plumb and level to the ground. Fasten the draft control assembly to the top cover using sheet metal screws at three locations, or more, as required.

Damper or other obstructions must not be installed between the heater and the barometric draft control assembly.

Do not adjust settings on gate.

When installed, the damper gate must pivot freely in the ring guides. This gate will automatically adjust to regulate the chimney draft imposed on the heater.

VENT CONNECTIONS

Vent connections must be made to an adequate stack or chimney. Refer to the National Fuel Gas Code or to the vent pipe manufacturer’s gas vent and chimney sizing table to properly design and size the venting system. Refer to Table 1 for the vent pipe size required for installation to the barometric draft control assembly outlet.

 

TABLE 1.

Model

 

Flue Outlet

BTP-540A

 

9” (228.6 mm)

BTP-650A

 

9” (228.6 mm)

BTP-740A

 

9” (228.6 mm)

Single-wallor type B venting may be used with these heaters in vertical vent installations. All local and utility regulations on venting must be followed.

FIGURE 4.

In venting systems where a continuous or intermittent back (positive) draft is found to exist, the cause must be determined and corrected. In some cases, a special vent cap may be required.

WARNING

Failure to correct back drafts may cause air contamination and unsafe conditions.

Do not connect the heater to a common vent or chimney with solid fuel burning equipment. This practice is prohibited by many local building codes as is the practice of venting gas fired equipment to the ductwork of ventilation systems.

Connectors shall not be connected to a chimney, vent or venting system served by a power exhauster, unless the connection is made on the negative pressure side of the exhauster.

Do not connect any heater vented by natural draft to any vent serving mechanical draft equipment operating under positive vent pressure such as category III or category IV appliances.

HORIZONTAL (SIDE-WALL)VENTING -

FOR BTPV MODELS

An exhaust vent hood, vent hood and a flue reducer are supplied with any unit intended for through-the-wallhorizontal venting. These parts must be installed without alteration. The vent hood adapter is designed for use with Selkirk Metalbestos Model PS or Model G venting, see Figure 7 on page 10.

7

Refer to Table 2 for limitations of venting system design for horizontal venting.

TABLE 2

 

 

 

BTPV-540A-740A

Flue Outlet Dia. (Inches/mm)

 

9” (228.6)

Flue Reducer

 

9” x 8”

Dimensions -Supplied(Inches/mm)

228.6 x 203.2

Minimum Outlet Vent Dia. (Inches/mm)

8” (203.2)

Maximum Number

 

90°

4

Of Elbows

 

45°

8

Maximum Total Vent System

 

75

Length, Equiv. Feet/Meters

 

(23 m)

 

 

 

 

When calculating the equivalent length of a venting system each 90° elbow is equivalent to 10 feet (3 m) of straight pipe. In no case 45° elbow is equivalent to 5 feet (1.5 m) of straight pipe. In no case may the sum of the straight pipe lengths and the equivalent length of the elbows exceeds 80 feet (24.3 m).

Note the minimum vent diameter in Table 2.

Refer to Table 3 for the correct vent terminal size for each heater. The dimensions noted in Table 3 refer to Figure 5.

TABLE 3

Heater

Terminal

 

 

 

 

Rough-In

Model

Model

A

B

C

D

Dimensions

BTPV

 

 

 

 

 

 

540A-

VH-1-8”

19-7/8”

13”

10-9/16”

8-5/8”

11-1/16”

740A

 

 

 

 

 

 

 

 

 

 

 

 

 

FIGURE5

Use only the sidewall vent terminal supplied with the heater. These terminals are specifically listed for use on these A.O. Smith heaters.

VENT TERMINAL LOCATIONS-EXHAUST

When considering location for sidewall vent terminals refer to the latest edition of the National Fuel Gas Code which recommends that vent terminals:

1.Shall be located not less than 12” (304.8 mm) above grade.

2.Shall be located not less than 7 feet (2.1 m) above grade when adjacent to a public walkway.

3.Shall terminate at least 3 feet (0.9 m) above any forced air inlet within 10 feet (3 m).

4.Shall terminate at least 4 feet (1.2 m) below, 4 feet (1.2 m) horizontally from or 1 foot above any door, window or gravity air inlet into any building.

5.Shall not be closer than 3 feet (0.9 m) from the inside corner of an L- shaped structure.

6.Shall be located above the snow line in geographical areas where snow accumulates.

VENT SYSTEM INSTALLATION

This heater is a category III appliance when horizontally vented through a wall using the supplied sidewall vent terminal. All national and local codes pertaining to the installation of such venting systems must be followed.

Horizontal portions of the vent system must be installed with a minimum upward slope of 1/4” per foot of length.

All joints and seams in the venting system must be sealed gas tight. If a silicone sealer is used, it must have a continuous temperature rating of at least 500°F (260°C); Dow Corning 736 or equivalent must be used.

CAUTION

Use only the vent hood supplied with this kit. Only supplied hood provides required clearances from combustibles, both through the wall and the exterior siding. Termination of a sidewall vent system with a device other than the supplied vent hood could affect system performance and result in a safety hazard.

IMPORTANT

Plan the layout of the vent system backward from the vent termination to the water heater.

1.Use the layout of the vent system backward from the vent termination to the water heater.

BEWARE OF CONCEALED WIRING AND PIPING INSIDE OF WALL. REFER TO TABLE 5 FOR THE MAXIMUM WALL THICKNESS “B” FOR EACH MODEL.

2.Slide hood through opening from outside. Fasten hood to exterior wall with anchors and screws supplied.

3.Install covers plate and fasten to inside wall with 4 screws.

4.Attach a seal ring (Meltalbestos SR or equivalent) to the vent hood collar, see Figure 7. Attach Selkirk Metalbestos model PS or model G venting to the seal ring following the venting manufacturer’s instructions. For total safety, it is recommended that only venting listed for use with category III appliances (positive vent pressure, non-condensing)should be used between the heater and the vent hood, even through national or local codes may allow the use of type B or singlewall vent.

5.Install the remaining vent sections back to the heater, following the venting manufacturer’s instructions on assembling and sealing joints. Follow good venting practice regarding properly supporting vent system and keeping the number of offsets to a minimum. See Table 2 for the maximum allowable number of elbows in venting system.

6.Install the flue reducer included with the exhaust hood between the vent system and the heater.

7.Seal all vent connections and venting with sealants supplied by vent pipe manufacturer or with a high-temperaturesilicone sealant suitable for continuous temperatures of 500°F (260°C). Acceptable sealant include Dow Corning 736 or equivalent.

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FIGURE 6.

DIRECT VENTING - FOR BTPV MODELS

TABLE 5.

All exhaust vent terminal, flue reducer, and intake vent terminal are supplied with any unit intended for direct venting. These parts must be installed without alteration.

This heater is category III appliance when used in a direct vent application. All national and local codes pertaining to the installation of such an appliance must be followed.

Horizontal portions of the exhaust vent system must be installed with a minimum upward slope of 1/4” (6.35 mm) per foot of length.

Selkirk metalbestos model PS or G vent is approved for use as exhaust venting on these models. Model PS is a double-wallvent with a 1” (25.4 mm) air space between pipes. Model G is asingle-wallvariation of model PS for use where combustible clearance is not a concern, see Table 4.

TABLE 4.

Selkirk Metalbestos Model PS

Clearance to Combustibles

Interior

6” (152.4 mm)

Exterior

6” (152.4 mm)

 

 

8” diameter PVC or galvanized pipe is approved for use as intake venting on these models. Class 63, 100, 125, 200, and schedule 40 pipe may be used for PVC pipe. Intake venting must be adequately supported to avoid unnecessary stress on vent hood, venting, or burner.

See Table 5 limitations on venting system design for direct vent installations.

Dimension in

 

BTPV

Inches (mm)

 

540A -740A

Flue Outlet Dia.

 

9

(229)

Flue Reducer Dimension

 

9 x 8

(Supplied)

 

(229 x 203)

Min. Exhaust Vent Dia. Inch (mm)

 

8

(203)

Min. Intake Vent Dia. Inch (mm)

 

8

(203)

Maximum Number Of

 

90°

 

4

Elbows, Intake

 

45°

 

8

Maximum Number Of

 

90°

 

4

Elbows, Exhaust

 

45°

 

8

Total Intake Vent

 

Max.

75

(23 m)

Length, Equiv. Ft.

 

Min.

3

(1 m)

Total Exhaust Vent

 

Max.

75

(23 m)

Length, Equiv. Ft.

 

Min.

6 (1.8)

 

 

 

 

 

Note: Barometric draft control is not used in direct vent installations as the venting system must be sealed.

When calculating the equivalent length of a venting system each 90 elbow is equivalent to 10 feet of straight pipe. Each 45 elbow is equivalent to 5 feet (1.5 m) of straight pipe. Do not exceed the maximum number of elbows as shown in Table 5. In no case may the sum of the straight pipe lengths and the equivalent lengths of the elbows exceed the valves in Table 5.

VENT TERMINAL LOCATIONS-EXHAUST

See “Horizontal Venting” in this manual for acceptable locations for exhaust hoods.

VENT TERMINAL LOCATIONS-INTAKE

When considering locations for the intake terminal, bear in mind that the terminal:

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1.Shall be located not less than 12” (304.8 mm) above grade.

2.Shall be located not less than 3 (.9144 m) feet horizontally from and not less than 3 feet (.9144 m) below an exhaust vent terminal.

3.Shall not be located directly above an exhaust terminal.

4.Shall be located 12” (304.8 mm) above the snow line in geographical areas where snow accumulates.

5.Shall be located not less than 7 feet 2.1 m) above grade when adjacent to a public walkway.

6.Shall not be closer than 3 feet (.9144 m) from the inside corner of an L - shaped structure.

7.Shall be located not less than 3 feet (.9144 m) horizontally or 3 feet (.9144 m) vertically from gas line, meter, or other gas supply entering a structure, see Figure 6.

DIRECT VENT SYSTEM INSTALLATION

Plan the vent system backwards from the vent hood to the heater.

1.Use the inside wall cover plate as a template to mark two holes in the appropriate places on the wall. Cut holes 1/2” (12.7 mm) larger to facilitate easy installation of vent hoods, see Figures 6 and 7.

BEWAREOFCONCEALEDWIRINGANDPIPINGINSIDEWALL. REFER TO TABLE 3 FOR THE MAXIMUM WALL THICKNESS “B” FOR EACH MODEL.

2.Slide hoods through openings from outside. Fasten hoods to exterior wall with anchors and screws supplied.

3.Install cover plate and fasten to inside wall with 4 screws

4.Attach a seal ring (Selkirk Metalbestos Model SR or equivalent) to the vent hood collar, see Figure 7.

FIGURE 7B.

FIGURE 7.

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