A.O. Smith 500A User Manual

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CYCLONE Xi® Model BTH 300A, 400A, 500A

COMMERCIAL GAS WATER HEATER

GAS-FIREDPOWER BURNER

FOR DOMESTIC HOT WATER

• INSTALLATION • OPERATION • SERVICE • MAINTENANCE • LIMITED WARRANTY

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

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS:

Do not try to light any appliance.

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

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

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 OUTLINED IN RED CONTAINS

 

 

INFORMATION RELATIVE TO YOUR SAFETY. PLEASE

 

 

READ THOROUGHLY BEFORE INSTALLING AND USING

 

 

THIS APPLIANCE.

www.hotwater.com

 

 

 

PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.

 

PRINTED 0307

 

97373-003

ROUGH-IN-DIMENSIONS

 

 

GAS VALVE PIPING

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BTH-300

1 1/4" NPT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BTH-400

1 1/4" NPT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BTH-500

1 1/2" NPT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 1 RECOVERY CAPACITIES.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

U.S. Gallons/Hr and Litres/Hr at TEMPERATURE RISE INDICATED

 

 

 

 

 

TYPE OF

 

INPUT

 

 

Approx.

20F°

30F°

40F°

50F°

60F°

70F°

80F°

90F°

100F°

110°

120F°

 

130F°

140F°

MODEL

 

GAS

 

BTUH

KW

 

 

Capacity

11C°

17C°

22C°

28C°

33C°

39C°

44C°

50C°

56C°

61C°

67C°

 

72C°

78C°

BTH-300

 

NATURAL

 

 

300,000

 

 

130 US Gals.

GPH

1746

1164

873

699

582

499

436

388

349

318

291

 

269

250

 

 

 

88

 

 

492 Litres

LPH

6610

4406

3304

2644

2203

1888

1652

1469

1322

1201

1102

 

1017

945

 

 

 

 

 

 

 

 

 

 

BTH-300

 

PROPANE

 

300,000

 

 

130 US Gals.

GPH

1746

1164

873

699

582

499

436

388

349

318

291

 

269

250

 

 

 

88

 

 

492 Litres

LPH

6610

4406

3304

2644

2203

1888

1652

1469

1322

1201

1102

 

1017

945

 

 

 

 

 

 

 

 

 

 

BTH-400

 

NATURAL

 

399,900

 

 

130 US Gals.

GPH

2328

1552

1164

931

776

665

582

517

466

423

388

 

359

332

 

 

 

117

 

 

492 Litres

LPH

8813

5875

4406

3525

2938

2518

2203

1958

1763

1602

1469

 

1356

1259

 

 

 

 

 

 

 

 

 

 

BTH-400

 

PROPANE

 

399,900

 

 

130 US Gals.

GPH

2328

1552

1164

931

776

665

582

517

466

423

388

 

359

332

 

 

 

117

 

 

492 Litres

LPH

8813

5875

4406

3525

2938

2518

2203

1958

1763

1602

1469

 

1356

1259

 

 

 

 

 

 

 

 

 

 

BTH-500

 

NATURAL

 

499,900

 

 

130 US Gals.

GPH

2878

1919

1439

1151

959

822

720

640

576

523

480

 

443

411

 

 

 

146

 

 

492 Litres

LPH

10894

7263

5447

4358

3631

3113

2724

2421

2179

1981

1816

 

1676

1556

 

 

 

 

 

 

 

 

 

 

BTH-500

 

PROPANE

 

499,900

 

 

130 US Gals.

GPH

2878

1919

1439

1151

959

822

720

640

576

523

480

 

443

411

 

 

 

146

 

 

492 Litres

LPH

10894

7263

5447

4358

3631

3113

2724

2421

2179

1981

1816

 

1676

1556

 

 

 

 

 

 

 

 

 

 

Recovery capacities are based on heater performance at 96% thermal efficiency for BTH 300A, 400A, and 95% thermal efficiency for BTH 500A.

FOREWORD

These designs comply with the current edition of the American National Standard for Gas Water Heaters, Volume III, ANSI Z21.10.3 / CSA 4.3 as an automatic circulating tank water heater, and automatic storage water heaters.

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

Particularattentionshouldbegiventotheinstallationofthermometers 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, NFPA 70 or CAN/CSA-B149.1,the Natural Gas and Propane Installation Code and CSAC22.1, the Canadian Electrical Code.All documents are available from the Canadian StandardsAssociation, 8501 East Pleasant Valley Road, Cleveland, OH 44131. NFPA documents are also available from the National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02269.

TABLE OF CONTENTS

ROUGH-INDIMENSIONS.........................................................................

2

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

2

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

3

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

3-5

Water Temperature Setpoint Adjustment Procedure..............................

5

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

5

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

5

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

6

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

6

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

6

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

6

Locating The Heater..............................................................................

6

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

7

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

7

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

7

Mechanical Exhausting of Room Air......................................................

7

Unconfined Space.................................................................................

7

Confined Space.....................................................................................

7

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

7

Installation Requirements for the

 

Commonwealth of Massachusetts.........................................................

8

VENTING..............................................................................................

8-11

Vent Pipe Termination..........................................................................

11

Direct Venting......................................................................................

11

Direct Vent Terminal Installation.....................................................

11-12

Installation Sequence..........................................................................

12

Vertical Vent Terminal Installation........................................................

12

Installation Sequence.....................................................................

12-13

Installation of Vent System..................................................................

13

Vent Pipe Preparation..........................................................................

14

CONTROLS AND SWITCHES.................................................................

14

Blower Prover Switch...........................................................................

14

Blocked Outlet Prover Switch..............................................................

14

Blocked Inlet Prover Switch.................................................................

14

Low Gas Pressure Switch....................................................................

14

On/Off Switch..................................................................................

14-15

Hot Surface Igniter...............................................................................

15

GAS PIPING............................................................................................

15

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

15-16

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

16

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

16

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

16

SYSTEM CONNECTIONS.......................................................................

16

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

16

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

16

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

16

Closed System................................................................................

16-17

Water (Potable) Heating & Space Heating.

.........................................17

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

17 -19

OPERATION............................................................................................

20

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

20

ELECTRONIC CONTROL.......................................................................

20

Overview..............................................................................................

20

Operating States.............................................................................

20 -21

Adjusting the Operating Set Point........................................................

21

Changing the Display Units.................................................................

22

Fault and Warning Conditions.........................................................

22 -23

Access to the Current Fault or Warning...............................................

23

Viewing the Fault History.....................................................................

24

Viewing Information About the Heater.................................................

24

PRIOR TO START-UPREQUIRED ABILITY...........................................

25

OPERATING INSTRUCTIONS................................................................

25

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

25 -26

Lighting Instructions.............................................................................

26

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

27

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

27

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

27

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

27

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

27

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

27

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

27

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

27

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

27

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

28

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

28

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

28

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

28 -29

Powered Anode System......................................................................

29

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

29

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

29

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

29

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

30 -34

Multiple Unit Installations.....................................................................

35

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

36

Burner Operational Problems..............................................................

36

Not Enough or No Hot Water...............................................................

36

Water Is Too Hot..................................................................................

36

Water Heater Makes Sounds...............................................................

36

Water Leakage is Suspected...................................................................

36

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

36 -38

REPLACEMENT PARTS..........................................................................

38

LIMITED WARRANTY..............................................................................

39

FEATURES

IMPORTANT

IT IS REQUIRED THAT A QUALIFIED SERVICE TECHNICIAN

PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME

THE USER SHOULD NOT HESITATE TO ASK THE TECHNICIAN ANY QUESTIONS WHICH HE MAY HAVE IN REGARD TO THE OPERATION AND MAINTENANCE OF THE UNIT.

ACHECKLISTAND SERVICE INFORMATION 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.

WATER TEMPERATURE CONTROL

DANGER

THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE THERMOSTAT 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 TIME OF 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 HAVE ACCESS TO

SET TEMPERATURES.

The water temperature is controlled using the Temperature Control Up/Dn 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.

“AT A GLANCE” BTH 300/400/500 QUICK INSTALLATION TIPS

Horizontal Sidewall Venting

 

Vertical Rooftop Venting

 

 

 

The temperature may be adjusted from 80°F/27°C to 180°F/82°C. The temperature was adjusted to 120°F/49°C before the heater was shipped from the factory. It is recommended that lower water temperatures be used to avoid the risk of scalding. It is further recommended, in all cases, that the water temperature be set for the lowest temperature which satisfies your hot water needs. This will also provide the most energy efficient operation of the water heater and minimize scale formation.

Valves for reducing point-of-usetemperature 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.

WATER TEMPERATURE SETPOINT ADJUSTMENT

PROCEDURE

CAUTION

THE TEMPERATURE OF THE WATER AT THE TANK OUTLET MAY NOT CORRESPOND TO THE TEMPERATURE SETPOINT PROGRAMMED IN THE CONTROLLER. THE USER CAN EASILY CHANGETHETEMPERATURESETPOINTATANYTIMEBYUSING THE FOLLOWING PROCEDURE. INALLCASES, INPUT POWER MUST BE APPLIED TO THE CONTROLLER TO PERFORM ANY

PROGRAMMING OPERATIONS.

The Operating Set Point of this water heater determines the regulated temperatureforthewaterinthetank.Thisparameterisadjustedinthe 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. To change the current programmed temperature setpoint value, see OPERATION section for details.

Figure 1 shows the approximate time-to-burnrelationship 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 (11C°). 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 1-1/2seconds

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.

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 water temperature must drop below 140°F/60°C before the controller can be reset. The following is a possible reason 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.

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 (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-offto the dishwashing machine. Adjust flow by means of the plug cock in the circulating line. (See installation diagrams.)

CIRCULATING PUMP

Acirculatingpumpisusedwhenasystemrequiresacirculatingloopor thereisastoragetankusedinconjunctionwiththeheater.Refertothe pipingdiagramsatrearofmanualforelectricalhookupinformationand install in accordance with the current edition of the National Electrical Code, NFPA 70 or the Canadian Electrical Code, CSA C22.1.

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

Although circulators are oiled and operated by the manufacturer some circulators must be oiled again before operated. Please refer to manufacturer's instructions.

INSTALLATION INSTRUCTIONS

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.

INSULATION BLANKETS

Insulation blankets available to the general public for external use on gas water heaters are not approved for use on your A.O. Smith water heater. The purpose of an insulation blanket is to reduce the standby heat loss encountered with storage tank water heaters. Your A.O. Smith water heater meets or exceeds the ASHRAE/IES 90.1-1999standards with respect to insulation and standby loss requirements, making an insulation blanket unnecessary.

WARNING

Should you choose to apply an insulation blanket to this heater, you should follow these instructions. Failure to follow these instructions can result in fire, asphyxiation, serious personal injury or death.

Do not apply insulation to the top, or the upper 15" (38 cm) of the water heater, as this will interfere with safe operation.

Do not cover the temperature & pressure relief valve.

Do not cover the instruction manual. Keep it on the side of the water heater or nearby for future reference.

Do obtain new labels fromA.O. Smith for placement on the blanket directly over the existing labels.

THEHEATERSHALLBELOCATEDORPROTECTEDSOITISNOT 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 LOCATIONS CLOSE TO OR ACROSS FROM WINDOWS AND DOORS. AVOID ANCHORING THE VENT AND INTAKE PIPES DIRECTLY TO FRAMED WALLS, FLOORS OF CEILINGS UNLESS RUBBER ISOLATION PIPE HANGERS

ARE USED. THIS PREVENTS ANY VIBRATIONS FROM BEING

TRANSMITTED INTO THE LIVING SPACES.

WARNING

FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST NEVER BE PLACED ON ORADJACENTTO THE HEATER. OPEN CONTAINERS 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 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, it is recommended that a suitable drain pan, adequately drained, be installed under the appliance.

WARNING

This water heater isacondensing unitand requires a drain to be located in close proximity to allow the condensate to drain safely. The condensate drains from the unit at the exhaust elbow located at the bottom of the unit. Note: It is important that the condensate hose not be elevated above the exhaust elbow (see Figure 3). The condensate buildup will block the exhaust outlet, which will cause improper operation.

LOCATING 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 VEHICLESARE 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 LOCALCODES PERMIT OPERATION OF GAS APPLIANCES IF INSTALLED 18 INCHES (46 cm) OR MORE ABOVE THE FLOOR. THIS MAY REDUCE THE RISK IF LOCATION IN SUCH AN AREA CANNOT BE AVOIDED.

FIGURE 3.

WARNING

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 ANYPARTOFTHE CONTROLSYSTEMANDANYGAS CONTROL WHICH HAS BEEN UNDER WATER.

CLEARANCES

MECHANICAL EXHAUSTING OF ROOM AIR

These heaters are approved for installation on combustible flooring in an alcove when the minimum clearances from any combustion construction are followed as indicated in Figure 4.

In all installations the minimum combustible clearances from any vent piping shall be 0". Vent piping passing through a combustible wall or ceiling must be a continuous run (no joints).

A service clearance of 24" (61 cm) should be maintained from serviceable parts such as relief valves, thermostats, cleanout openings, drain valves and venting connections.

Always disconnect electrical power before servicing the unit.

*ILLUSTRATION OF MINIMUM COMBUSTIBLE CLEARANCES IN AN ALCOVE.

FIGURE 4.

HARD WATER

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

See MAINTENANCE section for details of tank cleanout procedure.

AIR REQUIREMENTS

KEEP APPLIANCE AREA CLEAR AND FREE OF COMBUSTIBLE MATERIALS, GASOLINE AND OTHER FLAMMABLE VAPORS AND LIQUIDS.

DO NOT OBSTRUCT THE FLOW OF COMBUSTION AND

VENTILATING AIR.

WARNING

FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR COMBUSTION AND VENTILATION. AN INSUFFICIENT SUPPLY OF AIR WILL CAUSE RECIRCULATION OF COMBUSTION PRODUCTS RESULTING IN CONTAMINATION THAT MAY BE HAZARDOUS TO LIFE. SUCH A CONDITION OFTEN WILL RESULT IN 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, sufficientopeningsforairmustbeprovidedinthewalls. UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN INTO THE ROOM THROUGHTHE HEATER’S VENTING SYSTEM, CAUSING POOR COMBUSTION. SOOTING MAY RESULT IN SERIOUS DAMAGE TO THE HEATER AND RISK OF FIRE OR EXPLOSION. IT CAN ALSO CREATE A RISK OF ASPHYXIATION.

UNCONFINED SPACE

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

When drawing combustion air from inside a conventionally constructed building to a confined space, such a space shall be provided with two permanent openings, ONE IN OR WITHIN 12 INCHES (31 cm) OF THE ENCLOSURE TOP AND ONE IN OR WITHIN12INCHES(31cm)OFTHEENCLOSUREBOTTOM. Each opening shall have a free area of at least one square inch per 1000 Btuh (2,203mm2/kW) appliances in the enclosure, but not less than 100 square inches (645 cm²).

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 per 4000 Btuh (551mm2/kW) 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 per 2000 Btuh (1,102mm2/kW) of the total input of all appliances in the enclosure.

CHEMICAL VAPOR CORROSION

WARNING

CORROSION OF THE FLUE WAYS 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 and sodium chloride, waxes, and process chemicals are typical compounds which are potentially corrosive.

PRODUCTS OF THIS SORT SHOULD NOT BE STORED NEAR THE HEATER. ALSO, AIR WHICH IS BROUGHT IN CONTACT WITH THE HEATER SHOULD NOT CONTAIN ANY OF THESE CHEMICALS. IF NECESSARY, UNCONTAMINATEDAIR SHOULD BE OBTAINED FROM REMOTE OR OUTSIDE SOURCES.

INSTALLATION REQUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS

For all side wall terminated, horizontally vented power vent, direct vent,and powerdirectventgas fueled waterheaters installedinevery dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven

(7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:

INSTALLATION OF CARBON MONOXIDE DETECTORS

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-upis 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-upmay 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 NFPA720 and beANSI/UL2034 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 NFPA 54 as adopted by the Board; and

2.Product Approved side wall horizontally vented gas fueled equipment installed in a room or structure separate from the dwelling, building, or structure used in whole or in part for residential purposes.

MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM PROVIDED

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 ProductApproved side wall horizontally vented gas fueled equipment does not provide the parts for venting the flue gases, but identifies “special venting systems,” the following requirements shall be satisfied by the manufacturer:

1.The referenced “special venting system” instructions shall be included with the appliance or equipment installation instructions; and

2.The “special venting systems” shall be ProductApproved 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.

VENTING

WARNING

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.

Heater must be protected from freezing downdrafts during shutdown periods.

US DIRECT VENT

CAUTION

TO PREVENT EXHAUSTING PRODUCTS FROM CIRCULATING TO THE AIR INTAKE IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL DISTANCE BETWEEN THESE TWO TERMINALS IS RECOMMENDED.

CANADIAN DIRECT VENT

FIGURE 5.

US HORIZONTAL VENT

CAUTION

TO PREVENT EXHAUSTING PRODUCTS FROM CIRCULATING TO THE AIR INTAKE IN WINDY/COLD AREAS, THE MAXIMUM PRACTICAL DISTANCE BETWEEN THESE TWO TERMINALS IS RECOMMENDED.

CANADIAN HORIZONTAL VENT

FIGURE 6.

10