A.O. Smith BT- 80 warranty Clearances, High Altitude Installations, Hard Water, AIR Requirements

Drain pans suitable for these heaters are available from your distributor or A. O. Smith Water Products Company, 500 Tennessee Waltz Parkway, Ashland City, TN 37015.

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 shutoff 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 shutoff 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.

For appliance installation locations with elevations above 2000' (610m), refer to HIGH ALTITUDE INSTALLATIONS section of this manual for input reduction procedure.

specified on the heater rating plate is not permitted.

The input reduction is primarily achieved by reducing the size of the main burner orifices. To do this, the main burner orifices require replacement with orifices sized for the particular installation elevation. Correct orifice sizing and parts may be obtained from A.O. Smith Water Products Company. When ordering, be sure to state the model number and the altitude of the location where the water heater is being installed.

Upon completion of derating of the heater, adjustment to the gas pressure regulator may be required. See CHECKING THE INPUT section in this manual for inlet and manifold pressure requirements.

Also due to the input rating reduction required at high altitudes, the recovery rating of the appliance is also reduced and should be compensated for in the sizing of the equipment for application.

CLEARANCES

These heaters are approved for installation on combustible flooring in a closet having a ceiling 12" (30.5cm) above top cover and with clearances to combustible construction of 6" (15.2cm) from flue or vent connector, 0" (0cm) at the sides and rear and 4" (10.1cm) to front to prevent a possible fire hazard condition. A minimum of 4" (10.1cm) shall be allowed for installation of serviceable parts.

HIGH ALTITUDE INSTALLATIONS

WARNING

INSTALLATIONSABOVE 2000' (610m) REQUIRE REPLACEMENT OF THE BURNER ORIFICE IN ACCORDANCE WITH SECTION

8.1.2OF THE NATIONAL FUEL GAS CODE (ANSI Z223.1). FOR CANADIAN INSTALLATIONS CONSULT THE NATURAL GAS AND PROPANE INSTALLATION CODE CAN/CSA-B149.1. FAILURE TO REPLACE THE ORIFICE WILL RESULT IN IMPROPER AND INEFFICIENT OPERATION OF THE APPLIANCE RESULTING IN THE PRODUCTION OF INCREASED LEVELS OF CARBON MONOXIDE GAS IN EXCESS OF SAFE LIMITS WHICH COULD RESULT IN SERIOUS PERSONAL INJURY OR DEATH.

You should contact your gas supplier for any specific changes which may be required in your area.

As elevation above sea level is increased, there is less oxygen per cubic foot of air. Therefore, the heater input rate should be reduced at high altitudes for satisfactory operation with the reduced oxygen supply. Failure to make this reduction would result in an overfiring of the heater causing sooting, poor combustion and/or unsatisfactory heater performance.

U.S. REQUIREMENTS

Ratings specified by manufacturers for most appliances apply for elevations up to 2000 feet (610m). For elevations above 2000 feet (610m), ratings must be reduced at the rate of 4% for each 1000 feet (305m) above sea level. For example, if a heater is rated at 75,100 Btu/Hr (22.0 kW) at sea level, to rate the heater at 4000 feet (1219m), you subtract 4 (once for each thousand feet) x 0.04 (4% input reduction) x 75,100 Btu/Hr (original rating) from the original rating. Therefore, to calculate the input rating at 4000 feet (1219m): 4 x 0.04 x 75,100 Btu/Hr = 12,016 Btu/Hr (3.5 kW); 75,100 Btu/Hr (22.0 kW) - 12,016 Btu/Hr (3.5 kW) = 63,084 Btu/Hr (18.5 kW). At 6000 feet (1829m) the correct input rating should be 57,076 Btu/Hr (16.7 kW).

CANADIAN REQUIREMENTS

Appliances with inputs up to and including 400,000 BTU (117.1 kwh) must be factory equipped with orifices for operation at specific elevations. Standard (sea level) orifices permit operation up to 2000' (610m) elevation. For operation between 2000' (610m) and 4500' (1370m) specify "HIGH ALTITUDE OPERATION" when ordering the heater(s). For operation above 4500' (1370m) consult factory before ordering. Field conversion for operation at altitudes other than that

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 PREVENTIVE MAINTENANCE section for details of tank cleanout procedure.

AIR REQUIREMENTS

REFER TO THE CURRENT EDITION OF THE NATIONAL FUEL GAS CODE ANSI Z223.1/NFPA 54.

KEEP APPLIANCE AREA CLEAR AND FREE OF COMBUSTIBLE MATERIALS, GASOLINE AND OTHER FLAMMABLES, VAPORS AND 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 HAZARDOUS TO LIFE. SUCH ACONDITION OFTEN WILL RESULT IN AYELLOW, LUMINOUS BURNER FLAME, CAUSING CARBONING OR SOOTING OF THE COMBUSTION CHAMBER, BURNERS AND FLUE TUBES AND CREATES A RISK OF ASPHYXIATION.

Where an exhaust fan is supplied 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.

UNCONFINED SPACE

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

If the unconfined space is within a building of tight construction (buildings using the following construction: weather stripping, heavy

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