COVERAGE:

WATER HEATER. A closed vessel, in which water is heated by the combustion of fuels,
electricity or any other source and is withdrawn for use external to the vessel at
pressures not exceeding 160 psig, including the apparatus by which heat is generated and
all controls and devices necessary to prevent water temperatures from exceeding 210?F.

REQUIREMENTS:

The certified designs of gas water heaters are such that temperatures of adjacent
combustible walls and surfaces will not be excessive when the water heater is installed
and used as specified in the manufacturer's instructions and on the marking plate.

Input ratings are shown in Btu per hour unless indicated otherwise.

In the U.S., listings are for elevations up to 2,000 feet. For elevations above 2,000
feet, input should be reduced 4 percent for each 1,000 feet above sea level.

In the U.S., testing for use with liquefied petroleum gases under American National
Standards Z21.10.1 and Z21.10.3 has been conducted in accordance with the OSHA Nationally
Recognized Testing Laboratory Program.

In the U.S., water heaters with input ratings of 75,000 BTU's per hour or less fall
within the scope of the Energy Policy and Conservation Act of 1975 and the National Energy
Conservation Policy Act of 1978. Labels which are required by Federal Trade Commission
regulations are supplied with each unit. They contain efficiency related information based
on test procedures published in Appendix E. Uniform Test Method for Measuring the Energy
Consumption of Water Heaters. Part 430 – Energy Conservation Program. (Title 10 CFR Part
430).

In the U.S., the installation of water heaters in recreational vehicles should conform
with the current edition of the Standard for Recreational Vehicles, ANSI A119.2(NFPA
501C), obtainable from the Recreation Vehicle Industry Association, P.O. Box 204, 14650
Lee Road Chantilly, Virginia 22021. Installation in manufactured (mobile) home should
conform with the current edition of the Manufactured Home Construction and Safety
Standard, Title 24CFR, Part 3280.

Water heaters may be of the following types:

CIRCULATING HEATER. A water heater, which furnishes hot water to be stored in a
separate vessel.  Circulating may be either gravity or forced.  An automatic
circulating water heater is controlled by a thermostat, which is an integral part of the
water heater.  A nonautomatic circulating water heater is controlled by a thermostat
installed in the storage vessel.

INSTANTANEOUS.  A water heater which has an input rating of at least 4,000 Btu per
hour per gallon of stored water.

AUTOMATIC STORAGE. A water heater that heats and stores water within the appliance at a
thermostatically controlled temperature for delivery on demand, and which has an input
rating of less than 4,000 Btu per hour be gallon of stored water.

DIRECT VENT.  A water heater for indoor installation which includes:

1. combustion air connections between the water heater and the outside atmosphere;
2. flue gas connections between the water heater and the vent terminal; and
3. vent terminal for installation outdoors, supplied by the manufacturer and constructed so
   all air for combustion is obtained from the outside atmosphere and all flue gases are
   discharged to the outside atmosphere.

BOOSTER TYPE.  A water heater intended only for use in conjunction with commercial
dishwashers that raises the temperature of the preheated water supplied to the unit
typically between 110 F (43.3C and 60.0C) to 180F – 195F (82.2C – 90.6C),

/mac