Bradford-White Corp THROUGH-THE-WALL GAS WATER HEATER instruction manual Water Connections

Installation (Combustion Air Supply) continued-

All Air From Inside the Building: The confined space must be provided with two permanent openings communicating directly with an additional room(s) of sufficient volume so that the combined volume of all spaces meets the criteria for an unconfined space. The total input of all gas utilization equipment installed in the combined space must be considered in making this determination. Each opening must have a minimum free area of 1 square inch per 1000 BTU (6.5 cm2/0.29 kw) per hour of the total input rating of all gas utilization equipment in the confined space, but not less than 100 square inches (645 cm2). One opening must be within 12 inches (31 cm) of the top and one within 12 inches (31 cm) of the bottom of the enclosure.

All Air From Outdoors: The confined space must be provided with two permanent openings, one commencing within 12 inches (31 cm) of the top and one commencing within 12 inches (31 cm) from the bottom of the enclosure. The openings must communicate directly, or by ducts, with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors.

1.When directly communicating with the outdoors, each opening must have a minimum free area of 1 square inch per 4000 BTU (6.5 cm2/1.2 kw) per hour of total input rating of all equipment in the enclosure.

2.When communicating with the outdoors through vertical ducts, each opening must have a minimum free area of 1 square inch per 4000 BTU (6.5 cm2/1.2 kw) per hour of total input rating of all equipment in the enclosure.

3.When communicating with the outdoors through horizontal ducts, each

opening must have a minimum free area of 1 square inch per 2000 BTU (6.5 cm2/0.6 kw) per hour of total input rating of all equipment in the enclosure.

4.When ducts are used, they must be of the same cross-sectional area as the free area of the openings to which they connect. The minimum dimension of rectangular air ducts must be not less than 3 inches (7.5 cm).

Specially Engineered Installations

The requirements noted under CONFINED SPACES above must not necessarily govern when special engineering, approved by the authority having jurisdiction, provides an adequate supply of air for combustion, ventilation, and dilution of flue gases.

Water Connections

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