Power Vent, Indoor Combustion Air Installation In Confined Or Unconfined Space - Westinghouse WBRC 140W Series Installation Manual

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4. Power Vent, Indoor Combustion Air Installation in Confined or
Unconfined Space
This heater requires fresh, uncontaminated air for safe operation and must
be installed in a mechanical room where there is adequate combustion
and ventilating air. NOTE: To prevent combustion air contamination,
see Table 8.
Combustion air from the indoor space can be used if the space has
adequate area or when air is provided through a duct or louver to supply
sufficient combustion air based on the heater input. Never obstruct the
supply of combustion air to the heater. If the heater is installed in areas
where indoor air is contaminated (see Figure 16) it is imperative that the
heater be installed as direct vent so that all combustion air is taken directly
from the outdoors into the heater intake connection.
Unconfined space is space with volume greater than 50 cubic feet per
1,000 Btu/hour (4.8 cubic meters per kW) of the total input rating of all
fuel-burning appliances installed in that space. Rooms connected directly
to this space, through openings not furnished with doors, are considered
part of the space.
Confined space is space with volume less than 50 cubic feet per 1,000
Btu/hour (4.8 cubic meters per kW) of the total input rating of all fuel-
burning appliances installed in that space. Rooms connected directly to
this space, through openings not furnished with doors, are considered part
of the space.
When drawing combustion air from inside a conventionally constructed
building to a confined space, such space should be provided with two
permanent openings: one located 6" (15 cm) below the space ceiling, the
other 6" (15cm) above the space floor. Each opening should have a free
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area of one square inch per 1,000 Btu/hr (22cm /kW) of the total input of
Figure 16 – Do Not Install in a Contaminated Space
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all appliances in the space, but not less than 100 square inches (645cm ).
If the confined space is within a building of tight construction, air for combustion must be obtained from the outdoors as outlined in the
Venting section of this manual. See Figure 17.
WHL-012 REV. 4.8.16