Whirlpool WFAU Installation Instructions Manual page 7

Equipment in Confined Space (All Air from Inside)
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2
1. Chimney or gas vent
2. Furnace
Confined Space Installation/Air from Outside Structure
If air from outside is brought in for combustion, the confined
space shall be provided with two permanent openings. One
opening shall be within 12 in. of the ceiling and one opening
within 12 in. of the floor. Several methods can be used to bring
the outside air in through these openings. The openings must
open directly or by ducts to the outdoors, through spaces (crawl
space or attic) that freely open to the outdoors, or indirectly
through vertical ducts.
NOTE: If any of these methods are used, the inlet and outlet air
openings must each have a free area of 1 square inch per 4000
BTU per hour of the total input rating of all equipment within the
enclosure.
Equipment in Confined Space - All Air from Outside
(Inlet air from crawl space and outlet air to ventilated attic)
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2 2
3
1. Chimney or gas vent
2. Furnace
3. Ventilation louvers
(for unheated crawl space)
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4
3. Water heater
4. Openings
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5
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7
4. Ventilation louvers
(each end of attic)
5. Outlet air
6. Water heater
7. Inlet air
Equipment in Confined Space - All Air from Outside
(All air through ventilated attic)
1
2
1. Chimney or gas vent
2. Furnace
3. Ventilation louvers
(Each end of attic)
Equipment in Confined Space - All Air from Outside
(All Air from Horizontal Ducts)
1
2
1. Chimney or gas vent
2. Furnace
NOTE: Another option is to use horizontal combustion ducts. If
horizontal combustion ducts are run, 1 square inch per 2000
BTU/HR of the total input rating of all equipment in the enclosure
is required. If the equipment room is located against an outside
wall and the air openings communicate directly with the
outdoors, each opening shall have a free area of at least one
square in. per 4000 BTU/HR of the total input rating of all other
equipment in the enclosure.
Contaminated Combustion Air
Excessive exposure to contaminated combustion air will result in
performance-related problems. The recommended source of
combustion air is outdoor air.
Outdoor air as the source of combustion air
If the furnace is installed in a confined space, it is recommended
that the necessary combustion air come from the outdoors by
way of an attic, crawl space, air duct, or direct opening.
Outdoor air is required as the source of combustion air when the
indoor air is contaminated with chemical substances and in the
following types of installations:
Furnaces installed in commercial buildings
Furnaces installed in buildings with indoor pools
Furnaces installed in hobby or craft rooms
Furnaces installed near chemical storage areas
Furnaces installed in laundry rooms
Furnaces installed in hair salons
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4
5
6
4. Outlet air
5. Inlet air (Ends 12" above bottom)
6. Water heater
3. Outlet air
4. Water heater
5. Inlet air
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4
5
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