Carrier PG92MSA - Page 32

PG92MSA: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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outdoor atmosphere. Air for combustion must be supplied as described
in the Air For Combustion and Ventilation Section. Do not use an
abandoned chimney to supply outside air to the furnace. See Fig. 44 for
references to vent clearances required by National code authorities.
A combustion air pipe to the outdoors is not required for a single-pipe
vent system. A 12-in. (304 mm) long pipe with a 2-in. (51 mm) tight
radius 90 degree elbow is required to be attached to the combustion air
pipe adapter on the furnace. See Fig. 49. This short inlet air pipe helps to
ensure stable combustion, as well as allow for sound attenuation. To aid
sound attenuation, point the inlet air pipe away from occupants. An extra
elbow and/or five feet of pipe may be used to accomplish the sound
attenuation function.
A13305
Fig. 40 – Combustion Air and Vent Pipe Termination for Direct Vent (2-Pipe) System
A05091
Fig. 41 – Vent Pipe Termination for Non-Direct Vent and Ventilated Combustion Air System
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12 in. (305mm) min. separation
between bottom of combustion
air and bottom of vent (Typ.)
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