912SD: 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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abandoned chimney to supply outside air to the furnace. See
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
. 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
¾ in. (222mm) for 3 in. (76mm)
12 in. (305mm) min. separation
between bottom of combustion
air and bottom of vent (Typ.)
¾ in. (172mm) for 2 in. (51mm)
Abandoned masonry
used as raceway
(per code)
12 in. (305 mm) min. from
overhang or roof
Maintain 12 in. (305mm)
minimum clearance
above highest anticipated
snow level or grade
whichever is greater.
Side wall termination
with 2 elbows (preferred)
12 in. min. (305 mm)from
overhang or roof
Maintain 12 in. (305mm)
minimum clearance
above highest anticipated
snow level or grade
whichever is greater
6 in. (152mm) minimum clearance
between wall and end of vent pipe.
10 in. (254mm) maximum pipe length
Sidewall Termination
with Straight Pipe (preferred)
Roof Termination (Preferred)
Vent
Maintain 12 in
.
minimum clearance
above highest anticipated
snow level maximum of
24 in. (610mm) above roof
.
90
°
(305mm)