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-- 44 --
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)
A05091
Fig. 43 -- Vent Pipe Termination for Non-Direct Vent (1-pipe) System
CARBON MONOXIDE POISONING AND PROPERTY
DAMAGE HAZARD
Failure to follow this warning could result in property damage,
personal injury or death.
Vent pipe must be installed and fully seated against inducer
housing internal stop. Clamp must be tightened to prevent any
condensate leakage.
!
WARNING
6. Install casing hole filler cap (factory-supplied in loose
parts bag) in unused vent pipe casing hole.
Attachment of Vent Extension Pipe
Furnaces with 100,000 Btuh and larger input are supplied with a
PVC vent extension pipe (2--in. (51 mm) diameter by 12--in. (305
mm) long). This pipe has a built-in channel to assist vent
condensate disposal. When this vent extension pipe is supplied, it
MUST be used to connect the field vent pipe to furnace inducer
housing on ALL upflow and downflow applications.
NOTE
: See label on vent extension pipe for proper installation.
This pipe may be shortened if an elbow is used to connect vent
extension tube to field-installed vent pipe.
Installation Guidelines for Combustion Air Pipe and Vent
Pipe
It is recommended that all pipes be cut, prepared, and
pre-assembled before permanently cementing any joint.
1. Attach combustion air pipe and vent pipe per instructions
in sections “Combustion Air Pipe” and “Vent Pipe.”
2. Working from furnace to outside, cut pipe to required
length(s).
3. Deburr inside and outside of pipe.
4. Chamfer outside edge of pipe for better distribution of
primer and cement.
5. Clean and dry all surfaces to be joined.
6. Check dry fit of pipe and mark insertion depth on pipe.
7. After pipes have been cut and preassembled, apply
generous layer of cement primer to pipe fitting socket and
end of pipe to insertion mark. Quickly apply approved
cement to end of pipe and fitting socket (over primer).
Apply cement in a light, uniform coat on inside of socket
to prevent buildup of excess cement. Apply second coat.
8. While cement is still wet, twist pipe into socket with 1/4
turn. Be sure pipe is fully inserted into fitting socket.
9. Wipe excess cement from joint. A continuous bead of
cement will be visible around perimeter of a properly
made joint.
10. Handle pipe joints carefully until cement sets.
11. Horizontal portions of the venting system shall be
supported to prevent sagging support. Support combustion
air piping (if applicable) and vent piping a minimum of
every 5 ft (1.5 M)(3 ft (.9 M) for SDR-21 or -26 PVC)
using perforated metal hanging strap.
12. Slope combustion air piping (if applicable) and vent piping
downward towards furnace a minimum of 1/4 in. (6 mm)
per linear ft with no sags between hangers.
13. Horizontal portions of the venting system shall be installed
so as to prevent the accumulation of condensate.
14. Use appropriate methods to seal openings where
combustion air pipe (if applicable) and vent pipe pass
through roof or sidewall.
VENT TERMINATION
General
Combustion-air (direct vent/2-pipe system only) and vent pipe
must terminate outside structure, either through sidewall or roof.
For vent termination clearance, refer to Table 8 for Direct
Vent/2-Pipe system and Table 9 for Non-direct Vent/1-Pipe
system. For exterior piping arrangements, refer to Fig. 42 for
Direct
Vent/2-Pipe
system
and
Fig.
43
for
Non-Direct/1-Pipe system.
Roof termination is preferred since it is less susceptible to
damage or contamination, and it has less visible vent vapors.
Sidewall termination require sealing or shielding of building