COMBUSTION AND VENTILATION AIR
(DIRECT/NON-DIRECT VENT MODELS)
26
Rev. 0
bustion air intake to prevent inadvertent blockage. The tee
used in the vent/flue termination must be included when
determining the number of elbows in the piping system.
Unit Input
(BTU)
Pipe
Size
(inc.)
1
2
3
4
5
6
7
8
45,000
2
71
68
65
62
59
56
53
50
70,000
2
71
68
65
62
59
56
53
50
90,000
2
62
60
57
55
52
50
47
45
115,000
2
47
45
42
40
37
35
32
30
[0 - 4,500 ft]
3
114
111
107
104
100
97
93
90
115,000
2
27
25
22
20
17
15
12
10
[4,500 - 11,000 ft]
3
61
58
55
52
49
46
43
40
Non-Direct Vent (Single Pipe)
Maximum Allowable Length of Vent/Flue Pipe (ft)
(1) (2)
Number of Elbows
(3)
(1) One 90° elbow must be secured to the combustion air intake con-
nection.
(2) Minimum vent length is five feet and one elbow/tee.
(3) Tee used in the vent/flue termination must be included when deter-
mining the number of elbows in the piping system.
Vent/Flue Pipe Terminations
The vent/flue pipe may terminate vertically, as through a
roof, or horizontally, as through an outside wall.
Vertical vent/flue pipe terminations should be as shown in
the following figure. Refer to
Vent/Flue Pipe and Combus-
tion Air Pipe - Termination Locations section for details con-
cerning location restrictions. The penetration of the vent
through the roof must be sealed tight with proper flashing
such as is used with a plastic plumbing vent.
12 " Min To
Roof Or
Highest Anticipated
Snow Level
TEE
Vertical Termination (Single Pipe)
Horizontal vent/flue pipe terminations should be as shown
in the following figure. Refer to
Vent/Flue Pipe and Com-
bustion Air Pipe - Termination Locations section for details
concerning location restrictions. A 2 3/8” diameter wall pen-
etration is required for 2” diameter pipe while a 3 1/2” diam-
eter hole is required for 3” diameter pipe. To secure the
pipe passing through the wall and prohibit damage to pip-
ing connections, a coupling should be installed on either
side of the wall and solvent cemented to a length of pipe
connecting the two couplings. The length of pipe should be
the wall thickness plus the depth of the socket fittings to be
installed on the inside and outside of the wall. The wall pen-
etration should be sealed with silicone caulking material.
MIN.
12"
FROM
WALL
12"
TO GROUND OR
HIGHEST ANTICIPATED
SNOW LEVEL
WALL
INSIDE
OUTSIDE
TEE
COUPLING
ELBOW OR
COUPLING
Horizontal Termination (Single Pipe)
12' MIN.
VENT/FLUE
TEE
12' MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
Horizontal Termination (Single Pipe)
Above Highest Anticipated Snow Level
In a basement installation, the vent/flue pipe can be run
between joist spaces. If the vent pipe must go below a joist
and then up into the last joist space to penetrate the header,
two 45° elbows should be used to reach the header rather
than two 90° elbows.
