19
If the combustion air intake pipe is to be installed above a finished
ceiling or other area where dripping of condensate will be objec-
tionable, insulation of the combustion air pipe may be required.
Use 1/2” thick closed cell foam insulation such as Armaflex™ or
Insultube™ where required.
V
ENT
/F
LUE
AND
C
OMBUSTION
A
IR
P
IPE
T
ERMINATIONS
The vent/flue and combustion air pipes may terminate vertically, as
through a roof, or horizontally, as through an outside wall.
1
2
3
4
5
6
7
8
Standard
2 or 2 1/2
71
68
65
62
59
56
53
50
Alternate
2 or 2 1/2
58
55
52
49
46
43
40
37
2 or 2 1/2
49
46
43
40
37
34
31
28
3
71
68
65
62
59
56
53
50
2 or 2 1/2
36
33
30
27
24
21
18
15
3
57
54
51
48
45
42
39
36
Standard
3
71
68
65
62
59
56
53
50
Alternate
3
57
54
51
48
45
42
39
36
Standard
3
49
46
43
40
37
34
31
28
Alternate
3
35
32
29
26
23
20
17
14
*Maximum allowable limits listed are individual lengths for inlet & flue and NOT a combination.
1
2
3
4
5
6
7
8
2 or 2 1/2
49
46
43
40
37
34
31
28
3
71
68
65
62
59
56
53
50
2 or 2 1/2
36
33
30
27
24
21
18
15
3
57
54
51
48
45
42
39
36
2 or 2 1/2
61
58
55
52
49
46
43
40
3
71
68
65
62
59
56
53
50
2 or 2 1/2
48
45
42
39
36
33
30
27
3
57
54
51
48
45
42
39
36
Standard
3
71
68
65
62
59
56
53
50
Alternate
3
57
54
51
48
45
42
39
36
*Maximum allowable limits listed are individual lengths for inlet & flue and NOT a combination.
115,000
Number of Elbows
(1)(2)(3)(5)
Direct Vent (Dual Pipe) Maximum Allowable Length*
of Vent/Flue & Combustion Air Intake Pipe
(ft)
UPFLOW
Pipe
(4)
(inch)
Termination
Style
Unit Input
(Btu)
45,000
Standard
Alternate
70,000
90,000
115,000
COUNTERFLOW
Direct Vent (Dual Pipe) Maximum Allowable Length*
of Vent/Flue & Combustion Air Intake Pipe
(ft)
Unit Input
(Btu)
Termination
Style
Pipe
(4)
(inch)
Number of Elbows
(1)(2)(3)(5)
90,000
Standard
Alternate
70,000
Standard
Alternate
1) Elbows and/or tees used in terminations must be included when determin-
ing quantity of allowable elbows in the system.
2) Number of elbows tabulated are for each (Vent/Flue & Combustion Air
Intake) pipe.
3) Minimum requirements for each Vent/Flue & Combustion Air Intake pipe is
five (5) feet in length and one elbow/tee.
4) 2 1/2” or 3” diameter pipe can be used in place of 2” diameter pipe.
5) Increased Clearance Configurations using (2) 45 deg. Long Sweep el-
bows should be considered equivalent to one 90 deg. elbow.
Vertical pipe terminations should be as shown in the following
figure.
Refer to Vent/Flue Pipe and Combustion Pipe - Termina-
tion Locations
for details concerning location restrictions. The
penetrations through the roof must be sealed tight with proper
flashing such as is used with a plastic plumbing vent.
VENT/FLUE
COMBUSTION
AIR INTAKE
SCREEN
(OPTIONAL)
12" MIN. TO ROOF
OR HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN.
TEE (OPTIONAL)
_______________________
SCREEN
(OPTIONAL)
12" MIN. TO ROOF
OR HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN.
VENT/FLUE
Vertical Terminations (Dual Pipe)
Horizontal terminations should be as shown in the following figure.
Refer to
Vent/Flue Pipe and Combustion Pipe - Termination Loca-
tion
for location restrictions. A 2 3/8” diameter wall penetration is
required for 2” diameter pipe. A 3” diameter hole is required for a 2
1/2” pipe and a 3 1/2” diameter hole is required for 3” diameter
pipe. To secure the pipe passing through the wall and prohibit
damage to piping connections, a coupling should be installed on
either side of the wall and solvent cemented to a pipe connecting
the two couplings. The pipe length 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 penetration should be sealed with
silicone caulking material.
90º or 45°
MEDIUM RADIUS
ELBOWS
3" MIN
24" MAX
12" MIN. TO ROOF OR
HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN. TO ROOF OR
HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN
3" MIN
24" MAX
SCREEN
(OPTIONAL)
Standard Horizontal Terminations (Dual Pipe)
