20
NOTES:
■
Minimum length of each vent/flue and combustion air intake
pipe is 60" (1.5 m) and one elbow/tee.
■
Elbows and/or tees used in the terminations must be
included when determining the number of elbows in the
piping system.
■
2
¹⁄₂
" (6.4 cm) or 3" (7.6 cm) diameter pipe can be used in
place of 2" (5.1 cm) diameter pipe.
■
Increased clearance configurations using two 45º long-sweep
elbows should be considered equivalent to one 90º elbow.
Vent/Flue and Combustion Air Pipe Terminations
The vent/flue and combustion air pipes may terminate vertically,
as through a roof, or horizontally, as through an outside wall.
Vertical pipe terminations should be as shown in “Vertical
Terminations (Dual Pipe)” illustration. Refer to “Termination
Locations” in this section for details concerning location
restrictions. The penetrations through the roof must be sealed
tight with the proper flashing such as is used with a plastic
plumbing vent.
Vertical Vent Terminations (Dual Pipe)
Horizontal terminations should be as shown in “Standard
Horizontal Vent Terminations (Dual Pipe)” illustration. Refer to
“Termination Locations” in this section for location restrictions.
■
A 2
³⁄₈
" (6.1 cm) diameter wall penetration is required for 2"
(5.1 cm) diameter pipe.
■
A 3" (7.6 cm) diameter hole is required for a 2
¹⁄₂
" (6.4 cm)
pipe.
■
A 3
¹⁄₂
" (8.9 cm) diameter hole is required for 3" (7.6 cm)
diameter pipe.
■
To secure the pipe passing through the wall and prohibit
damage to the piping connections, a coupling should be
installed on either side of the wall and solvent cemented to a
length of pipe connecting the 2 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 penetration should be sealed with silicone caulking
material.
Direct Vent (Dual Pipe) Maximum Allowable Length of Vent/Flue and Combustion Air Intake Pipe—ft (m)
Number of Elbows
Unit Input (Btu)
Termination Style
Pipe—in. (cm)
2
3
4
5
6
7
8
040_3 or 045_3
Standard
2 or 2
¹⁄₂
(5.12 or 6.4)
68 (20.7)
65 (19.8) 62 (18.9) 59 (18)
56 (17.1) 53 (16.2) 50 (15.2)
Alternate
2 or 2
¹⁄₂
(5.12 or 6.4)
55 (16.8)
52 (15.8) 49 (14.9) 46 (14)
43 (13.1) 40 (12.2) 37 (11.3)
060_3 or 070_3
Standard
2 or 2
¹⁄₂
(5.12 or 6.4)
68 (20.7)
65 (19.8) 62 (18.9) 59 (18)
56 (17.1) 53 (16.2) 50 (15.2)
Alternate
2 or 2
¹⁄₂
(5.12 or 6.4)
55 (16.8)
52 (15.8) 49 (14.9) 46 (14)
43 (13.1) 40 (12.2) 37 (11.3)
070_4
Standard
2 or 2
¹⁄₂
(5.12 or 6.4)
46 (14)
43 (13.1) 40 (12.2)
Not Recommended
3 (7.6)
68 (20.7)
65 (19.8) 62 (18.9) 59 (18)
56 (17.1) 53 (16.2) 50 (15.2)
Alternate
2 or 2
¹⁄₂
(5.12 or 6.4)
33 (10.1)
30 (9.2)
27 (8.2)
Not Recommended
3 (7.6)
54 (16.5)
51 (15.5) 48 (14.6) 45 (13.7) 42 (12.8) 39 (11.9) 36 (11)
090_4
Standard
3 (7.6)
68 (20.7)
65 (19.8) 62 (18.9) 59 (18)
56 (17.1) 53 (16.2) 50 (15.2)
Alternate
3 (7.6)
55 (16.8)
52 (15.8) 49 (14.9) 46 (14)
43 (13.1) 40 (12.2) 37 (11.3)
080_5 or 090_5
Standard
3 (7.6)
68 (20.7)
65 (19.8) 62 (18.9) 59 (18)
56 (17.1) 53 (16.2) 50 (15.2)
Alternate
3 (7.6)
55 (16.8)
52 (15.8) 49 (14.9) 46 (14)
43 (13.1) 40 (12.2) 37 (11.3)
100_5 or 115_5
Standard
3 (7.6)
68 (20.7)
65 (19.8) 62 (18.9) 59 (18)
56 (17.1) 53 (16.2) 50 (15.2)
Alternate
3 (7.6)
55 (16.8)
52 (15.8) 49 (14.9) 46 (14)
43 (13.1) 40 (12.2) 37 (11.3)
A. 12" (30.5 cm) minimum
B. Combustion air intake pipe
C. 45º or 90º medium radius elbows
D. Tee
E. Vent/flue pipe
F. 24" (61 cm) maximum, 3"
(7.6 cm) minimum
G. Screen (optional)
H. 12" (30.5 cm) minimum to roof or
highest anticipated snow level
E
D
C
B
G
F
A
H
