28
VENTING
8.7 Rear Venting
IMPORTANT: Horizontal vent sections require 1/4 in (6 mm) rise
for every 12 in (305 mm) of travel.
IMPORTANT: A wall thimble pass-through must be used on all
horizontal vent runs that pass through interior or exterior walls.
Follow vent manufacturer’s instructions.
8.7.1 Horizontal Terminations
Table 8.6, NG/LPG - Minimum / Maximum Horizontal Venting
Minimum Horizontal Length (H
MIN
)
Maximum Horizontal Length (H
MAX
)
6 in
152 mm
24 in
610 mm
Table 8.7, NATURAL GAS ONLY REAR VENT OPTION
Horizontal Venting
Maximum Horizontal Length
45° elbow
18 in
457 mm
8.7.2 Combination Venting
Table 8.8, NG/LPG - Minimum / Maximum Vertical Terminations
Horizontal to Vertical
Venting
Minimum Vertical
Length
Maximum Vertical
Length
90° elbow
3 ft
914 mm
50 ft
15.2 m
Table 8.9, NG/LPG - Max Vertical / Max Horizontal Combination
Maximum
Vertical Rise
Maximum
Horizontal Run
Total Length
20 ft
6.1 m
20 ft
6.1 m
40 ft
12.9 m
Maximum number of 90° elbows: 4
0
2
4
6
8
10
12
14
16
20
22
18
24
26
28
30
40
38
36
34
32
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
(6.1m)
(12.9m)
(6
.1
m
)
(9
.1
4m
)
(ft.)
42
44
46
48
50
(15.2m)
Figure 8.3, NG/LPG Rear Vent Combination Venting (H/V)
REAR VENTING DIAGRAM (HORIZONTAL & VERTICAL TERMINATIONS)
(A)
Stand-off Brackets
(B)
Stand-off Heat Shields
(C)
90
°
Elbow
(D)
Termination Cap
D
B
A
B
A
D
C
H
MIN
H
MAX
NG/LPG - 6” (152mm) H
MIN
/ 24” (610mm) H
MAX
NATURAL GAS OPTION ONLY : 45° ELBOW + 18” (457mm) MAX
NG/LPG - 90° ELBOW + 3ft (914mm) MIN / 50ft (15.2m) MAX
