507762-01
Issue 1907
Page 20 of 46
Table 6.
Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated Attic or Crawl
Space For Intake Air in Feet
Standard Termination at Elevation 0 - 4500 ft
Number of 90°
Elbows Used
2" Pipe
3" Pipe
Model
Model
040
060
080
100
040
060
080
100
1
71
56
34
14
118
117
98
98
2
66
51
29
9
113
112
93
93
3
61
46
24
4
108
107
88
88
4
56
41
19
n/a
103
102
83
83
5
51
36
14
98
97
78
78
6
46
31
9
93
92
73
73
7
41
26
4
88
87
68
68
8
36
21
n/a
83
82
63
63
9
31
16
78
77
58
58
10
26
11
73
72
53
53
NOTE
- Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length
calculation.
* When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.
TRANSITION
2”
2”
2”
3”
2”
2”
or
DO NOT transition
from smaller to larger
pipe in horizontal runs
of
exhaust pipe
.
EXHAUST
*2”
INTAKE
TRANSITION
3”
*2”
EXHAUST
INTAKE
2”
Appliance
Adaptor
Appliance
Adaptor
Figure 26.
Typical Exhaust and Intake Pipe Connections in Upflow Direct Vent Applications
