Lennox A97UH2E Installation Instructions Manual page 21

Maximum Allowable Exhaust Vent Lengths with Furnace Installed in a Closet or Basement Using Ventilated
1-1/2" Pipe
Number
Model
of 90°
Elbows
030
70
Used
045
1 20 15
2 15 10
3 10
4
5
6
n/a
7 n/a
8
9
10
1-1/2" Pipe
Number
Model
of 90°
Elbows
030
70
Used
045
1 20 15
2 15 10
3 10
4
5
6
n/a
7 n/a
8
9
10
NOTE: Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length
calculation.
508390-01
Attic or Crawl Space for Intake Air in Feet
Standard Termination at Elevation 0 - 4,500 ft
2" Pipe
Model
030
90 110 70
045
66 51
61 46
56 41
51 36
46 31
n/a n/a
41 26
36 21
31 16
26 11
21 6
Standard Termination Elevation 4,501 - 10,000 ft
2" Pipe
Model
030
90 110 70
045
66 51
61 46
56 41
51 36
46 31
n/a n/a
41 26
36 21
31 16
26 11
21 6
2-1/2" Pipe
Model
030
90 110 70
045
29 9 95 95
24 4 90 90
19 85 85
14 80 80
9 75 75
4 70 70
n/a
65 65
60 60
n/a
55 55
50 50
2-1/2" Pipe
Model
030
90 110 70
045
29 95 95
24 90 90
19 85 85
14 80 80
9 75 75
n/a
4 70 70
65 65
60 60
n/a
55 55
50 50
Table 5C.
Issue 2327
3" Pipe
Model
030
90 110 70
045
73 38 113 112
68 33 108 107
63 28 103 102
58 23 98 97
53 18 93 92
48 13 88 87
43 8 83 82
38 3 78 77
33 73 72
n/a
28 68 67
3" Pipe
Model
030
90 110 70
045
73 38 113 112
68 33 108 107
63 28 103 102
58 23 98 97
53 18 93 92
48 13 88 87
43 8 83 82
38 3 78 77
33 73 72
n/a
28 68 67
90 110
93 93
88 88
83 83
78 78
73 73
68 68
63 63
58 58
53 53
48 48
90 110
93 93
88 88
83 83
78 78
73 73
68 68
63 63
58 58
53 53
48 48
Page 21 of 60