Lennox ML196UHE Installation Instructions Manual page 21

Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using
NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total
vent length calculation.
1-1/2" Pipe
No 90° Model
Elbows
030 045 070
1 20 15 10
2 15 10
3 10
4
5
6 n/a
n/a
7 n/a
8
9
10
Ventilatd Attic or Crawl Space For Intake Air in Feet
Standard Termination at Elevation 0 - 10000 ft
030
090 110 135 070
045
71 56
66 51
61 46
56 41
51 36
n/a n/a n/a
46 31
41 26
36 21
31 16
26 11
TABLE 6
2" Pipe
Model
030
090 110 135
045
34 14 100
29 9 95
24 4 90
19 85
14 80
n/a
9 75
4 n/a 70
65
n/a 60
55
Page 21
2-1/2" Pipe
Model
030
070 090 110 135
045
100 78 43 118
95 73 38 113
90 68 33 108
85 63 28 103
80 58 23 98
n/a
75 53 18 93
70 48 13 88
65 43 8 83
60 38 3 78
55 33 n/a 73
3" Pipe
Model
070 090 110 135
117 98 98 60
112 93 93 55
107 88 88 50
102 83 83 45
97 78 78 40
92 73 73 35
87 68 68 30
82 63 63 25
77 58 58 20
72 53 53 15