Lennox MERIT ML195UH Installation Instructions Manual page 20

Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated
NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent
length calculation.
2" Pipe
Number
Model
Of 90°
Elbows
045 070 090
1 71 56
2 66 51
3 61 46
4 56 41
5 51 36
6 46 31
7 41 26
8 36 21
9 31 16
10 26 11
2" Pipe
Number
Model
Of 90°
Elbows
045 070 090
1 71 56
2 66 51
3 61 46
4 56 41
5 51 36
6 46 31
7 41 26
8 36 21
9 31 16
10 26 11
Attic or Crawl Space For Intake Air in Feet
Standard Termination at Elevation 0 - 4500 ft
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
Standard Termination Elevation 4500 - 10,000 f
110 135 045
34 100
29 95
24 90
19 85
14 80
n/a n/a
9 75
4 70
65
n/a 60
55
TABLE 6
2-1/2" Pipe
Model
070 090 110 135
100 78 43
95 73 38
90 68 33
85 63 28
80 58 23
n/a
75 53 18
70 48 13
65 43 8
60 38 3
55 33 n/a
2-1/2" Pipe
Model
070 090 110 135
100 78 43
95 73 38
90 68 33
85 63 28
80 58 23
n/a
75 53 18
70 48 13
65 43 8
60 38 3
55 33 n/a
Page 20
3" Pipe
Model
045 070 090 110
128 117 98 98
113 112 93 93
108 107 88 88
103 102 83 83
98 97 78 78
93 92 73 73
88 87 68 68
83 82 63 63
78 77 58 58
73 72 53 53
t
3" Pipe
Model
045 070 090 110
118 117 98 98
113 112 93 93
108 107 88 88
103 102 83 83
98 97 78 78
93 92 73 73
88 87 68 68
83 82 63 63
78 77 58 58
73 72 53 53
135
94
89
84
79
74
69
64
59
54
49
135
94
89
84
79
74
69
64
59
54
49