Lennox MERIT Series Installation Instructions Manual page 17

NOTE - Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake
and Exhaust must be same pipe size.
NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent
length calculation.
Num- 2" Pipe
ber Of
Model
90° El-
045 070
bows
1 81 66
2 76 61
3 71 56
4 66 51
5 61 46
6 56 41
7 51 36
8 46 31
9 41 26
10 36 21
Num- 2" Pipe
ber Of
Model
90° El-
045 070
bows
1 81 66
2 76 61
3 71 56
4 66 51
5 61 46
6 56 41
7 51 36
8 46 31
9 41 26
10 36 21
Standard Termination at Elevation 0 - 4500 ft
090 110 045
44 24 115
39 19 110
34 14 105
29 100
24 95
19 90
14 n/a 85
80
n/a 75
70
Standard Termination Elevation 4500 - 10,000 f
090 110 045
44 115
39 110
34 105
29 100
24 95
n/a
19 90
14 85
80
n/a
75
70
TABLE 7
2-1/2" Pipe
Model
070 090 110
115 93 58
110 88 53
105 83 48
100 78 43
95 73 38
90 68 33
85 63 28
80 58 23
75 53 18
70 48 13
2-1/2" Pipe
Model
070 090 110
115 93 58
110 88 53
105 83 48
100 78 43
95 73 38
90 68 33
85 63 28
80 58 23
75 53 18
70 48 13
Page 17
3" Pipe
Model
045 070 090
138 137 118
133 132 113
128 127 108
123 122 103
118 117 98
113 112 93
108 107 88
103 102 83
98 97 78
93 92 73
t
3" Pipe
Model
045 070 090
138 137 118
133 132 113
128 127 108
123 122 103
118 117 98
113 112 93
108 107 88
103 102 83
98 97 78
93 92 73
110
118
113
108
103
98
93
88
83
78
73
110
118
113
108
103
98
93
88
83
78
73