Lennox MERIT Series Installation Instructions Manual page 18

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 - dditional 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 73 58
2 68 53
3 63 48
4 58 43
5 53 38
6 48 33
7 43 28
8 38 23
9 33 18
10 28 13
Num- 2" Pipe
ber Of
Model
90° El-
045 070
bows
1 73 58
2 68 53
3 63 48
4 58 43
5 53 38
6 48 33
7 43 28
8 38 23
9 33 18
10 28 13
TABLE 7 Continued
Concentric Termination at Elevation 0 - 4500 ft
090 110 045
42 22 105
37 17 100
32 12 95
27 90
22 85
17 80
12 n/a 75
70
n/a 65
60
Concentric Termination Elevation 4500 - 10,000 f
090 110 045
42 105
37 100
32 95
27 90
22 85
n/a
17 80
12 75
70
n/a 65
60
2-1/2" Pipe
Model
070 090 110
105 89 54
100 84 49
95 79 44
90 74 39
85 69 34
80 64 29
75 59 24
70 54 19
65 49 14
60 44 n/a
2-1/2" Pipe
Model
070 090 110
105 89 54
100 84 49
95 79 44
90 74 39
85 69 34
80 64 29
75 59 24
70 54 19
65 49 14
60 44 n/a
Page 18
3" Pipe
Model
045 070 090
121 121 114
116 116 109
111 111 104
106 106 99
101 101 94
96 96 89
91 91 84
86 86 79
81 81 74
76 76 69
t
3" Pipe
Model
045 070 090
121 121 114
116 116 109
111 111 104
106 106 99
101 101 94
96 96 89
91 91 84
86 86 79
81 81 74
76 76 69
110
114
109
104
99
94
89
84
79
74
69
110
114
109
104
99
94
89
84
79
74
69