Lennox 20256877, Unit Information

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Page 25
TABLE 13
Maximum Allowable Intake or Exhaust Vent Length in Feet
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.
Standard Termination at Elevation 0 - 10,000
Number
Of 90°
Elbows
Used
1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model Model
030/
045
070 090 110 030/
045
070 090 110
030/
045
070 090 110
030/
045
070 090 110
1 25 20
n/a n/a
81 66 44 24 115 100 68 43 137 137 118 118
2 20 15 76 61 39 19 110 95 63 38 132 132 113 113
3 15 10 71 56 34 14 105 90 58 33 127 127 108 108
4 10 66 51 29
n/a
100 85 53 28 122 122 103 103
5
n/a
61 46 24 95 80 48 23 117 117 98 98
6 56 41 19 90 75 43 18 112 112 93 93
7 51 36 14 85 70 38 13 107 107 88 88
8 46 31
n/a
80 65 33
n/a
102 102 83 83
9 41 26 75 60 28 97 97 78 78
10 36 21 70 55 23 92 92 73 73
Concentric Termination Elevation 0 - 10,000
Number
Of 90°
Elbows
Usedl
1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model Model
030/
045
070 090 110 030/
045
070 090 110
030/
045
070 090 110
030/
045
070 090 110
1 20 15
n/a n/a
73 58 42 22 105 90 64 39 121 121 114 114
2 15 10 68 53 37 17 100 85 59 34 116 116 109 109
3 10
n/a
63 48 32 12 95 80 54 29 111 111 104 104
4
n/a
58 43 27
n/a
90 75 49 24 106 106 99 99
5 53 38 22 85 70 44 19 101 101 94 94
6 48 33 17 80 65 39 14 96 96 89 89
7 43 28 12 75 60 34
n/a
91 91 84 84
8 38 23
n/a
70 55 29 86 86 79 79
9 33 18 65 50 24 81 81 74 74
10 28 13 60 45 19 76 76 69 69
TABLE 14
VENT LENGTHS (EXHAUST) - VENTILATED ATTIC OR CRAWLSPACE INTAKE AIR - FEET
STANDARD TERMINATION AT ELEVATION 0 - 10,000 ft.
Pipe Size 1-1/2 in. 2 in. 2-1/2 in. 3 in.
Input 030/
045
070 090 110 030/
045
070 090 110 030/
045
070 090 110 030/
045
070 090 110
No. of
90 ELL
1 20 15 N/A N/A 71 56 34 14 100 100 78 43 118 117 98 98
2 15 10 N/A N/A 66 51 29 9 95 95 73 38 113 112 93 93
3 10 N/A N/A N/A 61 46 24 4 90 90 68 33 108 107 88 88
4 N/A N/A N/A N/A 56 41 19 N/A 85 85 63 28 103 102 83 83
5 N/A N/A N/A N/A 51 36 14 N/A 80 80 58 23 98 97 78 78
6 N/A N/A N/A N/A 46 31 9 N/A 85 75 63 18 93 92 73 73
7 N/A N/A N/A N/A 41 26 4 N/A 70 70 48 13 88 87 68 68
8 N/A N/A N/A N/A 36 21 N/A N/A 65 65 43 8 83 82 63 63
9 N/A N/A N/A N/A 31 16 N/A N/A 60 60 38 3 78 77 58 58
10 N/A N/A N/A N/A 26 11 N/A N/A 55 55 33 N/A 73 72 53 53
NOTES - Additional vent pipe and elbows used to terminate vent pipe outside the structure must be included in the total vent length calculation.