Lennox DAVE SIGNATURE SL297UHNV Installation Instructions Manual page 17

Closet or Basement Using VentilatedAttic or Crawl Space For Intake Air 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
Number Of 90°
Elbows Used
040
1 71
2 66
3 61
4 56
5 51
6 46
7 41
8 36
9 31
10 26
TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN UPFLOW DIRECT OR
EXHAUST
Appliance
Adaptor
2"
Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a
Standard Termination at Elevation 0 - 4500 ft
2" Pipe
Model
060
56
51
46
41
36
31
26
21
16
11
NON-DIRECT VENT APPLICATIONS
EXHAUST
3"
TRANSITION
*2"
2"
INTAKE
* When transitioning up in pipe size, use the shortest length of 2" PVC pipe possible.
TABLE 6
080
34
29
24
19
14
9
4
n/a
INTAKE
Appliance
Adaptor
3"
*2"
TRANSITION
Figure 20
Page 17
3" Pipe
Model
040 060
118 117
113 112
108 107
103 102
98 97
93 92
88 87
83 82
78 77
73 72
2"
2"
2"
or
DO NOT transition
from smaller to larger
pipe in horizontal runs
of exhaust pipe.
080
98
93
88
83
78
73
68
63
58
53
2"