Lennox ELITE EL196UHE Installation Instructions Manual page 25

Maximum Allowable Exhaust Vent Pipe Length (in ft.)
Vent
Winter Design
Pipe
Temp °F (°C)
1
Diam
1-1/2 in
32 to 21
2 in
(0 to -6)
2-1/2 in
3 in
1-1/2 IN
2 in
20 to 1
(-7 to -17) 2-1/2 in
3 in
1-1/2 in
2 in
0 to -20
(-18 to -29) 2-1/2 in
3 in
1Refer to 99% Minimum Design Temperature table provided in the current edition of the ASHRAE Fundamentals Handbook.
2 Poly-Propylene vent pipe (PP) by Duravent and Centrotherm.
NOTE - Concentric terminations are the equivalent of 5' and should be considered when measuring pipe length.
NOTE - Maximum uninsulated vent lengths listed may include the termination(vent pipe exterior to the structure) and cannot exceed 5 linear feet or
the maximum allowable intake or exhaust vent length listed in table 5 or 6 which ever is less.
NOTE - If insulation is required in an unconditioned space, it must be located on the pipe closest to the furnace. See Figure 31.
3 Vent length in the table is equivalent length. Each elbow is equivalent to 5ft of straight pipe and should be included when measuring total length.
Winter Design Temperatures Single - Stage High Efficiency Furnace
030
PVC PP PVC
2
25
18
13
9
15
9
N/A N/A
5
1
10
5
1
N/A
Conditioned
Conditioned
Space
TABLE 7
3 Without Insulation In Unconditioned Space For
Unit Input Size
045 070
PP PVC
2 2
N/A 20 N/A
16 31 28
N/A 24 N/A
9 18 18
N/A 20 N/A
8 18 16
N/A 13 N/A
8
1
N/A 15 N/A
12 10
3
7 N/A
N/A
2
N/A
Space
Pipe Insulation
Unconditioned
Space
Figure 31
Page 25
090
PP PVC PP
2
N/A N/A
50 48
42 N/A
35 35
N/A N/A
32 29
24 N/A
8 19 19
N/A N/A
22 19
15 N/A
2 10 10
Exhaust
Pipe
Intake
Pipe
110
PVC PP
2
N/A N/A
30 30
56 N/A
47 47
N/A N/A
30 30
34 N/A
26 26
N/A N/A
30 27
22 N/A
16 16