Lennox EL195UHE Installation Instructions Manual page 25

Maximum Allowable Exhaust Vent Pipe Length (in ft.) Without Insulation In Unconditioned Space For
Vent
Winter Design
Pipe
Temp °F (°C)
1
Diam
32 to 21
2 in
(0 to -6)
2-1/2 in 13
3 in
2 in
20 to 1
2-1/2 in 5
(-7 to -17)
3 in
2 in
0 to -20
2-1/2 in N/A
(-18 to -29)
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 figure30.
Winter Design Temperatures Single - Stage High Efficiency Furnace
030
030 045
PP
PVC 2 PVC
17 16 18
N/A 13
10 10 9
9 7 9
5
N/A N/A
4 N/A 5
N/A
N/A N/A
Conditioned
Space
TABLE 7
Unit Input Size
070
PP PP
2 PVC 2 PVC
16 31 28
N/A 24 N/A
9 18 18
8 18 16
13 N/A
8 8
N/A 12 10
7 N/A
N/A N/A
Conditioned
Space
Pipe Insulation
Unconditioned
Space
FIGURE 30
Page 25
090 110
PP
2 PVC 2
50 48 30
42 N/A 56 N/A
35 35 47
32 29 30
24 N/A 34 N/A
19 19 26
22 19 30
15 N/A 22 N/A
10 10 16
Exhaust
Pipe
Intake
Pipe
135
PP PP
PVC 2
30 N/A N/A
N/A N/A
47 52 52
30 N/A N/A
N/A N/A
26 30 30
27 N/A N/A
N/A N/A
16 18 18