Lennox ELITE EL195UHE Installation Instructions Manual page 25

Maximum Allowable Exhaust Vent Pipe Length (in ft.) Without Insulation In Unconditioned Space For
Winter Design Temperatures Single - Stage High Efficiency Furnace
Winter Design
1
Temperatures °F (°C)
32 to 21
(0 to -6)
20 to 1
(-7 to -17)
0 to -20
(-18 to -29)
1
Refer to 99% Minimum Design Temperature table provided in the current edition of the ASHRAE Fundamentals Handbook.
2
Poly-Propylene vent pipe (PP)
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.
Vent Pipe
Diameter
045
2
PVC PP
2 in. 26 24
2-1/2 in. 18 N/A
3 in. 14 12
2 in 16 15
2-1/2 in. 12 N/A
3 in. 9 8
2 in. 10 9
2-1/2 in. 8 N/A
3 in. 4 3
Conditioned
Conditioned
Space
TABLE 7
Unit Input Size
070 090
2
PVC PP PVC
44 41 44
32 N/A 50
26 23 38
28 26 40
20 N/A 30
16 14 26
20 18 30
14 N/A 20
10 8 16
Space
Pipe Insulation
Unconditioned
Space
FIGURE 30
Page 25
110
2 2
PP PVC PP PVC
44 24 24 N/A
N/A 58 N/A N/A
33 55 49 60
37 24 24 N/A
N/A 44 N/A N/A
23 32 28 40
28 24 24 N/A
N/A 32 N/A N/A
14 26 23 30
Exhaust
Pipe
Intake
Pipe
135
2
PP
N/A
N/A
53
N/A
N/A
35
N/A
N/A
26