Maximum Allowable Exhaust Vent Pipe Length (In Ft.) Without Insulation - Lennox EL296UH045XE36B Unit Information

Maximum Allowable Exhaust Vent Pipe Length (in ft.) Without Insulation

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 17 or 18 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 figure27.
In Unconditioned Space For Winter Design Temperatures
Vent Pipe
Diameter
045
2
PVC PP
2 in. 20 18
2-1/2 in. 15 N/A
3 in. 12 10
2 in 12 11
2-1/2 in. 10 N/A
3 in. 6 5
2 in. 8 7
2-1/2 in. 6 N/A
3 in. 2 1
Conditioned
Conditioned
Space
FIGURE 27
TABLE 19
Unit Input Size
070 090
2
PVC PP PVC
30 28 40
22 N/A 30
18 15 25
20 18 25
14 N/A 20
10 8 15
12 11 18
8 N/A 12
6 5 10
Space
Pipe Insulation
Unconditioned
Space
Page 33
110
2 2
PP PVC PP PVC
36 24 24 N/A
N/A 40 N/A N/A
21 32 28 42
22 24 24 N/A
N/A 24 N/A N/A
12 20 17 22
16 22 20 N/A
N/A 16 N/A N/A
10 12 11 15
Exhaust
Pipe
Intake
Pipe
135
2
PP
N/A
N/A
37
N/A
N/A
18
N/A
N/A
12