Allied A93UH1E - Page 27

508107-01 Issue 2041 Page 27 of 58
Use the following steps to correctly size vent pipe diameter.
030, 045,
070, 090,
110, 135
Standard or
Concentric?
See Table 3
Intake or
Exhaust?
1-1/2”, 2”,
2-1/2”
or 3”
Furnace capacity?
1
Which termination?
2
Which needs most
elbows?
3
How many?
4
Desired pipe size?
5
What is the altitude?
6
Use Table 11 through
Table 13 to find max
pipe length.
7
Figure 22. Vent Pipe Diameter Sizing