Use the following steps to correctly size vent pipe diameter.
Piping Size Process
What is the
furnace capacity?
1045, 070, 090,
110 or 135?
Which style termination
2being used?
Standard or concentric?
See table 4.
Which needs
3most elbows?
Intake or exhaust?
How many elbows?
4Count all elbows inside and outside house.
Desired pipe size?
52”,
What is the altitude of
6the furnace installation?
Use table 5 or 6 to find max intake or exhaust pipe
7length. Includes all vent pipe and elbows inside and outside the house.
FIGURE 23
IMPORTANT
Do not use screens or perforated metal in exhaust or intake terminations. Doing so will cause
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