Question on powervent water heater

[Michael Roberson]

I dont have a picture handy, but I seem to remember that a vent pipe (sch 40) must run vertical off of the blower for a distance before making any turns. Anyone know how far that is, or if I am all wet?

[Bob Elliott]

Yeah you are correct and no do not recall without lookup.

[Michael Roberson]

24" sticks in my head. But I cant remember exactly. At least I know to differ to a plumber.

[Michael Roberson]

Ok heres the picture.

[Christopher Currins]

This is from an AO Smith I installed for my brother. Factors are BTU's and size of pipe, 2, 3, or 4 inch.

MAXIMUM AND MINIMUM VENT LENGTHS
40,000 BTU Units:
For 2" Venting, the maximum equivalent feet of pipe allowed is 40

feet (12.2 m).

This does not include the supplied vent termination for

the water heater. For the 2" venting, one 90° elbow is approximately

equal to 5 feet (1.5 m). One 45° elbow is approximately equal to 2.5
feet (0.8 m). It is recommended that at least 2 feet (0.6 m) of spacing
be used in between all 45° elbows and all 90°elbows.

For 3" Venting, the maximum equivalent feet of pipe allowed is
120 feet (36.6 m).

This does not include the Vent Termination (supplied

locally) for the water heater. For the 3" venting, one 90° elbow is

approximately equal to 5 feet (1.5 m). One 45° elbow is approximately
equal to 2.5 feet (0.8 m). It is recommended that at least 2 feet (0.6 m)
of spacing be used in between all 45° elbows and all 90°elbows.

For 4" Venting, the maximum equivalent feet of pipe allowed is
160 feet (48.8 m).

This does not include the Vent Termination (supplied

locally) for the water heater. For the 4" venting, one 90° elbow is

approximately equal to 8 feet (2.4 m). One 45° elbow is approximately
equal to 4 feet (1.2 m). It is recommended that at least 2 feet (0.6 m)

of spacing be used in between all 45° elbows and all 90°elbows.

http://www.hotwater.com/lit/im/res_gas/315465-000.pdf