Power Vented Hot Water Heater Question

[Mike L]

I am a housing inspector for a non-profit PHA in the area. I have a question that came up today during inspection and have not found any overly useful information in my brief search online.

We have a requirement in regards to hot water heaters that states, "hot water heater exhaust must have a minimum of 1/4" upward pitch to chimney/exterior." I ran into a hot water heater today that had a power vented unit on top of the hot water heater, and the exhaust was PVC and did not have an upward pitch. It did in fact have several 90 degree bends and went 90 degrees straight down before turning 90 degrees again.

My question boils down to this; does a power vented hot water heater need to have an exhaust pipe that pitches upward as it travels away from the water heater or can it have an even/downward pitch because of the vent unit on top?

I normally do not need to tackle issues such as this, but wanted to get the right information before forcing a landlord to fix an issue that isn't an actual issue.

Thank you!

 

[houndzilla]

I would need to consult my code books to verify, but my understanding is that the stated pitch is only for atmospheric vent heaters.

 

[Sponsor]

 

[Master Plumber Mark]

I would think it needs to at least be level because of the fact that the power vented unit
can get condensation water building up in the line..... I have seen them build up with water badly
and on many units there is a condensatoin drain port right on the top of the motor .....

Some older Smith units used to have a drain port in the 3 inch pvc high up overhead to prevent the building up of
water in the line...... If like you say, this unit goes down and across then goes back up again its basically
going to become like a glorified trap over time.......

Does that help some???