CPVC Connected to Water Heater

I’m fairly new to the NACHI boards and I hate to post two questions almost back-to-back but here goes…

In the past I’ve seen CPVC connected directly to the water heater and have written it up with the following:

Currently, CPVC piping is connected directly to the water heater. The Plastic Pipe and Fittings Association (PPFA) recommends, “that on gas water heaters there should be at least 6 inches of clearance between the exhaust flue and any CPVC piping. Twelve inch long metal nipples or appliance connectors should be connected directly to the heater so that the CPVC tubing cannot be damaged by the build-up of excessive radiant heat from the flue.” I recommend a licensed plumber inspect further and repair as necessary.

Attached is the PPFA document I quote. It’s on the second PDF (Page 7) since I had to break it up into 3 PDF files to bypass the 256K upload limit for PDF files.

Do you agree/disagree with this write-up? If you agree, and this is what I saw yesterday, what if the lines are wrapped in an insulation sleeve? If the problem with CPVC connected directly to the WH is due to the radiant heat from the flue, would insulated sleeves remedy that problem? Or, if the heat from the flue can cause problems to the CPVC, would it also cause problems to an insulated sleeve?

Thanks guys in advance…I really appreciate this community of experts (and all the rest of you too:))!

I agree. Did you write up the foam insulation…I bet it’s in contact with the flue.

Did you write up the water heater laying sideways? :mrgreen:

Actually the foam insulation was not in contact with the flue…it’s was wrapped tightly around the pipe. So if there is insulation around the pipe protecting the CPVC from the radiant heat from the flue and the insulation is not touching the flue, would you let it pass?

The foam is a combustible material. Single wall vent pipe has a 6 inch clearance to combustible materials , double wall has a 1 inch clearance.


Okay, if it was a double walled vent pipe and there was 1" clearance from the foam insulation, would you then allow the CPVC?

I’ve never seen a double walled vent pipe at a water heater. They are always single until they merge into the furnace flue. and then both go double through the floor or wall.

Mark, a B-vent (double-walled) is what I see 95% of the time.

I think your recommendations are sound based on what you quoted. (I didn’t take the time to read the documents.) I don’t recall ever seeing CPVC connected like that.

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I agree with Joe, I have never seen CPVC attached like that. I would write it up as a substandard installation.


Thanks guys…I appreciate your input.

What distance is required for a power vented gas hot water heater using pvc pipe for vent and cpvc pipe directly connected to the hot water heater?

Is a power vent to pvc a flue ?

Is a flue a metal pipe