Atwood water heater plumbing question

[kkocan72]

In 2022 my water heater developed a slow leak and I had to replace a PVC fitting near the tank. It is a GCH10A-3E model.

This last weekend, the same thing happened and when I got the parts out the same fitting was cracked and leaking. In the image it is the white PVC coupling, it develops a crack running the length of the fitting on the section attached to the grey PEX 90.



My assumption is that since it is on the HW side of the backflow fitting that it gets HOT and cannot handle the heat. I'm working on redoing the plumbing and wonder if I can remove the grey 90 PEX fitting and replace with a brass 90. I have one with the proper threads but am wondering if that part of the water heater is also aluminum (my heater is and I don't need an anode rod) and the brass will react with the aluminum.

I also plan on getting rid of the PVC fitting and using a brass coupling if needed, plus I am also planning on running a longer PEX line from the 90 coming out of the heater and putting the backflow on the side instead of behind the heater to make it easer to maintain if needed. Is that a sound plan or does the backflow need to be close to the supply inlet of the actual heater?

My goal is to make this the LAST time I have to reach behind and work on this thing!

[Unplanned Tourist]

I wouldn't worry about going to full brass fittings. Seal the threads with teflon tape.

[kkocan72]

Originally Posted by Unplanned Tourist

I wouldn't worry about going to full brass fittings. Seal the threads with teflon tape.

To clarify, the leak has not been happening because of the threads. The leak occurs when the white coupling (1/2 PVC Female-Female) actually splits right up the length of the coupling. I would say the split is about 40% of the length with it happening on the end where it connects to the 90 coming out of the tank.

[Mudfrog]

That white PVC fitting is good for temperatures up to 140°. Some RV water heaters get hotter than that at times. I would nix that fitting and use a CPVC fitting instead. Don't see any reason to go to brass.

Also, it appears there's been a lot of pressure applied to the fitting in the OP's image. It should not have to be tightened to the extreme. Teflon tape is good but there are pipe dopes out there that may be better for this application.

[kkocan72]

Originally Posted by Mudfrog

That white PVC fitting is good for temperatures up to 140°. Some RV water heaters get hotter than that at times. I would nix that fitting and use a CPVC fitting instead. Don't see any reason to go to brass.

Also, it appears there's been a lot of pressure applied to the fitting in the OP's image. It should not have to be tightened to the extreme. Teflon tape is good but there are pipe dopes out there that may be better for this application.

Thanks, I was looking at CPVC also for the higher temp. I'm OP and in my original post I clarified that the "chewed up" was from trying to tighten it in the compartment behind the water heater. Almost no room to get pliers on it and could only turn it about 1/4 inch at a time. It wasn't that tight though.

Knowing the limit is 140ish I'm definitely thinking it just can't handle the heat being that close to the HW heater even though it is on the supply side but its on the wrong side of the backflow preventer. Maybe just going to CPVC will work.

Thanks!

[Old-Biscuit]

Brass is fine...the T&P Relief Valve is brass

Check Valve only needs to be located to stop backflow into tank via Hot outlet port when BYPASSED

Atwood T-stat opens at 140*F so PVC should not be used...Can use CPVC as it is rated up to 200*F
**ECO (Energy Cut Off/Hi Temp T-stat)trips at 180*F
T&P Relief Valve pops open at 210*F/150 psi

Use Brass or hi temp plastic for connections

[mokurt]

Originally Posted by Mudfrog

Also, it appears there's been a lot of pressure applied to the fitting in the OP's image. It should not have to be tightened to the extreme. Teflon tape is good but there are pipe dopes out there that may be better for this application.

Agree.
NPT threads are tapered and will expand the female thread when tightened.

[kkocan72]

Originally Posted by Old-Biscuit

Brass is fine...the T&P Relief Valve is brass

Check Valve only needs to be located to stop backflow into tank via Hot outlet port when BYPASSED

Atwood T-stat opens at 140*F so PVC should not be used...Can use CPVC as it is rated up to 200*F
**ECO (Energy Cut Off/Hi Temp T-stat)trips at 180*F
T&P Relief Valve pops open at 210*F/150 psi

Use Brass or hi temp plastic for connections

Thanks for confirming. I will be switching to all brass since its only a few more $ and worth the peace of mind!