# Water Heater Backflo Valve



## HogaRoo (Oct 23, 2007)

Our first camping trip of the season had us with no hot water pressure on the second day. After much head scratching and help from some seasoned campers I found the check valve in the outlet of the hot water tank was sticking, so I removed it. What is its purpose, do I need it and if so where do I get one?


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## W4DRR (May 17, 2005)

I had two of those to go out on me so far. The quick fix is just remove it, pull the plunger out, and re-install it. Of course, then it will just be a pipe union, and no longer a back-flow preventer check valve. If you want to replace it, try your local RV dealer, or go to go-rv.com. They are on P.350 of their current on-line catalog. Their purpose in life is to prevent anti-freeze from entering the water heater when you have the bypass valve in the bypass position, and are pumping in the pink stuff.
I think what is happening with them is the spring is corroding and finally breaks. Without a spring, they slam shut and do not allow any water out of the tank. One theory of mine is, since some, if not all, Atwood water heaters do not have an anode rod to prevent corrosion, the spring becomes the sacrificial metal and corrodes. After the second failure, I have also installed an aftermarket (Camco) anode rod in my Atwood heater as a just-in-case, feel good, thing.
As for me, I have always blown the lines out instead of using anti-freeze, so with the second failure of the valve, I may not replace it until time to sell the trailer.

Bob


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## HogaRoo (Oct 23, 2007)

When I took it apart the needle type valve came out but I didn't see a spring. there was a rubber gasket that wasn't seated correctly so I reseated it and put it back together. It didn't work but there was no spring and I couldn't figure how it could work without one. I guess if I want to repair it correctly I have to replace the whole assembly you can't just get the spring and needle? I also used air to purge my lines instead of antifreeze. I believe I'll just leave it alone for now. It works and is not leaking. That tells me to leave well enough alone.


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## CamperAndy (Aug 26, 2004)

W4DRR said:


> One theory of mine is, since some, if not all, Atwood water heaters do not have an anode rod to prevent corrosion, the spring becomes the sacrificial metal and corrodes. After the second failure, I have also installed an aftermarket (Camco) anode rod in my Atwood heater as a just-in-case, feel good, thing.
> As for me, I have always blown the lines out instead of using anti-freeze, so with the second failure of the valve, I may not replace it until time to sell the trailer.
> 
> Bob


There is no significant benefit to an Anode in an Aluminum tank unless the anode is a much less noble metal, a zinc anode would not do much but a I think a Magnesium anode could help some. The spring should not corrode due to electrolysis in the water (as the tank take over there) but could oxidize when exposed to air while in storage.


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## W4DRR (May 17, 2005)

CamperAndy said:


> There is no significant benefit to an Anode in an Aluminum tank unless the anode is a much less noble metal


The anode rods they sell for Atwood are magnesium. You are right, the anode rod needs to be more "active" than the metal it is protecting.

Bob


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