Water tank leak

[deerislandbrew]

This has been discussed on the forum in length, with several different solutions. If it is a concern Grainger sells aluminum pipe nipples.

Where on the forum? What subject thread?

[dryfly]

Where on the forum? What subject thread?

Here is one that had several ideas:

https://www.mygrandrv.com/forum/show...020-350M/page3

[deerislandbrew]

I looked at the thread where this was discussed previously. The consensus seems to be of using a non conductive fitting between the tank and brass check valve. It seems that doing that would re-create the issue of breaking a plastic or nylon fitting just the same as before when the original plastic check valve breaks. Someone suggested using an aluminum pipe nipple. After looking around the web, I found an aluminum 90 street elbow that would be a space saver and have female threaded end for my 1/2" mpt brass check valve. I'm wondering if the corrosion would start at the end of that elbow where the brass check valve is threaded into it and stay localized for awhile before working its corrosion into the female threaded tank fitting. If I was looking at a few years of service, I could just swap that aluminum elbow out periodically. Or would corrosion happen equally from one end of the aluminum fitting to the tank . Thoughts?

[deerislandbrew]

I'm also late to this party, but dissimilar (galvanic) corrosion is a real concern. If the tank is steel, a brass fitting will not be much of a problem, but I have heard that newer water heaters are becoming aluminum.

Brass and aluminum REALLY don't like each other and your first indication of a problem is you will never get the fitting apart.

To be safe, I would use a stainless fitting between brass and aluminum. It is not ideal, but the alternative is much worse.

I came to the conclusion that if I want to avoid corrosion and have peace of mind, I need to isolate my brass check valve from the aluminum tank. Any dissimilar metal is a risk that may lead to locked up threads and or corrosion of the tank. What I decided is to 1st use an aluminum 1/2" 90 street elbow threaded into the aluminum tank. Next is a PVC 1/2" female x male NPT fitting as a non conductive. The the brass check valve. The PVC is rated for 175*f so I'm not going to worry about that too much. The advantage of the aluminum elbow is that if the PVC fails or needs replacing, the elbow can be removed from the tank to clean out stubborn pvc material on the other end of the elbow. Much better then doing this in the tank! The other advantage is that with the elbow, there is more room to make connections. I did find an aluminum elbow on Amazon after looking all over. Not easy to find aluminum pipe fittings.