Hot Water Tank Leak

[Jlawles2]

So it just occurred to me, why not just use an AL valve?? https://www.mscdirect.com/product/details/78254703 they are cheap.

[Cate&Rob]

So it just occurred to me, why not just use an AL valve?? https://www.mscdirect.com/product/details/78254703 they are cheap.

Well . . . that’s an obvious solution that no one has thought of. Just another excellent idea from Joseph .

Rob

[Lonestar]

So it just occurred to me, why not just use an AL valve?? https://www.mscdirect.com/product/details/78254703 they are cheap.

Problem is my tank output has a female fitting, meaning I would need an aluminum pipe nipple to connect.

Any chance an anti-seize compound would work?

By the way, other than preventing back flow of anti-freeze when winterizing, what purpose does the valve serve?

[Jlawles2]

I thought about the fact that the check valve is female to female. Either a stainless nipple or an AL nipple would be needed. https://www.mscdirect.com/product/details/57067571

I would avoid anti seize compounds. Read the label, petroleum based chemicals and water do not mix and will contaminate the system. Also I do not think anti seize compounds are sealing compounds.

The more I think of how thread sealant tape works, I would not be surprised if the tape actually provides a protective coating between the 2 metals. If there is metal to metal contact it is then minor which results in micro corrosion spots. I don't think I have the T&P valve out of the original TT when I changed it. Only reason for change is the valve would pressure leak due to thermal expansion (took me a while to figure out it was pressure causing the issue). Once I figured out what the problem was, I would just burp the hot valve at any sink about 15 min after turning on the HWH.

[Lonestar]

I have in my plumbing junk box a 1/2" brass male to CPVC pipe. I'm going to use that and a CPVC male fitting on the other end and call it a day. Basically a CPVC bridge between the tank and the brass check valve. It crazy that of all the trailers I've had through the years I've never had a check valve go bad, but they probably were not plastic.

[TedS]

Problem is my tank output has a female fitting, meaning I would need an aluminum pipe nipple to connect.

Any chance an anti-seize compound would work?

By the way, other than preventing back flow of anti-freeze when winterizing, what purpose does the valve serve?

You are correct. The only reason for the check valve is to prevent the backflow. It takes the place of a manual valve in older, non-control panel, water heater bypass setups.

[Lonestar]

You are correct. The only reason for the check valve is to prevent the backflow. It takes the place of a manual valve in older, non-control panel, water heater bypass setups.

And only the backflow when winterizing, right? I can't see a that backflow would be and issue when in normal operation, unless I'm missing something. In that case a CPVC ball valve with male fittings on both ends would work great.

[Cate&Rob]

I thought about the fact that the check valve is female to female. Either a stainless nipple or an AL nipple would be needed. https://www.mscdirect.com/product/details/57067571

I would not be surprised if the tape actually provides a protective coating between the 2 metals.

To enable galvanic corrosion, all that is required is electrical conductivity between the two metals. It is unlikely that the thread tape would be unbroken. You can check this with an ohm meter between the fitting and the tank. Low resistance means that galvanic corrosion is possible. A stainless nipple between brass and aluminum will not reduce the potential for anodic corrosion of the aluminum, but a stainless part between two aluminum parts would have much lower potential for galvanic interaction.

Rob

[Cate&Rob]

And only the backflow when winterizing, right? I can't see a that backflow would be and issue when in normal operation, unless I'm missing something. In that case a CPVC ball valve with male fittings on both ends would work great.

You are correct. A manual valve on the outlet of the water heater, to be closed only when the water heater is bypassed would accomplish the same thing as the check valve.

Rob

[howson]

And only the backflow when winterizing, right? I can't see a that backflow would be and issue when in normal operation, unless I'm missing something. In that case a CPVC ball valve with male fittings on both ends would work great.

I disagree the check valve is "only" for winterizing in all situations. Study the diagrams that are in: https://gdrvowners.com/forum/operati...abled-disabled

Unless I messed up the diagrams, when the red valve on the Nautilus is set to "disable" cold water pressure "sits" on the check valve. Perhaps unlikely, but if an owner tried to drain their tank without a check valve installed (even with the Naultilus Red valve set to "disable") cold water would flow into the tank through the hot out port on the tank (and, obviously, continuously out the drain).

Let me caveat this post by stating this is to the best of my knowledge as applicable to the P1 version of the Nautilus panel and the plumbing in a '19 315RLTS. I won't be surprised in the least if there's a "but..." that applies to other rigs and configurations.

Howard

[Cate&Rob]

howson

Hi Howard,

Think of the water heater output check valve as an “automatic” valve that closes to water (or air) trying to enter the water heater from that direction. If the check valve is replaced with a manual valve, this has to be opened or closed depending on whether you want flow in that line. The earlier reference to winterizing probably should have said emptying the water heater while there is still liquid in the plumbing lines. Once the valve on the panel transfers cold water from the water heater inlet to the the hot water plumbing system, back flow into the water heater has to be stopped. Once panel valve and the outlet valves are closed, the water heater is isolated and can be drained.

The earlier Kantleak system switches both inlet and outlet of the water heater at the same time, so no check valve is required. This would be the same as switching the Nautilus panel valve to bypass and closing the valve that replaces the check valve.

Rob

[TedS]

When I am winterizing there is no city water supply to the system. Draining the water heater has no chance of pressurized water flowing out, only the cold and hot water lines would drain through the water heater if there was no check valve. The check valve does prevent backflow of antifreeze when the water panel is set to winterize.

[Lonestar]

Draining the water heater has no chance of pressurized water flowing out, only the cold and hot water lines would drain through the water heater if there was no check valve .

Without valve I can see how existing standing water in the hot line could drain back into the WH, but how would the cold water lines drain into WH? It would seem the WH output only goes to hot water supply lines, with no interconnection with cold lines.

Yes, there would be no reason to try to drain the water heater with city water or 12vdc pump on, so no issue there.

[TedS]

Lonestar the cold water is connected to the water heater inlet and free to flow when the water heater is drained, except when the bypass valve is set to bypass. Then the cold water is connected to the water heater outlet and will flow into the water heater without the check valve.