Thor Forums

[Pete'sMH]

Well, I unwinterized my Class A today. Everything works properly except the fresh water pump doesn’t shut off. By way of diagnostics I disconnected the output side of the pump. Get a super volume of water flow. Then I tried capping the output side of the pump. Pump still runs so I conclude it’s not a downstream leak (whew!). Next I tried feeding the pump from a bottle of water through the winterizing valve with the output capped by a pressure valve. I.e. the pump was completely isolated from the RV. The pump ran for a moment and shut off normally and the pleasure gauge read 44 lbs. From this I conclude that the pump is fine. So now I’m left to conclude that the only remaining possibility is that the pump is sucking air somehow from the single PEX pipe that leads from the fresh water tank to the winterizing valve. Or the check valve that prevents back flow through the pump when on city water. Am I missing anything? Any other possibilities?

My RV does not have a tank fill valve. It is a gravity fill only. Everything works fine on city water.

If it’s the check valve would capping the city feed connection prevent the pump from sucking air?

And/or would disconnecting the output side of the pump and seeing if there is any discharge through the pump when on city water be the definitive test?

I haven’t located the valve yet - it’s dark, crowded and messy in there! But there has to be one....

As always, I appreciate the help of my forum friends,