Water pump check valve - fresh tank overflowing

[bigorange]

Just returned from 2-week trip and one night while connected to city/shore water our fresh tank overflowed. (Fresh tank has separate open fill port...not connected to city water as far as tank filling goes) I kept a close watch on it after that and only one other time did the fresh tank appear to fill up so I turned off the shore water connection.

Searching a little bit it appears to be something with the check valve on the water pump allowing water to backfill the fresh water tank, but I'm not sure how to resolve this. Anyone have experience with this or any advice? New water pump recently replaced by dealer under warranty so I may just add it to the list and take it back to them to fix it. Didn't seem to happen consistently though, so I'm not sure.

[Gottahaveit]

Had the same problem awhile back...replaced the check valve and all is good.

[ScottG]

I've fixed several of these.
Take the head off the pump (very easy) and rinse all the parts off. Then re-assemble.
It's good insurance to install and inlet filter to prevent re-occurrence.

[bigorange]

Thanks for all of the input. I’ve actually thought about using tank-only based on several threads here. Our next stop was in a friend’s driveway so we used the tank there for several days which may have flushed the pump out. No issues for another 5-6 days when I had gotten in the habit of checking fresh tank periodically and noticed it was filling up again before it overflowed. I’ll see what the dealer can do about it under warranty and ask about the check valve or strainer on the suction line.

[Straylight]

It's certainly something that Shouldn't Happen™, and if it's under warranty I would certainly add it to the list for the dealer to take care of.

If it happens again out of warranty, all the advice here already is valid. I exclusively use my water tank; filling the tank every couple of days is WAY worth avoiding overpressure, backpressure, hose trouble, etc. for me.

[mobeewan]

Make sure there is a strainer installed on the suction side of the pump. It will have a fine stainless steel mesh screen. The manufacturer doesn't install them. If you don't have one you should add one. It will help to keep trash and fine sand from getting sucked into the pump.

[DutchmenSport]

Run water from your fresh water tank and use the on-board pump. No worries about anything that way. No worries about over pressure, or pressure regulators, or check valve failures, or back filling and over flowing into the fresh water tank, or hoses laying in the grass for someone to trip over, or hoses on the ground that could potentially burst.

The trade-off is: You do have to fill the fresh tank and keep an eye on usage (which makes you conscious of your water usage and I think makes you a better more responsible citizen). You do have to be aware of the cleanliness of your water tank. And you will get some noise from the water pump when it runs. But, you do not have to worry about anything pointed out above, which is exactly why we run water from the tank and use the pump all the time and never connect directly to the city water connection.

I suggest you run water from your tank using the on-board pump for a while and see if that cleans out any particles that might be affecting the check valve or back-flow valve, or any particles caught in the pump itself allowing a back flow situation.

[DrewE]

Sometimes they leak due to a tiny bit of dirt or sand or something in the seals, which can get washed out with pump use and have the problem resolve itself.

If it's a more or less chronic problem, rather than replacing the pump (assuming it's otherwise satisfactory and working properly), it's usually a pretty straightforward task to install a separate check valve in the pump suction line, and not too expensive either.