Fresh water tank filling itself when connected to city water Help!

[FreeBird]

I know this sounds bizarre but i have been hooking up to city water for over a year and only use the water pump when traveling down the road when not hooked up to city water for things like flushing the toilet, etc. Last night and again tonight we pulled into an RV park, turned off water pump on panel, and hooked up to city water. Fresh water tank was about half full. Went out later and FW tank had filled to capacity and water was coming out the overflow. There is NO water hose going into the FW tank fill hole! Water pump is OFF! Water at fawcets is coming from city water as we have the Hose hooked up from park source going into the labeled City water entry point on the RV. I can not for the life of me figure out how that darn tank is filling up. Is the a switch or lever that could have gotten turned in error. This is driving me crazy! HELP!

Marilyn & Gene
2013 FR Berkshire 400Q

[Teamfour]

99% chance that the check valve is stuck in the water pump allowing the city water to backfill the tank through the pump. Disconnect the city water and run the pump for a while. It may reseat the check valve. I just went through this and ended up installing a shut off valve on line out from the pump.

[Mr. Dan]

Originally Posted by FreeBird

I know this sounds bizarre but ....

No, it doesn't sound bizarre to some of us. It actually gets reported 5-8 times per week. Many times Teamfour's "run pump" process works; sometimes people install Teamfour's cut-off valve; sometimes people jump up and buy a new pump without further diagnosis; Uncle Gene had a back-flow-preventer installed in his line.

BTW, welcome to the forum. We lived in Highland Village and Lake Dallas before we moved back to the country near Sherman.

[youroo]

Originally Posted by Teamfour

99% chance that the check valve is stuck in the water pump allowing the city water to backfill the tank through the pump. Disconnect the city water and run the pump for a while. It may reseat the check valve. I just went through this and ended up installing a shut off valve on line out from the pump.

Team four has this covered! Freebird,did you have your City water "Incoming Pressure Regulator" set and installed? Youroo!!

[FreeBird]

Yep....always use the regulator!

[Mark1]

I had the same problem a few weeks ago.dealer found the 4 way selector valve (city/tank/normal/winterize) had broke.they replaced it and things are good now. but most often I hear it's a check valve in by the water pump.

[Mark1]

I also recently bought the "Real' water pressure regulator that is adjustable.I set it for 50# and showers/washer and toilets seem to work much better. Worth the $50.00

[hbillsmith]

I experienced this same problem the last few days of a long trip last month. I'll be trying the various solutions next time out and if it doesn't help, my unit is under warranty, just didn't want to take it in to sit at the dealer. Might call FR and ask to have them ship me a new pump. One thing I did notice when I peeled the storage wall back to get to the pump is that road shakes and bounces seemed to have bounced the pump enough that the screws holding it down are stripped out. My first thought was "oh well, time to stick a mouse pad under there for the noise" but now I'm thinkin' that pump looks like a pretty easy swap. In the meantime, I have a 50gal fresh tank and as much as I hate to waste water, I can always open the drain before it overflows.

[mdstudey]

I am taking my Grey Wolf in for the same problem. When I stopped by and talked to the service guys at the dealers, one said he had not heard of that before (huh ). I told him that it is a common problem reported on RV forums, he asked the other guy and he said it is a common problem especially with a certain pump manufacture. I did not catch the name.

[fedatty]

The first time we took a trip in our new FR3 30DS the same thing happened to us. The solution for me was to take the water pump apart and found the check valve had debris in it from when the unit was built. Cleaned it out and it works fine now. Simple if you are handy.

[slipf18]

It's the check valve on the water pump. You can fix it yourself, if you're a bit handy.

[jrmorris]

Am on our first trip of year and have a 2015 Sabre. After two nights at RV park hooked up to City water my fresh water holding tank started to fill up. When it was overflowing I turned the city water off and am running the water pump. Have a mobile repairman coming out Tuesday? I now have an idea what is going on thanks to all. Wonder if this is a warranty item?

[gottogo4247]

This just happened to me, fresh water holding tank overflow. I seldom put 1/2 tank worth of water in there and seeing it flow out certainly was un-nerving. Disconnected the 'city water' and turned on the pump and it sounded like a small jack hammer under the bathroom. Turned the pump off and drained the line and repeated. Maybe???
Is the water pump not a sealed unit? You can get into it? (Gawd, I sound like such a non-mechanic - but I do remember when you could do lots of repairs yourself.)

Thanks for suggestions.
John

2015 MBS 2401S

[hbillsmith]

Originally Posted by hbillsmith

I experienced this same problem the last few days of a long trip last month. I'll be trying the various solutions next time out and if it doesn't help, my unit is under warranty, just didn't want to take it in to sit at the dealer. Might call FR and ask to have them ship me a new pump. One thing I did notice when I peeled the storage wall back to get to the pump is that road shakes and bounces seemed to have bounced the pump enough that the screws holding it down are stripped out. My first thought was "oh well, time to stick a mouse pad under there for the noise" but now I'm thinkin' that pump looks like a pretty easy swap. In the meantime, I have a 50gal fresh tank and as much as I hate to waste water, I can always open the drain before it overflows.

UODATE: My unit is still under warranty. Sent an email to FR customer support. Next day they replied that they were sending me a replacement pump. New unit arrived UPS 4 days later. I looked at the docs and youtubes, it is a simple swap out.

[jrmorris]

Had the water pump replaced and am waiting for warranty reimbursement. Was told junk gets in the water pump during manufacture and messes up the check valve.