Fresh water tank bypass

[Jimnye]

We have a 2019 flagstaff super lite 5th wheel. Every time we connect water to it the fresh water tank fills up. We then have to drain it each morning before hitting the rd. Is this normal? Or is there a bypass valve to shut this off? We have never put water in the tank from the outside valve that’s located by the door.... it’s just filling up every time we connect the water.

[Kimber45]

common problem. check valve in the water pump is stuck open allowing water past and into the tank. turning the water pump on may reset the check valve.

[Jimnye]

Thanks! The bypass is actually in the pump then?

[Kaadk]

No, it's a one-way check valve, not a bypass. What should happen, is when the city water is connected, the pressure from the city water closes the valve, which stops water from reaching the pump. Sometimes a bit of dirt can get in there, preventing the valve from fully closing. Disconnect from city water, run the pump, and open a tap so the water actually flows, will sometimes move that bit of dirt and let the valve then close. If that doesn't work, then the valve has failed. Rare on a new rig like yours, but it does happen. Easy enough to replace, but if the 'run the pump' option doesn't work, I'd just have the dealer deal with it under warranty.

[Jimnye]

Thanks! We will try turning the pump on/off tonight when we stop. I’ll post again once we try this.

[Jimnye]

Thank you!

[Handydc]

Yes, the check valve is in the pump. I'm getting ready to put an additional check valve in line with the pump hopefully as a backup. Camco 23303 on Amazon. It was like $7.

[Jimnye]

So when we set up tonight I turned the pump on while the water was running in the kitchen sink & turned it right back off..... the fresh water tank is not filling up! Thank you so much for solving our dilemma!