City h20 is draining into my fresh tank & overflowing out my fresh water tank

[Lynnmarie0123]

Hello !

ive got a 2019 5th wh super lite flagstaff 528IKWS REAR living rm and it appears as though While hooked up at a campground our city water is overflowing into our fresh water tank so what happens is the freshwater tank is now overfilled and flowing out of a drain onto the ground? Is there a dysfunctional valve that is Supposed to open and shut to keep the that from happening?

The fresh water tank works fine all by itself by the pump — no problem there. Pressure out the faucets is perfect…..But when we try to run city water alone, it just overflows into the fresh water tank. The pressure coming out of faucets is very low then as well.

Any clue here? Thank u so much…..

[stephndudb]

Sounds like a bad check valve on the back of your water pump.

[Mr. Dan]

This issue gets reported here often. It can be a bad check valve in your pump. It could be a bad O-ring around that check valve. It could be a piece of debris in the check valve. What I've done is turn off the city water and run from my fresh water tank a while. If the problem is debris in the check valve, this often corrects the problem.

[NavyLCDR]

Originally Posted by stephndudb

Sounds like a bad check valve on the back of your water pump.

The vast majority of RV's just use the check valve built into the pump, very few have external check valves on the back of the water pump. Although they can be added to solve the problem without having to replace the water pump, or get into the internals of the water pump.

[Reverse_snowbird]

This solution has been posted by another member and worked with a friend's rv. It's no cost, so you can try it before trying solutions that cost money. Hasn't happened to us yet.

Fresh Water Tank overflowing

Try this
The check valve on your water pump is not seating properly, allowing city water to fill the fresh water tank. One thing to try:
1) Turn off city water at the source;
2) Turn on your water pump and open-and-close various faucets in your camper allowing the water pump to cycle on and off;
3) Turn off water pump, open a faucet and relieve water pressure;
4) Turn city water back on.

[Falcon900Guy]

Originally Posted by Lynnmarie0123

Hello !

ive got a 2019 5th wh super lite flagstaff 528IKWS REAR living rm and it appears as though While hooked up at a campground our city water is overflowing into our fresh water tank so what happens is the freshwater tank is now overfilled and flowing out of a drain onto the ground? Is there a dysfunctional valve that is Supposed to open and shut to keep the that from happening?

The fresh water tank works fine all by itself by the pump — no problem there. Pressure out the faucets is perfect…..But when we try to run city water alone, it just overflows into the fresh water tank. The pressure coming out of faucets is very low then as well.

Any clue here? Thank u so much…..

Exact same thing happened to me.
Cause? Already mentioned but its a valve in your water pump that is sticking and allowing the water to fill fresh water tank.

Two choices: Rebuild the pump or replace the pump. 2019 would already be 4 years old so if t were me, I wold just replace the pump.
I would also get one with at least 50-55 psi pressure.

[5picker]

Originally Posted by Falcon900Guy

Exact same thing happened to me.

Cause? Already mentioned but its a valve in your water pump that is sticking and allowing the water to fill fresh water tank.



Two choices: Rebuild the pump or replace the pump. 2019 would already be 4 years old so if t were me, I wold just replace the pump.

I would also get one with at least 50-55 psi pressure.

There are other causes for the pump's check valve to leak such as high city water pressure with not using a regulator or using the pump while also using city water.

Debris is the most common culprit as many report after doing the oft mentioned cleaning procedure, things are OK.

No need to replace the pump for any of the things I mentioned. And even if the pump's check valve still sticks, an inline check valve or a manual valve added inline will remedy the problem way cheaper than a new pump.

[NavyLCDR]

Originally Posted by Falcon900Guy

Two choices: Rebuild the pump or replace the pump. 2019 would already be 4 years old so if t were me, I wold just replace the pump.
I would also get one with at least 50-55 psi pressure.

Third choice is to add an external check valve.