City water backs up to water tanks

[Polariste]

We have a 2019 Jayco JayFlight 21QB and when connected to city water our fresh water tanks are filling up. Looks like a defective check valve on water pump. Did anyone installed a second check valve on the water line of the pump? Does it works ok?

Sometimes when you are connected to the city water, there is not much pressure and in order to have a decent pressure in my other RV I would simply turn on the water pump (while still being connected to city water) to have a greater pressure. I cannot do this in our new travel trailer is there something that can be done to be able to have the two system working at the same time?

[Jagiven]

Sounds a bit like the pumps check valve is defective or stuck ajar.

You can pull the pump and sevice it. It might have some construction debris stuck in the valve.

I would not see any issue added a second check valve other than it might restrict the water flow from the pump.

[Cavie]

Originally Posted by Polariste

We have a 2019 Jayco JayFlight 21QB and when connected to city water our fresh water tanks are filling up. Looks like a defective check valve on water pump. Did anyone installed a second check valve on the water line of the pump? Does it works ok?

Sometimes when you are connected to the city water, there is not much pressure and in order to have a decent pressure in my other RV I would simply turn on the water pump (while still being connected to city water) to have a greater pressure. I cannot do this in our new travel trailer is there something that can be done to be able to have the two system working at the same time?

Don't run both at the same time. That is what screws up the pump check valve.

[WeRJuliian]

It may not be defective, if may just be stuck.
We had the same problem, and found that running the pump a few times (city water off), exercised the valve enough to unstick it.

Yiu might try that, before you start pulling things apart

[Tumbler]

I had this happen on my old Forest River trailer. I ended up putting a secondary check valve after the pump. Was a lot cheaper and easier then messing with the pup itself and works just fine.

As for running the pump to boost pressure when on city water doesn't make sense to me unless your check valve was shot on your old trailer, which should have resulted in the same issue you are having now. Plus, this would only work if you had water in the fresh water tank, which if your check valve was leaking, you would have. In any case, as mentioned, this is not generally a good idea as it can create issues with the valve.

[Polariste]

Thanks to all ! I just came back from the dealer and they replaced the pump. They also fixed the water heater that would light up once then it would not start again, they replaced the high and low sensors and it works fine now.