fresh water vent

[Pete C]

Hello all,
We have a 2017 Alpine 3900re, can someone tell me why when I'm on city water hook up water starts to trickle out of the freshwater tank vent??
If I switch the valve to Normal and use the pump the system pressurizes for about a minute then it re-pressurizes and continues that pattern but I don't see any leaks anywhere.

Thanks in advance

[chuckster57]

Sounds like the check valve in the water pump is not working. There are a few threads on this including fixes.

[bobbecky]

Might try turning off the city water supply and run the pump for your water pressure for a while. If there is debris in the check valve of the pump, this may clear the debris and stop the leakage back into the fresh tank. Another option is to disassemble the pump head to clean it out and see if that resolves the issue. The next step if that doesn't work would be replacement of the pump. Then, there is what I did years ago for the same issue, install a Sharkbite check valve on the pressure side of the pump in the PEX line. The brass device in the lower center of the photo is the check valve and fixed the problem.

[nosnow]

I had the same issue in my 2017 Keystone Avalanche 300RE, which uses an Anderson 4-way valve to manage water distribution. One of the O-rings on the cartridge moved out of position, and when the valve was set to City, it allowed water to enter the fresh water tank, eventually exiting via the vent.



I purchased two replacement cartridges, so I'd have a spare and only turn the valve clockwise. I also found this video very helpful.

https://www.youtube.com/watch?v=O3ApaFkU418

Best of luck!