2008 CS city water overflowing fresh water tank.

Sam452 · July 14

This is a first for me. I had thought that the city water and freshwater container were separate systems. When we purchased this used and hooked city water to the T@B it never filled up the fresh water container. On the times when we didn't hook up city water, we used the pump to draw water from the container.

I see that the pump appears to be the meeting point for city water and container water. Either my pump has gone bad or something has changed.
Now when I turn on city water, I find my freshwater container are overflowing which never happened before. If it did, that bottom would have rotted out years ago.
Full disclosure, I used my pump to draw water from the container when I foolishly did not use the pressure regulator from the city water spigot into my T@B which blew out the poly pipes under the sink. Now that I have the pipes Hooked back up again, I'm using city water again. Except when I don't need it.
Am I misunderstanding how this system is supposed to work?

Pardon if this was easily searchable, but it didn't come up for me.
Sam

rfuss928 · July 14

There is a check valve in the pump to prevent the backflow you describe. It is possible the high pressure event you describe has caused the valve to stick.

Sam452 · July 14

Thank you. This pump is a ShurFlo 105-003. In searching for this valve, is this check valve internal to the pump, or external in the pipe from the pump? Not clear yet.