Water pump cycles on/off

Why not just turn off the water pump? You live in it full time while connected to city water so you don't need it.

Thank you all for the quick replies.as soon as i get back home tomorrow i will start exploring.

Turn the pump off and it won't run.

If your fresh water tank mysteriously fills itself while connected to city water, then the check valve built into the pump is leaking, either from a bit of grit or something, or from age and wear. In the latter case, using the pump for awhile can sometimes clear it out; in the latter case, of course, replacing the pump or installing a separate external check valve on the pump suction line is the only real solution.

I would tend to suspect it's running periodically on city water because the tank is empty and it's pumping air and the check valve, etc. isn't airtight even if it is watertight. In that case, you might be able to get rid of the problem by having a bit of water in the tank and running the pump a bit to get the air out of the lines.

If you had any significant leak, you would presumably know it by now after being on city water for an extended period of time.

I think if the city water pressure is higher than pump pressure, the pump should not run. If camping where city hookup pressure is low, it helps to turn the pump on, like when taking a shower.

Your pump may have enough wear, that it is not holding pressure, causing it to cycle frequently. When running pump for longer while, it will build more pressure. In any case, I'd shut off city water, listen for pump, look for leak. If no leak, I'd replace pump, rather than try to repair.

Jerry

You do not need the water pump on if you are on city water. To test your pump for leaks, put some water in the fresh water tank, turn off the city water, and turn on your pump. When the lines get pressurized the pump will turn off. If it starts cycling check for leaks. If you cannot find any check the membrane in the pump, it could be leaking.