Water pump runs when not using water

I think I have it solved..kind of anyway. There is an adjustment on the pump. A small set screw. I turned it about one full turn and I can tell the pump pumps with a slight bit more pressure. Now, the pump comes on one more time after using water for a few seconds and then didn't seem to come back on at all.
There is no leak. I left it on almost 24 hours straight and there is no water inside or on the driveway under the trailer. It seems the pump was bringing the lines up to full pressure, but stopping just a little too soon. It would then come on a couple three more times for a few seconds soon after and then it seems like it held pressure fine from then on. It just wasn't getting to full pressure after running water and had to run a couple more times to get it topped off. Now, it seems like it just comes on one more time for a few seconds and then that is it. I can live with that.

If your pump is going on every 4 or 5 mins that is a substantial leak somewhere. In addition to the advise already posted I would check the fittings going to the WH in the back and the pressure relief valve in the front to see if it is weeping water. Another place to look is the valve and fitting in the back of the toilet. Put toilet paper under these areas then check for wetness.

Usually a small leak somewhere in the system that's not noticed when on city water. Took me weeks to locate where the "expert" installers put a screw thru a hot water line behind a cabinet. Our pump was only cycling every ten minutes.

If the pump is leaking back into the fresh water tank, you can verify it by making sure the tank is full and using the city water connection. If the tank starts overflowing out through the fill and or vent openings the pump is leaking back into the tank.

Oh, ok. That is not the case for me.

Some rigs have a valve so you can fill your fresh water tank through the city water connection rather then the gravity port.

Fill valve? I just put a hose in the fill hole on the side of the trailer and run it till it over flows and then I put the cap back on. I don't think there is any kind of "fill valve".

Do you have a fill valve? It could be in wrong position.

I had a similar problem for about 2 years. It wasn't running every 5 minutes, more like, very intermittent. But the intermittent became more consistent, and then finally about once every 30 minutes. Then it increased more.

After 2 years, I finally decided it was time for new pump after trying to track every possible place for a slow drip, and nothing showed up.

When I pulled the old one, this is what I found:



Turns out, the screws had worked loose, and two actually fell out. I was able to tighten all but two. They were completely missing. I think they fell in the hole where the pipes came through the floor and fell into the underbelly. So I went ahead and installed the new one. Works fine now. Never runs on it's own now.



So, before you do anything, check to make sure all of those screws are tight or not missing completely.

Where do you get the parts?