Demand pump runs for 20 minutes!
I have a rain harvesting system, which means I collect rain water off my roof for drinking purposes. Yes, I have it filtered to the Nth degree, and it has a UV filtration unit as well. My problem is that recently the centrifigual pump (Grundfos MQ3-45) started running for long periods of time (20+ minutes) and the pressure varies. I have no leaks around the house, and the pressure tank (WellXtrol WX203) varies from 20 psi to 50 psi. When I shut off the system to just the pump and filtering system, the pump shuts off after 20 seconds. Open it back up to the pressure tank and it runs forever. Also, I can shut off the house piping after the tank, and there is no change. So, it seems to me I have some sort of pressure tank problem. Can someone help me with this?