I thought I would share this with you. My fresh water pump (Sure flow pump) was coming on for a moment then shut off, my first thought was I have a leak in the system. I spent several hours looking for a leak no leak found. I didn’t like listening to the pump run so I turned the pump off and ran shore water pressure, the next day I had water coming out of the fresh water tank vent. I scratched my head for a few and realized there’s only 1 check valve in the system ( hot water tank cold water inlet). I researched the fresh water pump and it has a internet check valve that was leaking and filling the water tank. I replaced the pump and both problems are gone. Hope this helps someone in the future.