Fresh water pump problem.

Dan50 wrote:
Thank you everyone. I'll check for a leak on the suction side. All valves are as they should be.(pump, hot water and winterizing valves.

Good advice, here. I just experienced the exact same problem... whenever opening a faucet, the pump would run, pressure would drop, water volume would be very low with a lot of air purging out of the faucet. After the air was purged, pressure and water flow would increase to the point that it was usable, but it would take as much as 5 or 10 minutes before we'd get to this point. After use, when the faucet(s) were shut, the pump would pressurize the lines and shut off just as it should.

My initial thought was that I had a bad pump, so pulled it out and opened it up on the bench. All looked good... diaphragm in good shape, seals all looked good... so I put it back in and watched the water flow through the incoming water line on the suction side. Noticed that whenever the pump was running, there was a steady march of air bubbles coming up the intake line from the fresh water tank. Hmmm.... Air leak seemed to be the culprit. Traced the line back towards the tank and ran into the SurFlo water strainer. It looked good... no cracks visible... but took it out of the line anyway. Sure enough, no air in the lines on the suction side, and all is well. Thinking that it either has a hairline crack somewhere or more likely, the O ring started to leak under pressure.

Received a replacement strainer from Amazon just yesterday ($6 or $7 bucks) and will be putting it in this weekend. One of those "20 hours to diagnose and 10 minutes to repair" situations.

Hope this helps.