Water pump sucking air

[cgrisham]

Our fresh water tank is full. I know that because I can see water starting to rise in the overflow tube. The problem we've had this year is the pump doesn't shut off - when taking water from the on board fresh water tank. The pump and system work great if I take the input from an external tank - making sure the intake is fully submerged in water. I'm pretty sure the pump isn't shutting off using the on board tank because the intake is not fully submerged and the pump is sucking air. Is there a way to check this out and / or reseat the intake line without dropping the underbelly cover? We have a 2008 Rockwood 8296SS. Thanks for any help.

[Bama Rambler]

Have you checked to be sure all the fittings all the way to the top of the tank are tight and have washers/gaskets?

If it's sucking air it has to be a leak on the suction side between the pump and tank.

[youroo]

Do you have a "Winterizing Kit"? If so check it! Youroo!!

[cgrisham]

Thank you. That's actually my question. Is there an easier way (rather than dropping the underbelly) to check the connections at the tank. My intake goes through the floor of the trailer and (as far as I can tell) into the fresh water tank. There is a lot of play in the intake hoes and, because it sucks air, I'm assuming, the end of the hose is not in the tank all the way.

[cgrisham]

Thanks. Yep. That was the first thing I did - take the winterizing valve and hose out. I also ran a hose directly to the intake side of the pump into a full water carrier. In that configuration (intake in a water carrier) everything works as it is supposed to. I'll add, we replaced the pump last year. And I put a new pressure switch on the pump earlier this summer (before I realized it was sucking so much air).

[youroo]

Originally Posted by cgrisham

Thank you. That's actually my question. Is there an easier way (rather than dropping the underbelly) to check the connections at the tank. My intake goes through the floor of the trailer and )as far as I can tell) into the fresh water tank. There is a lot of play in the intake hoes and, because it sucks air, I'm assuming, the end of the hose is not in the tank all the way.

Your pick up hose is attached to the Side of your F/W tank! Most are 1" or More up the Side of Tank,thus Members asking WHY is our pump NOT working when Water is IN the Tank! Ours is Changed to a "Bottom Feeder" the P/U hose is Now at the Same location as the "Tank Drain" we use every last Drop of Water! I know you said your Tank is Full but I just wanted to Clear up your Hose question in regards to "NOT far enough in the Tank"! Youroo!!

[youroo]

Do you still have the little "Screw on Filter screen" on the Suction side of your pump? These can leak and cause your problem also! Youroo!!

[cgrisham]

No filter screen / strainer that I know of. There is a filter, but it's the larger one on the outlet side of the pump.

[ronandpat]

There is usually a plastic bowl filter at the input to the pump. These plastic bowls are notorious for developing small cracks that allow the pump to suck air. On my last 5er I just removed it and added a short direct pipe in its place. Problem solved.