Need Help On This One!!!!!!!

[DCTENT]

My Water Pump For Inside Coach, SOMETIMES Will Run & Run & Run, With No Water Pressure at Faucets, Then An Hour Later It will Work Fine, I Have cleaned all Faucet Ends so there is no restriction there, ALSO When Hooked To City Water I Have Three Position Switch for adding water when Switch Is Up Or In Down Position Water is suppose to go into Tank which it does, HOWEVER, Over the weekend I Tried to Use City water & with Switch In Middle Position (TO BYPASS TANK), I Still get water entering tank, What's up with that?.

[Robi.1014]

Can't help you with city-water entering tank.

As for the 12VDC onboard water pump...
When these pumps ingest just a small amount of air, the impeller (or diaphragms, actually) cannot compress the air effectively....so water-flow stops. Also a constant air leak (even a small amount) on the input side of the pump will halt pumping operations.

On my '04 Diplomat, on the input -side of the pump, I had to remove the hard-walled plastic tubing (with metal crimps) and replaced it with the clear tubing designed for freshwater use....now crimped with small "radiator" -style clamps. Problem fixed.

One more gotcha happens when we're traveling with our water tank at about 1/3 full (or less). Water sloshing in the tank seems to aerate the water just enough that my pump ingests air and will stop pumping. On my rig, my problem is exaserbated because I have a accumulator (surge) tank on the output side of the pump. So my pump has trouble pumping into this "pressure" if there is the smallest amount of air in the pump's intake line. To recover from this condition, I have to open a faucet (cold and hot valves) to allow the accumulator-tank to "pressure down" completely ... at which time the pump clears itself of air and begins to pump real water!!

[Mike Canter]

You what it sounds like is the water is being pumped in a loop from the bottom of the tank to the top of the tank because a valve is stuck in the wrong position that the switch controls. The reason I say that is on my Signature if I leave a manual fill valve in the wrong position then the pump starts up and runs forever and I get no water out of the faucets.

[itdave]

I believe there is check valve in the system that may be stuck

[wa8yxm]

On my coach there is a quick fill valve for filling my on-board tank from the city water inlet instead of the gravity feed.

Like this | I get city water to the "house"

Like this -- I get city water to the tank

Like this \ I get both tank and city water to the tank (As well as the house).. In short the pump runs constantly as the water circulates .

Good for stiring things up but frankly useless for everything else.