water seeping slowly into my fresh water tank when hooked up to shore water.Every morning i have to drain some from tank due it draining out overflow pipe.The only way i know this could happen is seeping by my fill valve but it appears to tightly close.Before i take floor out of cabinet to replace thought i would ask if there are other ways it could enter and if anyone else has same issues.1995 U300.
Thanks Curley
Two most likely suspects are the fill valve and the check valve in the water pump. Either could be leaking.
We avoid ever experiencing your problem by filling our water tank and then shutting off the shore water connection. We believe it is a safer procedure to use the water out of the tank and shut off the water pump whenever not actively using water.
I know that's not the answer to your question, but it is a way to both circumvent your problem AND avoid potential floor flooding scenarios. TIFWIW
We do exactly the same. That insures that water in the tank is always fresh and eliminates the potential for a broken hose or fitting to allow thousands of gallons of water to flood the coach.
If it was the pump check valve the pump would recycle. The valve replacement is simple if you use sharkbites. 15 minutes.
If still on shore water, it would not cycle (shore water PSI greater than water pump cut-in PSI.
But, as you say, if the check valve is leaking an no shore water, then, yes PSI would fall below pump cut-in PSI and pump would cycle on.
The valve that opens your tank should be at 90 degrees, perpendicular to the line. You can pull back the carpet to see the line and know where that is. My ball valve can actually exceed the 90 degrees, and this could lead to a small amount slipping by. You may want to check that you're 90 degrees perpendicular on that valve.
Cycling the water pump a couple of times with a faucet open might clear it.
Curley states that his fill valve appears to be "tightly closed" which sounds to me like he has the faucet washer type valve and not a ball gate valve. The faucet washer is rubber and tends to deteriorate over time and the slow leakage starts.
How do I know this? Had it happen to me until I replaced the faucet type with the gate ball valve.
City water does not enter the tank through the pump. The tank will only fill through the fill valve.
Yes, that is how it SHOULD BE.
But,. a defective check valve can allow water from the "pressure side" to leak back to the tank.
On my coach water was reverse moving through the water pump and filling the tank (slowly) when connected to city water and with the waterpump off. I could hear it and I could feel it. And when I cleared it by cycling the pump it stopped. Real world fact.
The water pump is connected to the fresh tank. It can back fill the tank. The check valve can hang up, or have debris in it.
Good point.
it is a gate valve with lever.It has always operated properly and appears not to be moving past closed position.
No, a gate valve will have a round handle-- like any house hose spigot.
Ball valves have handles and are less likely to fail.
To test the water pump check valve:
Turn off/disconnect from shore water.
Turn on water pump.
If you hear it cycling, you either have a leak (water leaking somewhere) OR the check valve is allowing water to go back to the tank, which will lower pressure to below the cut-in pressure of the water pump and it will cycle.
Keep the city water shut off at the city faucet and use your tank water. Too much chance of a leak. If your tank is slowly filling and overflows, guess where the water is going? That could be an expensive leak. And then imagine if a connection failed in the coach and water flooded everywhere.
Pierce