Need help with Fresh Water Tank

[shulerd]

I have a 2000 Fleetwood American Dream 40 DDS.  I have a problem with the Fresh water tank refilling anytime I have the city water connected.
It only fills when I am drawing water from from any of the faucets.  The "Water Tank Bypass Valve" is closed.  If I open it water flows into the fresh water tank.  I have placed valve 1 and valve 2 in various positions, can't seem to find any way to keep the tank from filling and over flowing except watching the level indicator and draining as necessary. 

Any ideas about what is happening?

Thanks     

Staff edit: Remove excessive white space

 

[NY_Dutch]

The check valve in the pump may be opening when the pressure drops from opening a faucet.  Temporarily disconnecting and plugging the inlet line to the pump and then opening a faucet should show if that's the case or not. If water runs out of the pump inlet when you do that, disassembling the pump head and cleaning out any particle or mineral buildup may be all that's needed.

 

[JudyJB]

You may also have a hole in the water pump diaphragm.  That is what happened to me.  I had to turn off the water pump until I could get it replaced.  Water filled fresh water tank and then overflowed onto the ground.

 

[shulerd]

Wow!  That was quick!  Both responses make sense from what I am seeing and hearing.  I'll take a look at the water pump and see if this solves my problem.  Thanks for the help.