HELP! City water running and water pump won't off. Fresh tank filling...

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Phil Hyde

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Sep 5, 2011
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This evening we arrived in Los Angeles after several long travel days from Oregon.  After connecting the city water, I noticed that a 'running' noise was coming from behind the RV connections (behind the panel where the city connection is and near where the water pump is).  After running around like mad trying to make sure all of the faucets were turned off, we were completely stumped how the water was still running, and more importantly, where it is going. 

While we were standing there, the fresh water filler vent spurted water and started to gurgle.  The same gurgle that is heard when the tank is being filled from the outside.  My RV also has a "power" fill valve which seems to divert water from the city connection into the fresh tank.

So, it would seem that the fresh tank is being filled by the 'running' water I am hearing.  Since I assume the water pump can pull from the fresh tank, my only guess is that some part of the pump failed which is allowing water from the city side back through the pump into the fresh tank.  Does this make any sense?

Any other suggestions?

Thanks in advance...
 
Did you leave the switch for your water pump on? Mine will do the same thing, if I forget to shut the pump off, after connecting to city water.
 
If the internal diaphragm or check valve in the pump fails, water will run through the pump back into the tank. It could also be the City Fill valve that is open, either by mistake or a failure in the valve.

The pump will not auto-shutoff in either of these situations, since the shutoff is a pressure-actuated switch and the pump can't build pressure. The pump switch should turn it off, however.
 
There are repair parts available but if there is room between the pump connections you can add an external check valve at the output end of the pump to prevent it back flowing into the tank.
 
Jeff said:
There are repair parts available but if there is room between the pump connections you can add an external check valve at the output end of the pump to prevent it back flowing into the tank.

BUT... before simply throwing parts at it, try to determine what the problem really is and fix it accordingly
 
Well, replacing the pump fixed the problem. It most likely was the check valve inside the pump. While I was at it I upgraded to a quieter pump.

So now one of the water fittings is leaking. Before I replace that hose, can Teflon tape be used on pex fittings?
 
If it is leaking where it is threaded you can use tape. If it is leaking at a crimp fitting or barb you will have to re crimp. if you do not have the tools they make quick connect fittings. I put them on my pump and carry a spare pump. That way it can be changed quickly.
 
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