Fresh water tank

[Davion206]

Why would fresh water tank fill while hooked to city water? Thanks for your ideas.

[69_Avion]

The quality of check valves that are used in todays RVs is nothing like they used to be when everyone used nice Brass, quality check valves. Even with a quality valve, debris can get behind the seat. I'm glad to hear that the debris was flushed out. Many times it ends up being a bad check valve.

[jjjandrbaker]

I just wanted to follow up on this. I finally got to go on another trip this weekend. As soon as I was set up, I ran the entire freshwater tank empty through the pump. After I did that, I connected the city water. It's been almost 24 hours, and there's no overflow. When I turn the water off and run the pump there's still no water in there. I think it fixed my problem. Thanks ScottG.

[Old-Biscuit]

puravidadon wrote:
Nice schematic Old-Biscuit. Got any others?

Sure......


GO here for more.......LINK

[ckwjl]

This happened to me last summer during a weekend trip hooked up to city water. Between Friday evening and Sunday noon, our 30 gallon fresh water tank filled completely. It started out almost empty because I usually don’t keep much water in it. After scratching my head I realized it filled from backflow through the pump. I was expecting to have to replace something, but there must have just been debris causing the leak which was cleared out with use of the pump. This has not happened since. I believe about 25 gallons leaked back through the pump.

[ScottG]

To answer your question, yes - the valve could correct itself. If it had a piece of something blocking or holding it open, then enough flow could flush it out.
I would run the pump for a while and then check to see if it's still having the problem.

[puravidadon]

Nice schematic Old-Biscuit. Got any others?

[Old-Biscuit]

The typical RV water pump has an internal check valve (flapper diaphragm).
Debris can allow them to leak by. Running the pump can clear the debris so they can close properly.

If worn/torn then they have to be replaced to fix leak by.

The Shurflo 4008 & 4048 models have the internal bypass feature

Now if you have a water panel with switches/valves then the problem could be with the 'fill' position at water panel.

Basic RV water system

[jjjandrbaker]

I just had the same problem last week. This was my first trip after dewinterizing. I know the pump was full of antifreeze. Is there any chance that after running the pump for awhile the valve might just "self-correct"? I meant to test that theory before breaking camp, but forgot.

[brulaz]

Some Shurflo pumps (4008?) have a bypass valve built into the pump to smooth out the pump's flow. If that goes haywire and we're on city water, we can hear it burp when the toilet is flushed, and that "burped" bypass water goes right into the freshwater tank.

We also have a separate bypass valve that moves the pump intake from the tank to a hose for winterizing. By switching that to the hose and making sure the hose is clamped shut, the problem is temporarily fixed when on city water. But really, pump needs fixing, or at least its bypass valve.

[darsben]

I have a valve on my class A that allows me to fill my water tank while hooked up to city water.
Could your TT have the same arrangement and the valve has come open?

[BTPO1]

DutchmenSport wrote:
The check valve that keeps the city water from back filling into the fresh tank is failing.

x2 They do go bad occasionally.

[Davion206]

We spent the winter down south, so was no need to winterize. Problem arised after one day on the road traveling back north.

[NanciL]

DutchmenSport wrote:
The check valve that keeps the city water from back filling into the fresh tank is failing.

Yup,
Probably didn't get pink stuff in it when it was winterized and now is toast.


jack L

[DutchmenSport]

The check valve that keeps the city water from back filling into the fresh tank is failing.