2005 Adventurer Water Tank Overfilling on City Water

[Our05Winneba]

Within the last few months I began to have this sporadic problem of my fresh water tank overfilling when connected to city water. Have used this RV for years - mostly hooked up at RV parks to city water, using a pressure regulator set to 55psi. No problem.

But suddenly last summer I found my fresh water tank overflowing onto the ground. Not every time, and sometimes the overflow would just stop on its own. Only to resume a few days later. Again - fill selector switched to City Fill and hooked up to city water externally.

* After researching many forums I rebuilt the water pump. At less than 1 year old it has not seen that much use, but it was very clean. In particular I cleaned the built-in check valve. Same problem continued intermittently.

* Added a separate in-line check valve to the inlet side of the pump to ensure that city water pressure was not working it's way through the pump back to the tank. Same problem continued intermittently.

* Replaced the City Fill / Tank Fill valve. This was the only other place I could find where water could make it's way back to the tank. Very awkward job but installed a new brass ball valve. As I suspected the old valve appeared fine and showed no signs of allowing any leakage. Same problem continued intermittently.

* I called Winnebago customer help line. While I felt that the tech I spoke with did not really understand the problem he did point me to the on-line water system diagrams on their web site, relevant to my model. I was hoping that he might have had some internal knowledge of this problem, because as I have learned I will not be the 1st to have this issue. But he offered no such wisdom.

So studied the Winnebago plumbing diagrams very carefully. Very hard to interpret. What I learned was that (1) I actually have 2 fresh water tanks side-by-side, connected by a large hose. (2) tank fill appears to come directly from the fill selector valve and from the separate outside pour-fill fitting. (3) the overflow simply connects the top of both tanks - no other connection.

I was hoping to find some other line feeding into the tanks, maybe with a separate check valve. Maybe used for flushing / winterization? Could not make this out from the diagrams.

So any ideas on how water could be going into the fresh water tanks when on city fill if not from the water pump or from City fill? It just seems there has to be something else connected into the tanks that is not obvious. Any one else experienced this problem? Thanks for bearing with me.

2005 Winnebago Adventurer 37b

[Yellowboat]

If I read your post correctly you cleaned the built in check valve but you didn't replace the spring or rubber parts.

My tank also leaked water out the overflow, gravity fill port. I contacted Sureflo since I was in warranty and they sent me the parts to rebuild the built in check valve. That fix lasted about two years and then the leak started again. This summer I ordered the top end of the pump with the built in check valve which cost about $25.00. All is well again.


Safe travels. JD

[Old-Biscuit]

2 means of water getting into fresh water tank
*TANK Fill (Valve---Gravity Port)

*Backflow thru pump


Cleaned the pump internals and ADDED an in-line check valve to pump suction
***That elimiates the on-board pump system


Installed NEW FILL Valve
***That should have eliminated that source


BUT i would suspect the NEW valve is culprit
Valve internals allowing leakage.....seals have become dislodged from swapping between FILL to City Water under pressure




Simple check........
Disconnect in-line check valve on fresh water tank side and hookup city water source.
IF the in-line check valve is NOT sealing off you will have water coming out of it


Could be the in-line but suspect the FILL valve........








NO OTHER means to put water in fresh water tank.