Fresh water tank over filling while on city water

[AUImagine]

I need some help on water logic...

So the past several days while on city water, my fresh water tank has been “phatom” filling despite the fresh water valve being in the city position. It’s just a slight, creep fill, you wouldn’t even know it’s happening, other than in the morning the tank is near empty, going to bed it’s at half, the next morning it’s trickle over-flowing!

I initially suspected the three-way, blue handle, city/fresh water valve had a slipped o-ring, maybe some debris, and I flipped it back and forth several times as mentioned in another thread.

No change.

In reading other sites, another culprit might be a failed check valve downstream of the electric water pump. My Shurflow 4008-101-A65 has an integral check valve, so if it’s failed, I either replace the whole pump (expensive), or install a second check valve downstream the pump (cheap and easy) Right?

To test for the failed check valve, I had the city water ON, blue handle on city, electric water pump OFF, and then opened my antifreeze bypass fill valve, upstream the pump.

If the city water back-flowed through the pump, it would pour out the antifreeze fill line.

Sure enough, a few seconds after setting everything up, trickle water is coming out the antifreeze fill line.

Two questions to the plumbers out there:
1) Does this seem like a failed check valve?
2) Any links to replacement inline check valves you can recommend?

Thanks!
AUImagine

2018 Imagine 2800BH

[AUImagine]

Don’t know how to rotate image, but black line is from fresh water tank. White line is antifreeze fill line, blue line enters strainer on electric water pump.

[powerscol]

Check valve on pump must be going bad. Try tapping on it. If that does not work it can be replaced

[Buckskin]

There is a allen screw on pump housing that can be adjusted to change cutoff/cutin pressure. Get your model number and search internet for instructions on how to adjust it. In most cases pump doesn't have to be removed to access allen head adjustment screw. I had this happen to me also while under warranty and GD replaced pump. I then did research and found out it only needed simple adjustment.

[powerscol]

There is a allen screw on pump housing that can be adjusted to change cutoff/cutin pressure. Get your model number and search internet for instructions on how to adjust it. In most cases pump doesn't have to be removed to access allen head adjustment screw. I had this happen to me also while under warranty and GD replaced pump. I then did research and found out it only needed simple adjustment.

On off pressure ( allen screw adjustment,) has nothing to do with the check valve, The check valve is supposed to prevent back flow - thus the leak. The allen screw only adjust when the pump cycles.

Hope this helps

[Buckskin]

Here are instructions and yes you can just buy valve from Amazon to replace just valve - not very expensive. I replace valve on my old pump and now keep it at spare in compartment with camper water pump.
ShurfloPump


Need5/64 allen wrench


Quickreview of the steps involved in adjusting the pressure switch ofa SHURflowater pump talkedabout in the video:

1. You don’t need to take the pump out of the camper – or take the pressure switch apart!
   
2. Look for the allen screw on the top of the pressure switch
   
3. Turning clockwise will result in a more sensitive switch (more likely to cycle)
   
4. Turning counterclockwise makes the pump less likely to cycle
   
5. Use your shower and determine when the pump cycles
   
6. Turn the allen screw counterclockwise until the pump no longer cycles while the shower is on (the pump should remain on while you are taking a shower, and turn off when you shut the shower fixture)

Importantto remember: you don’t want the pump turning off when you’retaking a shower!

[MaxxHadron]

That did the trick for me. A light tapping on several spots along the pump got it unstuck. I emphasize a light tapping, as too hard might damage the pump.

[gottria]

MaxxHadron, did you ever have to replace the pump? Took out our new to us 2021 2400BH and have the same issue. Getting ready to order a new upper assy to swap out.

[Buckskin]

MaxxHadron, did you ever have to replace the pump? Took out our new to us 2021 2400BH and have the same issue. Getting ready to order a new upper assy to swap out.

GD sent me new pump. Then I ordered replacement housing for old pump and installed it. Now I have backup pump.