Fresh water tank fills while connected to water

Duckbill59 · 04-05-2021, 07:13 AM

My 2017 LX27N fresh water tank fills while shore water is being used. I know there is a fill valve in the wet bay that I have bought and replaced for this reason but it is still slowly filling. I did not pressure check the new valve before I installed it but thought the new valve would solve my problem. This weekend I cycled the valve multiple time thinking I could flush any debris out of the valve but that didn't fix it. I have looked at the Winnebago water system drawing to see if there was anything else where water could be entering the tank but did not see anything. Any suggestions on how to solve this before purchasing another water fill valve?

Bones2003 · 04-05-2021, 08:59 AM

Duckbill59, your water pump has a one-way check valve on the output side it. This check valve prevents shore water from flowing back through the pump into your fresh water tank. They can commonly become leaky due to debris or might just go bad. You might try disconnecting shore water and cycling your water pump a few times to flush out the valve or you might have to take it out to clean it or it may need to be replaced. This is a common problem. You can search for water pump check valves on the forums to find more detailed information.

Duckbill59 · 04-05-2021, 09:59 AM

Never knew that nor thought of it! Thanks so much for the information and I will certainly check the check valve!

IOS 3 · 04-05-2021, 05:38 PM

Duckbill - As already stated, it will be the check valve in the pump. I have your same rig and had this same problem. I replaced the valve but also put a manual valve after the pump that I close when connected to city water. Prevents this from happening again, at least for THAT reason....

Duckbill59 · 04-05-2021, 07:49 PM

Thanks for the reply! Luckily a valve after the pump on our model would be pretty easy to get to without too much hassle. I also thought about an in line check valve as a secondary valve. Thanks again!!!

audvid1 · 04-06-2021, 07:09 AM

We just had the same issue, was able to adjust the bypass to 11 turns and it stopped the bypassing.
To troubleshoot, I turned the valve next to the input of the water pump used for winterizing which closed the path for city water to get into tank and opened the drain valve located at the input of the pump and had a slow drip, so was able to confirm the issue.
I then removed the bypass screw and counted number of turns, and it was 13. Re-inserted screw and put in 11 turns and tested and no more drip/bypass.
I thought about another check valve, but on mine there is no easy way to add so will consider when we are back home
I attached the instructions for adjusting bypass

Duckbill59 · 04-06-2021, 07:20 AM

Thanks for the post above about the adjustment of the bypass. I ordered a new pump as I was thinking of having a spare anyways but I intend to take my existing pump apart to clean and will now go out and see if I can get to the adjustment described in your post before I do that. Thanks again!

Park Super · 04-06-2021, 08:45 AM

Try and cycle the pump on and off when hooked to city water and under pressure. Also, if you use a pressure regulator it may be too low. Seems like a little more pressure solved this problem for us. We used a standard non adjustable 35 pound regulator. I replaced it with an adjustable regulator and run it at 45 pounds. This seems to have corrected the water bypassing the pump.

Duckbill59 · 04-06-2021, 09:15 AM

Thanks for the suggestion to cycle the pump while connected to city water. I walked into the MH this past weekend and saw that someone (probably wife) had turned on the pump while we were connected to city water and I played around with that a little all while thinking the fill valve was leaking by. Now that I know about the check valve in the pump, it seems that is the problem. With the tank drain valve open, connected to city water, the trickle of water out of the drain never stops. I will have to check my pressure regulator to see what it's set at. Thanks again!

**creativepart** · 04-06-2021, 09:48 AM

One thing to note on this problem, if your fresh water tank is now full turn off the city water and use the pump for a few days. Then turn off the pump and then turn on the city water again and monitor the fresh water levels. Many times this issue is intermittent and it can take more than a quick recycle of the pump to flush out the tiny spec of grit in the check valve that usually causes the issue.

Duckbill59 · 04-06-2021, 12:32 PM

Thanks! Great advice you have provided. I have been dealing with this issue for at least 6 months......maybe more but after replacing the fill valve thinking that was the culprit, I have cycled that valve under pressure thinking it would "pass" any debris as well as using the pump only for a trip. But after this weekend and the tank filling again I thought I would seek the help of this forum for answers. I have received many good suggestions including yours. Thank you!

**creativepart** · 04-06-2021, 02:52 PM

There is another alternative to fix the issue once and for all and that's installing a separate inexpensive plastic check valve on the discharge side of the pump. It's an easy modification and it just blocks water from the city water valve from flowing back into the fresh water tank. It's much more reliable than the pump's built in check valve and you can get a 1/2" check valve at any hardware/plumbing store and it's a super quick install.

Duckbill59 · 04-06-2021, 04:00 PM

I like that idea! I didn't really want an extra valve installed that I had to manually turn on or off based on city water or pump. I need to locate one for PEX tubing and install it on the outlet of my pump. Thanks very much!

jerichorick · 04-11-2021, 06:20 PM

Quote:

Originally Posted by Duckbill59

My 2017 LX27N fresh water tank fills while shore water is being used. I know there is a fill valve in the wet bay that I have bought and replaced for this reason but it is still slowly filling. I did not pressure check the new valve before I installed it but thought the new valve would solve my problem. This weekend I cycled the valve multiple time thinking I could flush any debris out of the valve but that didn't fix it. I have looked at the Winnebago water system drawing to see if there was anything else where water could be entering the tank but did not see anything. Any suggestions on how to solve this before purchasing another water fill valve?

Saw this post the other day. Didn't have time to respond.

Is your "City/Fill" valve plastic or brass? I was having the same issue several years ago. I pulled my valve apart to discover that the thing was engineered to fail IF you moved it while city water pressure was on. Because I had done that very thing it failed in the partial open position leaking water to the tank. I replaced it with a good brass ball valve. No more problems.