Overflowing Fresh Water Tank

lewisedge · 01-27-2019, 05:40 PM

Recently I've noticed that my fresh water tank is slowing filling up while I'm hooked up to my campground's water supply even though the fill valve is NOT in the fill position. After I have shut off the campground water supply and turned on my water pump it will run for about a second every couple of minutes even while all faucets are off I'm guessing that those two issue are somehow related.

This morning my fresh water tank was actually overflowing. On my 2011 Itasca 33C I'm guessing there is some kind of check valve in the system that is supposed to prevent back flow coming from the campground's water supply into my fresh water tank, but I can find nothing about it in my owners manual. I'm also unable to find such a valve in the compartment where the water pump is located.

If anyone has had a similar problem and found a solution for it, I will be grateful for advice.

BirchyBoy · 01-27-2019, 06:05 PM

It’s likely the three way valve that you operate to fill the tank. Mine is this way a fair amount, too. Maybe replacing it would help, or just turning it off an on several times to clear anything that may be keeping it from fully closing.

RVingDan · 01-29-2019, 10:20 AM

Please see the video by RVGeeks

RV Plumbing Leak Troubleshooting & Repair - Practically For Free!

What you described is the same problem they fixed in the video.

Good luck!

old_engineer · 01-29-2019, 04:27 PM

If yours is similar to our trailer the check valve is in the water pump. If you have antifreeze control valves on your pump you could use these to test it out. Leave the antifreeze valve off and turn off the pump to water tank valve. The tank should stop filling. The first thing I would try is using the pump in case something is interfering with the valve and needs flushing. If that doesn't do it you probably need a new check valve. If the check valve is in the pump like ours your choice is to replace the pump or add an external check valve.

lewisedge · 02-03-2019, 04:24 PM

Thanks for all of your suggestions which give a pathway to solving the problem.

Ramjet · 02-03-2019, 09:12 PM

My solution was to leave pump on, turn off park water, then pump water off. Turn park water back on to re-set water pump check valve with at least 50 psi water pressure.

I’ve had this issue for two years on 2017 Tour and even had water valve replaced with no luck. It seems to work if you do it with each step as I mistakenly pressed water pump switch early one morning by mistake while hooked up to park water and fresh water tank filled during the day. Went with switching as mentioned and have had no additional issues.

Richw · 02-03-2019, 09:26 PM

I had the same problem. The water pump has a check valve and if it fails water will leak into your water tank. Sometimes cycling the water tank can fix the problem. The other options are to replace the water pump or add an external check valve. I added the external check valve.

Markaustx · 02-04-2019, 06:58 AM

I had the same problem on my 2015 Winnebago View. I called the Winnebago tech department and was told it was the check valve on the water pump. It’s being replaced now so I’m hoping they were right.

BirchyBoy · 02-04-2019, 07:16 AM

I’ve had intermittent filling as well. I have a new check valve to install when I can. Does it harm anything to have the pump left on if the outside water is turned on?

geneorpana · 02-04-2019, 03:33 PM

I had that problem off and on in my 2015 Journey 40R. Took the suction side hose off the pump and sure enough, there was water flowing. Smacked the pump with the vise grips I had used to take the line off with and the water quit flowing and haven’t had a problem in 2 years.
Or, you could clean or replace the valve or pump.
Sometimes a hammer IS your friend. Just sayin’.