Water hook up leaking into the fresh water tank

Live Oak1 · 10-05-2018, 10:16 PM

Thor 2018 ACE 30.4. I had the water hose hooked up and turned on for a couple days. Went outside yesterday and saw a large puddle of water under the MH. Found it was coming from the potable water tank overflow. Removed the filler cap and water shot out. Apparently the water is getting into the holding tank when I'm hooked up to city water line. I've saw this once in an RV park (RV was not a Thor) and the RV owner said there's a check valve to prevent this from happening. If this is the problem I have no idea where to find this check valve. Anyone know where to look?

We bought this 2018 the end of April 2017. Not sure if it's under warranty..

javelin · 10-05-2018, 10:53 PM

The check valve is most likely in your water pump. It is used among other things, to prevent city water feed from coming backwards through the pump into your fresh water tank. Some folks say you can try to fix this by running the water pump for a few minutes to try to clear any obstruction that may be responsible for the antibackflow valve from not working. Then try your city water feed again and see if it is still flowing back into your fresh water tank. One cheap way to fix this (or use it as a backup insurance), rather than replacing the pump, is to buy and install a standalone anti-backflow valve from your local RV place or on line. Just plumb it into the fresh water feed line to your pump.

JamieGeek · 10-05-2018, 11:16 PM

Yeah turn off the city water, and run the water pump for a few minutes. That should dislodge any debris from the pump valves.

Live Oak1 · 10-06-2018, 10:11 PM

Thanks to javelin and JamieGeek. Today I did what you both suggested and it worked. I also found a small round wire screen filter on the inlet side of the pump which has a screw off cap. I'm thinking this might be the antibackflow valve. That had some crap lodged inside the screen that I cleaned out. I opened a drain which was just outside the pressure side of pump and ran the pump for a couple minutes with the pump pushing water out of the drain. Set everything back to normal and turned on the city water. Ran some water thru the system then left the water pressure on. That was about 6 hours ago and it's not coming thru the tank overflow so I guess that did it. The crap I removed from the screen looked like filter pieces. Thinking back, about 2 months ago I replaced the outside filter element that I always use and also installed a water softener. Could have been some junk from either or both. I probably didn't flush the new filter element nor the softener long enough.

**16ACE27** · 10-06-2018, 10:54 PM

Quote:

Originally Posted by Live Oak1

Thanks to javelin and JamieGeek. Today I did what you both suggested and it worked. I also found a small round wire screen filter on the inlet side of the pump which has a screw off cap. I'm thinking this might be the antibackflow valve. That had some crap lodged inside the screen that I cleaned out. I opened a drain which was just outside the pressure side of pump and ran the pump for a couple minutes with the pump pushing water out of the drain. Set everything back to normal and turned on the city water. Ran some water thru the system then left the water pressure on. That was about 6 hours ago and it's not coming thru the tank overflow so I guess that did it. The crap I removed from the screen looked like filter pieces. Thinking back, about 2 months ago I replaced the outside filter element that I always use and also installed a water softener. Could have been some junk from either or both. I probably didn't flush the new filter element nor the softener long enough.

No, that's a suction strainer. It has no check-valve in it.

Miramar Owner · 10-06-2018, 10:56 PM

That screen filter would have nothing to do with your issue. It is there to remove particles from damaging the pump that might find it's way into your water supply. I agree with others, running the pump for awhile was probably the answer.

Live Oak1 · 10-07-2018, 12:03 AM

Thanks for clearing up the strainer question. Now I know. Thanks.

Live Oak1 · 10-07-2018, 03:20 PM

UPDATE:
Flushing the pump seemed to work yesterday afternoon however I left the water pressure on last night and got up this morning to find the water overflowing again from the tank. I'm going to flush the system today and run the pump for awhile then try again. Question, Can the pump be at least partially disassembled and manually cleaned out

ACEroad · 10-07-2018, 04:22 PM

Look up your specific pump model. Most can be disassembled and clean or replace the check valve.

simidrm · 10-08-2018, 03:18 AM

The city water connection on mine is where the sewer drains are and has a valve lable city and tank and I found if its hooked to city water and the valve is still on holding tank that I can hear water going into my tank and move valve to city and it stops filling the tank.

javelin · 10-08-2018, 12:38 PM

The other option is a separate check valve plumbed into the water pump feed line similar to the link below. If you don't want to take your pump apart (assuming it is even repairable) just insert new check valve (back flow preventer). Note the direction of desired water flow marked on the side of the fitting. If you cut it into the low pressure side of the pump......arrows would face the pump. Simple fix.

https://www.amazon.com/Camco-23303-B.../dp/B000EDUTN6

KMac · 10-08-2018, 10:22 PM

I have the same issue...found that when I have city water connected I can hear the water overflowing...the control valve is either "City" or "Tank"...when I move the valve slightly back towards "Tank", the overflow stops.

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