City water supply filling the fresh water tank

[Capt. Mike]

We've been camping in Charleston and have a problem that I haven't experienced before. If the campground "city water" supply is hooked up to the trailer, we have fresh water, but it is also "backfilling" the fresh water tank. The first time this happened it filled the tank completely, leaking out the regular fresh water fill, which is on the opposite side of the tt. Tonight, I had the freshwater tank drain open. The campground water began to fill the freshwater tank, but with the drain open, it immediately began draining out of the tank onto the ground. Isn't there a valve in the line somewhere that prevents the "city water" from backfilling the freshwater tank? If so, where is it located. could someone post a picture, please? This is on a 2014 Windjammer 3008W. The on-board water pump is located beneath the sink in the bathroom, fairly easily accessible. Any help will be appreciated.

Mike

[OldCoot]

Capt, I believe there is a back flow valve that should be somewhere around the tank or water pump. It probably has a pc of debris in it. Try shutting off the city water off and turning on the water pump and cycling it several times.

ps, still waiting on my cap.

[joshuajim]

The backflow valve is the pump itself. There are 2 "flapper" valves in the pump that prevent backflow and hold pressure when on the pump. Most likely grit got in the pump and compromised the valves.

I've tried to clean them and it has not worked. Since the valve assembly for a Sureflo is less than $15, I would just replace it. It's not a difficult job, but you do have to remove the pump.

[Capt. Mike]

Originally Posted by OldCoot

Capt, I believe there is a back flow valve that should be somewhere around the tank or water pump. It probably has a pc of debris in it. Try shutting off the city water off and turning on the water pump and cycling it several times.

ps, still waiting on my cap.

I shut off the city water and used the pump for nearly two days to use up all of the fresh water in the tank. Still does the same thing...filled up the freshwater tank again tonight, so just cycling the pump hasn't gotten rid of any obstruction in the valve, if, indeed that is what is going on.

[bubbles]

If you have the winterization bypass tubing installed and it has a plug/cap on the end you can set the bypass valve to winterization position and that will allow you to use city water without filling the holding tank. This is what I did as an interim to repairing my pump.