Fresh Water Tank Overflowing from City water Hookup!!

That pump does not have a simple check valve, it has a bypass valve. The manual describes it -

The by-pass is a spring loaded diaphragm that opens up allowing water from the discharge side back to the inlet side. The by-pass is set to begin opening at about 40 psi and creating full by-pass at about 62 psi

The manual describes how to adjust it.

So, the valve may be working exactly as intended, but the city water pressure is high enough to open the bypass valve, filling the tank. Do you use a pressure regulator on the city water line? What pressure is it set at? It could also be leaking.

It's interesting that more people don't report similar problems - that's a common pump and common RV pressure regulators provide 40-50 PSI. So if the bypass begins opening at 40 PSI as stated, one would expect to see this happening a lot. I wonder how common it is for manufacturers to put check valves between the pump and tank. As mentioned earlier, that should fix the issue.

Ale_Brewer wrote:
This is very common on new units. When the manufacturer is installing the fresh water tank, they have to drill out the holes for the connections. When they do this, lots of little plastic flakes fall into the tank and they NEVER clean them out. That's usually what causes this problem.

THIS IS TRUE.

And when I did replace the pump I installed a filter assy.

So far...nothing in it.:)

This is very common on new units. When the manufacturer is installing the fresh water tank, they have to drill out the holes for the connections. When they do this, lots of little plastic flakes fall into the tank and they NEVER clean them out. That's usually what causes this problem. The best thing to do on a new unit is to install an inline screen filter BEFORE the pump before the pump is used for the first time. This is also a good idea for the future because it's not uncommon to get occasional particulate in the city water you'll be using to fill the tank.

Had the same problem second time out cleaned the screen on the pump ran with the water in the tank couple days. No problem since
Ken

K Charles wrote:
Maybe if you shut off the city water and use the pump for a few days it will clean the debris out of the check valve.

Had the same issue. Running on the pump for a day cleared the debris...

augustpilot wrote:
New Rockwood 2906ws. Pump is ShruFlo, model is 4008-101-A65. Parked at campground. Fresh water tank was 1/3 full. Hooked up to city water. In one day fresh water tank was overflowing. Called Rv repair. On phone. Was told the spring valve was not closing in pump and allowing water to feed through pump into fresh water tank. And I need new pump. Has anyone experienced this? Thanks

Mine is doing the same thing right now.
My trailer is only two months old. It is the check valve. It could just have trash in it. I haven't checked it.
I disconnected the fitting from the pump discharge and installed a shut off on it, so it won't leak through any more.
I am going to remove the pump and take it back to the dealer and tell them I either want it fixed or a new pump.
It's more garbage that Forest River is putting in their trailers

jack L

Double post -Please delete

Jack L

This is a typical simplified water flow diagram for the RV's...

You can see where ONE WAY VALVEs are handy to have...


Google Image

The newer trailers all seem to now have a water panel it seems for using the different methods for water flow...

The basic concept is when using city water the on-board fresh water tank and associated water pump is by-passed using the one-way water flow valves...

I think my very simple water flow setup between the fresh water tank and the water pump must have the one-way valve inside the water pump motor. I have never noticed a one-way valve in-line...

Roy Ken

You could save some money by adding a check valve in the line to the pump instead of replacing the pump.

Had the same problem as described. found the valve that is used to fill tank or diverts it to pressure up city water in the tt was bad,would not stop water from entering the fresh tank when turned that direction.