Fresh water inlet fills tank?

[jeffcarp]

I am camping this weekend and used my fresh water tank until is was 25% full. At that point I hooked up a hose with a pressure reducer inline. Pressure reducer is working. This morning I woke up to find my fresh water tank to be 75% filled. Is it designed this way somehow? This made me nervous about what would happen when the tank would reach 100% with a hose still connected? Water pump is confirmed off.

[bcope01]

That isn't right. There is a one-way valve somewhere that isn't working correctly. Maybe some others have more details.

Bill

[jeffcarp]

I'm looking at the fresh water diagram in the manual and it appears that the city inlet has a direct connection to the fresh water tank through the water pump. Can water flow backwards through the pump?

[Tahoe]

I guess it could, but in my limited experience I thought there would be one way check valve to prevent that. When I was into Vintage Airstreams I used to redo the plumbing and would always have a check valve installed to prevent that possible issue. I don't recall exactly, but I did model the plumbing off of Internet diagrams of RV's.

[Roger H]

One of two things is happening; either your notoriously unreliable system indicator system is, in fact, being unreliable; or, more likely the back flow preventer in your water pump is leaking. They typically don't fail unless there's something stuck in the valve holding it open like a grain of sand or some plastic shard. You might try running your pump for a while and see if it dislodges and sends it into the pipes. If it does, the problem is solved.

If it doesn't, you can check your pump's back flow preventer by draining your fresh water tank, disconnecting the supply side of the pump, and then hooking up the water at the city inlet and see if you have some amount of water flowing back through the pump.

If it is, in fact, leaking, and you can't get it to spit out whatever is holding it open by pumping water through it, you could install a separate back flow preventer in the plumbing past the pump, but it's likely more simple just to replace the pump unit.

If it's the system indicator, well... good luck with that.

[Tahoe]

My coach came with all the original manufactures manuals and I just checked out the Shurflow specs. It has an internal check valve rated at 200 psi, so as stated it could be debris letting in a small amount of water to back fill or a bad pump. Oh and don't forget the level indicators. I trust mine so much I open the door and with a flash light check the real level.

[jeffcarp]

The gauge seems to be fine because I can physically see the water tank and it had definitely gone from 25% to 75% over the course of a day. It must be the backflow preventer on the pump as others have indicated here. Thanks all.