Check valve on water system?

[bnsonger47]

With out 02 Dutch Star, we are on our fourth motorhome since 2007. I think we've come across the "keeper". With it came all the manuals that talk about appliances and accessories but no owner's manual. So, I downloaded the manual. While it may seem well written, it is a bit deficient and too generic (in my opinion) in some areas. For instance, understanding the fresh water system. I do wish there were a schematic or "as built" drawing so I can better understand it. Every motorhome seems to handle fresh water differently.
So my question is this: Is there a check valve (to prevent back flow) on the water inlet?
The DS has only the one water inlet. Above and below it states how to "open" the valve to fill the tank with water and to "close" the valve when the tank is filled. After turning on a faucet, water comes out the inlet (back flow condition) about as fast as any firefighter would want on a Class A pumper (slightly exaggerated). I have temporarily (I hope) remedied the system by installing an inline cut-off valve on the inlet. However, this isn't as it should function.
I'm suspecting that there is, indeed, a check valve that isn't closing. Is my assumption logical? On a Holiday Rambler we had no check valve. I have no idea how our Airstream was configured since it's behavior was odd. Our first moho had a check valve. Your thoughts will be appreciated.

[GaryKD]

Hi bnsonger47,
Yes there is a check valve where the shore supply hose connects to the coach. It is made of plastic and over time will fail. I have already replaced mine. The valve is on the back side of where the shore supply hose connects to the coach. One must reach up from under the panel where all the connections are placed. You will be able to feel the valve. All I had to do is disassemble the connection and take the valve to the local RV store and show them what I needed. It is an industry standard connection on both ends.

[shaman52]

Should look like this. Has built-in check valve.

Good luck!

[bnsonger47]

Thanks, folks. I'll take a look at it.

Plastic -- interesting. I'm a brass guy.

["007"]

The check valve is spring loaded you push the plunger and get the water in face.
Calcium deposits can get caught in valve stopping it from closing shut completely you have to push the valve to get antifreeze in the short pipe from valve to your whole house filter when winterizing.
You maybe able to clean but other wise valve needs to be changed.
The valve is all brass inside it and has stainless steel spring.

[bnsonger47]

Thanks. My current solution is working well. I got an angle fitting with shut-off valve. I wanted something to provide strain relief to the hose anyway. I'll change out the inlet later.