Hi Folks
I wanted to pass along a “learning” about the check valve on your fresh water inlet valve. I was sanitizing the camper water system today getting ready for a long trip we are going to take. And I did a goof, again…..

I knew better but thought I could control the problem as this has happened to me before. Live and re-learn….
In your fresh water inlet to the camper there is a check valve that creates a back flow preventer. This protects the water source from anything in the camper flowing backwards that might contaminate the source. This is common practice in water systems and is most likely a RIVA requirement and a plumbing code.
OK so what happened?
Well I wanted to purge the fresh water inlet piping with the chlorine solution. I had the water pump turned on, pressurized the system, shut the pump off and opened a faucet to bleed down the pressure. So far so good. But not really….. There was still too much pressure left in the system and it is very hard to control what you have left. I pushed the fresh water inlet check valve to burp the water out of it to clean the inside of that line. When I pressed the valve with too much pressure left in the camper plumbing, the O-ring on the valve stem of the check valve will pop off and then the darn thing will not seal up and water comes pouring out of the pipe and will not stop.
Lesson:

What ever you do, do not press that valve in with much more then 5 psi of pressure in the camper water system. If you have no idea how to get that low, then just do not do it under any pressure.....
Now that you have this problem how do you get out of it

Well here is how.
You have to remove the entire fresh water inlet valve from the camper and take it apart.

I did not get the camera out until after I had it all apart, so the picture sequence is putting it back together. Figured this may help someone else some day.
Here are all the parts inside the valve. Sunline used a good brand called B & B. It is an all brass body valve. Some are all plastic and I myself prefer the metal ones better.
You have the following parts that make up the inside of the valve:
Here is the bottom inside of the valve body. (Outlet side) The O-ring seals against this surface.
Here is the inlet inside of the valve body. The fresh water inlet hose screws on this end.
Here is the valve stem with the infamous O-ring that pops off this grove and then leaks like a sieve.

The O ring is put back on. This entire procedure is all to put that O ring back on.
You insert the valve stem in the bottom (outlet end) of the valve and hold it up in there with your small finger.
Then install the spring
And now install the retainer clip. First how this thing goes together. There is a sharp edge grove in the valve stem. It is hard to see here but it is a groove at the tip.
The retainer snaps over that groove. The plastic just expands over it.
So to install you just place it over the valve stem and push it on until it clicks into place. I used a set of angled needle nose pliers to push down even on both sides. To pop this thing off to get it out you have to get under the retainer and pry it off. Heads up, This thing is spring loaded and take care the retainer and spring does not fly off somewhere as the spring is pushing it off.
And assembled it looks like this
Then install the Pex tubing washer on the discharge end.
Put new butyl sealing tape on the flange.
Install in the camper. Here I wired the pipe so it would not fall back in the camper. Mine is buried inside a bathroom cabinet with little room to get to it. I could easily pull it outside and take the Pex tubing nut off outside.
Then screw in the flange to the camper and before installing the screen washer, go turn on the water pump and make sure it holds pressure. Yup good a water tight, again….
Then the screen washer
And I use a screw in cap in case this thing ever leaks it does not drain my system.
And then wash up the outside of the camper flange.
So the lesson, don’t go pushing that valve stem in with much of any pressure in the system, it WILL pop that O-ring off the stem. If you find some how it happened anyway…. Use this post to help correct the problem.
Hope this helps someone prevent the problem from occurring and how to get out of it if it happens.
John
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