I'm getting very tempted to try and get into a wall that houses the black tank flush water line. I am pretty sure it's leaking at a fitting that it up in the wall, and cannot be pulled down.When using the black tank flush water runs down the line from this location, as best as I can figure that's the high point of the route.I'm looking for suggestions on the best way to get into the wall. It's a wall between the bunk room and kitchen. Closed off with the very thin, decorative panel material. This material is stapled into the wood frame all over the place. Pulling the stables is either way too involved, or will likely destroy the piece in the process.I was thinking of cutting an access panel of some kind, but then am wondering how to best patch it back up and finish it so it looks clean. Any personal experiences like this?Thanks

One option: look at your local building supply place; there are prefabricated access panels/doors available in various sizes. If you get one and cut the hole to suit, you should be able to mount it with at most a little bit of ingenuity or trimming and have something that at least looks intentional. You could also see about mounting a picture or mirror or cabinet or something over the hole if it's not too unreasonable of a place for one.In my Coachmen RV, they just use a piece of the wall material (finished in either woodgrain or stick-on wallpaper as appropriate) attached to the larger wall with a few screws where a panel is needed. It's not the most beautiful looking, but works fine and they're located in places that are not immediately in sight most of the time.

You can find those panels online in several places. Cut the hole from the middle of 2 studs and make a patch panel that overlays the entire hole. Wrap the edges with seam tape and it will look like a factory install access panel.Here's just an example.

My black tank flush anti siphon valve was located between the shower wall and the back wall of my entry closet. There was an access panel there, but located in the wrong area. But I could reach in and feel the valve and know where to cut a new hole. I cut a new hole there, saved the piece I cut out, and used some trim wood to make a picture frame for it, and used 4 small black screws to attach it. Looks better than the plastic frame on the original cutout.Note that I eliminated the anti siphon valve and now use an external check valve at the outside flush connection. Those anti siphon valves have a history of leaking.

Those are great pics and specifics. Thanks everyone!

Bet it is the back flow prevention valve. Mine was a plastic thing that broke. I epoxyed it back together as I remember and it is working after several years.

Cutting into a wall, ideas/closing back up | Good Sam Community

12 Replies

acritzer
Explorer II
Jun 25, 2017
Actually never mind. I think I fixed it. As gross as this sounds I think a bug had gotten into the vacuum breaker and caused the seal to not actually seal. I cleaned it out, tested it with air and then reattached it, tested with water and all seems ok.

Theoretically if something goes wrong now I have the trap door set up so it shouldn't be too hard.
acritzer
Explorer II
Jun 25, 2017
Want to bring this back up from for follow up help. I managed to get the wall open and found the vacuum breaker piece, which is leaking straight out of the top. As best as I can tell, the seal isn't closing when he water comes through. I think there's a seal that's suppose to close off the top?

So...does this piece just need to be replaced? Can it be fixed? Or can it simply be removed, and I attach the remaining tubing? I was surprised to see that a new one costs close to $50.
BB_TX
Nomad
Jun 20, 2017
Looking at my picture above, one of the two 90 degree fittings used to be the anti siphon/vacuum breaker valve. I replaced that valve with a new 90 degree fitting and short piece of PEX tubing. And that is located about 2' above floor level.

The other two pipes go up to the shower faucet. The pipes are pink since pic was taken after I had winterized.
acritzer
Explorer II
Jun 19, 2017
wa8yxm wrote:
A common leak point is the vacuum breaker, IT MAY be accessible from the bathroom. IT may be in the Utility riser, not in the wall.

Not sure what the utility riser is. This leak seems to be falling down from the wall section approx 2 feet from the hook up for the black tanks flush. The line starts to ascend, goes into the wall and then I assume moves down and somehow crosses the trailer to reach the black tank.
acritzer
Explorer II
Jun 19, 2017
Edited for a misread
wa8yxm
Explorer III
Jun 19, 2017
A common leak point is the vacuum breaker, IT MAY be accessible from the bathroom. IT may be in the Utility riser, not in the wall.
FlatBroke
Explorer II
Jun 19, 2017
Would it be faster and less mess by running a new line to the black tank and just put a back flow preventer valve on it.
camperguy99
Explorer
Jun 19, 2017
Bet it is the back flow prevention valve. Mine was a plastic thing that broke. I epoxyed it back together as I remember and it is working after several years.
acritzer
Explorer II
Jun 19, 2017
Those are great pics and specifics. Thanks everyone!
BB_TX
Nomad
Jun 19, 2017
My black tank flush anti siphon valve was located between the shower wall and the back wall of my entry closet. There was an access panel there, but located in the wrong area. But I could reach in and feel the valve and know where to cut a new hole. I cut a new hole there, saved the piece I cut out, and used some trim wood to make a picture frame for it, and used 4 small black screws to attach it. Looks better than the plastic frame on the original cutout.

Note that I eliminated the anti siphon valve and now use an external check valve at the outside flush connection. Those anti siphon valves have a history of leaking.