black tank valve stuck open

[Ray Bates]

Farco, Thanks for the info. The cable runs behind the water panel and I can only see about a foot of it. I think the valve is between 2 or 3 feet back under the floor. I will see if I can hold my phone back enough to see if it is visible.

[Morich]

With the idea that we never have too much info when working blind, I did a few snips of the drawings to let you see a little bit of what might be there. I did some guesing on thing slike where the wall fits and how much distance from the drain outlet. Those are guesses so don't bet the farm on my guess!
Maybe a little help to spot where to look?

From above


From side


And looking from below

[Farco]

Hiding the valve where it’s inaccessible is just lousy engineering!
I guess until you can resolve this, the extra valve and elbow will have to do.
I still carry mine….just in case.

[Morich]

Originally Posted by Farco

Hiding the valve where it’s inaccessible is just lousy engineering!
I guess until you can resolve this, the extra valve and elbow will have to do.
I still carry mine….just in case.

I guess I'm missing part of the question on this. If we take it to a shop, they remove part of the cover underneath and change the valve or fix the linkage, so is that not what we would have to do also, but at a cheaper price ?

I have not done a newer RV on this but I assume it is still just some form of waterproofing layer and then insulation, so it should not be hard to cut out a section and then replace and tape the joint or glue over the seam on the hole we've made.

Seems very much like any plumbing repair inside a wall where we have to make access and then patch the access. Very much like sheetrock repair! This repair seems much less trouble than when a PVC drain gets drilled in a house and the water ruins the entire wall!
The repair on the underbody of an RV seems much easier as we don't spend much time looking at it, so the repair doesn't have to be great looking!
They don't put access holes in houses either!

The only reason for knowing about where the valve is located is to better plan where to cut???