28BHS black tank flush

[Jayco28bhs2021]

Black tank flush not allowing water in the inlet. When I unhook the hose, pressurized air is released. No water goes in. The black tank itself is wide open. Is there a valve I need to open to allow water in? Is there a reset for the backflow? Where can I find the plumbing to check for installation issues? Please help.

[Midnightmoon]

It sounds like there is a check valve installed backward on the black flush line.

[Jayco28bhs2021]

Any idea how I would find it?

[CTGT]

Take the three screws out and see if you have any slack. Also, is there any access from the inside?

[Midnightmoon]

Without knowing your exact trailer, it is hard to guess. Hopefully someone here with a 28BHS will chime in if they see this post. The black water flush, fresh water fill, and the outside shower all come in through underneath the lavatory cabinet on my trailer. That may be a good place to start looking. I don't however know where the check valve will be in that line.

[Jayco28bhs2021]

What would that do so I know. And I have no clue where inside access would be. I checked under sink and didn’t see anything.

[Midnightmoon]

This may not be identical to your system. But, it should give you a basic idea of how the systems work.

https://www.youtube.com/watch?v=-YPkEcyhf3k