Blank Tank Flush

[XJ TENN]

2021 243 BHS black tank flush not working.

I thought that maybe the check valve was installed backwards so I removed it to switch it around. It is not obvious to me which line goes to the tank and which comes from the hook up as both lines enter the bathroom cabinet from the same hole. For a temporary fix I installed a ball valve in its place. I still have no water flow.

What else might be the issue? Is there any other common factory "mistakes" that I should investigate?

[tech740]

Sounds like you need to start at the water inlet for the black tank flush. Is the back of that accessible? If no issue there you will need to follow the water line until you find the kink or plug.

[MarkEHansen]

Sounds like a warranty issue. Perhaps let your dealer take care of it, if that's practical.

[jxnbbl]

I have the 273BHS and have the same problem and just figured it out. We only used the trailer one long trip and really never used the flush yet.

The other day I was blowing out the lines and I couldn't get air flow through the black tank flush connector. At the time I was thinking it was because the black tank dump valve was shut (which I could not open) and would deal with it later. Today I could deal with everything.

Under the bathroom sink there is a check valve connected to a 'white water line' and a 'white painted black water line' (black tank). I took off this valve and found that it was installed correct, but probably defective. Since the trailer is going into storage I'll bring the valve and video to the dealer to see if I can just get a new one under warranty. But at least I can blow out the line now.

I should add that 'each side' of the check valve can be unscrews by hand so it is a simple fix.