black tank flush

[jbailey2]

03 Jayco has black tank flush as a hose fitting on side of trailer. hose connection and piping goes in and up to bathroom sink and then back down and i think into top of black tank. I can not get water to go into tank, even after letting it set with pressure for a while. Am I missing something or is it stopped up. Why does hose line make a loop under the sink?

[green haven]

That loop has a check valve that only lets the water go one way. I had a Holiday Rambler 5th whl that had the same problem. I discovered the check valve was reversed from the factory. I turned it around and it worked fine.

[Paul R. Haller]

I had a Jayco with exactly the same trouble.The valve didn't work at all. It had to be replaced. My new trailer also had the very same trouble. Seems to be a common problem.
-Paul R. Haller-.

[shipwreck1]

sounds like the check valve is broke or reversed.