More knowledge than I expected to receive

[Chasnracin]

Last time I used the black tank flush in the convenience center, I noticed a leak dripping from the frame every time I turned it on. Since it started quickly, I turned it off. Yesterday I finally had the time to tear things apart and see what was the problem. After tearing apart the convenience center cover and storage area bulkhead, I was even more perplexed than ever. Seems the black water flush, along with 3 other water lines (1 hot, 1 cold, 1 unknown) also run up in the wall behind the shower wall. hmmmmm
Next, I go in and take the faucet off in the shower and start looking, or more like feeling, around. Ah HA! Seems there is a one way check valve of sorts on the wall behind the shower. Flush water goes in and out the other side, except in my case it goes in and out the vent top!

Anyone had to replace this check valve before? Any idea where to order it?

I'm getting ready to go out to our local Keystone dealer and try to explain to Gilligan what I am looking for fully expecting to see him scratch his head. Wish me luck!