what is this

[KennyMitt]

Hi sorry for the double post. New to the forum. Wondering if someone could tell me what the black object is that i have photographed. And why is it vibrating?

[Mr. Dan]

That is the black tank flush check valve/vacuum breaker. Water under pressure passes through it when you're flushing your black tank. Be happy you can see yours. Mine is hidden behind the shower enclosure.

[KennyMitt]

Thank you Mr. Dan. I really appreciate the quick response. I had a splitter from the city water that I had the black tank flush hose hooked up to. The valve wasn't completely getting shut off so it was continuing to run and making that check valve vibrate! My new process will be to disconnect the black tank flush hose each time. Thanks again for the help!

[Mr. Dan]

That "disconnect" process will save some grief. Uncle Gene left his hooked up and his grandkids passed by and wanted to wash their hands. They turned on the black tank flush by mistake, turned on the correct faucet and left without turning off the black tank flush. Later when someone flushed the toilet, they got an unwanted surprise.