Plumbing help

[Beartooth]

Could someone tell me what this is and do they go bad with what results. I have a 2021 Cougar 315RLS. This is under the bath sink.
Sorry for the side ways pic. The flat cap should be on top with white water lines running down.
Thanks

[travelin texans]

Originally Posted by Beartooth

Could someone tell me what this is and do they go bad with what results. I have a 2021 Cougar 315RLS. This is under the bath sink.
Sorry for the side ways pic. The flat cap should be on top with white water lines running down.
Thanks


Attachment 41811

It's the anti siphon backflo preventer valve on the black tank flush line. Yes they can go bad, they can be installed backwards not allowing flow to the black tank & are prone to leak from loose fittings.
You can replace it with a much better quality brass valve found at most hardware stores, just be sure to correct flow before installing or remove it & add a couple 90 degree elbows .

[JRTJH]

That valve is responsible for more "flooded trailers" than, IMO, any other device or failure. They are NOTORIOUS for failing, so to answer your question, It's the anti-siphon valve to prevent black tank contents and gasses from flowing from the black tank to your fresh water supply while a hose is connected to the black tank flush system.

They are "fragile" and can start to leak at any time, usually when you least expect it, and can fill the vanity with water before you realize what's happening. If you use it "as is" then I'd recommend always having someone with a flashlight watching the valve while in use. Alternatively, as Danny said, many (maybe most) people either replace it with a better, more reliable valve or just completely remove it from the system by installing a "homemade PEX fitting" and then install a "backflow preventer" on the backflush connector outside on the trailer sidewall. https://www.amazon.com/Homewerks-Wor...35478475&psc=1