Flush line

[Rayray04]

Hey guys how how u winterize your black tank flush line ... I have a cougar 369BHS

[chuckster57]

With the anti siphon valve at the high point, as long as it’s open the water will drain out on both sides, no need to winterize it.

[Brantel]

No way to know for sure they drain out. There can be some distance and many places for water to get trapped in those lines in low spots on the horizontal runs.

I use my outside shower hose and pump a shot of antifreeze through them. Better safe than sorry and it only takes a few seconds.

[JRTJH]

I remove the anti-siphon valve, clear it of water and store it in a zip-lock baggie under the vanity. The water will drain from the PEX tubing (unless there is a "low pocket in the tubing") PEX is "advertised as capable of expanding 4 times its size without damage, so freezing won't affect it. That said, any "cheap plastic fittings" crimped in the PEX lines may not fare so well.

If in doubt, blow the line with low pressure air (low enough not to damage the anti-siphon valve, then instill antifreeze. If you have the OEM anti-siphon valve, it's the weakest link and I would not leave it connected to the system. YMMV

[ChuckS]

I’d at least blow some air through that plastic valve.. I removed mine several years ago and don’t use the black tank flush nowadays..

[gkainz]

mine is right next to my outdoor shower. I remove the shower head and have an adapter that connects the shower hose to the flush inlet. Pump some pink stuff into the line and call it good.