Winterize Black Tank Flush Line

[retired rob]

On our cougar the only way I could get antifreeze in the black tank flush line was to gravity feed some then shoot a little air in and repeat. The line did not crack last winter, but why take a chance. Does anyone else do this ?

[Old-Biscuit]

Shouldn't need to 'winterize' it


Water in line AFTER the anti-siphon vacuum breaker will just drain down into tank thru spray nozzle
Water in line BEFORE the anti-siphon vacuum breaker will just drain back out hose connection when hose is removed

[TonyDi]

[happycamperz]

I couldn’t decide if it was necessary or not, so I just put my air fitting on the hose fitting and blew air through at 30 psi. Took 30 seconds and was peace of mind, even if completely unnecessary.

[bkrahn]

Yes the lines SHOULD drain on their own but you never know how the factory ran the lines. As an RV tech I always blow the flush line with air when I winterize just to be on the safe side.