[BB_TX]

When you are winterizing and pumping the pink stuff thru the pipes, make sure to run pink stuff thru your outside shower faucet, both hot and cold. Then connect the outside shower hose to your black tank flush connection, turn on either faucet and pink stuff will go thru the flush line.

Water may drain from the anti siphon valve down into the black tank. But it will not drain from the anti siphon valve back out the flush connection in the wet bay if that connection has a check valve. I removed my anti siphon valve and water would not drain either direction as you can see by the pink stuff in my flush lines where the anti siphon valve was removed. (the other 2 lines are to my shower)

And don't forget the pink stuff thru your low point drains also.