Originally Posted by 5picker
Well... yes... anything can go bad.
Your brass valve is the 2nd one I've heard of.
I have read/heard of several dozen plastic ones.
Take it for what you paid for it... nothing.
Although I keep my rig heated allwinter, we did have a power outage for a day when the temps were barely below freezing. I can not remember if I blew out the black tank flush line or not. But I’m also thinking the batteries should have had enough juice to run the furnace for a while to kept the temps above freezing. So, I think it just failed.
What happens is, when turning on, and turning off water to the flush, water sprays out of the vacuum breaker.