Might have been a coincidence, and I'm hoping it was, but last year I used compressed air like I have done for 30 years and the back flow valve at the city water hookup failed. I couldn't get city water to go in after that, and when I turned my pump on the water went out the city water hookup.
I even took the whole thing apart and put it back together, it looked so simple, and got the same result. Ordered an new one online, installed it and all is well.
So the last two days it's been in the mid 20's overnight and I have left the furnace on at the lowest setting, but this weekend I'll get up my nerve and blow it out again. My low point drains work well and it's easy to drain the hot water tank.
My truck camper and vintage trailer are both winterized properly with antifreeze.
Hans
