Mikey
Aspiring Old Fart, EE, computer & networking geek
Really appreciate the feedback; now I'm encouraged to measure mine and see how it compares to theory. I still like the idea of heating the drain line somehow (I are an EE, not a plumber), but I'd only be guessing without knowing your exact situation. But while thinking about that, power failure came to mind. So the next question is -- what happens if the power fails while the valve is in the backwash postion? Does the backwash continue until power is restored? I've been assuming all along, for some reason, that you're on municipal water, which, unfortunately, is likely NOT to stop in the event of power failure. HJ's solution, to design the outside drain & vent so it WON'T freeze, avoids this issue, but you could wind up with a skating rink in the yard.
74° here today...
74° here today...