Hey all. I live in the warm climate of North Carolina, and have never winterized my system before. This year I upgraded my heads to the Rainbird 5000 series with the SAM feature to prevent leakage down to the low spot of my zones. I replaced them all and now my system works great with no air in it at all. We don't get severe cold for any long periods, but there will be a few days below freezing. I'm worried that since these heads are designed to keep water from flowing back out of them that they...
