I tried winterizing by just opening the low drains once, and faucets inside. then, because of my ocd, I figured I'd hook up air and give 'r a blow too.
Glad I did, since there was several gallons of water still in the lines that did not drain out the low point. Who knows how much damage that water freezing could have done. Spending the extra few minutes blowing probably saved me $100s.
Even with blowing, I couldn't figure out how to purge the pump, pressure bladder and strainer bucket without taking them apart, so I ran some pink stuff through.
