Hello all. Every year I blow out my lines without issue. This year, not so much. Not sure why. You know how when you do something almost by rote then suddenly scratch your head wondering what the heck to do? Well, that's me right now. I thought I was supposed to keep the backflow preventer valves open. Is this correct? I DO NOT want to break anything! The issue might also be my (new) compressor. But I want to resolve this issue first. Thank you!