At my old house the system had drains so I just opened the valves and let them drain. That worked just fine for 15 years. I built this new system and left out drains so I will be blowing it out every year.I did something very similar for mine, but at our irrigation pump. I don’t have a BFP. I don’t usually blow out lines.. but now I can when I want to. I think I have twice in my life.