Jim, Just for your information. I have a Coleman 1.75 HP 4 gallon air compressor that I use to winterize my sprinkler ahd have been for the past 3 years, along with 1/2 my neighbors! The thing most people don't really realize about blowing water from sprinkers is that you don't need much pressure, but you need air volume. The 4 gallon tank will empty very fast so with some little tricks and an on/off action you can purge water from your sprinkler. Also, on each zone there may be many heads, so when the closest head to the valve is purged a lot of your compressed air is going to escape there leaving water in the other heads. I know how my sprinklers are piped and I simply turn off all of them except the last one on that particular zone and force the water to all leave that head. Make sense??? I hope this helps.