Quote Originally Posted by Gman View Post
The issue for me is tank volume. You can dump a lot of air through the lines pretty quickly. If the pressure drops too low the backflow preventer will lose its seal. Once that happens, I have no way to get it to reseal using just air.
There should be a cutoff valve between your valves and your back flow preventer. Your air hook up should be after the valve to the bf.
Project time!