Hello All,

Trying to winterize my irrigation system using a compressor at 40 PSI. I did it last year with a small compressor I borrowed. Done in 30 minutes. This year, I buy a compressor, and every time I turn the air on (slowly) the Back flow device opens and does noat build pressure in the zone. Yes, the timer/zone solenoid is on. I can re-seat the Backflow device by turning the water back on, but then it will open again with the air, any odeas what I'm doing wrong??

Thanks

Dan