"__ Bob __" wrote in message
...
A friand of mine bought a new house, complete with a built in sprinkler
system. With cold weather coming, he knows he needs to winterize the
system, which is equipped with a quick-connect air fitting. He's
assuming he's supposed to hookup an air hose and purge the system with
air. Question is : how much pressure to use ?? ?? ??


Your looking for volume not pressure per say.
Are you going to remove the heads or just blow it out?

If your going to blow it out then use 200 psi, and let me know when so I
can come by with my camera.