What's the air adjusting valve for on my HVLP gun?

[timinator]

I just bought a new Devilbiss HVLP gun. I understand what the fan control and fluid needle control are, but at the bottom of the gun where the hose connects, there's a "air adjusting valve". What's this for and how do I set it?

[Drop Top]

Its used to control the air pressure. As a rule its left alone.Turn it all the way on and controll your air from the regulator on the wall. There are time when you are painting a car that you my need to turn down the pressure a little, like doing tite areas like jams. In this case you can turn the pressure down temporarlly and put it right back and keep spraying with out going to the regulator. This is used mostly by the profesionals. First timers need to not wory about it. They have too much on there minds as it is. The best thing to do is play with the gun a little before you use it. Practice on an old junk yard fender first to familerize your self with it. The go at it on your car.