The air supply in the booth should be at 75psi, the paint gun uses a needle valve not a regulator to restrict the flow down to what ever the manufacture recommends 21-27 psi for instance. Do not put a mini diaphragm regulator at the paint gun, read the info sheet attached. Conventional paint guns use the regulators, HVLP use the needle valves. You will not get proper air flow through an HVLP when using the regulator. I have often seen guys using them on their HVLP paint guns when I go out and visit them and wondered why the paint gun sounded like it was starving for air. I don't know the exactly why you don't use the mini regulators on HVLP guns but I do know from experience they work better with out them. I think it's a CFM related issue. When using an HVLP it should make some noise. The first thing I do when watching a guy demonstrate his painting set up is listen to the sound of the paint gun. It needs to go PSHHHHHHH !!! - Not - ppssss.....
