I received my PP60S and it seems to function well. The question I have is: should there be ANY air pressure leakdown type noises when not powered up but connected to air source? Mine hisses a little when setting unpowered with compressed air attached and dialed down to appropriate float pressure (via tester) at torch nozzle (about 88 PSI). It seems as if the sound is coming from within the cabinet. If it isn't supposed to be releasing pressure, how does one correct this leakdown issue?