Our sister company recently purchased a used Adira QHA-1606, and I have been asked to help breathe some life into it.
So far, so good... however:
I can not figure out what the adjusting knob does... shown in the attached picture, the smaller knob directly under the pressure gauge.
(Apologies, I cannot get the image to upload without it getting rotated 90 degrees.)

Any assistance would be greatly appreciated.


Attachment 184234