Air Compressors are on-demand tools.
An air compressor will start (Kick On) when the pressure (PSI) in the air tank drops to a pre-set PSI (example 90 PSI).
The air compressor will continue to run until the pressure (PSI) in the air tank reaches the Max PSI (that is pre-set) and Kick Off (shut off) (example Max 120 PSI).
The maximum PSI cannot exceed the maximum PSI of the safety valve.
If the PSI exceeds the maximum PSI of the safety valve, the safety valve will open and release air as a saftey precaution.
The Kick On and Kick Off PSI is set for a 30 PSI spread (example 90 PSI to 120 PSI). This spread cannot be changed.
From the video below you can see how to adjust the Kick On and Kick Off PSI.
There is a set screw you turn to move the Kick On and Kick Off PSI.
Many times you will need to release air from the air tank to start the air compressor and see when the air compressor will Kick On and Kick Off.