The principle of rotary screw air compression is really no different than reciprocating (piston) compression. Both are positive displacement machines that take in a fixed volume of air at atmospheric press.
[pdf] Rotor clearance issues or debris can lead to metallic contact sounds Loose or worn belts squeal or howl, especially under load Airflow pulsations, valve leaks, or turbulence create hissing or whistling Bolts, nuts, and mounting pads loosen over time, amplifying noise
[pdf] When pressing “Enter” the following interface will pop up and the password will be required (9999). NOTE: Customer Password can be modified in the CUSTOMER PARAMETER menu. Page 23 KRSD series ENTER PASSWORD ****. Page 24 UNLOAD P. *.**Mpa Unload pressure setting.
[pdf] 
