The Ingersoll Rand 47600594001 Air Compressor Unloader Valve Assembly helps relieve pressure from the compressor system during shutdown to support easier restarting. Designed as a replacement unloader valve assembly, it works with the compressor control system to release trapped air from the discharge line when the unit stops. Proper unloader operation can reduce starting load and sup... https://www.wholetoolbox.com/ingersoll-rand-47600594001-air-compressor-unloader-valve-assembly/47600594001.html