1312100497 OEM Air Compressor PIlot Unloader Valve, 145-175psi, For Gas Driven Compressors, Chicago Pneumatic, Atlas Copco
The 1312100497 pilot valve has a 3/4" compression side inlet where your discharge tube connects to the pump. The pilot valve connects to the tank via a 1/2" MPT fitting on the bottom of the valve. A 1/8" line is also included where your line then connects back to the throttle engine. Both a muffler for venting and a cold start valve are pre-installed.
The unloader pilot valve prevents back flow as the compressor builds pressure. The pilot remains closed until the downstream pressure reaches the unload setting. The pilot then opens and pressurizes the unloader valve. This causes the unloader valve to open and vent the excess air from the compressor to the atmosphere. As the compressed air downstream is used and the pressure drops to the load setting the pilot closes and depressurizes the unloader valve. The unloader valve then closes and the pressure begins to build again and repeats the cycle. A signal is also sent via a pnuematic line to the engine to slow down the engine speed during unloaded operation.
This pilot unloader valve is used on the following gas driven air compressors.