Conrader Piloted Unloader Check valves are an all-in-one combination valve to run an air compressor for continuous operation. The valve includes a pilot valve, discharge unloader valve, and check valve. This can be used on gas engine or electric motor driven air compressors.
In operation, the check 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.