This switch is used on semi-hermetic compressors to protect them in the event there is an oil pressure problem causing the lack of lubrication of the reciprocal compressor. The operation of this control is relatively simple, yet many technicians become confused when working with the control. The opfc is a pressure actuated control, using two opposing pressure diaphragms. The capillary tube of one diaphragm is connected to the oil pump port. It senses the actual oil pressure being produced by the pump. The other capillary tube from the other diaphragm pumps is connected to the low side (suction) of the system. For example, the oil pump has an output pressure of 30 psi. It is an R-22 system with a 65-pound back pressure. A spring will apply pressure on the oil pump diaphragm of the control. The spring is adjusted to a 35-psi pressure causing equal pressure also have a wet rag or other type of heat sink to absorb excessive heat as not to warp the valve body causing inconsistent of possibly no operation.