Refrigerant Pressure Sensor / Switch: Description and Operation

DUAL PRESSURE SWITCH
The pressure switch (Dual pressure switch) (4) is installed on the upper part of the receiver/drier, to detect excessively high pressure (high pressure switch) and prevent compressor seizure due to the refrigerant leaking (low pressure switch), so that the compressor is able to be turned ON or OFF.

The pressure characteristics of HFC-134a refrigerant differ from those of R-12. Thus, the pressure switch operation for HFC-134a systems has been changed from R-12.