Refrigerant Pressure Sensor / Switch: Description and Operation

A/C Cycling Switch
The A/C cycling switch is mounted on a Schrader valve-type fitting at the top of the suction accumulator/drier. The switch allows the pressure inside the suction accumulator/drier to control the operation of the switch.

A/C Pressure Cut-Off Switch
The A/C pressure cut-off switch is used to interrupt A/C compressor operation in the event of high system discharge pressures.

The A/C pressure cut-off switch:
^ is located on a Schrader valve-type fitting on the high-pressure side of the A/C manifold and tube.
^ is a valve depressor, located inside the threaded end of the A/C pressure cut-off switch, and is used to monitor the compressor discharge pressure.
^ opens and disengages the A/C compressor whenever the discharge pressure rises to approximately 2,896 kPa (420 psi).
^ closes and engages the compressor whenever the pressure drops to approximately 1,724 kPa (250 psi).
^ can be removed without discharging the refrigerant from the system.