Low Pressure Sensor / Switch: Description and Operation

LOW CHARGE PROTECTION SWITCH

The low charge protection switch is used to prevent A/C compressor damage in the event of a low refrigerant charge.
- The electrical switch contacts open when the suction pressure drops below normal levels. The contacts close when the suction pressure rises. For specifications regarding operating pressure(s), refer to Heating and air Conditioning.
- When the low charge protection switch contacts open, the A/C clutch field coil is de-energized and compressor operation stops.
- The low charge protection switch is mounted on a Schrader-type valve fitting on the top of the suction accumulator.
- A valve depressor, located inside the threaded end of the low charge protection switch, presses in on the Schrader valve stem, allowing the suction pressure inside the suction accumulator to control the operation of the low charge protection switch.
- It is not necessary to recover the refrigerant to remove the low charge protection switch.