Low Pressure Sensor / Switch: Description and Operation

AIR CONDITIONING (A/C) LOW CHARGE PROTECTION SWITCH

The A/C 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 A/C low charge protection switch presses in on the Schrader-type valve stem.
- This allows the suction pressure inside the suction accumulator to control the operation of the A/C low charge protection switch.
- The electrical switch contacts open when the suction pressure drops to 80-90 kPa (11-13 psi).
- The contacts close when the suction pressure rises to 276 max kPa (40 psi max).
- While the A/C low charge protection switch is closed, voltage is sent to the PCM signaling normal pressure in the A/C system, and the PCM continues to control operation of the A/C compressor based on other inputs.
- When the A/C low charge protection switch contacts open, voltage is removed to the PCM and the A/C compressor is disengaged.
- It is not necessary to discharge the refrigerant system to remove the A/C low charge protection switch.