A/C Pressure Cut-Off Switch

The A/C pressure cut-off switch is located in discharge line, between compressor and condenser. It interrupts compressor operation if high discharge pressures are sensed.

Normally closed set of contacts will open if high pressure is around 420 psi (29.5 kg/cm² ). This will cut off compressor operation to protect compressor. This function helps ensure refrigerant is contained in system, helping to maintain high side pressures, and not venting through the pressure relief valve. The contacts will close if compressor head pressure drops to 250 psi (17.5 kg/cm² ), to restore normal compressor operation.