High Pressure Safety Valve HVAC: Description and Operation

Pressure Relief Valve
The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.
When the pressure of refrigerant in the system increases to an abnormal level [more than 3,727 kPa (38 kg/sq.cm, 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into
the atmosphere.