High Pressure Safety Valve HVAC: Description and Operation

Air Conditioning

A/C Pressure Relief Valve

NOTE: If the A/C compressor is operating within limits and the A/C pressure relief valve is venting, or if the A/C pressure relief valve is leaking around the threads, replace the A/C pressure relief valve and O-ring seal. If the A/C pressure relief valve still vents after it is replaced, diagnose the refrigerant system for a restriction between the A/C compressor and A/C pressure transducer.

An A/C pressure relief valve is incorporated in the A/C compressor, as a redundant backup to the A/C pressure transducer, to prevent damage to the A/C compressor and other system components by relieving unusually high system discharge pressure buildups. The valve will open at approximately 3,792 kPa (550 psi), and will close at approximately 2,756 kPa (400 psi). Under normal conditions the A/C pressure relief valve will never vent. Only a failure of the A/C pressure relief valve, A/C pressure transducer or A/C clutch control system, overheating of the refrigerant system, or a restriction in the refrigerant system between the A/C compressor and A/C pressure transducer will cause the A/C pressure relief valve to vent.

The A/C pressure relief valve is a separate component and can be replaced separately from the A/C compressor. It is necessary to recover the refrigerant before removing the A/C pressure relief valve.