F 150 4WD V8-4.6L VIN 8 (2010)
High Pressure Safety Valve HVAC: Description and Operation
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. Under normal conditions the A/C pressure
relief valve will never vent. Only a failure of the A/C pressure transducer, a failure of the A/C clutch control system (clutch stuck on), 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.
