Compressor HVAC: Description and Operation
COMPRESSOR - A/CDESCRIPTION
A/C COMPRESSOR
The A/C system uses a Denso 10SR15 reciprocating swash plate-type compressor (1). This A/C compressor has a fixed displacement of 150 cubic centimeters (9.153 ci.). The discharge port (2) is located on the top of the housing and the suction port (3) and the pressure relief valve (5) are located on the cylinder head (4) at the rear of the compressor. A label identifying the use of R-134a refrigerant and ND-8 PAG oil is located on the A/C compressor.
HIGH PRESSURE RELIEF VALVE
A high pressure relief valve is located on the compressor cylinder head at the rear of the A/C compressor. This mechanical valve is designed to vent refrigerant from the A/C system to protect against damage to the A/C compressor and other A/C system components, caused by condenser air flow restriction or an overcharge of refrigerant.
OPERATION
A/C COMPRESSOR
The A/C compressor is driven by the engine through an electric clutch, drive pulley and belt arrangement. The A/C compressor is lubricated by refrigerant oil that is circulated throughout the refrigerant system with the refrigerant.
The A/C compressor draws in low-pressure refrigerant vapor from the A/C evaporator through its suction port. It then compresses the refrigerant into a high-pressure, high-temperature refrigerant vapor, which is then pumped to the A/C condenser through the compressor discharge port.
CAUTION: Be certain to adjust the refrigerant system oil level when replacing an A/C compressor. Failure to properly adjust the refrigerant oil level can prevent the A/C system from operating as designed and can cause serious A/C compressor damage.
The A/C compressor cannot be repaired and must be replaced if inoperative or damaged. The compressor clutch, pulley and bearing assembly, and clutch field coil are available for service. If an internal failure of the A/C compressor has occurred, the A/C accumulator must also be replaced.
HIGH PRESSURE RELIEF VALVE
The high pressure relief valve vents refrigerant from the A/C system when a discharge pressure of 3445 to 4135 kPa (500 to 600 psi) or above is reached. The high pressure relief valve closes with a minimum discharge pressure of 2756 kPa (400 psi) is reached. The high pressure relief valve vents only enough refrigerant to reduce the A/C system pressure, and then re-seats itself. The majority of the refrigerant is conserved in the A/C system. If the high pressure relief valve vents refrigerant, it does not mean the valve is inoperative.
The high pressure relief valve is factory-calibrated and cannot be adjusted or repaired, and must not be removed or otherwise disturbed. The valve is only serviced as a part of the A/C compressor.