Compressor HVAC: Description and Operation

A/C Compressor Replacement Information

- After installing a new A/C compressor or fresh refrigerant oil has been filled into compressor (for example, after blowing through the A/C system), turn ribbed belt pulley of A/C compressor 10 rotations by hand before starting the engine. This prevents damage to the A/C compressor.

• Start the engine only after assembling the refrigerant circuit.

• Only start the engine when the refrigerant circuit is filled.

• The A/C compressor is always driven by the ribbed belt pulley/torsion elastic clutch. It does not have a magnetic clutch.

• If an A/C compressor locks-up the overload protection for the A/C compressor shaft is triggered. An indication that the A/C compressor is blocked is deformations/bumps on the ribbed belt pulley/overload protection in front of the A/C compressor, but these are not always easy to detect. Another indicator is abraded rubber material in the area of the ribbed belt pulley / overload protection.

• The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm3 of refrigerant oil remains in the A/C compressor.

• The engine may only be started when the refrigerant circuit is installed correctly. For example; if the refrigerant lines are not connected to A/C compressor, when the engine is running the A/C compressor may heat up (via internal heat generation) so much that the A/C compressor will be damaged.

• A/C Compressor Regulator Valve (N280) is not activated when the refrigerant circuit is empty and the A/C compressor idles with the engine.

• If it is necessary to start the engine with a discharged refrigerant circuit:

• Refrigerant circuit must be fully assembled.

• At least 1/4 of the prescribed refrigerant oil must be in the A/C compressor.

• Do not rev engine higher than 2000 rpm.

• The engine should run less than 10 minutes and the A/C system should be switched off.

- Pay attention to the following when starting the engine for the first time after filling the refrigerant circuit:

- Start engine with A/C compressor switched off ( ECON or AC ) and wait until the idling speed stabilizes.

- Open the instrument panel vents.

- Select the temperature setting Lo on the Front A/C display control head (E87).

- Switch the A/C compressor on (AUTO or AC ON) and let it run at least 5 minutes at less than 1,500 RPM with the engine running.