Compressor HVAC: Description and Operation

GF83.55-P-2109CW A/C Compressor, Component Description

Component Identification:

Location
The A/C compressor is located at the front of the engine.

Task
The refrigerant compressor is responsible for induction and compression of the refrigerant. The A/C compressor is continuously performance-controlled up to 100 % via the compressor control valve by the automatic air conditioning control and operating unit (N22/7). The control and operating unit sends the request for switching on via interior CAN (CAN B). The front SAM control unit with fuse and relay module (N10/1) receives the request and actuates the compressor control valve.

The A/C compressor is switched off depending on the outside temperature.
If the outside temperature T < 2 °C, the A/C compressor is generally switched off.
By pressing the A/C button on the control and operating unit, the A/C compressor is also switched off.

Component Identification:

The A/C compressor is equipped with a limiter. This performs a protection function by means of torque limitation. Breakage of the limiter, e.g. with a stuck A/C compressor, ensures that the belt drive continues to function.

For an initial qualified estimate of the functionality of the A/C compressor, a visual inspection of the shaft can be performed. If the shaft does not turn with the engine running, the limiter is broken and the A/C compressor is defective. A defect at the limiter can be identified by a lack of cooling output.