Volkswagen Golf 1999 Service Manual page 3992

General information on refrigerant circuit
A/C compressor is driven by vehicle engine via a ribbed
belt.
An electromagnetic clutch attached to A/C compressor
provides the power link between the ribbed belt pulley and
A/C compressor crankshaft with A/C system switched on.
A fuse installed in ribbed belt pulley of A/C compressor
triggers the electromagnetic clutch when A/C compressor
runs with resistance and protects the ribbed belt drive
against overload.
The A/C compressor extracts the refrigerant gas from the
evaporator, compresses it and relays it to the condenser.
Note:
- The A/C compressor contains refrigerant oil, which can be
mixed with refrigerant R134a under any temperature.
- The refrigerant for which the A/C compressor is designed
is listed on the manufacturers plate. A regulator valve
regulates pressure within the specified range (control
characteristics) on the low pressure side.
- So that the A/C compressor is not damaged when
refrigerant circuit is empty, the A/C clutch is switched off
and the A/C Compressor Regulator Valve N280 is no
longer activated (A/C compressor runs at idle with engine).
A/C compressor without A/C clutch
A/C compressor is driven by vehicle engine via a ribbed
belt.
An overload safeguard (bearing-type connection) installed
in ribbed belt pulley of A/C compressor triggers when A/C
compressor runs with resistance and protects the ribbed
belt drive against overload.
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13/2/2005