Volkswagen Golf 1999 Service Manual page 4010

General information on refrigerant circuit
gauge is below the temperature of the refrigerant.
Note:
- The relationship between pressure and temperature
indicated on the gauges no longer applies if no liquid is
present and the pressure is built up solely by gas.
Service and recycling units
At this time, service units for extracting, cleaning and filling
refrigerant for motor vehicle A/C systems are available on
the market from various manufacturers.
Classification of extraction systems in groups
Group 3:
Mobile extraction and charging systems for filling
compressed-gas vessels permanently connected to the
system.
The refrigerant or refrigerant/oil mixture is transferred to
compressed gas vessels which are permanently connected
to the mobile systems. In accordance with 3 Para. 5 No. 3
of pressure vessel regulations, compressed-gas vessels
are classified as pressure vessels in this case.
The charging systems require:
- no permit
- Do not require expert testing, as the gas is transferred to
compressed- gas vessels which are classed as being
pressure vessels (systems used for transfer from these
pressure vessels to compressed gas vessels for supplying
to third parties do however require a permit and are subject
to mandatory testing)
Note:
- The service and recycling units used in motor vehicle
workshops are extraction and charging systems not
requiring a permit (Group 3) but which are only to be
operated by qualified personnel. Instructions for unit
operation and maintenance can be found in the relevant
manufacturers documentation.
Charging systems not requiring a permit
Charging systems not requiring a permit are ones used for
transferring compressed gases to mobile compressed-gas
vessels for internal use only.
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13/2/2005