Volkswagen Golf 1999 Service Manual page 4026

Refrigerant circuit
- Always flush components in direction opposite to
refrigerant flow.
Restrictor, expansion valve, compressor, receiver and
reservoir cannot be flushed with compressed air and
nitrogen.
- Remove dryer cartridge on condensers with dryer.
- First flush out old refrigerant oil and dirt using compressed
air and then use nitrogen to remove component moisture.
The compressed air must be routed through a compressed-
air purifier for cleaning and drying. Use is therefore to be
made of filter and dryer for compressed air (included in
scope of delivery as tool for painting work).
Workshop equipment and special tools catalog
Note:
- Observe the following items to prevent oil and moisture
from the compressed- air system penetrating into the
refrigerant circuit.
- For refrigerant pipes with thread or union nut at
connection, make use of adapters from adapter set V.A.G
1785 ( 1785/1 to adapter V.A.G 1785/8 ) for connection of
5/8" -18 UNF charging hoses.
- For refrigerant pipes with no thread or union nut at
connection (for connecting adapters), make use of
commercially available flushing gun with rubber end piece.
- Flush refrigerant circuit with compressed air and then with
nitrogen.
- Compressed air/nitrogen emerging from components is to
be drawn off by way of an appropriate system (workshop
extraction system).
The circuit must be flushed:
- In the event of dirt or other contamination in the circuit.
- If vacuum reading is not maintained on evacuating a leak-
free refrigerant circuit (pressure build-up due to moisture in
refrigerant circuit).
- If refrigerant circuit has been left open for longer than
normal (e.g. following an accident).
- If pressure and temperature measurements in the
refrigerant circuit indicate the likelihood of moisture.
- In the event of doubt about the amount of refrigerant oil in
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13/2/2005