Refrigerant Circuit, Cleaning (Flushing) With Compressed Air and Nitrogen

Refrigerant Circuit, Cleaning (flushing) With Compressed Air And Nitrogen

- Compressed air and nitrogen are to be used in order to force out moisture and other contaminants as well as old refrigerant oil as efficiently as possible, without wasting refrigerant, without the need for extensive assembly work and without endangering the environment.

CAUTION:
- Make exclusive use of pressure reducers for nitrogen cylinders.
- Use appropriate extraction units to draw off gas mixture escaping from components.

- 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.
- Adapters for connecting pressure hose to refrigerant circuit and Heating, air conditioning or Air conditioning
- 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.
Pay attention to the following items to prevent oil and moisture from the compressed-air system penetrating into the refrigerant circuit.

NOTE:
- For refrigerant pipes with thread or union nut at connection, make use of adapters from Adapter Set V.A. G 1785 (adapter V.A.G/1 to adapter V.A.G/8) for connection of 5/8 inch - 18 UNF charging hoses.
- For refrigerant pipes with no thread or union nut at connection (for installing 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 the circuit
- If the compressor had to be replaced on account of internal damage (e.g. noise or no output)
- If stipulated by the vehicle-specific following replacement of certain components

Refrigerant circuit, flushing

NOTE:
- In the case of vehicles on which the refrigerant pipes have no threads for connection of adapter set V.A. G , use is to be made, for example, of a flushing gun with rubber end piece for flushing the individual components. Special care must be taken not to damage the connections (crushing or scratching).
- Evaporator is to be flushed by way of connection for low-pressure pipe (large diameter) after removing expansion valve or removing restrictor.
- Always flush components in direction opposite to refrigerant flow.
- Check expansion valve and replace if dirty or corroded.
- Replace any components on which dark, sticky deposits cannot be removed with compressed air.
- Thin, light grey deposits on the insides of pipes do not impair the function of the components.
- After flushing, always replace receiver or reservoir and restrictor. Replace dryer cartridge on condensers with dryer.