Refrigerant Circuit, Flushing With Compressed Air Or Nitrogen
Special Tools And Workshop Equipment Required
- A/C Adapter Set :VAG1785
For vehicles that have refrigerant lines with no threads for connecting the A/C Adapter Set -VAG1785-. Use, for example, an air blow gun with a rubber mouth piece or an adapter from the Refrigerant Circuits Adapter Set 1 for blowing through the individual components. When using an air blow gun with a rubber mouthpiece, take special care not to damage the connections (bending or scratching).
Evaporator is to be flushed via the connection for low-pressure pipe (large diameter) after removing expansion valve or removing restrictor.
Always blow through components in direction opposite to refrigerant flow (or flush with refrigerant R1234yf)
Check expansion valve and replace if dirty or corroded.
Locate any components on which dark, sticky deposits cannot be removed with compressed air and either flush them using refrigerant R1234yf or replace them.
Thin, light gray deposits on the inside of pipes do not impair the function of the components.
After blowing through the receiver/dryer (dryer cartridge) or reservoir and restrictor. Replace the dryer cartridge on condensers that have one installed in the integrated receiver/dryer.
Condensers with an integrated receiver/dryer or dryer cartridge that cannot be replaced separately or are not available as a replacement part must be replaced after flushing the refrigerant circuit. Refer to the Parts Information and DESICCANT BAG/DRYER CARTRIDGE, REMOVING AND INSTALLING (vehicle-specific repair information).
Receivers/dryers where it is possible to replace the dryer cartridge have an additional filter, which must also be replaced with the dryer cartridge.
After Blowing through the Refrigerant Circuit:
-- Replace these vehicle-specific components (restrictor and reservoir, expansion valve and receiver/dryer or dryer cartridge). Refer to Refrigerant Circuit (vehicle-specific repair information) and the Parts Information.
-- Depending on the concern replace the A/C compressor or let the remaining refrigerant oil flow out of the removed A/C compressor. Refer to A/C COMPRESSOR (vehicle-specific repair information), COMPONENTS, REPLACING and the Parts Information. Re-fill the prescribed quantity of fresh refrigerant oil. Refer to Technical Data (vehicle-specific repair information) and Technical Data (R1234yf Servicing) .
There is a defined and prescribed amount of refrigerant oil in the replacement compressor. On vehicles with two evaporators if necessary install an additional certain amount of refrigerant oil in the circuit. Refer to Technical Data and Refrigerant Circuit .
If the A/C compressor is not be replaced, replace the refrigerant oil quantity in the A/C compressor to the specified capacity (pour out the refrigerant oil and refill the prescribed quantity into the A/C compressor or refrigerant circuit). Refer to COMPONENTS, REPLACING and Technical Data .
-- Reassemble the refrigerant circuit completely. Refer to Refrigerant Circuit (vehicle-specific repair information).
-- Evacuate and fill the refrigerant circuit according to the procedure. Refer to REFRIGERANT CIRCUIT, EVACUATING and REFRIGERANT CIRCUIT, CHARGING .
-- Start the A/C system after filling. Refer to REFRIGERANT CIRCUIT and A/C SYSTEM, OPERATING AFTER CHARGING .