General Information For Blow Through With Compressed Air Or Nitrogen
Special Tools And Workshop Equipment Required
- A/C Adapter Set :VAG1785
- A/C Adapter Set - Adapter 1 :VAG1785/1
- A/C Adapter Set - Adapter 8 :VAG1785/8
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. Clean the refrigerant circuit using refrigerant R1234yf (flushing with refrigerant R1234yf). Refer to REFRIGERANT CIRCUIT, CLEANING .
Blowing through the refrigerant circuit with compressed air and nitrogen if for example to be used then only individual components are to be cleaned.
Only blow through refrigerant circuit with compressed air and then with nitrogen if there is no possibility of flushing the refrigerant circuit or the amount of work to flush individual components becomes excessive (for example minor contaminants and moisture can also be blown out of the removed refrigerant lines in a short period of time).
For the most part, blowing through the entire refrigerant circuit with compressed air and nitrogen requires significantly more work than cleaning (flushing) with refrigerant R134a. As flushing with refrigerant R1234yf cleans the components more efficiently, always flush in case of a complaint (blowing through should only be used for certain complaints and individual components).
Under certain conditions, it can be enough to blow out specific components (for example individual refrigerant lines or refrigerant hose) with compressed air (for example to push out old refrigerant oil from individual removed components) or with compressed air (to dry individual components).
Certain contaminants cannot or can only be insufficiently removed from the refrigerant circuit with compressed air, these contaminants can be removed, for example by cleaning (flushing) with refrigerant R1234yf. Refer to REFRIGERANT CIRCUIT, CLEANING .
When blowing through (with compressed air or nitrogen), the maximum work pressure of 15 bar (218 psi) must not be exceeded (corresponding to pressure that is reached in a filled refrigerant circuit with an ambient temperature of approximately 60 °C (140 °F), if necessary use pressure reducer also for compressed air)
If it is determined by the gas analysis that the refrigerant R1234yf is contaminated with another gas, it must be extracted from the refrigerant circuit and be disposed of as a gas from an unknown composition according to the legal requirements. Refer to CONTAMINATED REFRIGERANT, FILLING IN RECYCLING CONTAINER FOR ANALYSIS, PROCESSING, OR DISPOSAL .
Due to contaminated refrigerant decomposition products can be created and accumulate in the refrigerant oil which cannot be extracted with the refrigerant. The contaminated refrigerant oil in this case is to be removed from the refrigerant circuit by flushing with refrigerant. Refer to REFRIGERANT CIRCUIT, CLEANING .
The refrigerant circuit may be cleaned (flushed) with an A/C Service Station for the refrigerant R134a and flushed with refrigerant R1234yf if no suitable A/C Service Station for the refrigerant R1234yf is available. Currently the use of refrigerant R134a for cleaning the refrigerant circuit is permitted. Refer to Refrigerant Circuit, Cleaning .
- Use a pressure reducer for the nitrogen container.
-- Always clean (flush with refrigerant R1234yf) components in direction opposite to refrigerant flow or blow through.
-- Extract from the components the escaping mixture of refrigerant, refrigerant oil, compressed air or nitrogen via an extracting system.
Restrictor, expansion valve, compressor, receiver and reservoir cannot be flushed with compressed air and nitrogen.
-- The dryer cartridge must be removed on condensers that have a dryer cartridge in the integrated receiver/dryer.
If the receiver/dryer or dryer cartridge is integrated in the condenser, then they cannot be replaced separately and the condenser must be replaced after cleaning (flushing).
Receivers/dryers where it is possible to replace the dryer cartridge have an additional filter, which must also be replaced with the dryer cartridge.
-- First blow out refrigerant oil and dirt with compressed air, blow through the connected components with nitrogen (clean by blowing out or removing old refrigerant oil).
-- Adapter for sealing off the pressure hose to the refrigerant circuit VW/Audi - Passenger Vehicle Adapter Set. Refer to the Parts Information.
Note the following points to prevent oil and moisture from entering the refrigerant circuit from the compressed air system.
- The compressed air must be routed through a compressed air purifier for cleaning and drying. For this reason use the filter and dryer for the compressed air (included in scope of delivery as tool for painting work). Refer to the Parts Information.
- On refrigerant lines with thread or union nut on the connection, use the adapter from the A/C Adapter Set :VAG1785 (A/C Adapter Set - Adapter 1 :VAG1785/1 through A/C Adapter Set - Adapter 8 :VAG1785/8 ) to connect charge hoses 5/8" -18 UNF (a section of this adapter is also contained in the Refrigerant Circuits Adapter Set 1.
- On refrigerant lines without thread or union nut on the connection (for connecting adapters), use adapter from Refrigerant Circuits Adapter Set 1 or a standard blower pistol with rubber mouthpiece.
Compressed air/nitrogen emerging from components is to be drawn off by way of an appropriate system (for example, a workshop extraction system).
The Circuit (or Individual Components) Must Be Blown through (If There Is No Possibility for Flushing or Flushing Is Not Recommended):
-- In the event dirt or other contaminants are located in individual components of the circuit.
-- If vacuum reading is not maintained on evacuating a leak-free refrigerant circuit (pressure build-up due to moisture in refrigerant circuit).
-- The refrigerant circuit has been left open for longer than normal (for example, after a collision).
-- Pressure and temperature measurements in the refrigerant circuit indicate the likelihood of moisture in the refrigerant circuit.
-- It is stipulated by the vehicle-specific repair information following the replacement of certain components. Refer to Refrigerant Circuit, Cleaning .
Certain contaminants and old refrigerant oil cannot or can only be insufficiently removed from the refrigerant circuit with compressed air or nitrogen, these contaminants can be removed for example by flushing with refrigerant R1234yf. Refer to REFRIGERANT CIRCUIT, CLEANING .
- Refrigerant circuit, flushing with compressed air or nitrogen. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR OR NITROGEN .