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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017
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All vehicles
Note
♦ VW/Volkswagen/Audi does not endorse the use of chemical
substances (leak inhibitor additives) for purposes of sealing
leaks in refrigerant circuits.
♦ These chemical substances (leak stop additives) react mostly
with the ambient air or the humidity to stop leaks in the refrig‐
erant circuit. They cause deposits to build up in the refrigerant
circuit (and your air conditioner service station ), cause valves
to malfunction and defects in other components with which
they come into contact. These deposits cannot be completely
removed from the components again (not even by flushing).
The refrigerant circuit can only be repaired by replacing all
components that have come into contact with this substance.
♦ There are often no external signs to suggest that chemical
substances (leak stop additives) have been used to seal leaks
in a refrigerant circuit. Often, the stickers provided to mark
such systems are missing. Therefore, exercise caution on ve‐
hicles for which you have no service or repair record.
♦ If there is no suitable air conditioner service station available
for the R1234yf refrigerant, the air conditioner service station
designed for R134a refrigerant may also be used and the re‐
frigerant circuit may also be flushed with R134a refrigerant.
Using R134a refrigerant to clean the refrigerant circuit is cur‐
rently permissible ⇒ Air conditioning system with R134a re‐
frigerant; Rep. gr. 87 ; General information about the air
conditioning system and refrigerant circuit .
♦ If during the gas analysis it is found that R1234yf refrigerant
has been contaminated with a different gas, it must be extrac‐
ted from the refrigerant circuit and disposed of as a gas of
unknown composition in accordance with the relevant legisla‐
tion ⇒ VW / Audi-ServiceNet and
⇒ “2.13 Filling contaminated refrigerant in a recycling cylinder
for analysis, processing or disposal”, page 161 .
♦ Contaminated refrigerant can cause decomposition products
to form and accumulate in the refrigerant circuit. These cannot
be extracted with the refrigerant. The contaminated refrigerant
oil, in this case, must be removed from the refrigerant circuit
by flushing with refrigerant.
•
To work as cleanly as possible, without being wasteful of the
refrigerant, without complex assembly work and in an envi‐
ronmentally friendly manner when removing moisture, con‐
taminants (e.g. friction dust and particles from the defective air
conditioner compressor) and old refrigerant oil, the refrigerant
circuit must be flushed (using R1234yf refrigerant).
The refrigerant circuit must be cleaned (flushed) with refrigerant
R1234yf:
– If dirt or other contamination is in the circuit.
– The search for faults in the electrical system, the vacuum sys‐
tem and the air ducts did not turn up any fault.(Moisture is in
the refrigerant circuit and builds up pressure.)
– If the refrigerant circuit has been left open for longer than nor‐
mally required for repairs (e.g. following an accident).
– Pressure and temperature measurements in the circuit indi‐
cate that there is moisture in the refrigerant circuit.
– There is doubt about the amount of refrigerant oil in the refrig‐
erant circuit.
1. Refrigerant circuit
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