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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017
Note
♦ VW/Volkswagen/Audi does not endorse the use of chemical
substances (leak inhibitor additives) for purposes of sealing
leaks in refrigerant circuits.
♦ Chemical substances used to seal leaks form deposits in the
refrigerant circuit. These can impair the function of the air con‐
ditioning system and cause the air conditioning system (and
your air conditioner service station ) to fail.
lk
♦ 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 (not even by cleaning/flush‐
ing). The refrigerant circuit can only be repaired by replacing
all components that have come into contact with this sub‐
stance.
1.4.2
Searching for leaks in refrigerant circuits
using an electronic leak detector
Special tools and workshop equipment required
♦ Electronic leak detector or proprietary device
Note
♦ Leaks in R1234yf refrigerant circuits can only be found using
electronic leak detection devices designed for R1234yf refrig‐
erant.
♦ The various refrigerants have a different molecular structure.
The sensors of electronic leak detection devices are adapted
to these molecules. If an electronic leak detection device is
used that is not designed for R1234yf refrigerant, it will not
respond to R1234yf refrigerant at all or only in larger concen‐
trations in the vicinity of the leak. For this reason, electronic
leak detection devices designed only for R134a refrigerant
cannot be used for leak detection in the R1234yf refrigerant
circuit.
♦ Depending on the type of heater and air conditioner unit, a leak
from the evaporator can be investigated by holding the test
probe of the leak detector against the glove compartment
cooler connection in the heater and air conditioner unit, or by
holding the test probe against the open condensation drain
connection of the heater and air conditioner unit with the con‐
densation drain hose pulled off.
Performing leak detection on a completely empty refrigerant cir‐
cuit caused by a leak:
Note
With a completely empty refrigerant circuit, proceed as follows to
ensure that no more refrigerant than necessary enters the envi‐
ronment during testing:
– Evacuate refrigerant circuit using air conditioner service sta‐
tion ⇒ “2.5 Evacuating refrigerant circuit”, page 140 .
1. Refrigerant circuit
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