Note
♦
A large leak can be identified if a maximum of pressure of 15
bar can be generated in the refrigerant circuit using clean, dry
compressed air or nitrogen. Refer to
⇒ “1.4.12 Refrigerant Circuit Flushing With Compressed Air
and Nitrogen “, page 29 . If the leak is large enough, the sound
of escaping air or gas can be heard at the location of the leak.
♦
Add the compressed air or nitrogen to the closed refrigerant
circuit through the service connection after fitting it with a
quick-release connector adapter.
♦
The quick-release coupling adapter for service connections
can be connected to the air compressor using a modified filler
hose -A- (for example, with 5/8" 18 UNF threads, different from
the threads on the quick-release coupling adapter) and a suit‐
able adapter -B-. Refer to
⇒ “6.2 Improvised Tools“, page 203 . This keeps humidity, oil
and dirt coming out of the workshop compressed air system
from getting into the A/C refrigerant circuit. Also use a combi‐
nation fine-gauge filter for compressed air systems such as
those that are standard in paint shops. Install it between the
compressed air system and the filler hose -A- . Refer to the
Special Tools and Equipment Catalog.
♦
A compressed gas cylinder filled with nitrogen -3- can be con‐
nected to the closed refrigerant circuit using a pressure gauge
battery with a pressure reducer for nitrogen (maximum reduc‐
tion pressure: 15 bar) -1- and a filler hose -2- (for example,
with 5/8" 18 UNF threads) connected to the service connec‐
tion. A quick-release coupling adapter must also be connected
to the service connection. Refer to
⇒ “6.2 Improvised Tools“, page 203 .
– Slowly increase the pressure in the refrigerant circuit to a max‐
imum of 15 bar.
WARNING
♦ Nitrogen can leak uncontrolled from the cylinder.
♦ Make exclusive use of pressure reducers for nitrogen cyl‐
inders (maximum work pressure 15 bar).
♦ When testing for leaks with nitrogen (maximum permissi‐
ble pressure 15 bar), always work with a pressure reducer
for nitrogen bottles.
♦ Use appropriate extraction units to draw off gas mixture
escaping from components.
– Find the location of the leak by listening for the sound of vent‐
ing gas.
– Repair the leak.
– Evacuate and again observe the vacuum display over a period
of hours. Only when the vacuum is maintained can the refrig‐
erant circuit be charged.
♦ If there is a leak that is small enough that no air or very little
air vents through it and the A/C service station can generate
a sufficient vacuum: The vacuum indicator does not increase
after switching the A/C system service station or only increa‐
ses slowly, indicating that air is only entering through a small
leak.
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A2 2001 ➤ , A ...
Refrigerant R134a Servicing - Edition 01.2011
92 Rep. Gr.00 - General, Technical Data
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