Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...
Air conditioning system with refrigerant R134a - Edition 10.2014
Note
♦ A leak in the refrigerant circuit can be detected, for example,
by pressurising the circuit to a maximum of 15 bar using
cleaned and dried compressed air or nitrogen ⇒ page 65 . If
the leak is large, the leakage point can be detected by sound
as the air or gas escapes.
♦ Introduce the compressed air or the nitrogen through the serv‐
ice connection.
♦ The quick-release coupling adapter for service connection can
be fitted with a modified charging hose -A- (e.g. with a 5/8"-18
UNF thread, depending on the thread of the quick-release
coupling adapter) and a suitable adapter -B- to connect to the
workshop compressed air system ⇒ page 174 . To ensure no
moisture, oil or other contaminants can enter the refrigerant
circuit from the workshop compressed air system, use, for ex‐
ample, a supplementary combination fine filter element with
an oil, dirt and water separator as normally used in paint
shops. Install it between the compressed air system and the
charging hose -A- ⇒ Workshop equipment catalogue .
♦ Using the manifold gauge with pressure reducer for nitrogen
(maximum reduced pressure: 15 bar) -1- you can connect a
full nitrogen gas cylinder -3- via a charging hose -2- (e.g. with
5/8"-18 UNF threaded connection) to the service connection,
to which a quick-release coupling adapter is connected, of a
closed refrigerant circuit. ⇒ page 174
– Slowly increase pressure in refrigerant circuit to a maximum
of 15 bar.
lk
WARNING
♦ Maximum permissible working pressure: 15 bar
♦ When searching for leaks using nitrogen, work only with a
pressure reducer for nitrogen cylinders.
– Search for leak by sound, which is created by the escaping
gas. Use Ultrasonic tester - V.A.G 1842- to ease localisation
of sounds.
– Press nitrogen out of refrigerant circuit using cleaned and
dried compressed air. Nitrogen must not enter the service cyl‐
inder. This prevents the service cylinder from being filled with
condensable gases.
– Rectify leak.
– Evacuate again and observe the vacuum display over a period
of hours. Charging may be done only when vacuum is main‐
tained.
♦ If a leak is present of a size where no or very little air is drawn
in and the air conditioner service station can create sufficient
vacuum. The vacuum gauge does not increase or increases
very slowly after switching the air conditioner service station
off, this indicates there may be a very small ingress of air and
the vacuum is lost.
– Charge circuit with 100 g of refrigerant and search for the pos‐
sible leak using an electronic leak tester and rectify fault as
necessary ⇒ page 58 or add an approved UV contrast sub‐
stance to the refrigerant and search for the possible leak in the
circuit using leak detector system VAS 6201 or later model and
rectify fault as necessary ⇒ page 59 .
6. Detecting leaks in refrigerant circuit
57
English 
