Volkswagen Golf Service & Repair Manual: Leak detection in refrigerant circuit using compressed air or nitrogen
 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
→ Chapter. If the leak is large, the leakage point
can be detected by sound as the air or gas escapes. |
|
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|
| Introduce the compressed air or the nitrogen through the
service 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
→ Chapter. To ensure no moisture, oil or other
contaminants can enter the refrigerant circuit from the workshop
compressed air system, use, for example, 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. |
|
|
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| 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.
→ Chapter |
| – |
Slowly increase pressure in refrigerant circuit to a maximum
of 15 bar. |
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
cylinder. This prevents the service cylinder from being filled
with condensable gases. |
| – |
Evacuate again and observe the vacuum display over a period
of hours. Charging may be done only when vacuum is maintained. |
| 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
possible leak using an electronic leak tester and rectify fault
as necessary
→ Chapter or add an approved UV contrast substance 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
→ Chapter. |
| – |
Evacuating refrigerant circuit if necessary
→ Chapter |
| – |
Evacuate refrigerant circuit and observe the vacuum gauge
over a period of hours. Charging may be done only when vacuum is
maintained. |
|
|
 |
Note
Different processes are described in this workshop manual
for leak detection in the refrigerant circuit. These processes
have been tested an ...
Note
Small leaks can be detected with, for example, an electronic
leak detector.
–
Evacuate refrigerant circuit using an ...
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Trade names and designations
Refrigerant R134a is currently available under the following
trade designations:
H-FKW 134a
SUVA 134a
KLEA 134a
Note
Other trade designations ...
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Detecting leaks in refrigerant circuit
Searching for leaks in refrigerant circuits using leak detector -V.A.G 1796