Volkswagen Golf Service & Repair Manual: Checking pressures
| – |
Connecting air conditioner service station
→ Chapter. |
| – |
Read pressure from pressure gauges; two results may be
displayed. |
|
|
|
| Ambient
temperature (in degrees centigrade) |
Pressure in
the refrigerant circuit in bar positive pressure |
| +15°C |
3.9 |
| +20°C |
4.7 |
| +25°C |
5.6 |
| +30°C |
6.7 |
| +35°C |
7.8 |
| +40°C |
9.1 |
| +45°C |
10.5 |
 Note
| The temperature of the components of the refrigerant circuit
should be the same as the ambient temperature. |
| If individual components of the refrigerant circuit are
warmer or colder, then the pressure will deviate from the values
shown in the tables. |
| Absolute pressure means that 0 bar corresponds to an
absolute vacuum. The normal ambient pressure (positive pressure)
corresponds to 1 bar absolute pressure. On most pressure gauges,
a reading of 0 bar corresponds to an absolute pressure of one
bar (which is confirmed by the existence of - 1 bar marking
beneath the 0 scale marking). |
| Where vehicles have a high-pressure sender -G65- which
indicates the measured pressure in the measured values block,
the measured pressure should agree with the values in the
tables. |
| The pressure in the refrigerant circuit is lower than
indicated in the table |
| Insufficient refrigerant in circuit. |
| – |
Check for leaks in the refrigerant circuit
→ Chapter. |
| – |
Check the high-pressure safety valve. |
| If the high-pressure safety valve has blown off: |
| – |
Check activation of radiator fan. |
| – |
Check refrigerant pipes and refrigerant hoses for
restrictions in cross-section at bends that have too tight
radius. |
| – |
Check refrigerant pipes and refrigerant hoses for external
damage. |
| – |
If no defects are found, blow through refrigerant circuit
with compressed air and nitrogen. |
| The pressure in the refrigerant circuit is equal to or
greater than that in the table |
| – |
On vehicles with electrical air conditioner compressor,
switch off ignition. |
WARNING
| High voltage on high-voltage system of hybrid
vehicle. Danger of electric shock! Before starting work,
carry out a visual check of high-voltage components in
area of work. Comply with general warnings
→ Hybrid electrical system; Rep. gr.93. |
|
| – |
Set air conditioning system for maximum cooling output. |
Note
| If the low-pressure switch had been removed in order to
connect the air conditioner service station, bridge the
electrical connections in the respective connector for pressure
measurement. |
| The air conditioner compressor is driven by the engine via
the air conditioning system magnetic clutch -N25-. |
| The air conditioner compressor regulating valve -N280- is
activated by the Climatronic control unit -J255-. |
| If the air conditioner compressor is not driven or the
regulating valve not activated when the engine is running: |
| – |
Determine the cause, e.g. by reading the event memory for
the air conditioning system, and rectify it. |
| – |
Observe the test prerequisites. |
| – |
Check power supply for air conditioning system magnetic
clutch -N25-. If this is OK, repair magnetic clutch. |
| – |
Check actuation of air conditioner compressor regulating
valve -N280-. |
|
|
|
Radiator and condenser must be clean (clean them if
necessary).
The heat insulation on expansion valve is OK and properly
installed. See ...
Where vehicles have a restrictor and reservoir, check these
(with internally regulated air conditioning system compressor)
→ Chapter.
...
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Test prerequisites
Continuation of checking pressures