Volkswagen Golf Service & Repair Manual: Checking

Volkswagen Golf Service & Repair Manual / Air conditioning system with refrigerant R134a / Checking pressures on vehicles / Checking systems with an expansion valve and reservoir (without regulated air conditioner compressor) / Checking

Switch off ignition.

–	Connect manifold gauge (air conditioner service station).

–	Read pressure gauge. It may display two results, A and B.

Ambient temperature in degrees centigrade	Pressure in the refrigerant circuit in bar positive pressure
+15°C	3.9
+20°C	4.7
+30°C	6.7
+40°C	9.1

A- The pressure in the refrigerant circuit is less than shown in the table, (insufficient refrigerant in the circuit).

- Check for leaks using leak detector.

- The high-pressure safety valve has opened; check the activation for the radiator fan referring to the current flow diagram.

Check refrigerant pipes and refrigerant hoses for bends that have too tight radius (restrictions in cross-section) and for external damage. If no faults are found, purge the refrigerant circuit.

B- The pressure in the refrigerant circuit is greater than or equal to the value in the table.

–	Start engine.

–	Set air conditioning system to maximum cooling power.

–	Open doors.

–	Open vents in dash panel.

The air conditioner compressor is driven by the engine, via the V-belt and magnetic clutch.

Note

If the air conditioner compressor is not being driven, check the power supply for the air conditioning system magnetic clutch -N25- in accordance with the current flow diagram.

If power supply is OK, repair magnetic clutch.

If the air conditioner compressor is not being driven, check the refrigerant circuit:

–	Raise engine speed to 2,000 rpm.

–	Observe the manifold gauge.

Specifications

High-pressure side:

Increasing from the pressure when the engine is stopped to a maximum of 20 bar positive pressure.

Low-pressure side:

Decreasing from the pressure when the engine is stopped to 1.3 bar positive pressure.

Test prerequisites

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