Expansion Valve and Receiver (Without Internally Regulated Compressor), Checking

Expansion Valve And Receiver (without Internally Regulated Compressor), Checking

Test requirements
- Radiator and condenser clean (clean if necessary)
- Ribbed belt for A/C compressor and generator is correctly tensioned.
- All air ducts, covers and seals OK and properly installed
- Flaps reach their end positions.
- Engine at normal operating temperature
- Evaporator and heater not drawing in secondary air at maximum fresh-air blower speed.

Note the following points when engine is running and A/C system set to maximum cooling output:
- Fresh air blower running.
- Coolant fan in operation or is switched on.
- Recirculating/fresh air door in "recirculating air" position.
- Ambient temperature greater than 15 degree C.
- A/C Evaporator Temperature Switch E33 is correctly installed and its switching temperatures are OK.

Checking
- Switch ignition off.
- Connect pressure gauge set (service station).
- Take pressure gauge reading. Two results A and B can be displayed.

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

- A- Pressure in refrigerant circuit is lower than indicated in the table, not enough refrigerant in circuit.
- Localize leak using leak detector.
- Pressure relief valve opened, check activation for coolant fan according to wiring diagram.
Check for constricted refrigerant pipe and hose cross-sections caused by inadequate bending radii or external damage. If no malfunction can be found, flush refrigerant circuit.
- B- Pressure in refrigerant circuit in line with table or higher:
- Start engine.
- Set air conditioning system to maximum cooling output.
- Open doors.
- Open air vents in instrument panel.
Engine drives A/C compressor by ribbed belt via A/C Clutch.

NOTE:
- If A/C compressor is not being driven, check voltage supply for A/C Clutch N25 according to wiring diagram.
- If voltage supply is OK, repair A/C clutch.

If A/C compressor is driven, check refrigerant circuit:
- Set engine speed to 2000 RPM.
- Observe pressure gauge set:

Specified values

High pressure side:
Increasing from pressure with engine switched off up to maximum 20 bar positive pressure.

Low pressure side:
Decreasing from pressure with engine switched off up to 1.3 bar positive pressure.