Expansion Valve and Reservoir With Internally Regulated A/C Compressor, Checking

Expansion Valve And Reservoir With Internally Regulated A/C Compressor, Checking

NOTE:
- Connecting service station.
- Observe test requirements.

- Bring engine speed up to 2000 RPM.
- Observe manometer battery.

NOTE: Switching pressures and design of refrigerant circuit switches are vehicle-specific.

The pressures should be measured at the service connections. The location of these connections is vehicle-specific.

Specified Values

High-Pressure Side
Increasing from initial pressure (on connecting pressure gauges) to max. 20 bar

Low-Pressure Side







Decreasing from initial pressure (on connecting pressure gauges) to value in graph.
A - High pressure in bar
B - Low pressure in bar
C - Permissible tolerance range







NOTE:
- If no malfunction can be found and the function of the A/C system is not correct after repeating the test, flush (clean) refrigerant circuit with refrigerant R134a.
- If that is not possible in this workshop, flush refrigerant circuit with compressed air and remove moisture with nitrogen.







NOTE: If the function is not correct after flushing the refrigerant circuit, the expansion valve must be replaced.







NOTE: Always replace reservoir in case of this malfunction.







NOTE: If the function of the A/C system is not correct when the test is repeated, re-install old expansion valve and flush refrigerant circuit with compressed air and nitrogen. Then replace A/C compressor and reservoir.







NOTE:
- If A/C system function is not OK when the test is repeated, flush (clean) refrigerant circuit. Then replace A/C compressor and reservoir.
- With this malfunction, evaporator may ice up although quantity of refrigerant in circuit is OK.







NOTE:
- Overfilling with refrigerant oil can occur in the event, for example, the compressor has been replaced without adjusting the quantity of refrigerant oil.
- If the A/C compressor is not replaced, the refrigerant oil should be drained from the A/C compressor via the drain plug (replace O-ring). Out of the entire quantity of refrigerant oil, 50 grams should be put in the A/C compressor and the rest in the refrigerant circuit.