Assembly Work on the Air-Conditioning System

Assembly Work On The Air-conditioning System Service

Service unit SECU 134







INFORMATION: The manufacturer's operating and repair instructions must be observed when carrying out all work on the service unit.

Assembly work involving the refrigerant system
During all work on the air-conditioning system which necessitates opening the refrigerant system, the system contents must first be disposed of correctly. When doing so, follow the safety regulations.

Dirt and moisture must be kept out of the air-conditioning system's pipe system. Thorough cleanliness must therefore be ensured during all work. System components must never be cleaned on the inside with hot steam. Use only nitrogen for cleaning purposes.

When replacing a component, all openings must be closed off with suitable plugs.

General assembly sequence
1. Remove refrigerant by suction.
2. Remove faulty part.
3. Evacuate.
4. Check the system for leaks.
5. Rinse with refrigerant.
6. Empty the system by suction again.
7. Evacuate.
8. Fill.







INFORMATION: Pay attention to sealing rings when disconnecting or connecting the hose connections.

The charging valves are located in the area of the front right spring strut.

Removing refrigerant by suction and cleaning







INFORMATION: Close all valves before carrying out each work step.

Cleaning the refrigerant







Draining off old refrigerant oil







Evacuating







Topping up with new refrigerant oil







Filling via the high-pressure side







After using the SECU, perform internal suction removal; first close the hand valves on both suction lines.

Refilling the air-conditioning system

INFORMATION: In the event of insufficient refrigeration performance, remove the refrigerant by suction, top up with the stipulated quantity and check the system for leaks.

1. Remove the refrigerant by suction using the service unit.
2. Determine the refrigerant oil quantity after the refrigerant has been removed by suction.
3. Fill up with new refrigerant oil.
4. Evacuate.
5. Fill with the stipulated amount of refrigerant.
6. Check the system for leaks.

Distribution of the oil quantity in the refrigerant circuit

Total oil quantity 195 ± 15 cm3

After suction removal from the system, the following quantities remain in the

Condensor 2 x 20 cm3 ca. 40 cm3
Evaporator ca. 20 cm3
Fluid tank with lines ca. 30 cm3
Compressor ca. 50 cm3
Circulating oil quantity in the refrigerant circuit ca. 60 cm3

INFORMATION: In new vehicles, the amount of oil removed by suction is approx. 15 .... 40 cm3. Oil removed by suction must be returned to the system.

Refrigerant oil removed from a previously run air-conditioning system may no longer be used (special-category waste).

After the refrigerant has been removed by suction and a component has been replaced, the oil quantity must be determined and topped up by the quantity remaining in the removed component.