Assembly Work on the Air-Conditioning System

Assembly Work On The Air-conditioning System

Service unit SECU 134

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







- Low-pressure pressure gauge
- High-pressure pressure gauge
- Torr meter
- Low-pressure shut-off valve (blue)
- High-pressure shut-off valve (red)
- Torr meter shut-off valve (black)
- Vacuum pump shut-off valve (yellow)
- Low-pressure flange
- High-pressure flange
- Refrigerant inlet shut-off valve
- Refrigerant outlet shut-off valve
- Refrigerant oil inlet shut-off valve
- Refrigerant oil vent valve
- Moisture indicator
- Oil tank vacuum flange
- Hourmeter
- SUCTION/END indicator light
- SUCTION/CLEAN pressure switch
- ON/OFF main switch
- HEATING pressure switch
- MALFUNCTION indicator light
- VACUUM PUMP pressure switch
- Filling cylinder with weight scale
- Filling cylinder shut-off valve
- Filling cylinder high-pressure gauge
- Refrigerant oil suction nozzle
- Refrigerant oil reservoir inspection glass

Assembly work involving the refrigerant system

INFORMATION:
- The safety regulations must be observed during all work on 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.
- Dirt and moisture must be kept out of the air-conditioning system's pipe system.
- Thorough cleanliness must 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

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.

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.

Removing refrigerant by suction and cleaning







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







- Drain off refrigerant from the filling cylinder into a refrigerant bottle (approx. 50%).

Cleaning the refrigerant







Draining off old refrigerant oil







Evacuating







Evacuation time at least 15 minutes.

Topping up with new refrigerant oil







Filling via the high-pressure side







INFORMATION: Before carrying out internal suction removal of the SECU, the hand valves on both suction lines must be closed.

- After using the SECU, perform internal suction removal.

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

INFORMATION:
- 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.

Oil quantity
Total oil quantity 195 ± 15 cm(cubed)
After suction removal from the system,
the following quantities remain in the:
Condenser (2 x 20 cm(cubed)) approx. 40 cm(cubed)
Evaporator approx. 30 cm(cubed)
Fluid tank with lines approx. 30 cm(cubed)
Compressor approx. 50 cm(cubed)
Circulating oil quantity in the refrigerant circuit approx. 60 cm(cubed)