Assembly work on the air-conditioning system
Service unit SECU 134
Scheme 52
- 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
- Pilot light SUCTION END
- Pressure switch SUCTION/CLEANING
- Main switch ON/OFF
- Pressure switch HEATING
- Pilot light FAULT
- Pressure switch VACUUM PUMP
- Filling cylinder with weight scale
- Filling cylinder shut-off valve
- Filling cylinder high-pressure gauge
- Refrigerant oil suction nozzle
- Refrigerant oil reservoir inspection glass
Note. 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
- Remove refrigerant by suction.
- Remove faulty part.
- Evacuate.
- Check the system for leaks.
- Rinse with refrigerant.
- Empty the system by suction again.
- Evacuate.
- Fill.
Note. Pay attention to sealing rings when disconnecting or connecting the hose connections.
- A - High-pressure; B - Low pressure
- The charging valves are located in the area of the front right spring strut.
Scheme 53
Scheme 54
- close
- open
Note. Close all valves before carrying out each work step.
| Suction removal, start | End |
|---|---|
| 1-ON/OFF | 3-SUCTION/END |
| 2-SUCTION/CLEANING | 4-ON/OFF |
REFRIGERANT REMOVAL
*Pressure too high/filling cylinder full. Drain off refrigerant from the filling cylinder into a refrigerant bottle (approx. 50 %).
Scheme 55
- close
- open
| Cleaning, start | End |
|---|---|
| 1-ON/OFF | 3-CLEANING/END |
| 2-SUCTION/CLEANING | 4-ON/OFF |
CLEANING REFRIGERANT
*Pressure too high/filling cylinder full.
**One revolution OPEN. After approx. 15 minutes CLOSED.
Scheme 56
- close
- open
1-ON/OFF
Instructions
*1 open to *2 OFF, then *1 CLOSED and *3 OPEN.
Scheme 57
- close
- open
1-ON/OFF
2-VACUUM PUMP
Evaluation time at least 15 minutes.
Scheme 58
- close
- open
- 1-ON/OFF
Scheme 59
- close
- open
- ON/OFF
- HEATING
* Pressure 8... 10 bar.
**If pressure is less than 8 bar.
After using the SECU, perform internal suction removal; first close the hand valves on both suction lines.