Evacuating and Charging Air Conditioner (R-134A)
DRAIN OFF AIR CONDITIONER
Description Of Pressure-gauge Assembly
4 High-pressure Hose (red)
5 Low-pressure Hose (blue)
6 Refrigerant Inlet Valve
7 Refrigerant Outlet Valve
8 Vacuum-pump Valve
9 Low-pressure Valve
10 Low-pressure Gauge
11 Vacuum-meter Valve
12 Vacuum Meter
13 High-pressure Valve
14 High-pressure Gauge
Caution!
All shut-off valves of service station and both hose valves must be closed.
Connect service station to vehicle.
Connect blue hose to low-pressure side (thick pipe).
Connect red hose to high-pressure side (thin pipe).
The quick-action couplings are different in diameter to avoid mixing them up.
Switch on service station using main switch (1). After white indicator lamp (3) goes out, switch on suction. Suction is switched off automatically once all refrigerant has been drawn out of service station. Note volume in charge cylinder.
Open valves (6, 9 and 13). This causes refrigerant to flow into the service station and the white indicator lamp goes out.
Open valves on the quick-action couplings. Switch suction back on and drain entire system until device switches off again.
Caution!
All shut-off valves of service station and both hose valves must be closed.
Slowly open non-return cock (15) until gaseous refrigerant flows into service station. Switch on suction. Refrigerant is circulated (cleaned) in the service station. In this way, the complete refrigerant is converted into gas which had entered the oil trap in liquid state during drawing-out operation. After approx. 10 minutes, close non-return valve (115) again. Once the unit has switched off, read off fill quantity in charge cylinder on scale (17) and remember or note down (useful during troubleshooting for assessing the system).
Drain old refrigerant.
Open valve (15) slowly until white indicator light (3) goes out. Open valve (19) slowly about 1/4 turn and drain drawn-out refrigerant oil into the measuring cup. If there is more oil in the oil trap, it will close automatically. Measure amount of drained refrigerant oil. Close valve (19) again.
Draw out service station again afterwards.
Caution!
If the oil running out foams very strongly, there is still liquid refrigerant in the oil. In this case the refrigerant must be cleaned again.
Never re-use drained refrigerant oil and dispose of it as special refuse (semi-toxic waste). After evacuation, refill the system with the same volume of fresh refrigerant oil plus 10 cu. cm.
Evacuating The Air Conditioner
Caution!
All shut-off valves of service station and both hose valves must be closed.
Open valves (8, 9, 11 and 13).
Switch on vacuum pump. This causes only the pressure gauge battery and the filler hoses to evacuate as far as the quick-release couplings. Maximum possible vacuum is reached after about 1 to 2 minutes. The needle of vacuum meter (12) must then be above or below zero. This strongly depends on prevailing weather conditions. In high-pressure weather systems the maximum possible vacuum will be lower than in low-pressure weather systems. If the zero point is not even approached or no vacuum develops at all, this is indicating that the pressure gauge battery or filler hoses leak.
Close valve (8) and switch off vacuum pump after reaching maximum vacuum. If no rise in pressure is detected after approx. 1 ... 2 minutes, the pressure gauge battery and charge hoses do not leak. Afterwards set needle of vacuum meter (12) to zero (with adjusting screw on top of vacuum meter) and close valve (11).
Open Valves Slowly.
Caution!
If the pressure rises by more than 1 bar on pressure gauges (110 and 14), the system must be drained once again. Pressure can only rise if the air-conditioning system was not opened and instead, refrigerant was simply drawn out for troubleshooting purposes. Pressure rises as small residual amounts of liquid refrigerant gasify in the system.
Once pressure has risen, open non-return cock (6), switch on suction once again and run until device switches off again. Close valve (6) and open valves (8 and 11). Switch on vacuum pump and evacuate air conditioner for at least 15 minutes.
Refrigerant in the service station can be cleaned simultaneously to the discharging process. This is only necessary when moisture indicator (20) indicates moisture.
This requires opening valve (115) slightly (11 to 1 1/2 turns) an switching on suction.
Caution!
Terminate cleaning process after approx. 10 to 15 minutes by closing the non-return cock (15). Evacuation still in progress. If indicator (20) still indicates moisture after the cleaning period, discharging must also be interrupted and the drier in the service station replaced.
After discharging, close valve (8) and switch off vacuum pump. If indicator on vacuum meter (12) remains stationary for a period of at least 2 to 3 minutes, the system does not leak. However, if the needle rises in small jumps this is indication of moisture which is evaporating and causing the pressure to rise. In such a case discharging must be continued.
The system leaks if the needle rises continuously. In this event, the leak must be remedied.
Charging The System ( R 134a):
Prerequisites for correct charging are a sufficient amount of refrigerant as well as pressure in the charging cylinder of at least 9 to 11 bar. If there is not enough refrigerant in the charging cylinder, this must be compensated by drawing refrigerant out of the pressure cylinder. Insufficient pressure can be increased by switching on the charging cylinder heater or cleaning the refrigerant. Check on moisture indicator whether the refrigerant is dry. If not, clean the refrigerant.
Caution!
Charging must be carded out exclusively via the red high-pressure hose.
Caution!
All shut-off valves of service station and both hose valves must be closed.
Open valve (7) briefly and close again so that refrigerant can reach the red charging hose.
Read off charge cylinder level (1), nominal charge volume.
deduct from value and mark residual level in cylinder with rubber ring (2).
Open valve on red charging hose. Then open valve (7) again and observe charging volume level in the charging cylinder.
in the system, close non-return cock (7) in stages and open until nominal charge volume is in system.
Close valve on red charging hose. Open valves (6, 9 and 13) and switch on suction. This draws refrigerant out of the hoses and service station. Once the device has switched off, the charge process is complete and the filler hoses can be disconnected from the vehicle.
Installation: Insert sealing caps in the vehicle connectors again.