Evacuating and Charging Air Conditioner (R-134A)

Draw Out Refrigerant, Discharge and Recharge Air Conditioner (R 134a)

WARNING: Note safety measures when handling refrigerant







Suction drain
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





Bring service station into basic setting,
note safety measures 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). Switch on suction after white indicator light (3) has gone out. Suction is switched off automatically if all refrigerant has been drawn out of service station. Note volume in charging cylinder.





Open valves (6, 9 and 13). This causes refrigerant to flow into the service station and the white indicator light goes out.





Open valves on the quick-action couplings. Start suction again and such out entire system until the unit is switched off again.





Bring service station into basic setting,
note safety measures
Open valve (15) slowly until refrigerant gas flows into the 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 (15) again. Read volume in charging cylinder from scale (17) after unit has switched off and write down or note value (required for evaluation of system during troubleshooting).





Drain old refrigerant.
Open valve (15) slowly until white indicator light (3) goes out.
Slowly open non-return cock (19) approx. 1/4 turn and empty drained refrigerant oil into measuring beaker. 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 it as special refuse. After the evacuation procedure, fill the air conditioner with the same quantity of fresh refrigerant oil plus 10 cu.cm.






Discharge
Bring service station into basic setting,
note safety measures
Open valves (8, 9,11 and 13).

Switch on vacuum pump. This only discharges the pressure- gauge assembly and charging hoses up to the quick-action 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 current weather conditions.

In high-pressure weather zones the maximum possible vacuum will be lower than in deep-pressure weather zones. the pressure gauge assembly or charging hoses leak if the zero point is not approximately reached or the vacuum is not built up.

Close valve (8) and switch off vacuum pump after reaching maximum vacuum. If there is no rise in pressure after approx. 1...2 minutes, the pressure gauge battery or filler hoses are free of leaks. 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 this causes a rise in pressure in gauges (10 and 14), the system must be drawn out again. Pressure can only rise if the air-
conditioning system is not opened, but only refrigerant was drawn
out for troubleshooting. the pressure rise is caused by conversion
of small residual amounts of liquid refrigerant into gas in the system.





If the pressure has risen, open valve (6). Switch on suction again until the unit is again switched off. 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 (15) slightly (1 to 11/2 turns) and switching on suction.


CAUTION: Terminate cleaning process after approx. 10 to 15 minutes by closing the non-return valve (15). Discharging still runs.
If indicator (20) still indicates moisture after the cleaning period, discharging must also be interrupted and the drier in the service station replaced (refer to operating instructions of service station).





After discharging, close valve (8) and switch off vacuum pump.
there is no longer moisture in the system it the needle of the vacuum meter (12) remains at 0 over a period of at least 2 to 3 minutes. However, it 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 case the leak must be eliminated

Recharge
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 whether the refrigerant is dry on the moisture indicator. If not, clean the refrigerant, refer to Cleaning the Refrigerant.


CAUTION: Charging must be carried out exclusively via the red high-pressure hose.





Bring service station into basic setting,
note safety measures
Open valve (7) briefly and close again so that refrigerant can reach the red charging hose.





Read charging cylinder volume (1), subtract the specified volume from this value and mark this charging volume level with rubber band (2).





Open valve on red charging hose. then open valve (7) again and observe charging volume level in the charging cylinder. If the system has approximately the specified charge volume, close and open valve (7) in brief steps until the system has the specified charge volume.

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. If the unit switches off, charging has been completed and charging hoses can be disconnected from the vehicle.


Installation note: Insert sealing caps in the vehicle connectors again.






Leakage check
In the vacuum leak test it is possible for leaks not to be detected at loose pipe connections as they might be pressed against the sealing surface and therefore no longer leak. For this reason, leak detection is absolutely essential after charging the system. If leaks are determined while discharging the system, the system must be filled with about 200 to 300 grams of refrigerant. Afterwards calibrate leak detector (1) according to the operating instructions.

Check air-conditioning system for leaks with leak detector (1).
Tighten loose pipes and mark location of leaks (hairline). Draw out refrigerant, eliminate leaks and discharge again.


NOTE: Always check below an assumed point of leakage on pipes and components as refrigerant is heavier than air.