Adding Refrigerant and Removing By Suction

Adding Refrigerant And Removing By Suction

Tools







Draining and filling in refrigerant

Assembly work involving the refrigerant system

ATTENTION: Danger of injury when working on air-conditioned vehicles.

- Observe safety regulations for working on air-conditioned vehicles and dealing with refrigerant R134a.
- Observe safety regulations for working with extraction and filling systems.
- Observe instructions for repairing air-conditioning systems and storing spare parts.

NOTE:
- 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.
- Pay attention to sealing rings when disconnecting or connecting the hose connections.
- The charging valves are in the engine compartment, next to the feeder for the external power supply.







1. Remove the cover of the engine compartment lining.







2. Unscrew the two cover nuts -arrow 1- and -arrow 2-.

NOTE: Before connecting the high-pressure -3- and low-pressure lines -4- to the vehicle, remove any refrigerant remaining in the lines by suction.







3. Connect the high-pressure and low-pressure lines of the air-conditioning recycling system.

3.1. Let the engine run for a short while with the air-conditioning on, then connect the high-pressure and low-pressure lines of the air-conditioning unit.
3.2. Open the valves of the high-pressure and low-pressure lines.

NOTE: In the case of service units with transparent oil separator, read and take note of the oil level before removing the refrigerant.

Do not carry out this step with empty air-conditioning systems (pressure gauge approx. 0 bar), otherwise air will get into the refrigerant bottle.

In the case of cold vehicles, it may be necessary to repeat the
suction procedure until all refrigerant has been removed from the air-conditioning system. This step is carried out automatically with some units.

4. Remove refrigerant by suction.

4.1. Wait for approx. 2 minutes after the service unit has switched itself off. If the pressure gauge reading rises above 0 bar, repeat the suction process.

NOTE: In the case of service units with transparent oil separator, read and take note of the oil level before removing the refrigerant.

Do not carry out this step with empty air-conditioning systems (pressure gauge approx. 0 bar), otherwise air will get into the refrigerant bottle.

In the case of cold vehicles, it may be necessary to repeat the suction procedure until all refrigerant has been removed from the air-conditioning system. This step is carried out automatically with some units.

4.2. Drain the extracted refrigerant oil into a measuring cup on the service unit and determine the volume.

NOTE:
- The vehicle air-conditioning system is now completely empty. Necessary repairs, such as removing and fitting the dryer, can now be carried out.
- The open air-conditioning system should not be left open unnecessarily, but must be closed again as quickly as possible after being opened.
- If the air-conditioning system has been open for a long time, a new dryer must be fitted.

5. Carry out repairs.

5.1. If necessary, reconnect high-pressure and low-pressure lines.

6. Evacuate the system and check it for leaks.

6.1. Using the service unit, evacuate the system for 5 - 10 minutes.
6.2. Observe the pressure gauge for approx. 2 minutes. If the pressure rises, air is entering the vehicle air-conditioning system. The leak must be located and repaired. If the pressure remains constant, add refrigerant oil.

NOTE: Do not allow any air to be taken in, otherwise point 6 must be repeated.

7. Add refrigerant oil.

7.1. For units without oil filling system:
7.2. Start the vacuum pump. At the start of this vacuum phase, add the measured quantity of refrigerant oil using an oil injector or a hose disconnected from the service unit. Reconnect the hose to the service unit immediately after adding the oil.
7.3. In the case of units with an integrated oil filling system:
7.4. Add the measured quantity of refrigerant oil and wait for it to be taken in.

NOTE:
- If the air-conditioning system has been opened, evacuation should last at least 20 minutes so that the moisture can evaporate and be removed by suction.
- If the air-conditioning system has been open for a long time, evacuation can be carried out for up to 120 minutes.

8. Evacuate.

8.1. In the case of units with an integrated oil filling system, add refrigerant oil now.

ATTENTION: Low-pressure reading too high in refrigerant circuit.

- Destruction of air-conditioning compressor.
- Do not allow the low-pressure gauge to exceed 3 bar, otherwise liquid refrigerant can get onto the suction side of the compressor and destroy it.

NOTE: As refrigerant usually flows instead of being pumped, it may not be possible - especially if the vehicle is warm and the service unit cold - to add the entire quantity. If this is the case, switch the engine and the air-conditioning on. Wait for the suction pressure to fall below 2 bar. Now open the low-pressure valve on the unit slowly and carefully until the remaining quantity has been added.

9. Fill the air-conditioning system.

9.1. Using the service unit, add the refrigerant quantity stated into the air-conditioning lines.

NOTE: The refrigerant in the high-pressure and low-pressure lines is part of the filling capacity of the refrigerant in the air-conditioning system in the vehicle.

10. Add the refrigerant from both connection hoses to the air-conditioning system in the vehicle.

10.1. Close the valve on the high-pressure line and disconnect it from the vehicle.
10.2. Start the engine and air-conditioning system. When the pressure on both pressure gauges sinks below 2 bar, close the valve on the low-pressure line and disconnect it from the vehicle.