Draining And Filling In Refrigerant

870317 Draining And Filling In Refrigerant

Tools







General warning notes

Warning notes for handling refrigerant

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.

Technical values

Service unit
Air-conditioning recycling unit.

Draining and filling in refrigerant

Assembly work involving the refrigerant system

NOTE:
- 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
The charging valves are located in the radiator tank at the front right.

Protective caps on charging valves:

1. Screw off the protective caps on the charging valves.

Pay attention to sealing rings when disconnecting or connecting the hose connections.

Service connection:

Before connecting the high-pressure -2- and low-pressure lines -1- to the vehicle, remove any refrigerant remaining in the lines by suction.

2. Connecting the high-pressure and low-pressure lines of the air-conditioning unit.
2.1 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.
2.2 Open the valves of the high-pressure and low-pressure lines.
3. Remove refrigerant by suction.
3.1 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.
3.2 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.
3.3 The vehicle air-conditioning system is now completely empty. Necessary repairs, such as removing and fitting the dryer, can now be carried out.
3.4 The open air-conditioning system should not be left open unnecessarily, but must be closed again as quickly as possible after being opened.
3.5 Drain the extracted refrigerant oil into a measuring cup on the service unit and determine the volume.
4. Carrying out repairs.
4.1 If the air-conditioning system has been open for a long time, a new dryer must be fitted.
4.2 If necessary, reconnect high-pressure and low-pressure lines.
5. Evacuate the system and check it for leaks.
5.1 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.
5.2 If the air-conditioning system has been open for a long time, evacuation can be carried out for up to 120 minutes.
5.3 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.
6. Adding refrigerant oil
6.1 For units without oil filling system:
6.2 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.
6.3 For units with oil filling system: Add the measured quantity of refrigerant oil and wait for it to be taken in.
6.4 Do not allow any air to be taken in, otherwise point 5 must be repeated.
7. Evacuate.
7.1 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.
7.2 If the air-conditioning system has been open for a long time, evacuation can be carried out for up to 120 minutes.
7.3 In the case of units with fitted oil filling system, add refrigerant oil now.
8. Filling the air-conditioning system
8.1 Using the service unit, add the refrigerant quantity stated in the manual into the air-conditioning lines.
8.2 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. Add the refrigerant from both connection hoses to the air-conditioning system in the vehicle.
9.1 The refrigerant in the high-pressure and low-pressure lines belongs to the filling capacity of the refrigerant in the air-conditioning system in the vehicle.
9.2 Close the valve on the high-pressure line and disconnect it from the vehicle.
9.3 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.