Working With The Service Station
Working With The Service Station
Important notes for working with the service station
Pay attention to the following with regard to service station operation (e.g. V.A.G 1885):
- The filters and dryers installed must be replaced at the latest on completion of the service life specified in the relevant operating instructions.
- Exclusive use is to be made of refrigerant oils which have been approved for the vehicle-specific refrigerant circuit.
Parts List
In the following situations, extracted refrigerant is not to be re-used even after treatment in the service station:
- In the event of compressor damage causing decomposition of the refrigerant due to overheating If dark, sticky deposits are present in the refrigerant circuit (this can only be determined after opening system).
- If there is any doubt about the composition of the refrigerant extracted from the refrigerant circuit.
The service station is to be drained in all these cases, the system cleaned if necessary and the filters, dryers and refrigerant oil replaced.
Contaminated refrigerant can, e.g. in the Federal Republic of Germany, be returned to the supplier in so-called recycling containers for recycling or for environmentally safe disposal (other or additional regulations may apply in other countries).
Commercially available service stations can be classified in 2 groups:
- A. Service stations which clean extracted refrigerant for re-use (so-called extraction and recycling stations), e.g. V.A.G 1885
- B. Service stations which transfer extracted refrigerant to recycling containers (for large-scale recycling). These are referred to as extraction systems.
Service station, connecting for measurement and testing
- Work procedure may vary depending on the type of tools selected (the tool-specific operating instructions should therefore be followed).
NOTE: The work procedure is always to be performed as described in the operating instructions for the relevant service station (e.g. V.A.G 1885).
The charging hoses are to be connected as follows to prevent the ingress of air or moisture into the refrigerant circuit:
- Switch off ignition.
- Connect service station to power supply.
- Unscrew caps from service connections or connections with valve (refer to vehicle-specific refrigerant circuit) Heating, air conditioning or Air conditioning .
- Evacuate charging hoses if necessary.
- Connect quick-release coupling to service connection of refrigerant circuit.
CAUTION: Never open valves on low or high-pressure side with engine running, as otherwise compressor or service station could be destroyed by a short circuit between high and low-pressure sides of refrigerant circuit if air conditioning system is switched on.
NOTE: Screw valve adapters V.A.G /9, V.A.G /10 or Air Conditioning Adapter Set V.A.G 1786 to refrigerant circuit connections with valve and bleed charging hoses during connection to adapters (faintly audible escape of refrigerant gas is permitted).
Vehicles with one service connection only:
- The charging hose must be installed with a valve opener for opening valve in valve adapter.
- Only screw handwheel into quick-release coupling adapter to the extent required to reliably open valve in service connection (observe pressure gauge; take care not to strain valve).
- Start engine and perform planned tests and measurements.
- Compare values determined to specified measured values.
- Before disconnecting quick-release coupling, close it by screwing out handwheel.
Refrigerant circuit, discharging using service station
- Work procedure may vary depending on the type of tools selected (follow tool-specific operating instructions).
- The refrigerant circuit is to be discharged if parts of the refrigerant circuit are to be removed, if there is any doubt about the quantity of refrigerant in the circuit or if safety precautions so require.
- All the necessary usage information for working with the refrigerant service station can be found in the service station operating instructions.
Discharging:
- Switch off ignition.
- Connect service station in line with operating instructions to vehicle service connections (refer to vehicle-specific refrigerant circuit) and start up service station Heating, air conditioning or Air conditioning .
NOTE:
- There is a possibility of refrigerant oil being extracted from the refrigerant circuit together with the refrigerant. To ensure compressor lubrication, the refrigerant oil in the circuit must be topped up with fresh oil.
- On vehicles equipped with a compressor with no A/C clutch (with A/C Compressor Regulator Valve N280), the engine should not be run for longer than absolutely necessary with the refrigerant circuit empty and high engine speeds are to be avoided (compressor always in operation as well).
- On vehicles with a compressor with no A/C clutch, the engine is only to be started following complete assembly of the refrigerant circuit (avoid high engine speeds).
Refrigerant circuit, evacuating using service station
- The work procedure is always to be performed as described in the operating instructions for the service station.
- Quantity of refrigerant oil in circuit checked.
- Quantity of refrigerant in service station checked.
The refrigerant circuit must be evacuated before it is filled with refrigerant. Moisture is also extracted from the circuit.
Evacuation:
- Switch off ignition.
- Connect service station to power supply.
- Connect charging hoses of service station to vehicle refrigerant circuit with quick-release coupling adapter (refer to vehicle-specific refrigerant circuit) Heating, air conditioning or Air conditioning .
- Screw in handwheel of quick-release coupling adapters until valves of service connections are definitely open (take care not to strain valve).
NOTE: If pressure is to be measured after charging system on vehicles with a service connection on one side of the refrigerant circuit only, use valve adapter and charging hose with valve opener.
- Switch on service station and evacuate refrigerant circuit for at least 30 minutes. The pressure reading must indicate an absolute pressure of less than 10 mbar (corresponding to 990 mbar vacuum).
NOTE: At this pressure, both green LEDs light for example on service station V.A.G 1885.
- Switch off service station and allow to stand for at least 1 hour.
- If the vacuum display (LED chain) does not change, the system is free of leaks and can be charged.
NOTE: A current vacuum reading (LED) is only obtained using V.A.G 1885, for example, after pressing the "Evacuate" button again.
Proceed as follows if the vacuum is not maintained:
- Fill the circuit with 100 g of refrigerant, localize any leaks using leak detector and eliminate accordingly.
- Evacuate and again observe the vacuum display over a period of hours. Charging may only be performed if vacuum is maintained.
Refrigerant circuit, charging using service station
NOTE: The entire refrigerant charge can be added to either the high or low-pressure side.
- The work procedure is always to be performed as described in the operating instructions for the service station.
- Before pouring in refrigerant, correct quantity of refrigerant oil.
- Switch off ignition.
- Evacuate refrigerant circuit using service station .
- Screw out handwheel at quick-release coupling adapter (to close it).
- Allow refrigerant to flow into charging hose.
- Take charging cylinder reading.
- Screw in handwheel at quick-release coupling adapter (to open it) and charge with the specified quantity of refrigerant.
- Switch off service station.
Air conditioner, starting up after charging
NOTE: If the compressor has been removed, rotate it about 10 times by hand prior to initial start-up to prevent damage caused by liquid impact when first switched on (any oil in compressor cylinder is forced out on rotation).
- Start engine with compressor switched off (version with A/C clutch).
- Set compressor to minimum output, i.e. "Econ" or A/C off mode (version with no A/C clutch with regulator valve).
- Wait until idling speed has stabilized.
- Switch on compressor and operate system for at least 2 minutes at idling speed.
- If necessary, check pressures in refrigerant circuit using service station.
- Switch off engine.
- Screw out handwheel on quick-release coupling adapter.
- Disconnect charging hoses from refrigerant circuit.
- Screw protective caps back on.
Refrigerant, transferring to charging cylinder of service station
- The work procedure is always to be performed as described in the operating instructions for the service station.
- A certain quantity of refrigerant is specified as charge for each air conditioning system. To ensure that neither too much nor too little refrigerant is added (either would reduce the cooling output), the charging cylinder has a scale indicating the weight.
- The volume of a refrigerant changes as a function of pressure. The scale must therefore be set according to the pressure in the charging cylinder.
NOTE: Do not completely drain the charging cylinder, as the liquid column boundary layer cannot be traced in the tube during filling (outside visible range).
CAUTION: Do not overfill. A completely filled charging cylinder will explode when the temperature rises.
Service station, draining
NOTE:
- If it is necessary to drain the service station (e.g. due to extraction of contaminated refrigerant), all filters and dryers must always be replaced (do not remove filter and dryer from the air-tight packaging until immediately before installation to minimize moisture absorption).
- Refrigerant containers filled with contaminated used refrigerant are referred to as "Recycling containers".
- Always evacuate recycling containers prior to initial filling with refrigerant (if there is air in a refrigerant container it is not to be filled with refrigerant).
- Different types of refrigerant are not to be mixed (refrigerant mixtures cannot be recycled and are to be disposed of). If there is any doubt about the composition of the contents of the container, the refrigerant recycling company is to be informed accordingly.
CAUTION:
- When filling recycling containers (compressed-gas vessels), observe applicable regulations, technical rules and laws.
- Recycling containers are never to be overfilled (overfilled containers do not have a sufficient gas cushion to accommodate the liquid expansion caused by the effects of heat. There is a danger of rupture).
- To ensure safety, make exclusive use of recycling containers equipped with a safety valve.
- Recycling containers must be weighed on calibrated scales during the filling process. The maximum permissible capacity is 75% (charge factor 0.75) of the charge weight indicated on the recycling container (the possibility of refrigerant oil entering the recycling container along with the refrigerant cannot be ruled out).