Replacement of O-rings
Important: Although the o-rings may look identical, it is extremely important to ensure that only o-rings are used that are recommended for replacement when servicing the air conditioning system, otherwise severe refrigerant leakage may occur.
Important: The O-ring must always be placed over the flange tube to ensure proper positioning and sealing.
New o-rings from Daewoo recommended repair kits must be installed each time a joint or fitting is dismantled, unless the o-rings are supplied with new parts.
When replacing O-rings on an A/C assembly or split joint, the fitting design must be determined to ensure that the O-ring is installed from the correct type of repair kit. On some connections and nodes, a fitting with "exciting" o-ring design in which a groove is used to hold the o-ring. On other nodes, the groove is absent, and is used "uncapturable" or "standard" sealing ring. The order of assembly and tightening of both types of structures is the same, however, the o-rings are different.
Note: Before installation, make sure that neither the O-ring nor the fitting has been damaged or deformed. Deformed or damaged parts must be replaced. Failure to follow the instructions for using the correct type of spare parts and following the procedures may result in excessive refrigerant leakage.
Refrigerant Handling
Attention! Work in a well-ventilated area and avoid breathing refrigerant vapors. If breathing is difficult, seek immediate medical attention. If refrigerant comes into contact with any part of the body, rinse it with running water. Seek medical attention if rash or pain occurs.
Air conditioning systems contain refrigerant. It is a chemical compound that requires special handling to avoid injury.
When performing work involving opening the refrigeration system, always wear safety goggles and wrap fittings, valves and connections with a clean cloth. It is forbidden to carry out welding work and steam cleaning on the units and lines of the air conditioning system installed on the vehicle, as well as in their immediate vicinity.
All refrigerant bottles are supplied with a heavy metal screw cap. This cap is designed to protect the valve and protective plug from damage. It is strongly recommended that this cap be replaced after each use of the cylinder.
If it is necessary to transport a refrigerant container by car, do not transport it in the passenger compartment.
Handling refrigerant piping and fittings
Note: Too little or too much fitting torque results in loose connections or deformed parts. Both can lead to refrigerant leakage.
- Protect all metal pipelines from dents and bends. Any line limitation will degrade system performance.
- Do not bend flexible hose with a radius less than four hose diameters.
- Do not place flexible hoses closer than 65 mm (2-1/2") to the exhaust manifold.
- Regularly inspect flexible hoses for leakage or brittleness.
- If signs of deterioration or leakage are found, replace flexible hoses with new ones.
- Before disconnecting any fitting on a refrigeration system, all refrigerant must be pumped out of it.
- Be careful regardless of the readings of measuring instruments.
Attention! Keep your face and hands away from the fitting to avoid injury if there is liquid refrigerant in the line.
- Open fitting slowly.
- If pressure is detected while releasing the fitting, bleed the pressure as described in paragraph «Procedures for discharging, topping up oil, evacuating and charging the air conditioning system» in this section.
- Immediately after opening any refrigerant line, close it with a cap or tape. This prevents moisture and dirt from entering the system, which can cause internal wear on the compressor and lines passing through the condenser, evaporator heat exchanger, expansion valve, and compressor inlet strainers.
Important: Use two appropriately sized wrenches to attach O-ring fittings.
- Support the mating fitting to avoid deforming the connecting pipes or parts.
- Both the free connector fitting on the flexible hose and the mating connector to which it is attached must be supported with two wrenches to prevent the fitting from turning and damaging the socket bottom.
- O-rings and sockets must always be in perfect condition. A burr or dirt particle may cause refrigerant leakage.
- Soak new O-rings in clean PAG compressor oil prior to installation.
Maintaining the stability of the chemical composition in the refrigeration system
Reliability of functioning and durability of the air conditioning system depends on the stability of the chemical composition in the refrigeration system. When the refrigeration system becomes contaminated with foreign materials (dirt, air or moisture), the stability of the chemical composition of the refrigerant and the polyalkylene glycol (PAG) compressor oil. In addition, the pressure-temperature relationship changes, operation efficiency deteriorates, and internal corrosion and excessive wear of moving parts may occur.
To ensure the stability of the chemical composition in the system, the following recommendations must be observed:
- Before opening any joint, wipe off dirt and oil around it. This reduces the risk of dirt getting into the system.
- After opening the connection, close both ends of the connection with a cap, stopper or tape as soon as possible. This prevents dirt, foreign materials and moisture from entering the system.
- All tools, including the manifold pressure gauge set, and all spare parts must be clean and dry.
- When filling PAG compressor oil, use a clean and dry filling device and container. This prevents moisture from getting into the oil as much as possible. See «Procedures for discharging, topping up oil, evacuating and charging the air conditioning system» in this section.
- Everything you need should be at hand so that when opening the air conditioning system, all operations are carried out quickly. Do not leave the air conditioning system open longer than necessary.
- Vacuum and recharge the air conditioning system that was opened. For instructions on how to perform these procedures, see paragraph «Procedures for discharging, topping up oil, evacuating and charging the air conditioning system» in this section.
All spare parts are dehydrated and sealed before delivery. They must remain sealed immediately prior to installation. All parts must be at room temperature when opened. This prevents condensed moisture from the air from entering the system. All parts must be sealed as soon as possible.
Procedures for discharging, topping up oil, evacuating and charging the air conditioning system
Attention! Only use refillable refrigerant cylinders approved for use in charging stations. Use of other cylinders may result in personal injury and void the warranty. See the manufacturer's instructions for use of the charging station.
Attention! Always wear safety goggles and gloves when performing any work that involves opening the refrigeration system to avoid injury.
The charging station discharges, evacuates and charges the air conditioning system with a single installation. Filtering the refrigerant during the pump down cycle, together with filtering during the vacuum cycle, ensures that clean, dry refrigerant is supplied to the A/C system.
Note: Do not use the R-134A charging station for systems charged with R-12 refrigerant. Refrigerants and oils from different systems are not compatible with each other and should not be mixed, even in the smallest quantities. Mixing refrigerant residues will damage equipment.
It is forbidden to use adapters from one valve size to another. This connection creates contamination that can lead to system failure.
Setting up and operating the charging station
There are many charging stations. They all perform the various tasks required to discharge the system and pump out the refrigerant, evacuate the system, add a metered amount of oil, and charge the A/C system with a metered amount of refrigerant. Refer to the manufacturer's instructions for all initial setup and operation procedures.
Control panel features
The charging station has controls and displays that allow the operator to control and monitor ongoing processes. See manufacturer's instructions for more details. As a rule, among them there are the following elements:
1. Main power switch
- Provides power to the control panel.
2. Indicator
- Shows the time programmed for vacuuming.
- Displays the amount of refrigerant programmed for charging.
- See the manufacturer's instructions for details on programming.
3. Pressure gauge for low-pressure connection
- Shows the pressure on the low pressure side of the system.
4. Pressure gauge for high-pressure connection
- Shows the pressure on the high pressure side of the system.
5. Panel controls
- Manage various work functions.
6. Valve on the low pressure side
- Connects the low pressure side of the air conditioning system to the station.
7. Moisture indicator
- Indicates wet or dry refrigerant.
8. Valve on the high pressure side
- Connects the high pressure side of the air conditioning system to the station.
Refrigerant recovery
Important: Only use refrigerant bottles that are designed for the charging station being used. The station's overfill limiter mechanism is calibrated for use with a particular type of cylinder. Cylinder valves are also adapted to the particular type of station.
1. Connect the high pressure side hose with the quick connector to the high pressure fitting of the vehicle's A/C system.
2. Open the valve on the connector.
3. Connect the low pressure side hose with the quick connector to the low pressure fitting of the vehicle's A/C system.
4. Open the valve on the connector.
5. Check the pressure gauges on the high and low pressure sides of the station control panel to make sure there is pressure in the A/C system. If there is no pressure, there is no refrigerant in the system to pump out.
Important: If there is no refrigerant in the system, the pump down operation must be stopped, which under these conditions will pump air into the recovery bottle.
6. Open both valves on the high and low pressure sides.
7. Open the gas and liquid valves on the cylinder.
8. Drain any oil that may be in the oil separator.
9. Close the oil drain valve.
10. Connect the station to an outlet with the correct voltage.
11. Turn on the main power switch.
Note: Do not reuse compressor oil. Reuse of oil can damage the A/C system. Dispose of compressor oil in accordance with current regulations.
12. Start the pumping process. See the manufacturer's instructions for the charging station you are using.
Important: During pumping, some PAG may be removed (PAG) lubricating oil. The amount of oil removed may vary. The charging station separates the oil from the refrigerant and provides a means to determine the amount of oil removed. When charging the system, add the same amount of oil. See the manufacturer's instructions for the charging station you are using.
13. Wait 5 minutes, then check the suction gauge on the control panel. If vacuum is maintained in the A/C system, the pumpdown is complete.
14. If the pressure on the low pressure gauge is above zero, there is refrigerant left in the system. Extract the remaining refrigerant. Repeat this operation until the vacuum in the system is maintained for 2 minutes.
Important: If the check indicator shows that the refrigerant bottle is full during the recovery process and the station shuts down, install an empty bottle to collect the refrigerant needed for the subsequent steps in this procedure. Do not use other types of cylinders.
Vacuuming
There must be enough R-134a refrigerant in the station cylinder to charge. Check the amount of refrigerant in the cylinder. If it contains less than 3.6 kg (8 pounds) refrigerant, fresh refrigerant must be added to the cylinder. See manufacturer's instructions for adding refrigerant.
1. Make sure the low and high pressure side hoses are connected to the A/C system. Open both valves on the high and low pressure sides of the station control panel.
2. Open both valves (gas and liquid) on the balloon.
Important: See the manufacturer's instructions for the charging station you are using. Before charging the system with new or recycled refrigerant, the system must be evacuated.
3. Turn on the vacuum pump and start the evacuation process. Non-condensable gases (mostly air) removed from the cylinder automatically during the process of recharging the system. You can hear the pressure drop.
4. Check for leaks in the system. See the manufacturer's instructions for the charging station you are using.
Important: Change the oil in the vacuum pump regularly. See the manufacturer's instructions for the charging station you are using.
Topping up the air conditioning system with oil
The oil removed from the A/C system during the pump down process must be replenished at this stage.
1. Use an appropriate brand of PAG oil bottle for the R-134a system.
1. Use an appropriate brand of PAG oil bottle for the R-134a system.
Important:
- Oil flasks should be kept tightly closed at all times to keep moisture and contaminants out of the oil.
- For this operation, it is necessary to maintain a vacuum in the air conditioning system. Do not open the oil charge valve when there is positive air pressure in the A/C system. This will cause the oil to be ejected back through the neck of the flask.
- Do not allow the oil level to drop below the supply pipe during charging or replenishment of the system, as this will introduce air into the air conditioning system.
2. See the manufacturer's instructions for the charging station you are using. Add an appropriate amount of PAG oil to the system.
3. Close the valve after the required amount of oil has been pumped into the system.
Charger
Important: The system must be evacuated before charging.
1. Close the low pressure side valve on the control panel.
2. Open the high pressure side valve on the control panel.
3. See the manufacturer's instructions for the charging station you are using.
4. Enter the amount of refrigerant needed to charge the air conditioning system, making sure to select the correct unit of measurement - kilograms (kg) or pounds (lb).
5. Start the charging process.
Transfer completed successfully
1. Close the high pressure side valve on the control panel of the station. Both valves must be closed.
2. Start the engine and turn on the air conditioning system.
3. Run the engine until the pressure gauges on the high and low pressure sides stabilize.
4. Compare the readings with the data in the technical specifications.
5. Check the evaporator outlet temperature to ensure that the A/C system is operating within system specifications.
6. Leave the air conditioner running.
7. Close the connector valve on the high pressure side.
8. Disconnect the hose on the high pressure side from the vehicle.
9. Open the valves on the high and low pressure sides of the control panel. The system will quickly draw the refrigerant from the two hoses through the hose on the low pressure side.
10. Close the connector valve on the low pressure side.
11. Disconnect the hose on the low pressure side from the vehicle.
Transfer failed
Sometimes the entire portion of the refrigerant is not pumped into the air conditioning system. This can happen for two reasons:
1. Almost the same pressure in the cylinder of the station and in the air conditioning system.
- For this reason, the transfer will be too slow.
- See the manufacturer's instructions for the charging station you are using.
2. There was not enough refrigerant in the station's tank to fully charge it.
- It is necessary to pump out a partial charge of the refrigerant from the vehicle system, and then re-vacuum and charge the air conditioning system.
- See the manufacturer's instructions for the charging station you are using.