Discharging, Adding Oil, Evacuating, Charging Procedures

CAUTION: Use only refillable refrigerant tanks that are authorized for the charging station being used. The use of other tanks may cause personal Injury or void the warranty.

CAUTION: To avoid personal injury, always wear goggles and gloves when performing work that involves opening the refrigeration system.

A charging station discharges, evacuates, and recharges an air conditioning (A/C) system with one hookup. Filtering the refrigerant during the recovery cycle together with filtering during the evacuation cycle ensures a supply of clean, dry refrigerant for A/C system charging.

NOTE:
- Never use the R-134a charging station on a system charged with R-12. The refrigerants and the oils from each system are not compatible and must never be mixed, in even the smallest amount. Mixing refrigerant residue will damage the equipment.
- Never use adapters which convert from one size fitting to another. Such use allows contamination, which may cause system failure.

Charging Station Setup and Maintenance
There are many charging stations available. All perform the various tasks required to discharge the system and recover refrigerant, evacuate the system, add a measured amount of oil, and recharge an air conditioning system with a measured amount of refrigerant. Refer to the manufacturer's instructions for all initial setup procedures and all maintenance procedures.

Control Panel Functions
A charging station will have controls and indicators to allow the operator to control and monitor the operation in progress. Refer to the manufacturer's instructions for details. These can be expected to include the following:
1. Main Power Switch
- Supplies electrical power to the control panel.

2. Display
- Shows the time programmed for vacuum.
- Shows the weight of the refrigerant programmed for recharging.
- Refer to the manufacturer's instructions for detailed programming information.

3. Low-Side Manifold Gauge
- Shows the system's low-side pressure.

4. High-Side Manifold Gauge
- Shows the system's high-side pressure.

5. Control Panel
- Controls the various operating functions.

6. Low-Side Valve
- Connects the low side of the A/C system to the unit.

7. Moisture Indicator
- Shows whether the refrigerant is wet or dry.

8. High-Side Valve
- Connects the high side of the A/C system to the unit.

Refrigerant Recovery

IMPORTANT: Use only a refrigerant tank that is designed for the charging station in use. The unit's overfill limitation mechanism is calibrated specifically for use with this tank. The tank's valves are also manufactured specifically for this unit.

1. Attach the high-side hose with the quick disconnect coupler to the high-side fitting of the vehicle's A/C system.
2. Open the coupler valve.
3. Attach the low-side hose with the quick disconnect coupler to the low-side fitting of the vehicle's A/C system.
4. Open the coupler valve.
5. Check the high-side and the low-side gauges on the unit's control panel to ensure that the A/C system has pressure. If there is no pressure, there is no refrigerant in the system to recover

IMPORTANT: If there is no refrigerant in the system, do not continue with the recovery operation. Under this condition, this would draw air into the recovery tank.

6. Open both the high-side and the low-side valves.
7. Open the gas and the liquid valves on the tank.
8. Drain any oil that may be in the oil separator.
9. Close the oil drain valve.
10. Plug the unit into the proper voltage outlet.
11. Turn on the main power switch.

NOTE: Never reuse refrigerant oil. Damage to the A/C system may result. Dispose of the refrigerant oil properly.

12. Begin the recovery process. Refer to the manufacturer's instructions for the charging station in use.

IMPORTANT: Some A/C system polyalkalene glycol (PAG) lubricating oil may be removed with the refrigerant during recovery. The amount of oil removed varies. A charging station separates the oil from the refrigerant and provides a means of determining how much oil was removed. Replace the same amount of oil when re-charging the system. Refer to the manufacturer's instructions for the charging station in use.

13. Wait 5 minutes, then check the control panel low-side gauge. If the A/C has maintained vacuum, the recovery is complete.
14. If the low-side gauge pressure rises above zero, there is more refrigerant in the system. Recover the additional refrigerant. Repeat this step until the system maintains vacuum for 2 minutes.

IMPORTANT: If the control indicator shows that the refrigerant tank is full during the recovery process and the unit shuts off, install an empty unit tank to store the refrigerant needed for steps later in the procedure. Do not use any other type of tank.

Evacuation
The unit tank must contain a sufficient amount of R-134a refrigerant for charging. Check the amount of refrigerant in the tank. If there is less than 3.6 kg (8 pounds) of refrigerant, add new refrigerant to the tank. Refer to the manufacturer's instructions for adding refrigerant.
1. Verify that the high-side and the low-side hoses are connected to the A/C system. Open both the high-side and the low-side valves on the unit's control panel.
2. Open both the gas and the liquid valves on the tank.

IMPORTANT: Refer to the manufacturer's instructions for the charging station in use. It is necessary to evacuate the system before recharging it with new or recycled refrigerant.

3. Start the vacuum pump and begin the evacuation process. Non-condensable gases (mostly air) are vented from the tank automatically during the recycling process. The pressure being released may be heard.
4. Check for leaks in the system. Refer to the manufacturer's instructions for the charging station in use.

IMPORTANT: Change the vacuum pump oil frequently. Refer to the manufacturer's instructions for the charging station in use.

A/C System Oil Charge Replenishing
Any oil removed from the A/C system during the recovery process must be replenished at this time.
1. Use the correct graduated bottle of polyalkalene glycol (PAG) oil for the R-134a system.
2. Refer to the manufacturer's instructions for the charging station in use. Add the proper amount of PAG oil to the system.
3. Close the valve when the required oil charge has been pulled into the system.

Charging

IMPORTANT: Evacuate the A/C system before charging.

1. Close the low-side valve on the control panel.
2. Open the high-side valve on the control panel.
3. Refer to the manufacturer's instructions for the charging station in use.
4. Enter the amount of refrigerant needed to charge the A/C, making sure to use the correct system of measurement, i.e. kilogram (kg) or pound (lb).
5. Begin the charging process.

Successful Transfer Complete
1. Close the high-side valve on the unit's control panel. Both valves should be closed.
2. Start the vehicle and the A/C system.
3. Let the engine run until the readings on the high-side and low-side gauges stabilize.
4. Compare the readings to the system specifications.
5. Check the evaporator outlet temperature to ensure that the A/C system is operating within the system specifications.
6. Keep the A/C running.
7. Close the high-side coupler valve.
8. Disconnect the high-side hose from the vehicle.
9. Open the high-side and low-side valves on the control panel.
10. The system will quickly draw in refrigerant from both hoses through the low-side hose.
11. Close the low-side coupler valve.
12. Disconnect the low-side hose from the vehicle.

Unsuccessful Transfer
Sometimes the total charge does not transfer into the A/C system. There are two reasons why this may occur:
1. The pressure in the unit's tank and the pressure in the A/C system are roughly equal.
- This will cause the transfer to proceed too slowly.
- Refer to the manufacturer's instructions for the charging station in use.

2. There was not enough refrigerant in the unit's tank to transfer the full charge.
- It is necessary to recover the partial charge of refrigerant from the vehicle and then evacuate and charge the A/C system again.
- Refer to the manufacturer's instructions for the charging station in use.