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Anleitung Zusammenfassung
CAUTION When flushing existing line set and/or indoor coil, be sure to empty all existing traps. Residual mineral oil can act as an insulator, preventing proper heat transfer. It can also clog the thermal expansion valve, reducing system performance and capacity. Failure to properly flush system as explained in these instructions will void warranty. Required Equipment The following equipment is needed to flush the existing line set and indoor coil (see Figure 8): Two clean R22 recovery bottles, an oil-less recovery machine with a “pump down” feature, and two sets of gauges (one for use with R22 and one for use with R410A). IMPORTANT: The line set and/or indoor coil must be flushed with at least the same amount of refrigerant that previously charged the system. Check the charge in the flushing cylinder before flushing the unit. 1. Remove existing R22 refrigerant using the appropriate procedure. If the existing outdoor unit is not equipped with shutoff valves, or if the unit is not operational AND the existing R22 refrigerant will be used to flush the system: Disconnect all power to the existing outdoor unit. Connect the existing unit, a clean recovery cylinder, and the recovery machine according to the instructions provided with the recovery machine. Remove all R22 refrigerant from the existing system. Refer to the gauges after shutdown to confirm that the entire system is completely void of refrigerant. Disconnect the liquid and suction lines from the existing outdoor unit. If the existing outdoor unit is equipped with manual shutoff valves AND new R22 refrigerant will be used to flush the system: Start the existing R22 refrigerant system in cooling mode and close the liquid line valve. Pump all the existing R22 refrigerant back into the outdoor unit. Flushing Connections Note: The inverted R22 cylinder must contain at least the same amount of refrigerant as was recovered from the existing system. Figure 8 506467-01 Issue 1008 Page 7 (It may be necessary to bypass the low pressure switches to ensure complete refrigerant evacuation.) When the low side system pressures reach 0 psig, close the suction line valve. Disconnect all power to the existing outdoor unit. Refer to the gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system. Disconnect the liquid and suction lines from the existing outdoor unit. 2. Remove the existing outdoor unit. Set the new R410A unit and follow the brazing connection procedure outlined previously on this page to make line set connections. Do not install the R410A thermal expansion valve at this time. 3. Make low voltage and line voltage connections to the new outdoor unit. Do not turn on power to the unit or open the outdoor unit service valves at this time. 4. Remover the existing R-22 refrigerant flow control orifice or thermal expansion valve before continuing with flushing procedures. R-22 flow control devices are not approved for use with R410A refrigerant and may prevent proper flushing. Use a field-provided fitting to reconnect the lines. 5. Remove the pressure tap valve cores from the 4AC16LT units service valves. Connect an R-22 cylinder with clean refrigerant to the suction service valve. Connect the R-22 gauge set to the liquid line valve and connect a recovery maching with an empty recovery tank to the gauge set. 6. Set the recovery machine for liquid recovery and start the recovery machine. Open the gauge set valves to allow the recovery machine to pull a vacuum on the existing system line set and indoor coil. 7. Invert the cylinder of clean R-22 and open its valve to allow liquid refrigerant to flow in to the system through the suction line valve. Allow the refrigerant to pass from the cylinder and through the line set and the indoor coil before it enters the recovery machine. 8. After all of the liquid refrigerant has been recovered, switch the recovery machine to vapor recovery so that all of the R22 vapor is recovered. Allow the recovery machine to pull a vacuum on the sytem. NOTE: A single system flush should remove all of the mineral oil from the existing refrigerant lines and indoor coil. A second flushing may be done (using clean refrigerant) if insufficient amounts of mineral oil were removed during the first flush. After each system flush, allow the recovery machine to pull a vacuum on the system at the end of the procedure. 9. Close the valve on the inverted R-22 cylinder and the gauge set valves. Pump the remaining refrigerant out of the recovery machine and turn the machine off. 10. Use nitrogen to break the vacuum on the refrigerant lines and indoor coil before removing the recovery machine, gauges, and R-22 refrigerant drum. Re-install pressure tap valve cores into the 4AC16LT unit’s service valves. 11. Install the refrigerant expansion valve approved for use with R410A refrigerant in the liquid line at the indoor coil. Refrigerant Metering Device 4AC16LT units are designed for use with TX...