How To Replace the Compressor on a Ductless System

Follow these step-by-step instructions to replace the compressor on a ductless system after a burn out:

1. Use the remote control to turn off the indoor heads; this will open the Electronic Expansion Valves to 250 pulses.

2. Turn the power off at the outdoor disconnect (pull or breaker.)

3. Make sure that the power has been off for at least 10 minutes.

4. Remove the cap from the compressor and take a picture to remind yourself where each of the colored wires, (U,V,W) go.

5. Individually tape the exposed ends of the compressor wires with electrical tape to prevent them from shorting to the equipment or each other.

6. Remove and dispose of acidic refrigerant from the unit.

7. Cut the copper lines to the compressor with a tubing cutter and remove the old compressor; do not use a torch to un-braze the lines.

                                                                                                                                                       Figure 1

8. Use a flush kit designed for R-410A like the Rx11 Flush Kit by Nu-Calgon; first flush the line set and indoor unit, then flush the outdoor unit (see Fig 1.)

9. Pour the oil from the old compressor into a container so that you can establish the system’s oil capacity.

10. Add acid neutralizer like, Rx-Acid Scavenger by Nu-Calgon to the compressor oil of the new compressor based on system oil capacity (see Fig 2.)

11. Install the new compressor, braze in the suction, and discharge lines, DO NOT install a filter dryer. Remember to run low flow Nitrogen through the system while brazing to prevent scale from forming inside your lines. You may have to loosen the high side flair nut on the outside unit if you only have one access port, (single zone system.) Be sure to retighten the flair nut before evacuating.

12. Reconnect the high voltage wires (U,V & W) to the proper compressor terminals making sure that they are tight.

13. Evacuate the system of all non-condensable gasses and moisture. Using the Deep Vacuum method or Triple Vacuum method described in the Installation Instructions.

14. Refill the system with new R-410A Refrigerant according to the outdoor unit tag + any additional refrigerant required due to long line set. Restore power to the unit and use the remote controls to turn the indoor heads back on.

                Figure 2

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