Error Code: EC 72 – Lack Phase Failure of Outdoor DC Fan Motor

Error Code: EC 72 – Lack Phase Failure of Outdoor DC Fan Motor

What this means:
The outdoor DC fan motor is not receiving correct three-phase signals — meaning one or more of the phases is missing or not properly connected. This can result from damaged wires, incorrect motor installation, or internal motor failure. The system shuts down to protect the fan driver circuit.

Try this first (quick reset):

1. Turn off power to the unit completely.

2. Wait 2 full minutes.

3. Turn the unit back on and check if the error clears.

• If the error clears — the issue may have been temporary.

• If the error returns — proceed with the steps below.

Next steps (for technicians):

1. Check the outdoor fan motor wiring:

   • Inspect all wiring for signs of loose connections or open circuits.

   • If wiring is faulty → reconnect or replace as needed.

2. Test motor phase resistance (UVW-type fan):

   • Measure resistance between U–V, V–W, and U–W.

   • If resistance is not symmetrical → replace the fan motor.

3. Check fan motor rotation:

   • If the motor does not spin freely or appears seized → replace the fan motor.

4. If all wiring and motor tests pass:

   • Replace the outdoor main PCB.

What you might need:

• DC fan motor

• Outdoor main PCB

• Wiring harness

Helpful tip:
Lack of phase is usually caused by a damaged wire or terminal or a failed internal winding in the fan motor. Always verify equal resistance before replacing boards.

Click here to view the detailed guide.TS23