Error Code: PC 43 – Outdoor Compressor Lack Phase Protection

Error Code: PC 43 – Outdoor Compressor Lack Phase Protection

What this means:
This error is triggered when the system detects an imbalance in the three-phase current of the compressor — especially if one or more phases show zero or near-zero current. This suggests a loss of phase, wiring fault, or compressor failureTS39.

Try this first (quick reset):

1. Power off the unit.

2. Wait at least 2 minutes.

3. Restart and observe the error display.

• If the error clears — system resumes normal operation.

• If the error remains — follow the diagnostic steps.

Next steps (for technicians):

1. Check compressor three-phase output wiring:

   • Look for visible disconnections or broken wires.

2. Inspect both ends of the compressor connecting line:

   • If connections are loose → correct them.

   • If all are good → proceed.

3. Check compressor winding resistance:

   • Measure resistance across all three phases.

   • If not symmetrical → replace the compressor.

4. If resistance is normal but issue persists:

   • Replace the outdoor main PCB.

What you might need:

• Compressor

• Outdoor PCB

• Connection wires

Helpful tip:
Always verify three-phase balance before replacing components. A small variation is acceptable, but one phase reading zero usually means a disconnected or broken lead.

Click here to view the detailed guide. TS39