Error Code: PC 43 – Outdoor Compressor Lack Phase Protection

Error Code: PC 43 – Outdoor Compressor Lack Phase Protection

What this means:
The system has detected that one or more of the compressor’s three electrical phases is missing or not delivering proper current. This could be due to an open circuit, faulty wiring, or a failing compressor. The unit shuts down to prevent damage.

Try this first (quick reset):

1. Turn off the power completely.

2. Wait 2 full minutes.

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

• If the error disappears — it may have been a temporary phase drop.

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

Next steps (for technicians):

1. Inspect the 3-phase compressor wiring:

   • Look for visible signs of open circuits or disconnected terminals.

   • Ensure the wires are properly seated at both ends.

2. Check resistance between compressor terminals:

   • Measure U–V, U–W, and V–W.

   • If the resistance is not symmetrical (equal) → replace the compressor.

3. If wiring and compressor are good:

   • Replace the outdoor PCB.

What you might need:

• Compressor

• Outdoor PCB

• Connection wires

Helpful tip:
This error usually occurs when one phase drops out due to a burned wire, corroded terminal, or internal compressor fault. Resistance measurements are the most reliable way to confirm compressor health.

Click here to view the detailed guide.TS39