Error Code: PC 46 – Compressor Speed Has Been Out of Control

Error Code: PC 46 – Compressor Speed Has Been Out of Control

What this means:
This protection triggers when the system detects that the compressor’s actual speed cannot be regulated properly. This is often caused by abnormal current readings or control failures between the outdoor PCB and inverter module.

Try this first (quick reset):

1. Turn off power to the unit.

2. Wait 2 minutes.

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

• If the error clears — operation resumes.

• If the error remains — begin the diagnostics below.

Next steps (for technicians):

1. Check if the protection occurred during standby:

   • If yes → replace the outdoor PCB.

2. Measure the system current:

   • If abnormal → continue checking power and circuit integrity.

3. Verify voltage between L and N terminals:

   • If abnormal → correct wiring or wait for power to stabilize.

4. Check the bridge rectifier input and output:

   • If abnormal → replace the bridge rectifier.

5. Inspect the PFC module and reactor wiring:

   • If incorrect or loose → reconnect or replace as needed.

6. Measure voltage between P and N (DC bus):

   • Refer to the manual’s appendix for correct values.

   • If out of range → replace bridge rectifier or PFC module.

7. Check outdoor ambient temperature:

   • If over 50°C → shut down temporarily.

8. Evaluate ventilation and fan operation:

   • Ensure heat exchanger is clean and the outdoor fan runs properly.

9. Check system refrigerant pressure:

   • If overcharged → recycle excess refrigerant.

10. If all else fails:

• Replace the outdoor main PCB.

What you might need:

• Outdoor PCB

• Bridge rectifier

• PFC module or reactor

• Pressure switch

• Outdoor fan

• IPM module board

• Refrigerant tools

• Connection wires

Helpful tip:
PC 46 errors are often tied to airflow restrictions, power module wiring issues, or inverter control failures. Always work through the full diagnostic flow before replacing major components.

Click here to view the detailed guide. TS19