Midea M-Thermal Arctic HT R290 Mono fault P3

What it means

Protects the compressor from abnormally high currents. Triggered when compressor current rises above the model-specific Currentmax threshold.

Likely causes

1. Input voltage below 198V (insufficient power supply)
2. Abnormal current difference (>1.5A) between measured ODU current and displayed current indicating inverter control box fault
3. Insufficient installation space, high ambient temperature, or blocked heat exchanger
4. Dirty or obstructed finned tube heat exchanger
5. Fan motor not running normally
6. Inverter PCB failure
7. Electronic expansion valve not functioning
8. Blockage between electronic expansion valve and copper filter
9. Insufficient refrigerant charge
10. Compressor cables disconnected or misconnected
11. Compressor winding failure (shorted or low resistance)
12. Incorrect compressor cable connection (U,V,W)
13. Input voltage out of rated range (too low, <198V)
14. Power cable current to L on terminal block differs significantly from displayed ODU current (indicating inverter control box fault)
15. Compressor current exceeds Currentmax for the specific model
16. Abnormal state detected requiring compressor protection
17. Set temperature reached (normal stop)
18. Abnormal system state detected

Where to start

1. Identify ODU model variant
2. Measure actual compressor current and compare against corresponding Currentmax
3. Measure the input voltage of terminal block, check if it's <198V