U5 - 3 red flashes, 6 green flashes — Inverter heat sink temperature too high (TH8)

What does U5 mean?

This error means the inverter's heat sink temperature (TH8) is too high. This is usually due to insufficient airflow or a faulty thermistor.

• Lack of airflow around the heat sink
• Inverter fan not working
• Missing or degraded thermal paste
• Faulty TH8 thermistor

Click steps to track your progress.

1. 1

   Ensure there is adequate airflow around the inverter heat sink.

2. 2

   Check that the inverter fan is operating correctly.

3. 3

   Verify the TH8 thermistor is correctly installed and connected.

4. 4

   Read the temperature from the service tool to confirm TH8 reading.