Midea Heat pump fault F1

What it means

Protection triggered when the DC bus voltage on a single phase inverter PCB falls to or below 200VDC, indicating undervoltage condition on the inverter bus.

Likely causes

1. Faulty inverter power module
2. Faulty three-phase bridge rectifier (3Ph models)
3. Abnormal state detected requiring compressor protection
4. Set temperature reached (normal stop)

Where to start

1. Refer to Part 4 Appendix: Guide for identifying inverter PCB failure to determine PCB status before component replacement
2. Set multimeter to diode test function (secondary tube available)
3. For 1Ph models, test inverter circuit test points only