Midea R32 M thermal Arctic Mono fault H7

What it means

Error code 46. Abnormal main circuit voltage detected by user interface and refrigerant system main PCB.

Likely causes

1. AC power supply phase voltage at or above 265V for more than 30 seconds
2. Unstable or abnormal mains supply
3. Abnormally high AC supply voltage
4. Abnormally low AC supply voltage
5. Main circuit voltage fault
6. Power supply fault
7. Main board fuse damaged/blown
8. Insufficient refrigerant caused by refrigerant leakage
9. Low pressure side blocked by crushed or bent pipe, blocked EXV, or dirty filter
10. Poor air side heat exchanger heat exchange in heating or DHW mode
11. Insufficient water flow rate in cooling mode
12. Outdoor main PCB fault (last resort)
13. Inverter module damaged
14. Hydronic box main PCB fault
15. Damaged cables between hydronic box main PCB and outdoor unit main PCB
16. Outdoor unit main PCB fault
17. Incorrect or abnormal input power supply (N or L)

Where to start

1. Inspect wires between refrigerant system main PCB, AC filter board (on 3-phase models) and electric control box power supply terminals for loose connections.
2. Inspect for high voltage circuit errors including compressor malfunction, fan motor short-circuit, or inverter module short-circuit.
3. Inspect compressor for malfunction. Check fan motor for short-circuit. Check inverter module for short-circuit.