Midea M-Thermal Series Service Manual page 52

4.7 F1 Troubleshooting
Digital display output
Description
 Low DC generatrix voltage.
 M‐Thermal Split stops running.
 Error code is displayed on hydronic system main PCB and user interface.
Possible causes
 The DC generatrix voltage is too low.
Procedure
F1
Power supply is abnormal.
No
LED on the Inverter
Modules is lighting
No
The input power of
inverter module is
abnormal
No
The invert module is
damaged, change it.
201909 51
Yes
Provide normal power
Yes
Voltage of PN is 380V.
The main board is
Yes
damaged, change it.
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M‐Thermal Split
Yes
Check the main board.