Sinclair SCV-EB Series Service Manual page 54

5.10 F1 Troubleshooting
5.10.1 Digital display output
5.10.2 Description
 DC bus low voltage protection
 Heat pump stops running.
 Error code is displayed on the refrigerant system PCB digital tube and user interface.
5.10.3 Procedure
F1
Power supply is abnormal.
Wiring between IPM module
and PCB is wrong
Replace IPM module or PCB
52
Yes
No
Yes
No
Provide normal power
Ensure the wiring is right