Sinclair SCV-750EB Service Manual page 74

Procedure
The phase sequence of the 3-phase power
supply is incrorrect
Some power supply terminals are loose
The power supply is abnormal
Replace refrigerant system main PCB
Notes:
1. The A, B, C terminals of 3-phase power supply should match compressor phase sequence requirements. If the phase sequence is inverted, the compressor will
operate inversely. If the wiring connection of each outdoor unit is in A, B, C phase sequence, and multiple units are connected, the current difference between C
phase and A, B phases will be very large as the power supply load of each outdoor unit will be on C phase. This can easily lead to tripped circuits and terminal
wiring burnout. Therefore if multiple units are to be used, the phase sequence should be staggered, so that the current is distributed among the three phases
equally.
2. Loose power supply terminals can cause the compressor to operate abnormally and compressor current to be very large.
72
E1
1
No
2
No
No
Yes
Exchange any two of the 3 phase wires
Ensure all supply terminals are securely
Yes
Yes
Check the power supply equipment
fastened