Sinclair SCV-750EB Service Manual page 124

5.24 H5 Troubleshooting
Digital display output
Description
Abnormal power supply voltage.

All units stop running.

Error code is only displayed on main PCB and user interface.

Possible causes
Outdoor unit power supply voltage at or above 265V or drops below 170V or a phase is missing.

Loosened wiring within electric control box.

High voltage circuit error.

Main PCB damaged.

Procedure
For SCV-750EB and SCV-1400EB
The grid power input voltage is too high
(>456V) or too low (<342V)
Communication fault between the
compressor module board and the main
High voltage circuit error has occurred,
such as the compressor has
malfunctioned
short-circuited
Replace compressor module board
Notes:
1. The detected voltage is detected by the compressor module board and sent to the main control board, and the main control board judges according to the
voltage value sent by the compressor module board (report a fault if it is >456V or <342V).
2. Refer to Part 4, 3 "Wiring diagram" and PCB components to make sure wire connection is firm.
3. The normal resistances of the inverter compressor is 0.124Ω (at 20℃ ambient temperature) among U V W and infinite between each of U V W and
ground. If any of the resistances differ from these specifications, the compressor has malfunctioned.
4. The normal resistances of the fan motor coil among U V W are less than 15Ω. If a measured resistance is 0Ω, the fan motor has short-circuited.
5. Set a multi-meter to buzzer mode and test any two terminals of P N and U V W of the inverter module. If the buzzer sounds, the inverter module has
short-circuited. Refer to Part 4, 1 "Outdoor Unit Electric Control Box Layout".
122
H5
No
control board
No
3 , the fan motor has
4 , or the inverter module has
short-circuited 5
No
Yes
Provide normal power supply
Check the communication cable between
Yes
the compressor module board and the
main control board
Yes
Replace or repair the relevant parts