Boreal brisa BRS09HPJ1IA, Service Manual, Page: 64 / 105

6 1
Installation and Maintenance
4. Malfunction of Zero-crossing Inspection Circuit Malfunction of the IDU Fan Motor U8
Main detection points:
Turn power off for
1minute,the turn
back on
The unit returns to normal.
Conclusion:U8 is displayed due to
power off/on while the
capacitor discharges slowly.
U8 is still
displayed
The zero-cross detection circuit
of the mainboard is defined
abnormal. Replace the
mainboard with the same model
Yes
No
Start
End
● Instant energization after de-energization while the capacitor discharges slowly?
● The zero-cross detection circuit of the mainboard is defined abnormal? Malfunction diagnosis
process: