Hitachi mini-HNRQ1 Series Service Manual page 111

TROUBLESHOOTING
Alarm
57
Code
● The alarm code is flashed on the 7-segment display of the outdoor unit.
● The alarm code is displayed on the wired controller of the indoor unit.
★
If the revolution of the fan motor is less than 10rpm in 10 seconds after the fan motor starts operation, the
fan motor stops. The fan motor restarts operation automatically after 10 seconds (During this, the compressor
continues to operate). If this occurs again nine times in the next five minutes, this alarm code is displayed.
This alarm is caused by locking or electrical abnormality of the fan motor.
Restart operation
Does fan motor run when
inverter failure occurs?
Is the power supply voltage higher than
85% of the rated voltage during
operation?
Turn OFF power supply and check if the
fan blade rotates smoothly.
Fan motor damaged, replace fan motor.
Turn OFF outdoor unit
Yes
power supply and
No
disconnect compressor and
fan motor wiring.
Short circuit TCN10 (FCT)
connector.
Does it fail?
Yes
No
Yes
No
Yes
Abnormality of Fan Motor
No
Check fan
motor if wiring
is normal.
Yes
Check the power supply voltage, remove the
fault to avoid the voltage too low or too high
Check if there are any obstacles.
Replace the fan motor if it is damaged.
104
Yes
Replace
driver of fan
motor.
No
Replace fan
motor.
Replace
driver of fan
motor.