Hitachi RAS-8.0HNBRMQ1 - Page 108

101
Alarm
Code
53
Inverter Error Signal Detection
●
The alarm code is ashed on the 7-segment display of the outdoor unit.
●
The alarm code is displayed on the wired controller of the indoor unit.
★
If IPM (transistor module) error, ground fault detection or step-out detection occurs, the compressor stops.
The operation automatically restarts after three minutes. If this occurs again six times in the next 30 minutes,
this alarm code is displayed.
Condition of Activation:
1) IPM (Fault) signal error
Main causes: Abnormal compressor current, abnormal IPM control voltage, short circuited IPM, and so on.
2) Speed abnormality
Main causes: Compressor phase loss, output U, V, W are open.
3) FOC output phase loss
Main causes: Compressor phase loss and so on.
Restart Operation
Restart operation after the crank-
case heater is ON for 8 hours.
Driver board is damaged,
replace the driver board.
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Correct refrigerant charging
amount. 
Fasten the wiring.
Check the power supply voltage,
remove the fault to avoid the voltage
too low or too high.
Is electric reactor wiring loose?
Is crank case heater ON? 
Yes
Yes
Yes
Yes
No
No
No
No
Yes
Check if compressor wirings are
connected reversely? Is electric reactor
wiring secure?
Replace compressor, if
faulty.
Is the power supply voltage within the
range of the rated voltage?
Is refrigerant overcharged? 
Is the power supply voltage higher than
85% of the rated voltage during
operation?
Is there any other high-power equipment
starting during the operation? Is the
power voltage higher than 85% of the
rated voltage?
No
Yes
No
Yes
Yes
Yes
No
Is electronic expansion valve of outdoor
unit locked? 
Replace electronic expansion valve.
Check compressor.
Is the pressure too highϋ
Check if the electronic
expansion valve and stop
valves are not open.
Check if the heat exchanger is
blocked or the fan motor of
outdoor unit is not running.
No
Yes
No
No
TROUBLESHOOTING