Hitachi UTOPIA RAS-4HVRP2E Service Manual page 290

10 Troubleshooting
Troubleshooting procedure
Restart Operation
Does alarm code display
immediately after compressor
started operation?
No
Is electric reactor wiring loose?
No
Is the power supply voltage within the range of
the rated voltage?
Yes
Is the power supply voltage higher than 85% of
the rated voltage during operation?
Yes
Is there any other high-power equipment
starting during the operation?
Is the power voltage higher than 85% of the
rated voltage?
Yes
Is crankcase heater ON?
Yes
288 SMGB0136 rev.0 - 07/2021
Yes
Check if compressor wirings are connected
reversely?
Is electric reactor wiring secure?
Yes
No
No
No
No
Is refrigerant overcharged?
No
Is electronic expansion valve of outdoor unit
locked?
No
No
Is the pressure too high?
Yes
No
Fasten the wiring
Check the power supply voltage, remove
the fault to avoid the voltage too low or too
Restart operation after the crankcase
heater is ON for 8 hours
Yes
Correct refrigerant charging amount
Yes
Replace electronic expansion valve
Yes
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
Driver board is damaged, replace
the driver board
Replace compressor, if faulty
high
Check compressor
unit is not running.