HVAC Toolkit
H

Hitachi Error Codes

Inverter Mini-Splits & Air Conditioners ยท Japan

Prefixes: E=System/Sensor, F=Sensor/Protection, P=Protection, H=Status

Other Codes

Code Description Possible Cause Action
02 High pressure protection High pressure cut activated Check refrigerant charge, condenser, fan operation
03 Indoor/outdoor communication error Disconnected wires, loose terminals, incorrect wiring Check communication wiring between units
04 Outdoor PCB to fan controller error Blown fuse, loose connectors, broken wires Check outdoor fan controller circuit
06 Phase detection failure Phase sequence error or missing phase Check 3-phase power supply, correct phase sequence
0A Outdoor to outdoor communication error Damaged wiring, incorrect connections (multi-split) Check wiring between outdoor units
0B Main unit address error Multiple units set as main unit Check address settings, set only one main
0C Sub unit address error Address setting conflict Correct address settings on sub units
11 Indoor inlet air thermistor error Thermistor open/short circuit Check/replace inlet air thermistor
12 Indoor outlet air thermistor error Thermistor failure Check/replace outlet air thermistor
13 Indoor freeze protection thermistor error Evaporator thermistor fault Check/replace evaporator thermistor
14 Indoor gas piping thermistor error Gas pipe sensor failure Check/replace gas pipe thermistor
21 Outdoor high pressure sensor error Pressure transducer fault Check/replace high pressure sensor
22 Outdoor low pressure sensor error Pressure transducer fault Check/replace low pressure sensor
23 Outdoor discharge gas thermistor error Discharge temperature sensor fault Check/replace discharge thermistor
24 Outdoor heat exchanger thermistor error Condenser thermistor fault Check/replace condenser thermistor
25 Outdoor suction gas thermistor error Suction temperature sensor fault Check/replace suction thermistor
29 Outdoor air thermistor error Ambient temperature sensor fault Check/replace outdoor air thermistor
31 Capacity setting mismatch Indoor/outdoor capacity code incorrect Verify capacity code settings match
35 Indoor unit number duplicated Multiple units with same address Assign unique addresses to each unit
36 Incompatible unit combination Mismatched indoor/outdoor units Verify unit compatibility
39 Constant compressor overcurrent Running current abnormal Check compressor, current sensor, power supply
43 Low pressure protection Low suction pressure Check refrigerant charge, filter, expansion valve
44 High pressure protection (repeat) Repeated high pressure trips Check condenser, refrigerant charge, ambient conditions
45 Discharge temperature protection Compressor discharge overheat Check superheat, refrigerant charge, airflow
46 Inverter compressor overcurrent Inverter compressor drawing excess current Check compressor, voltage, refrigerant
47 Valve locking protection Service valve closed or restricted Open service valves, check for restriction
48 Electrical overload System drawing excessive power Check power supply, reduce load
53 Inverter PCB failure Inverter board malfunction Replace inverter PCB
54 Inverter overheating IPM module overheat Check ventilation around outdoor unit
55 Fan motor error Outdoor fan motor failure Check fan motor, replace if necessary

E-Series (System/Sensor Errors)

Code Description Possible Cause Action
E0 Water pump error Condensate pump failure Check drain pump operation
E1 Compressor thermal protection Compressor internal protection Check refrigerant charge, superheat
E3 High pressure protection High discharge pressure Check condenser, fan, refrigerant
E5 Inverter compressor error Compressor startup failure Check compressor, inverter, wiring
E9 Indoor fan motor error Indoor fan locked rotor Check fan motor, obstructions
EE Compressor protection alarm Repeated compressor trips (3x in 6 hours) Professional service required, check compressor

Hitachi Troubleshooting Tips

Before Calling for Service

  • Turn off unit, wait 5 minutes, then restart - some errors auto-reset
  • Check and clean air filters - many errors caused by restricted airflow
  • Verify power supply voltage is within specification
  • Check circuit breaker and disconnect switch
  • Note the exact error code and when it occurs for technician

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