Being a part of the DKB Group, Hitachi in its own turn, is a parent company of the Hitachi Group. The Japanese conglomerate company produces goods in more than ten segments, from electronics and information systems to railway and automotive systems. It is listed in the Forbes rankings of the world’s most influential companies on a regular basis.
Sometimes, error codes can give you enough information to fix your Hitachi air conditioner on your own. However, in most cases the help of a service engineer is indispensible. Anyway, the fault code will help you to find out what the problem is and decide whether you can deal with it on your own. The table below contains the error codes for Hitachi air conditioning systems, explained in all details.
Hitachi Inverter-driven Multi-Split system heat pump Air Conditioner error codes
|Code No.||Category||Content of Abnormality||Leading Cause|
|01||Indoor Unit||Tripping of Protection Device||Failure of Fan Motor, Drain Discharge, PCB, Relay|
|02||Outdoor Unit||Tripping of Protection Device||Activation of PSH|
|03||Transmission||Abnormality between Indoor (or outdoor) and|
Outdoor (or Indoor)
|Incorrect Wiring. Failure of PCB.
Tripping of Fuse. Power Supply OFF.
|04||Inverter||Abnormality between Inverter and Control PCB||Failure in Transmission between PCBs|
|05||Transmission||Abnormality of Power Source Wiring||Reverse Phase Incorrect Wiring|
|06||Voltage Drop||Voltage Drop by Excessively Low or High|
Voltage to Outdoor Unit
|Voltage Drop of Power Supply, Incorrect Wiring or
Insufficient Capacity of Power Supply Wiring
|07||Cycle||Decrease in Discharge Gas Superheat||Excessive Refrigerant Charge, Expansion Valve
|08||Cycle||Increase in Discharge Gas Temperature||Insufficient Refrigerant. Ref. Leakage, Clogging or
Expansion Valve Close Lock
|09||Outdoor Unit||Tripping of Protection Device||Failure of Fan Motor|
|11||Sensor on Indoor Unit||Inlet Air Thermistor||Failure of Thermistor, Sensor, Connection|
|12||Sensor on Indoor Unit||Outlet Air Thermistor||Failure of Thermistor, Sensor, Connection|
|13||Sensor on Indoor Unit||Freeze Protection Thermistor||Failure of Thermistor, Sensor, Connection|
|14||Sensor on Indoor Unit||Gas Piping Thermistor||Failure of Thermistor, Sensor, Connection|
|19||Sensor on Indoor Unit||Tripping of Protection Device for Fan Motor||Failure of Fan Motor|
|21||Sensor on Outdoor Unit||High Pressure Sensor||Failure of Thermistor, Sensor, Connection|
|22||Sensor on Outdoor Unit||Outdoor Air Thermistor||Failure of Thermistor, Sensor, Connection|
|23||Sensor on Outdoor Unit||Discharge Gas Thermistor on Comp.||Failure of Thermistor, Sensor, Connection|
|24||Sensor on Outdoor Unit||Evaporating Thermistor||Failure of Thermistor, Sensor, Connection|
|29||Sensor on Outdoor Unit||Low Pressure Sensor||Failure of Thermistor, Sensor, Connection|
|30 *||System||Incorrect Wiring Connection||Incorrect Wiring Connection between Outdoor Unit,
CH Unit and Indoor Unit
|31||System||Incorrect Setting of Outdoor and Indoor Unit||Incorrect Setting of Capacity Code.|
|32||System||Abnormal Transmission of Other Indoor Unit||Failure of Power Supply, PCB in Other Indoor Unit.
Failure of Other Indoor Unit of the Same
|35||System||Incorrect Setting in Indoor/Outdoor Unit No.||Existence of the same Indoor Unit No. in the same
|38||System||Abnormality of Protective Circuit in|
|Failure of Indoor Unit PCB. Incorrect Wiring
Connection to PCB in Outdoor Unit
|39||System||Abnormality of Running Current at|
|Overcurrent, Melted Fuse of Failure of Current
|43||Pressure||Pressure Ratio Decrease Protection Activating||Failure of Compressor, Inverter|
|44||Pressure||Low Pressure Increase Protection Activating||Overload to Indoor in Cooling, High Temperature of
Outdoor Air in Heating Expansion Valve Open Lock
|45||Pressure||High Pressure Increase Protection Activating||Overload Operation. Excessive Refrigerant
Clogging of Heat Exchanger
|46||Pressure||High Pressure Decrease Protection Activating||Insufficient Refrigerant|
|47||Pressure||Low Pressure Decrease Protection Activating||Insufficient Refrigerant. Expansion Valve Close
Lock. Refrigerant Leakage.
|51||Inverter||Abnormality of Current Sensor for Inverter||Failure of Sensor on Inverter PCB|
|52||Inverter||Overcurrent Protection Activating||Overload, Overcurrent, Locked to Compressor|
|53||Inverter||IPM Protection Activating||Automatic Stoppage of IPM (Overcurrent, Low
Voltage or Overheating)
|54 **||Inverter||Increase in Inverter Fin Temperature||Abnormal Inverter Fin Thermistor,
Abnormal Outdoor Fan
|56 **||Outdoor Fan||Abnormality of Detection for Fan Motor Position||Abnormal Detection Circuit of Transmission|
|57 **||Outdoor Fan||Fan Controller Protection Activating||Abnormal Fan Speed|
|58 **||Outdoor Fan||Abnormality of Fan Controller||Overcurrent, Abnormal Fan Controller Fin|
|59||AC Chopper||AC Chopper Circuit Protection||Failure of FET, Power Supply, CT for Fan Motor|
|EE||Compressor||Compressor Protection||3 Time Occurrence of Alarm Giving Damage to
Compressor within 6 hours
|dd ***||Transmission||Incorrect Wiring between Indoor Units||Incorrect Wiring between Indoor Units and Remote
* : For only FXG and FX3 series. Other code Nos. are common with FSG and FS3 series.
** : For only 24, 30FSG1/FSG5 (220V 60Hz), *** : In case of PC-2H2
Hitachi Room Air Conditioner range:
Indoor unit alarm codes
If timer lamp flashes for 1 second on, 1 second off, this indicates pre heating on the coil during heating mode and is not an error.
If timer lamp flashes for a number of times and then pauses, please reference table below. Display will flash as shown in diagram.
|LED 301 Flashes||Range: Summit/Mono/Multizone indoor unit|
|01||Indoor coil is too warm in cooling mode or too cold in heating mode.
Reversing valve or coil thermistor is faulty
|02||Forced operation from the outdoor unit.
This is not an error
Faulty wiring, indoor or outdoor PCB faulty
|04||Outdoor unit fault.
Check the number or flashes on outdoor PCB LED 301 to comfirm exact problem
|06||Float switch activated.
Check pump operation and drain
|07||Drain pump forced operation.
Drain test switch in test position, faulty PCB
|08||Louvre not opening.
Louvre motor faulty, microswitch faulty, PCB faulty (RAF unit only)
|09||Faulty indoor unit thermistor.
Air inlet or coil thermistor not connected, open or short circuited faulty PCB
|10||Indoor fan motor over current or abnormal rotation speed.
Faulty motor or PCB
|13||Eprom data error.
Outdoor unit alarm codes
|LED 301 Flashes||Range: Summit/Mono/Multizone outdoor unit|
|1||Normal, unit powered up|
|2||Over current on the compressor
Faulty PCB or locked compressor
with LED302 lit
|Over current on the compressor
System power module or PCB failure
|3||Compressor rotation speed is low, abnormal compressor rotor position
Faulty system power module, faulty compressor or PCB
|4||Switching failure on the compressor
Faulty system power module, faulty compressor or PCB
|5||Compressor rotation low with over current detected
High pressure detected, faulty fan motor/circuit or abnormally low voltage
|6||Discharge thermistor temperature rising
Short of refrigerant charge, faulty thermistor, faulty compressor faulty fan motor/circuit or main PCB
|7||Faulty thermistor (Summit and Monozone only)|
|8||Compressor not accelerating above minimum rotation speed
Short of refrigerant charge or faulty compressor
C/D terminals not connected, faulty interconnecting cable PCB failure (Summit and Monozone only)
Mains voltage incorrect or faulty reactor
|12||Fan motor rotation is abnormal
Faulty fan motor or PCB (check fuse)
Main PCB failure
|14||Over voltage is detected by system power module
If indoor unit filter lamp is flashing four times, this indicates an outdoor unit fault. This is identified by the number of flashes on LD 301, please see the table right.
If LD 303 is on permanently this is normal operation. If LD 301 is lit in conjunction with LD 303 his indicates an overload (1) condition but not an alarm. If LD 302 is lit in conjunction with LD 303 this indicates an overload (2) condition but not an alarm and if LD 301 and LD 302 are lit in conjunction with LD 303, this indicates an overload (3) condition but not an alarm.
On Multizone systems only, if LD 301 is lit permanently and LD 302 is flashing a number of times, this indicates a thermistor fault. Please refer to the table right for the thermistor that is faulty. If LD 304 is flashing, the number of flashes indicates a communication error with the corresponding indoor unit circuit number. Check cable connections, cable is not short circuited or open circuit and PCB operation.
|LD 302 FlashesFlashes||Thermistor that is faulty|
|1||Compressor overheat (OH)|
|4||Narrow pipe (expansion) thermistor, for circuit 1|
|5||Wide pipe (suction) thermistor, for circuit 1|
|6||Narrow pipe (expansion) thermistor, for circuit 2|
|7||Wide pipe (suction) thermistor, for circuit 2|
|8||Narrow pipe (expansion) thermistor, for circuit 3|
|9||Wide pipe (suction) thermistor, for circuit 3|
Hitachi Heat Pump Error Codes
If a Safety Device is activated, cutting out the compressor, the Run light on the Remote Control switch blinks continuously and ABNML is indicated on the LCD display.
The Unit Identification A* etc is shown along with the Code Number for the Fault that has occurred.
|02||*||Safety Device (Indoor or Outdoor Unit)|
|03||*||Transmission Indoor/Outdoor Unit|
|08||*||*||*||Compressor High Temperature|
|22||*||*||Ambient Air Thermistor|
|38||*||*||PCB Protection Circuit|
|41||*||*||Overload Operation for Cooling|
|42||*||*||*||Overload Operation for Heating|
|11-13||*||*||*||*||11 Fault = Air Inlet Thermistor
13 Fault = Freeze Protection Thermistor