An air conditioner is a complex appliance. Hence, users are advised not to try to repair these units themselves. First, users do not know much about the AC circuit and machinery. Secondly, Hitachi has trained personnel available to attend to service complaints.
Generally, users should restrict themselves to cleaning the AC filters alone. Other problems require professional intervention. Besides, Hitachi ACs are under extended warranties. So, it is not advisable to engage third-party AC service technicians to repair Hitachi ACs during the warranty period. Instead, consumers can contact Hitachi online and lodge their service requests.
Hitachi ACs display various types of error codes. They include blinking LED lights, Alarm Codes, and Numeric/Alphanumeric error codes. We shall discuss all the codes in detail.
Hitachi LED Blinking Codes
Hitachi AC units have three types of LEDs.
- Red – Filter
- Yellow – Power
- Green – Timer
The Filter (Red) LED blinks multiple times in the following Hitachi AC models, such as IOTA, Atom, Ace, FMS, CUT, OUT, Kaze, and I-Clean.
Hitachi AC Error Code 4 time blinking – I-Clean Error
The solution is to remove the filters and clean them. You can place them again and switch on the AC,
Hitachi AC Error Code 5 time blinking – Room Sensor Issue
The AC technician reconnects or replaces the room sensor to rectify the problem.
Hitachi AC Error Code 7 times blinking – Defrost Sensor problem
Usually, you can switch off the AC for some time to allow the frost to melt. If there is a problem with the sensor, it could need replacement. Under such circumstances, the AC technician is the right person to handle the matter.
Hitachi AC Error Code 9 times blinking – Indoor Fan motor problem
The fan motor winding could have come loose or there could be an issue with the capacitor. Rewinding the fan motor or replacing the capacitor should resolve the problem.
The Power or the Operation LED (Yellow) blinks continuously to indicate problems in specific models like Logicool and SAC.
Hitachi AC Error Code 15 times blinking – EEPROM error
The AC technician has to resolve this software problem.
Hitachi AC Error Code 5 times blinking – Fault with the room sensor
The sensor needs reconnection or replacement. The Hitachi AC technician should resolve this error.
Hitachi AC Error Code 9 times blinking – Defrost Sensor problem
You can try switching off the AC for some time and allow the ice to melt. If the error persists, you must book the service call online and summon the AC technician to handle the issue.
The Timer LED (Green) keeps blinking if there are problems with the Atom XL Hitachi AC model.
Hitachi AC Error Code Continuous Blinking – Fault with room and defrost sensor
The solution is to replace the sensors. There could be a loose connection. Under such circumstances, reconnecting the sensors should resolve the issue.
Hitachi AC Error Code 15 times blinking – Fault with the room sensor
The AC technician should reconnect or replace the defective sensor.
Hitachi AC Error Code 14 times blinking – Defrost sensor error
Switch off the AC for some time and check whether the ice melts away naturally. If the error continues, you must call the AC technician to resolve the issue.
Hitachi AC Error Code 10 times blinking – Indoor unit fan motor problem
A defect in the fan motor can set off the 10 times blinking error code. The solution is to repair the fan motor.
Hitachi AC Error Code 13 times blinking – EEPROM issue
The AC technician should resolve this software problem and set the matter right.
Hitachi AC Alarm Codes
Hitachi ACs are available in different models. Most Hitachi ACs display alarm codes, whereas some appliances display error codes. The IDU error and alarm codes flash on the IDU display unit, whereas the ODU codes display on the ODU back panel behind the cover.
We shall discuss the alarm and error codes for your convenience. Please note that some codes can overlap. So, it depends on which Hitachi AC model you use. Each of these diagnostic issues requires the services of authorized Hitachi AC service technicians.
Here are the Hitachi Alarm codes, the content of abnormality, and the primary causes.
Alarm Code – 01 – Tripping of the protection device – IDU fault
Hitachi ACs feature specific devices to protect the critical components of the appliance. These devices are usually circuit breakers that trip whenever an abnormality occurs. The Hitachi AC Alarm Code 01 indicates the tripping of the protection device because of PCB fault, relay issues, drain discharge, or a defective fan motor.
Alarm Code – 02 – Tripping of the protection device – ODU fault
The Alarm Code 02 is flashed on Hitachi ACs to indicate the tripping of the protection device when using the heating mode. This tripping is due to the activation of the multi-split heat pump.
Alarm Code – 03 – Miscommunication between the IDU and ODU – Transmission fault
Any miscommunication between the IDU and the ODU because of incorrect wiring, fuse tripping, lack of power supply, or PCB failure results in Alarm Code 03. The remedy is to replace the wiring or repair the PCB, depending on the failure cause.
Alarm Code – 04 – Abnormality between the Inverter and Control PCB – Transmission fault
Hitachi IDU and ODU have PCBs for controlling the functioning of the individual components. Therefore, a failure in the transmission between the inverter and the control PCB can trigger Alarm Code 04. Usually, PCBs are under warranty. So, the authorized technician repairs the circuit or replaces the PCB, depending on the extent of the damage.
Alarm Code – 05 – Power Source Wiring Abnormality – Power Supply fault
The Alarm Code 05 is an electrical problem caused by reverse phase incorrect wiring. A local electrician can rectify the situation by switching the phase.
Alarm Code – 06 – Voltage fluctuations – Voltage issue
Voltage fluctuations are common in India. Hitachi ACs can function well under a specific voltage range, usually between 160V and 260V. However, the input voltage can go beyond this operational range. Under such circumstances, the Hitachi AC flashes Alarm Code 06. The solution is to connect the appliance to an external voltage stabilizer that can function at a higher range. Users can also change the wiring and use better quality wires for proper power circulation.
Alarm Code – 07 – Decrease in refrigerant gas temperature – Cycle fault
The refrigerant is a vital component of the Hitachi AC. An excessive refrigerant charge or an expansion valve open lock can cause a decrease in discharge gas. The remedy is to check the refrigerant gas level and rectify it.
Alarm Code – 08 – Increase in discharge gas temperature – Cycle fault
Insufficient refrigerant, a leakage or clogging, or the expansion valve close lock can cause the temperature of the discharge gas to increase. The Hitachi AC displays the alarm code 08. The solution is to check the refrigerant levels and arrange for a refill.
Alarm Code – 09 – Tripping of a protection device –
The fan motor’s failure can result in the tripping of the circuit breaker, leading to the stopping of operations. The authorized AC technician is the right person to check for the issue and rectify it. Usually, the fan motors are sturdy and do not fail. However, the fan capacitor can overheat and become faulty. So, replacing the capacitor is the ideal solution.
Alarm Code – 11 – Inlet Air Thermistor issue – IDU sensor fault
The inlet air thermistor failure can result in the malfunctioning of the sensor. For example, a loose connection might cause this issue. The correct solution is to reconnect the sensor or replace it if damaged.
Alarm Code – 12 – Outlet Air Thermistor issue – IDU sensor fault
A faulty sensor or a loose connection can cause the outlet air thermistor failure. The AC technician replaces or reconnects the sensor, depending on the extent of the damage.
Alarm Code – 13 – Freeze Protection Thermistor Issue – IDU sensor fault
The failure of the freeze protection thermistor or a loose sensor connection can cause the Alarm Code 13. The solution is to reconnect the sensor or replace it accordingly.
Alarm Code – 14 – Gas piping thermistor issue – IDU sensor fault
Hitachi AC units feature various sensors to enhance the consumer experience. The failure of the gas piping thermistor, sensor, or a loose connection can cause Alarm Code 14. The AC technician should replace the sensor or reconnect it.
Alarm Code – 19 – Fan Motor Failure – IDU sensor fault
Generally, Hitachi AC fan motors are robust. However, they can fail, leading to the stoppage of AC operations. The AC technician is the right person to repair or replace the fan motor.
Alarm Code – 21 – High-pressure sensor issue – ODU sensor fault
A loose connection, sensor, or thermistor failure can cause Alarm Code 21. The remedy is to replace or reconnect the sensor if it has come loose. Users should book a service call and summon the authorized technician.
Alarm Code – 22 – Outdoor Air Thermistor issue – ODU sensor fault
The Alarm Code 21 results from a faulty outdoor air thermistor, sensor, or a loose connection. Repairing or replacing the sensor can rectify the problem.
Alarm Code – 23 – Discharge Gas thermistor issue – ODU sensor fault
The failure of the discharge gas thermistor, sensor, or a loose connection can cause the Alarm Code 23. Users should contact the Hitachi authorized service center and seek professional help.
Alarm Code – 24 – Evaporating thermistor issue – ODU sensor fault
The evaporating thermistor failure can occur because of a faulty sensor or a loose connection. Replacing or reconnecting the sensor can rectify the problem.
Alarm Code – 29 – Low-Pressure Sensor issue – ODU sensor fault
The failure of the thermistor, a loose connection, or a faulty sensor can cause the low-pressure sensor issue and Alarm Code 29. Repairing or replacing the sensor is the ideal solution.
Alarm Code – 30 – Incorrect wiring connection – Electrical issue
The Alarm Code 30 is an electrical fault. An incorrect wiring connection between the ODU, IDU, and CH unit causes Alarm Code 30. Replacing the wiring or repairing them can set the matter right.
Alarm Code – 31 – Incorrect setting of the IDU and ODU – System fault
The incorrect setting of the capacity code can use the AC to malfunction and display the Alarm Code 31. Therefore, the Hitachi AC technician is ideally suited to reset the capacity code and rectify the issue.
Alarm Code – 32 – Abnormal transmission of Other IDU – System fault
This issue is usually experienced in Hitachi ACs with multiple indoor units. The abnormal transmission of the secondary IDU can occur because of a faulty PCB or the failure of the other IDU of the same refrigerant cycle. The remedy is replacing the PCB and restoring the transmission issue.
Alarm Code – 35 – Incorrect setting in the IDU/ODU Number – System fault
An incorrect setting on the IDU/ODU number resulting in the existence of the same indoor unit number in the same refrigerating cycle can result in the flashing of Alarm Code 35. The solution is to reset the IDU/ODU number setting.
Alarm Code – 38 – Abnormality of the protective circuit in ODU – System fault
The failure of the indoor unit PCB or an incorrect wiring connection to the PCB in the ODU can cause the protection circuit in the ODU to trip. Users should not try to reset the circuit breaker without ascertaining other damages because it can result in extensive repairs.
Alarm Code – 39 – Abnormality of Running Current at Constant Compressor – System fault
Excessive input current flow or the melting of the current sensor fuse can result in the abnormal flow of current at the constant compressor. The authorized Hitachi AC mechanic can rectify the problem by regulating the current flow and replacing the fuse.
Alarm Code – 43 – Pressure Ratio Decrease Protection Activating issue – Protection Device issue
The failure of the compressor and the inverter can cause the pressure ratio to decrease and affect its protective device. The solution lies in replacing the device and setting the issue right.
Alarm Code – 44 – Low-Pressure Increase Protection Activating issue – Protection Device issue
The Alarm Code 44 can flash in Hitachi ACs when there is an overload to indoor in the cooling mode, high outdoor air temperature in heating, or an open expansion valve lock. The AC technician is the right person to rectify the issue.
Alarm Code – 45 High-Pressure Increase Protection Activating issue – Protection Device issue
An overload operation or excessive refrigerant clogging of the heat exchanger can cause the high-pressure increase protection activating issue. Users should contact the Hitachi service center and book their complaints online.
Alarm Code – 46 – High-Pressure Decrease Protection Activation issue – Protection Device issue
Insufficient refrigerant can cause the high-pressure decrease protection activation issue and Alarm Code 46. The solution is to summon the Hitachi AC technician and rectify the problem.
Alarm Code – 47 – Low-Pressure Decrease Protection Activating issue – Protection Device issue
A refrigerant leakage, insufficient refrigerant, and an expansion valve close lock can cause the low-pressure decrease protection activating issue. The Hitachi AC technician is qualified to rectify the problem. Users can lodge their complaints online.
Alarm Code – 51 – Abnormality of the current sensor for the inverter – Sensor issue
The sensor’s failure on the inverter PCB can cause the sensor to become faulty. The solution is to replace the sensor or repair the PCB.
Alarm Code – 52 – Overcurrent Protection Activating issue – Protection device issue
An overload in the current and a locked compressor can cause the overcurrent protection activating device to malfunction. Again, the authorized service technician is the right person to deal with this matter.
Alarm Code – 53 – IPM Protection Activating issue – Inverter issue
The automatic stoppage of the IPM (Intelligent Power Module) in smart ACs can cause the IPM protection activating problem, resulting in Alarm Code 53.
Alarm Code – 54 – Increase in the inverter fin temperature – Inverter issue
A faulty inverter fin thermistor or an abnormality in the outdoor fan can cause an increase in the inverter fin temperature, leading to Alarm Code 54.
Alarm Code – 55 – Inverter failure – Inverter issue
An inverter failure results in the Hitachi AC flashing error code 55. The solution is repairing the inverter.
Alarm Code – 56 – Abnormality of detection for fan motor position Fan motor issue
An abnormal detection transmission circuit can cause Alarm Code 56. The ideal solution is to call the authorized service technician to address the issue.
Alarm Code – 57 – Fan Controller Protecting Activating issue – Fan motor issue
At times the fan can rotate at an abnormal speed resulting in the fan-controlling activating problem. As a result, Hitachi ACs display the alarm code 57, requiring users to contact the Hitachi service center and summon the authorized service personnel.
Alarm Code – 58 – Abnormality of the fan controller – Fan motor issue
Excessive current flow or an abnormal fan controller fin can cause an abnormality of the fan controller, resulting in the flashing of Alarm Code 58.
Alarm Code – 59 – AC Chopper circuit protection issue – Protection device issue
A faulty FET (Field Effect Transistor), power supply, or CT for fan motor failure can result in the AC chopper circuit protection fault. The Hitachi AC service technician should handle this issue.
Alarm Code – EE – Compressor protection issue – Compressor protection issue
The flashing of the EE Alarm Code three times in succession, indicates an issue with the compressor protection. This situation can lead to compressor damage within six hours.
Alarm Code – dd – Incorrect wiring between indoor units – Electrical issue
A wiring fault between the indoor units and the remote control switch can result in the Alarm Code ‘dd.’ Repairing the wiring can resolve the issue.
Error Codes in Hitachi ACs
Besides these alarm codes, some Hitachi models display error codes. Here are the standard error codes observed in Hitachi ACs.
Error Code – 01 – IDU Protection device issue
The tripping of the safety device, also known as the internal thermostat ‘Float Switch,’ causes Error Code 01.
Error Code – 02 – ODU Protection device issue
The tripping of the ODU safety device triggers the error code 02. The protection device can include the high-pressure switch, internal thermostat for the outdoor/indoor fan motor, overcurrent relay, or the compressor chamber thermostat.
Error Code – 03 – Transmission error
The transmission failure between the IDU and the ODU activates the error code 03. Replacing the wires or pipes can rectify this problem.
Error Code – 05 – Phase issue
An abnormal picking-up phase causes the error code 05. This problem requires a change in the wiring.
Error Code – 08 – Compressor issue
Error Code 08 signifies an abnormally high temperature on top of the compressor, which could lead to other problems.
Error Code – 11 – Sensor issue
This error code indicates a thermistor abnormality for the inlet air temperature.
Error Code – 12 – Sensor issue
A thermistor abnormality for the outlet air temperature signifies the error code 12.
Error Code – 13 – Sensor issue
This error code 13 is because of the thermistor abnormality for freezing temperature.
Error Code – 20 – Sensor issue
A sensor fault for compressor top temperature can lead to error code 20.
Error Code – 22 – Sensor issue
This error code 22 indicates a thermistor fault for outdoor air temperature.
Error Code – 24 – Sensor Issue
Error Code 24 is a defrosting error where the sensor responsible for the outdoor evaporating temperature becomes faulty.
Error Code – 25 – Sensor Issue
The condensing temperature sensor fault causes Error Code 25.
All error codes can be resolved by replacing or repairing the respective sensors. Therefore, users should summon the authorized Hitachi service technician to replace or repair these sensors.
Error Code – 32 – Transmission issue
Lack of transmission or communication between the indoor and the outdoor units causes Error 32. In addition, there can be a wiring fault or a plumbing fault. Again, the authorized technician is the ideal person to rectify these faults.
Error Code – 38 – Electrical fault
This error arises because of an abnormality in the picking-up circuit protection. The circuit breaker trips and causes the AC to stop functioning.
Error Code – 41 – Overload error
An excessive overload during the cooling operation results in Error code 41.
Error Code – 42 – Overload error
An excessive overload during the heating operation results in Error code 42.
Hitachi Inverter AC Error Codes
Here are some more error codes usually observed in Hitachi inverter ACs. Most of these codes are similar to the Alarm codes or other error codes described above. Nevertheless, here is the complete list of Hitachi inverter AC error codes.
Error Code – E0 – Water pump malfunction
Error Code – E1 – High-pressure protection fault of the compressor
Error Code – E2 – Indoor Unit anti-freeze protection fault
Error Code – E3 – Low-pressure protection fault of the compressor
Error Code – E4 – Air discharge high-temperature protection fault of the compressor
Error Code – E5 – Inverter error or Overload protection issue of the compressor
Error Code – E6 – Communication failure between IDU and ODU
Error Code – E8 – Indoor fan protection error
Error Code – E9 – Water flow protection issue
Error Code – F0 – Sensor issue concerning the indoor environment sensor at the air return vent
Error Code – F1 – Evaporator sensor fault
Error Code – F2 – Condenser sensor fault
Error Code – F3 – Outdoor environment sensor issue
Error Code – F4 – Air discharge sensor error
Error Code F5 – Environment sensor on the displayer malfunction
Error Code – EH – Auxiliary electric heater fault
Error Code – H1 – Fault in the IDU
Error Code – H2 – Indoor ambient temperature malfunction
Error Code – H3 – Indoor coil temperature fault
Error Code – H4 – Indoor setting temperature issue
Error Code – FE – Communication error between Main Circuit Board and the wiring remote controller
Error Code – ER – Communication error between the main circuit board and display board
All these errors require professional handling by the authorized Hitachi AC service personnel.
Final Thoughts
We have discussed various errors and alarm codes observed in Hitachi ACs. Generally, the Hitachi ACs display different codes. But, the standard error codes are usually consistent. Therefore, users should not attempt to repair any Hitachi AC individually. Instead, one should call the authorized personnel to handle the AC issues. Then, users can note these error codes and help the technicians diagnose and repair the faults quickly.
