Hitachi air error codes

Air conditioners produced by the Tokyo-based company Hitachi require frequent servicing. If this requirement is neglected, the system becomes especially prone to failures. However, they can take place even in case your air conditioner is serviced in time. The table below provides you with advice on what to do in case something goes wrong.

Code No.CategoryType of AbnormalityMain cause
1Indoor unitActivation of protection device (float switch)Failure of fan motor, drain discharge, PCB, relay, float switch activated.
2Outdoor unitActivation of protection device (high pressure cut)Activation of PSH, locked motor, abnormal operation in the power supply phase.
3TransmissionAbnormality between indoor (or outdoor) and outdoor (or indoor) unitsIncorrect wiring. Loose terminals, Failure of PCB. Tripping of fuse. Power supply OFF.
4Abnormal operation between inverter and control PCBTransmission failure between inverter PCBs
5Power supplyAbnormal power supplyPower source with abnormal wave pattern.
6Voltage dropVoltage drop due to excessively low or high voltage in outdoor unitVoltage drop in power supply. Incorrect wiring or insufficient capacity of power supply wiring.
7Drop in discharge gas overheatingExcessive refrigerant charge. Expansion valve lock open.
8CydeIncrease in discharge gas temperatureInsufficient refrigerant charge, refrigerant leakage. Expansion valve closed or clogged.
11Inlet air thermistor
12Sensor in indoor unitOutlet air thermistor Anti-freeze thermistorFailure of thermistor, sensor, connection.
14Gas pipe thermistor
19Protection device for fan motor is triggeredFailure of fan motor
20Compressor thermistor
21Outdoor unit sensorAbnormality of high pressure sensor Outside air thermistorFailure of thermistor, sensor, connection.
24Evaporation thermistor
31Incorrect setting of outdoor and indoor unitsIncorrect setting of capacity code.
35SystemIncorrect setting of indoor unit numberDuplication of indoor unit number.
38Abnormality of protective circuit in outdoor unitFailure of indoor unit PCB; incorrect wiring; connection to indoor unit PCB.
41Cooling overload (possible activation of high pressure device)O.U. pipe thermistor temp, is higher than 55 °C and the compressor top temp, is higher than 95 °C, O.U. protection device is activated.
42Heating overload (high-pressure device may be activated)If I.U. freeze protection thermistor temp, is higher than 55 °C and compressor top temp, is higher than 95 °C, O.U. protec- tion device is activated.
45Activation of high pressure increase protection deviceIf the discharge pressure (Pd) of the compressor is higher than 3.8MPa for 1 minute.
47Activation of protection device for low pressure dropStop due to excessive decrease of evaporating temper- ature (Temp < -35 °C) is activated 3 times in one hour, motor locked in heating mode.
48Activation of overcurrent protectionOverload, overcurrent. Failure of DIP IPM, IPM or PCB2, heat exchanger clogged, locked compressor.
51Abnormality in inverter current sensorIncorrect wiring of current sensor. Failure of control PCB, DIP IPM, IPM or PCB2.
53Activation of transistor module protection deviceAbnormality of DIP IPM or PCB2 Compressor failure, heat exchanger clogged. Abnormal inverter fin thermistor
54Abnormality of inverter fin temperatureHeat exchanger clogged. Abnormal outdoor fan.
55Abnormality of inverter moduleFailure of DIP-IPM, IPM or PCB2.
57Fan motor abnormalityDisconnected wire or incorrect wiring between control PCB and inverter PCB.
Incorrect wiring or abnormality in fan motor.
EECompressor protection alarmCompressor failure.
bOIncorrect Setting of Unit ModelNo Setting of Unit Model, Incorrect Setting of Unit Model
b1Incorrect unit No. settingOver 64 indoor units, setting by no. or indoor unit address.
b5Incorrect Setting of Indoor Unit No. for H-LINK TypeAn indoor unit not supporting H-LINK II is set the indoor unit No. as 16 and after.

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