Hitachi Inverter-driven, Multi-split System, Heat Pump Air Conditioners;
Pressure ratio protection control
High pressure increase protection
Inverter current protection
Inverter fin temperature increase protection
Discharge gas temperature increase protection at the upper part of the compressor
Low pressure decrease protection
High pressure decrease protection
Demand current protection control
Low pressure increase protection
Pressure ratio decrease retry
Low pressure increase retry
High pressure increase retry
Constant speed compressor overcurrent retry
Discharge gas temperature increase retry / Low pressure decrease retry
Discharge gas super-heat decrease retry
Inverter anomaly retry
Abnormal Inverter voltage retry / Inverter failure retry
High pressure decrease retry
Hitachi Self-Diagnostic Malfunction Error Codes
If the unit malfunctions then an error code will display on the controller as below. Error codes and Drive Error Codes can also be interrogated using the Running Parameter function on the controller. They are also displayed on the outdoor PCB.
Content of Abnormality-Leading Cause
Tripping of Protection Device-Failure of Fan Motor, Drain Discharge, PCB, Relay.
Tripping of Protection Device-Activation of PSH.
Abnormality between Indoor (or outdoor) and Outdoor (or Indoor)-Incorrect Wiring. Failure of PCB. Tripping of Fuse. Power Supply OFF.
Abnormality between Inverter and Control PCB-Failure in Transmission between PCBs.
Abnormality of Power Source Wiring-Reverse Phase Incorrect Wiring.
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.
Decrease in Discharge Gas Superheat-Excessive Refrigerant Charge, Expansion Valve Open Lock.
Increase in Discharge Gas Temperature-Insufficient Refrigerant. Ref. Leakage, Clogging or Expansion Valve Close Lock.
Tripping of Protection Device-Failure of Fan Motor.
Inlet Air Thermistor-Failure of Thermistor, Sensor, Connection.
Outlet Air Thermistor-Failure of Thermistor, Sensor, Connection.
Freeze Protection Thermistor-Failure of Thermistor, Sensor, Connection.
Gas Piping Thermistor-Failure of Thermistor, Sensor, Connection.
Failure of Fan Motor-Failure of Fan Motor.
High Pressure Sensor-Failure of Thermistor, Sensor, Connection.
Outdoor Air Thermistor-Failure of Thermistor, Sensor, Connection.
Discharge Gas Thermistor on Comp-Failure of Thermistor, Sensor, Connection.
Evaporating Thermistor-Failure of Thermistor, Sensor, Connection.
Low Pressure Sensor-Failure of Thermistor, Sensor, Connection.
Incorrect Wiring Connection-Incorrect Wiring Connection between Outdoor Unit, CH Unit and Indoor Unit.
Incorrect Setting of Outdoor and Indoor Unit-Incorrect Setting of Capacity Code.
Abnormal Transmission of Other Indoor Unit-Failure of Power Supply, PCB in Other Indoor Unit. Failure of Other Indoor Unit of the Same Refrigerant Cycle.
Incorrect Setting in Indoor/Outdoor Unit No-Existence of the same Indoor Unit No. in the same refrigerant cycle.
Abnormality of Protective Circuit in Outdoor Unit-Failure of Indoor Unit PCB. Incorrect Wiring Connection to PCB in Outdoor Unit.
Abnormality of Running Current at Constant Compressor-Overcurrent, Melted Fuse of Failure of Current Sensor.
Pressure Ratio Decrease Protection Activating-Failure of Compressor, Inverter.
Low Pressure Increase Protection Activating-Overload to Indoor in Cooling, High Temperature of Outdoor Air in Heating Expansion Valve Open Lock.
High Pressure Increase Protection Activating-Overload Operation. Excessive Refrigerant Clogging of Heat Exchanger.
High Pressure Decrease Protection Activating-Insufficient Refrigerant.
Abnormality of Current Sensor for Inverter-Failure of Sensor on Inverter PCB.
Overcurrent Protection Activating-Overload, Overcurrent, Locked to Compressor.
IPM Protection Activating-Automatic Stoppage of IPM.
Increase in Inverter Fin Temperature-Abnormal Inverter Fin Thermistor, Abnormal Outdoor Fan.
Abnormality of Detection for Fan Motor Position-Abnormal Detection Circuit of Transmission.
Fan Controller Protection Activating-Abnormal Fan Speed.
Abnormality of Fan Controller-Overcurrent, Abnormal Fan Controller Fin.
AC Chopper Circuit Protection-Failure of FET, Power Supply, CT for Fan Motor.
Compressor Protection-3 Time Occurrence of Alarm Giving Damage to Compressor within 6 hours.
Incorrect Wiring between Indoor Units-Incorrect Wiring between Indoor Units and Remote Control Switch.
Hitachi Air Conditioner Remote Controller Alarm Codes
Remote Controller-Model: PC-2H2
Safety Device of the Indoor Unit is tripped (internal Thermostat, *Float Switch)
1. Safety Device of the Outdoor Unit is tripped (High pressure switch, Internal Thermostat for Outdoor Fan Motor and Overcurrent Relay) 2. Safety Device of the Outdoor Unit is tripped (Overcurrent Relay, Compressor Chamber Thermostat, High Pressure Switch and Internal Thermostat for Outdoor and Indoor Fan Motor)
Transmission Abnormality between Indoor Unit and Outdoor Unit
Picking up phase Abnormality
Abnormality High Temperature on the Top of Compressor
Thermistor Abnormality for inlet Air Temperature
Thermistor Abnormality for outlet Air Temperature
Thermistor Abnormality for Freezing Temperature
Thermistor Abnormality for Compressor Top Temperature
Thermistor Abnormality for Outdoor Air Temperature
Thermistor Abnormality for Outdoor Evaporating Temperature (defrosting)
Thermistor Abnormality for Condensing Temperature
Transmision Abnormality between Master and Slave
Abnormality in the Picking up Circuit protection
Excessive Overload during Cooling Operation
Excessive Overload during Heating Operation
Regarding the retry control, the lastest retry code will be indicated unless the protection control related with the frequency control is indicated.
Hitachi inverter AC Error Code List
Water pump malfunction
High pressure protection of compressor
Indoor anti-frozen protection
Low pressure protection of compressor
Air discharge high-temperature protection of compressor
Overload protection of compressor or Inverter error
Indoor fan protection
Water flow protection
Malfunction of indoor environment sensor at air return vent
Evaporator sensor malfunction
Condenser sensor malfunction
Outdoor environment sensor malfunction
Malfunction of air discharge sensor
Malfunction of environment sensor on displayer
Auxiliary electric heater malfunction
Indoor unit fault
Indoor ambient temperature
Indoor coil temperature
Indoor setting temperature
Communication between main control board and wiring remote controller fault.
Communication between main control board and display board fault.
Hitachi RAC Fault Codes-Indoor Units Flashing
Cause and Repair
Insufficient heating or cooling. Likely low on refrigerant.
Outdoor unit is in forced operation. Not a fault.
Indoor/Ourdoor communication error. Check interconnecting cable.
Outdoor unit error. Check outdoor unit.
Indoor fan motor rotation error. Check indoor fan motor.
5 Flashes(Summit Premium)
Power relay error. Check power relay.
Drain high water level alarm. Check drains and pump.
Drain pump in force operation. Not a fault.
Louver defective. Check louvers and wiring.
Indoor thermistor fault. Check air and pipe thermistor.
Fan rotation error. Check indoor fan motor.
High voltage genorator/Ionize fault. Check high voltage gen/Ionizer.
Indoor/Outdoor communication error. Check interconnecting cable.
EEPROM error on PCB. Check PCB.
Hitachi AC Troubleshooting
This Is Not Abnormal
Smells from Indoor Unit; Smell adheres on indoor unit after a long period of time. Clean the air filter and panels or allow a good ventilation.
Sound from Deforming Parts; During system starting or stopping, an abrading sound might be heard. However, this is due to thermal deformation of plastic parts. It is not abnormal.
Steam from Outdoor Heat Exchanger; During defrosting operation, ice on the outdoor heat exchanger is melted, resulting in making steam.
Dew on Air Panel; When the cooling operation continues for a long period of time under high humidity conditions (higher than 27°C DB/80% R.H), dew can form on the air panel.
Refrigerant Flow Sound; While the system is being started or stopped, sound from the refrigerant flow may be heard.
Not Cooling Or Heating Well
Check for obstruction of air flow of the outside or inside units.
Check if too much heat source exists in the room.
Check if the air filter is clogged with dust.
Check to see if the doors or windows are opened or not.
Check if the temperature condition is not within the operation range.
Check for electrical wiring.
Check for dip switch setting.
Check whether the “SET TEMP” is set at the correct temperature.
In the case that “RUN” lamp on remote control switch is flickering every 2 seconds, check for connection of remote control line.
In the case that “RUN” lamp flashes 5 times (5 seconds) with unit number and alarm code displayed, refer to the next item “18.2 Troubleshooting by Alarm Code” and the “Service Manual”.
In the case that no alarm code is indicated and normal operation is not available, refer to the “Service Manual” because abnormality of some device is suspected.
During heating, the operation indicator blinks and air blow stops
The unit is preparing to blow warm air. Please wait. The outdoor unit is defrosting. Please wait.
Hissing or fizzy sounds
Refrigerant flow noise in the pipe or valve sound generated when flow rate is adjusted.
Noise generated when the unit expands or contracts due to temperature changes.
Noise generated with the indoor unit fan’s rpm changing such as operation start times.
Noise of the motorized valve when the unit is switched on.
Noise of the ventilation fan sucking in air present in the drain hose and blowing out dehumidifying water that had accumulated in the condensed water collector. For details, consult your sales agent.
Changing operation noise
Operation noise changes due to power variations according to room temperature changes.
Mist is generated as the air within the room is suddenly cooled by conditioned air.
Steam emitted from the outdoor unit
Water generated during defrosting operation evaporates and steam is emitted.
Caused as the smells and particles of smoke, food, cosmetics, etc. present in room air become attached the unit and blown off into the room again.
The outdoor unit continues to operate even if operation is stopped.
Defrosting is underway (as the heating operation is stopped, the microcomputer checks frost accumulated in the indoor unit and instructs the unit to perform automatic defrosting if necessary).
The OPERATION lamp is blinking.
Shows preheating or defrosting operation is underway. As the protective circuit or preheat sensor operates when unit operation is stopped during preheating and then restarted, or when operation mode is switched from cooling to heating, the lamp continues to blink.
Does not reach the temperature setting.
Actual room temperature may deviate slightly from the remote controller’s temperature setting depending on the number of people in the room, indoor or outdoor conditions.
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