Hitachi Air Conditioner Error Codes

Complete Hitachi Air Conditioner Guide

This guide explains all Hitachi Air Conditioner error codes (CH series) with simple troubleshooting steps to help you identify and fix common issues safely before calling a technician.

01
Indoor Unit Communication Error
  • Turn off power and restart system.
  • Inspect indoor–outdoor wiring connections.
  • Check for loose or corroded terminals.
  • Replace control PCB if communication fails.
02
Outdoor Unit Communication Error
  • Inspect communication cable between units.
  • Ensure stable power supply to outdoor unit.
  • Check PCB connectors and wiring harness.
  • Replace outdoor control board if needed.
12
Signal Transmission Failure
  • Check communication line continuity.
  • Inspect terminal blocks for looseness.
  • Reset power supply system.
  • Replace communication PCB if needed.
03
Room Temperature Sensor Failure
  • Inspect room sensor wiring and placement.
  • Test thermistor resistance.
  • Check for moisture or corrosion.
  • Replace sensor if readings are abnormal.
04
Evaporator Sensor Fault
  • Check evaporator sensor connection.
  • Test resistance values with multimeter.
  • Inspect sensor mounting on coil.
  • Replace faulty sensor if needed.
05
Condenser Sensor Fault
  • Inspect condenser sensor wiring.
  • Check sensor resistance values.
  • Ensure proper placement on coil.
  • Replace sensor if defective.
13
Humidity Sensor Error
  • Check humidity sensor connection.
  • Inspect for dust or blockage.
  • Test sensor output signal.
  • Replace sensor if inaccurate.
06
Fan Motor Abnormal Operation
  • Check fan blades for obstruction.
  • Inspect motor wiring connections.
  • Test fan motor operation.
  • Replace fan motor if malfunctioning.
14
Indoor Fan Motor Failure
  • Inspect blower wheel for blockage.
  • Check fan motor capacitor.
  • Test motor winding resistance.
  • Replace motor if not running.
07
Compressor Overload Protection
  • Allow compressor to cool down.
  • Check refrigerant pressure levels.
  • Clean condenser coils for airflow.
  • Inspect compressor relay and capacitor.
15
Compressor Startup Failure
  • Check power supply stability.
  • Inspect start capacitor.
  • Test compressor resistance.
  • Replace compressor relay if needed.
08
EEPROM Error
  • Power cycle the unit.
  • Inspect PCB for moisture or damage.
  • Check memory IC connections.
  • Replace main board if error persists.
16
Control Board System Failure
  • Reset system power supply.
  • Inspect main PCB for burn marks.
  • Check firmware corruption.
  • Replace control board if needed.
09
Power Supply Instability
  • Check voltage supply stability.
  • Inspect circuit breaker and wiring.
  • Use voltage stabilizer if needed.
  • Replace power board if faulty.
17
Low Voltage Protection Activated
  • Check mains voltage level.
  • Inspect wiring connection stability.
  • Use stabilizer or AVR.
  • Restart system after voltage stabilizes.
10
Drain Pump Issue
  • Inspect drain hose for blockage.
  • Check drain pump operation.
  • Clean drain pan and filter.
  • Replace pump if defective.
18
Condensate Drain Blockage
  • Check drain pipe for clogging.
  • Clean indoor drain tray.
  • Ensure proper slope installation.
  • Flush drain line if necessary.
11
Outdoor Fan Motor Failure
  • Inspect outdoor fan blades for obstruction.
  • Check fan motor wiring connections.
  • Test fan motor operation.
  • Replace motor if not running.
19
High Pressure Protection Activated
  • Clean condenser coils for proper airflow.
  • Check refrigerant pressure levels.
  • Inspect outdoor fan operation.
  • Service refrigerant system if needed.
20
Low Pressure Protection Activated
  • Check for refrigerant leakage.
  • Inspect piping and joints.
  • Verify system gas levels.
  • Recharge refrigerant if required.
21
Refrigerant Leakage Detection
  • Inspect all refrigerant pipes and joints.
  • Check for oil stains or leaks.
  • Perform pressure test on system.
  • Repair leak and refill refrigerant.
22
Compressor Overheat Protection
  • Allow compressor to cool down completely.
  • Check condenser airflow and cleanliness.
  • Inspect compressor relay and capacitor.
  • Service compressor if overheating persists.
23
Inverter Module Communication Error
  • Inspect inverter PCB wiring connections.
  • Check communication cable between boards.
  • Reset power supply system.
  • Replace inverter board if faulty.
24
DC Bus Voltage Abnormal
  • Check power input stability.
  • Inspect inverter circuit components.
  • Test voltage regulation system.
  • Replace power board if needed.
25
Heat Exchange Sensor Fault
  • Inspect heat exchanger sensor wiring.
  • Test sensor resistance values.
  • Check for corrosion or loose connection.
  • Replace sensor if readings are incorrect.
26
Defrost Mode Malfunction
  • Check defrost cycle operation.
  • Inspect defrost sensor and heater.
  • Clean ice buildup on coils.
  • Replace control board if needed.
27
Indoor Coil Freeze Protection Activated
  • Clean air filters and vents.
  • Increase fan speed or airflow.
  • Check refrigerant level.
  • Allow coil to thaw before restart.
28
Outdoor Coil Overheat Protection
  • Clean outdoor condenser coil.
  • Ensure proper ventilation around unit.
  • Check fan motor operation.
  • Inspect refrigerant pressure.
29
Phase Loss or Power Phase Error
  • Check electrical supply stability.
  • Inspect wiring connections.
  • Verify voltage balance.
  • Contact electrician if issue persists.
30
Current Overload Protection
  • Check compressor load condition.
  • Inspect motor and wiring.
  • Ensure proper refrigerant levels.
  • Reset system after cooldown.
31
Expansion Valve Control Error
  • Inspect expansion valve wiring.
  • Check valve operation response.
  • Test control signal from PCB.
  • Replace valve if defective.
32
Main PCB Memory Corruption
  • Perform full system reset.
  • Check for firmware corruption.
  • Inspect PCB for damage or moisture.
  • Replace main board if needed.
33
Filter Blockage Warning
  • Clean air filters thoroughly.
  • Check airflow restriction.
  • Inspect indoor coil condition.
  • Replace filter if damaged.
34
Gas Flow Abnormality Detected
  • Check refrigerant piping system.
  • Inspect for blockage or leakage.
  • Verify system pressure levels.
  • Service refrigerant system if needed.
35
Thermal Cut-Off Activated
  • Allow unit to cool down fully.
  • Check overheating components.
  • Inspect fan and airflow system.
  • Replace thermal fuse if required.

Frequently Asked Questions


Why is my Hitachi air conditioner not cooling properly?
Check that Cool mode is selected and temperature is set lower than room temperature. Clean or replace air filters, ensure doors and windows are closed, and inspect outdoor unit airflow for blockages.
Why is my Hitachi air conditioner not turning on?
Check the power supply and circuit breaker. Ensure the plug is securely connected, replace remote batteries if needed, and reset the unit by turning off power for a few minutes.
Why is my Hitachi air conditioner leaking water?
Inspect the drain pipe for blockages or kinks. Clean the air filters, check for ice buildup on the evaporator coil, and ensure the indoor unit is properly leveled.
Why is my Hitachi air conditioner making loud noise?
Check for loose panels, debris in the fan, or vibration from improper installation. Inspect indoor and outdoor fan motors if noise continues.
Why does my Hitachi air conditioner smell bad?
Clean the air filters and evaporator coil to remove dust and mold buildup. Run Fan mode occasionally to dry internal components and reduce odor.
Why is my Hitachi air conditioner blowing warm air?
Ensure Cooling mode is active and settings are correct. Clean filters, check refrigerant levels, and inspect outdoor condenser for proper operation.
Why is my Hitachi air conditioner remote not working?
Replace batteries, remove obstructions between remote and indoor unit, and clean the IR sensor. Reset the unit if response remains weak.
Why does my Hitachi air conditioner turn off by itself?
Check timer settings, sleep mode, and power fluctuations. Ensure filters are clean to prevent overheating protection shutdown.
Why is my Hitachi air conditioner freezing up?
Dirty filters or restricted airflow can cause icing. Clean filters, ensure fan is working properly, and check refrigerant levels if freezing persists.
Why is my Hitachi air conditioner not heating?
Ensure Heating mode is selected and allow time for warm-up. Check outdoor unit operation and verify temperature settings are correct.
Why is my Hitachi air conditioner running constantly?
Check thermostat settings and ensure doors and windows are closed. Dirty coils or low refrigerant can also cause continuous operation.
Why is my Hitachi air conditioner not responding to controls?
Reset the unit by disconnecting power for 5–10 minutes. Check remote batteries and inspect control board for faults.
Why is my Hitachi air conditioner airflow weak?
Clean clogged filters, check for blocked vents, and inspect fan motor operation. Weak airflow may also indicate duct or blower issues.
Why does my Hitachi air conditioner display error messages?
Error messages may indicate sensor faults, communication issues, or protection mode activation. Reset the unit and check for persistent codes.
Why does my Hitachi air conditioner take time to start cooling?
This can happen during compressor protection delay or when the system is stabilizing. Wait a few minutes and ensure settings are correct.
How do I reset my Hitachi air conditioner?
Turn off the unit and disconnect power for 5–10 minutes. Restore power, then restart the system and reselect desired mode and temperature.
Important: If the error code continues after troubleshooting, disconnect power immediately and contact a certified GE technician.