This guide explains all Daikin Air Conditioner error codes (CH series) with simple troubleshooting steps to help you identify and fix common issues safely before calling a technician.
A1
Indoor PCB Failure
- Turn off the power supply immediately.
- Check indoor control board connections.
- Inspect for burnt or damaged components.
- Replace PCB if the fault persists.
A3
Drain System Malfunction
- Check the drain hose for blockage.
- Clean the condensate pan and drain pipe.
- Ensure proper water flow from the unit.
- Remove any debris in the drainage path.
A6
Fan Motor Error
- Inspect indoor fan motor for obstruction.
- Check wiring and electrical connectors.
- Clean dust buildup on fan blades.
- Replace motor if it is not operational.
C4
Heat Exchanger Sensor Fault
- Check temperature sensor connection.
- Inspect sensor for damage or corrosion.
- Replace thermistor if readings are incorrect.
- Secure wiring to ensure stable signal.
C7
Louver Motor Failure
- Check louver movement for obstruction.
- Inspect motor wiring and gear assembly.
- Reset system and test swing function.
- Replace louver motor if it fails to respond.
E1
Outdoor PCB Failure
- Turn off power before inspection.
- Check outdoor control board connections.
- Inspect for burnt or damaged components.
- Replace PCB if fault continues.
E5
Compressor Overload
- Allow compressor to cool down.
- Check refrigerant levels for imbalance.
- Inspect condenser airflow for blockage.
- Call a technician if overload persists.
E6
Compressor Startup Failure
- Check power supply stability.
- Inspect capacitor and wiring connections.
- Ensure compressor is not mechanically seized.
- Request servicing if startup fails repeatedly.
E7
Outdoor Fan Motor Fault
- Check fan blades for obstruction.
- Inspect motor wiring connections.
- Clean dust and debris from fan assembly.
- Replace motor if defective.
E9
Electronic Expansion Valve Error
- Check valve control wiring.
- Inspect refrigerant flow system.
- Reset system and retest operation.
- Replace valve if malfunction persists.
U0
Low Refrigerant Pressure
- Check system for refrigerant leaks.
- Inspect piping and flare connections.
- Recharge refrigerant to proper level.
- Contact HVAC technician if pressure drops again.
U2
Power Supply Voltage Issue
- Check incoming power voltage stability.
- Inspect electrical wiring and breakers.
- Avoid running other high-load appliances.
- Install voltage stabilizer if needed.
U4
Communication Error
- Check wiring between indoor and outdoor units.
- Inspect connectors for looseness or damage.
- Reset both units simultaneously.
- Replace communication board if needed.
U5
Freeze Protection Activation
- Allow unit to thaw before restarting.
- Check airflow and filter cleanliness.
- Inspect evaporator coil condition.
- Ensure proper fan operation.
J3
Discharge Pipe Temperature Fault
- Check discharge temperature sensor.
- Inspect refrigerant flow and compressor load.
- Clean condenser coils.
- Service system if overheating continues.
J6
Outdoor Heat Exchanger Sensor Error
- Inspect outdoor thermistor connection.
- Check sensor resistance values.
- Replace faulty sensor if needed.
- Ensure proper wiring insulation.
L4
Inverter Circuit Fault
- Turn off power immediately.
- Inspect inverter PCB for damage.
- Check compressor drive circuit.
- Replace inverter module if necessary.
H6
Compressor Lock Protection
- Check compressor for mechanical seizure.
- Inspect capacitor and start components.
- Verify voltage supply stability.
- Replace compressor if locked.
P4
High Pressure Protection
- Clean condenser coils and filters.
- Check for blocked airflow.
- Inspect refrigerant overcharge condition.
- Reduce system load and restart.
F3
Discharge Temperature Abnormal
- Check refrigerant charge level.
- Inspect compressor condition.
- Ensure proper cooling airflow.
- Service system if overheating persists.