Help & Advice
Daikin Air Conditioning Fault Codes Explained [Infographic]
From time to time, your air conditioning unit may encounter a fault, which can be difficult to diagnose without proper information. To help you find out what the cause of any potential issue could be, we’ve compiled a list of Daikin air conditioning fault codes and their descriptions.
Common Daikin Air Conditioning Fault Codes
A1 – Micro-computer in PCB is not working – this is a fault that occurs either in the assembly of the PCB or due to an external factor, such as noise.
A3 – Drain level is too high – This is caused by a clogging of dirt in the drain, or a faulty drain pump.
A5 – Overheating or freezing of indoor heat exchanger – This could be caused by a dirty air filter, a short circuit or trouble with the sensor in the heat exchange.
A6 – Fan motor error – The fan motor is either locked, overloaded or is suffering from a faulty connection.
A7 – Swing flap motor error – A fault with the swing flap motor, or a faulty connection.
AH – Dust collector error – A fault with the dust collector, or an element of it may be dirty.
AJ – Capacity setting error – The capacity or address setting is faulty.
C3 – Abnormal water level sensor resistance – The water level sensor has either disconnected, short circuited or developed a fault.
C4 – Abnormal resistance level of indoor heat thermistor – This means the thermistor has either become disconnected or it has short circuited.
C9 – The resistance of the indoor unit suction air thermistor is abnormal – Either a disconnection of the cable, or a short circuit has occurred.
CE – Abnormal radiation thermistor resistance – A faulty thermistor, disconnected cable or a short circuiting of the thermistor could be the source of the issue.
CJ – Abnormal remote controller thermistor resistance – The built in remote has encountered a fault.
E0 – Outdoor unit protection devices activated – The refrigerant piping system could be clogged, there may be insufficient refrigerant or there could be a fault with the compressor/fan motor.
E3 – High pressure is too high (HPS activation) – The condenser may have short circuited or overloaded, or the heat exchanger may be dirty.
E4 – Low pressure is too low (LPS activation) – The refrigerant piping system may be clogged, there may be insufficient refrigerant or the the LPS switch could be faulty.
E5 – Overheating of compressor (OL activation) – Refrigerant piping system could be clogged, there may not be enough refrigerant, or there could be a fault with the OL or the connection.
F3 – Outdoor unit discharge temperature is too high – Insufficient refrigerant, clogged refrigerant piping or the discharge temperature thermistor could be faulty.
H9 – Abnormal resistance of the outdoor air temperature thermistor – The outdoor air thermistor could be faulty, there may be a cable disconnection or the thermistor itself may have short circuited.
J5 – Abnormal resistance of the suction pipe temperature thermistor – There could be a faulty suction pipe thermistor, the cable could be disconnected or your thermistor may have short circuited.
J6 – Abnormal resistance of the outdoor heat exchanger thermistor – Either a faulty or short circuited outdoor heat exchanger thermistor, or the cable may be disconnected.
P1 – Open phase power voltage imbalance – This means there’s a three phase or open phase voltage imbalance.
U0 – Suction pipe temperature is too high – A fault with the refrigerant piping system – either clogging or a lack of refrigerant, or there may be a fault with the expansion valve.
U1 – Reverse phase – The three phase power supply has been reversed.
U2 – Open phase or power voltage imbalance – There may be an open phase or a voltage imbalance in the power supply. There also could be a power failure or the DC voltage of the fan motor could be too low.
U4 – Communication error between indoor and outdoor units/outdoor and BS units – A mistake with the interconnection wires, or an indoor/outdoor PCB fault.
U5 – Communication error between indoor unit and remote controller – A possible mistake with the interconnection wires, or a PCB fault with the indoor/outdoor remote controller.
UA – Combination error of indoor/BS/outdoor unit, setting error of PCB at site – There is an incorrect combination of indoor, BS or outdoor units (the wrong quantity or models, for example).
Looking for Assistance?
If you’re receiving Daikin air conditioning fault codes, then the above information may help you determine the source of the issue, which can speed up the repair process and possibly avoid the need for professional assistance. If you’re looking for further assistance, please don’t hesitate to get in touch with the professionals here at Airway Air Conditioning.