Daikin ASHP Error Codes
60 fault codes documented
7H-01 — Water flow problem
Indicates an issue with the water flow within the system. This could affect heating or cooling performance.
7H-04 — Water flow problem during domestic hot water production
This code signals a water flow issue specifically when the unit is trying to produce hot water for domestic use.
7H-05 — Water flow problem during heating/sampling
A water flow problem is occurring while the unit is in heating mode or performing a sampling operation.
7H-06 — Water flow problem during cooling/defrost
This error code relates to a water flow issue happening during the cooling cycle or the defrost process.
7H-07 — Water flow problem. Pump deblocking active
The system has detected a water flow problem and is attempting to clear a blockage in the pump.
7H-08 — Pump abnormality during operation (pump feedback)
This indicates an issue with the pump's operation, possibly due to incorrect feedback signals.
80-00 — Returning water temperature sensor problem
There is an issue with the sensor that measures the temperature of the water returning to the unit.
81-00 — Leaving water temperature sensor problem
This error code points to a problem with the sensor measuring the temperature of the water leaving the unit.
81-01 — Mixed water thermistor abnormality
An abnormality has been detected with the thermistor responsible for measuring the mixed water temperature.
89-01 — Heat exchanger freeze-up protection activated during defrost (error)
The system has detected a potential freeze-up in the heat exchanger and has activated protection during the defrost cycle. This is an error state.
89-02 — Heat exchanger freeze-up protection activated during heating / DHW operation. (warning)
A warning that the heat exchanger might be freezing up while the unit is operating in heating mode or producing domestic hot water.
89-03 — Heat exchanger freeze-up protection activated during defrost (warning)
This is a warning indicating a potential freeze-up in the heat exchanger during the defrost cycle.
89-05 — Heat exchanger freeze-up protection activated during cooling operation. (error)
The system has detected a freeze-up in the heat exchanger during the cooling operation and has activated protection. This is an error.
89-06 — Heat exchanger freeze-up protection activated during cooling operation. (warning)
A warning that the heat exchanger may be freezing during the cooling operation.
8F-00 — Abnormal increase outlet water temperature (DHW)
The outlet water temperature is abnormally high while producing domestic hot water (DHW).
8H-00 — Abnormal increase outlet water temperature
The temperature of the water leaving the unit is higher than expected.
8H-01 — Overheating mixed water circuit
The mixed water circuit within the unit is experiencing overheating.
8H-02 — Overheating mixed water circuit (thermostat)
The mixed water circuit is overheating, and the issue is potentially related to the thermostat.
8H-03 — Overheating water circuit (thermostat)
The main water circuit is overheating, and the problem is linked to the thermostat.
A1-00 — Zero cross detection problem
The unit is experiencing an issue with detecting the zero crossing point in its electrical cycle, which can affect operation.
A5-00 — OU: High pressure peak cut / freeze protection problem
The outdoor unit (OU) has detected a high-pressure peak or a freeze protection issue.
AA-01 — Backup heater overheated or BUH power cable not connected
The backup heater has overheated, or its power cable is not properly connected.
AC-00 — Booster heater overheated
The booster heater within the system has overheated.
AH-00 — Tank disinfection function not completed correctly
The scheduled disinfection cycle for the hot water tank did not finish as expected.
AJ-03 — Too long DHW heat-up time required
The unit is taking an excessively long time to heat domestic hot water (DHW).
C4-00 — Heat exchanger temperature sensor problem
There is an issue with the temperature sensor located in the heat exchanger.
C5-00 — Heat exchanger thermistor abnormality
The thermistor (temperature sensor) for the heat exchanger is showing an abnormal reading.
CJ-02 — Room temperature sensor problem
This error code indicates a problem with the sensor measuring the room temperature.
CO-00 — Flow sensor malfunction
The flow sensor responsible for monitoring water flow has malfunctioned.
CO-01 — Flow sensor malfunction
Indicates a malfunction with the flow sensor that measures water movement.
CO-02 — Flow sensor malfunction
Another instance indicating a problem with the flow sensor's functionality.
E1-00 — OU: PCB defect
The outdoor unit (OU) has a detected defect with its Printed Circuit Board (PCB).
E2-00 — Leakage current detection error
The system has detected a leakage current, which is a safety concern.
E3-00 — OU: Actuation of high pressure switch (HPS)
The high-pressure switch (HPS) in the outdoor unit (OU) has been activated.
E3-24 — High pressure sensor abnormality
The high-pressure sensor in the system is reporting abnormal readings.
E4-00 — Abnormal suction pressure
The suction pressure within the refrigeration system is outside of its normal operating range.
E5-00 — OU: Overheat of inverter compressor motor
The compressor motor in the outdoor unit (OU) is overheating.
E6-00 — OU: Compressor startup defect
The outdoor unit's (OU) compressor is failing to start correctly.
E7-00 — OU: Malfunction of outdoor unit fan motor
The fan motor in the outdoor unit (OU) is not functioning correctly.
E8-00 — Power input overvoltage
The voltage supplied to the unit is higher than the acceptable range.
E9-00 — Malfunction of electronic expansion valve
The electronic expansion valve (EEV), which controls refrigerant flow, is malfunctioning.
EA-00 — OU: Cool/heat switchover problem
The outdoor unit (OU) is having trouble switching between cooling and heating modes.
EC-00 — Abnormal increase tank temperature
The temperature in the hot water tank is rising abnormally high.
EC-04 — Tank preheating
The unit is currently in the process of preheating the hot water tank.
F3-00 — OU: Malfunction of discharge pipe temperature
The temperature sensor on the discharge pipe of the outdoor unit (OU) is malfunctioning.
F6-00 — OU: Abnormal high pressure in cooling
The system is experiencing abnormally high pressure in the outdoor unit (OU) during the cooling operation.
FA-00 — OU: Abnormal high pressure, actuation of HPS
The outdoor unit (OU) has detected abnormal high pressure, triggering the high-pressure switch (HPS).
H0-00 — OU: Voltage/current sensor problem
There is an issue with the voltage or current sensor in the outdoor unit (OU).
H1-00 — External temperature sensor problem
The sensor measuring the external air temperature is experiencing a problem.
H3-00 — OU: Malfunction of high pressure switch (HPS)
The high-pressure switch (HPS) in the outdoor unit (OU) is malfunctioning.
H5-00 — Malfunction of compressor overload protection
The compressor's overload protection has been triggered, indicating it's drawing too much current or is overheating.
H6-00 — OU: Malfunction of position detection sensor
The position detection sensor in the outdoor unit (OU) is malfunctioning. This may affect component operation.
H8-00 — OU: Malfunction of compressor input (CT) system
There is a malfunction related to the compressor's current transformer (CT) system in the outdoor unit (OU).
H9-00 — OU: Malfunction of outdoor air thermistor
The thermistor (temperature sensor) measuring the outdoor air temperature in the outdoor unit (OU) is malfunctioning.
HC-00 — Tank temperature sensor problem
This error code indicates a problem with the sensor measuring the hot water tank temperature.
HC-01 — Second tank temperature sensor problem
An issue has been detected with a secondary temperature sensor for the hot water tank.
HJ-10 — Water pressure sensor abnormality
The water pressure sensor in the system is reporting abnormal readings.
J3-00 — OU: Malfunction of discharge pipe thermistor
The thermistor (temperature sensor) on the discharge pipe of the outdoor unit (OU) is malfunctioning.
J6-00 — OU: Malfunction of heat exchanger thermistor
The thermistor (temperature sensor) for the heat exchanger in the outdoor unit (OU) is malfunctioning.
J6-07 — OU: Malfunction of heat exchanger thermistor
This code indicates a malfunction of the heat exchanger thermistor within the outdoor unit (OU).