Fujitsu 410A Multi-Zone Mini-Split Systems

This error indicates a problem with the active filter or PFC circuit, often due to high (over 425V) or low (under 80V) inverter input DC voltage, or a brief power cut-off at low voltage.

This indicates an Intelligent Power Module (IPM) error, meaning an abnormal current value was detected at the IPM, or heat radiation is blocked.

This error occurs when the discharge pipe temperature thermistor is detected as open or short-circuited either at power-up or while the compressor is running.

All five LEDs on the branch box are illuminated, indicating an error related to the combination of connected indoor and outdoor units.

LED 401 and LED 405 are lit, indicating the branch box is functioning as the primary unit in a multi-unit setup. This is a normal status.

Four LEDs on the branch box are lit, but the fifth (LED 405) is unlit, indicating an issue with the power frequency.

LED 402 flashes once, indicating an error with the EEPROM (Electronically Erasable Programmable Read-Only Memory) in the branch box.

LED 402 flashes twice, indicating that the model information stored in the branch box is incorrect or corrupted.

LED 402 flashes three times, indicating a serial communication error either between the outdoor unit and the branch box, or between multiple branch boxes.

LED 402 flashes four times, specifically indicating a serial communication problem between different branch boxes in a multi-zone system.

LED 402 flashes five times, indicating a serial communication error between the branch box and Indoor Unit A.

LED 402 flashes six times and LED 403 is lit, indicating an error with the liquid pipe thermistor for Indoor Unit A.

LED 402 flashes six times and LED 404 is lit, indicating an error with the liquid pipe thermistor for Indoor Unit B.

LED 402 flashes six times and LED 405 is lit, indicating an error with the liquid pipe thermistor for Indoor Unit C.

LED 402 flashes seven times and LED 403 is lit, indicating an error with the gas pipe thermistor for Indoor Unit A.

LED 402 flashes seven times and LED 404 is lit, indicating an error with the gas pipe thermistor for Indoor Unit B.

LED 402 flashes seven times and LED 405 is lit, indicating an error with the gas pipe thermistor for Indoor Unit C.

LED 402 flashes eight times and LED 403 is lit, indicating an error with the Electronic Expansion Valve (EEV) control for Indoor Unit A.

LED 402 flashes eight times and LED 404 is lit, indicating an error with the Electronic Expansion Valve (EEV) control for Indoor Unit B.

LED 402 flashes eight times and LED 405 is lit, indicating an error with the Electronic Expansion Valve (EEV) control for Indoor Unit C.

LED 402 flashes nine times, indicating a communication error with the remote controller.

LED 402 flashes once, indicating the branch box is functioning as secondary unit 1 in a multi-unit setup. This is a normal status.

LED 402 flashes twice, indicating the branch box is functioning as secondary unit 2 in a multi-unit setup. This is a normal status.

The sensor that measures room temperature (thermistor) is detecting an abnormal temperature reading.

The system has detected an incorrect number of connected indoor units, or an issue with the wired remote control address setting.

The outdoor unit is sending a signal even though the main relay is off, which indicates a problem with the main power relay.

The thermistor sensing the indoor heat exchanger temperature is reporting an abnormal reading.

The thermistor sensing the outdoor heat exchanger temperature is reporting an abnormal reading.

The thermistor measuring the compressor's discharge temperature is detecting an abnormal reading.

There's a communication issue between the wired remote control and the indoor unit, or between multiple indoor units.

The current value during operation drops to zero amps one minute after the compressor starts, indicating a current transfer issue.

There is an error with the Electronically Erasable and Programmable Read Only Memory (EEPROM) on the indoor unit's controller PCB, which stores model information.

The indoor unit motor's voltage or current values have gone beyond their safe limits.

The manual auto switch on the indoor unit is detected as being 'on' (pressed) for 60 or more consecutive seconds.

There is an issue with the power supply to the indoor fan motor, possibly due to a voltage drop, electrical noise, or a connection problem.

The system cannot recognize the power supply frequency within 4 seconds of being powered on, leading to a permanent stop.

The thermistor measuring the outdoor ambient temperature is reporting an abnormal reading.

The room temperature thermistor in the indoor unit is detecting an abnormal temperature.

The forced auto switch is detected as being held in the 'on' (pushed-in) position for 30 seconds or more.

The thermistor that detects the temperature of the evaporator pipe in the indoor unit has identified an abnormal temperature.

There is an issue with the human presence sensor, potentially due to a loose connection, an open cable, or a faulty sensor/main PCB.

The indoor unit's fan motor is not rotating at at least one-third of its target speed for more than 56 seconds, or has stopped.

The compressor speed is not synchronizing with the control signal, or the compressor failed to start.

An abnormal current value is detected at the IPM (Intelligent Power Module), possibly due to blocked heat radiation.

The float switch in the drain pump system has been activated for more than 3 minutes, indicating a blockage or pump malfunction.

The limit switch did not detect the closing of the damper (upper airflow) even though the damper was commanded to close.

The micro switch for the intake grille is detected as open while the compressor is running, meaning the grille may not be properly closed.

An abnormal current or a fan motor lock error is detected in the outdoor unit's condenser fan motor.

The outdoor unit's main control board (PCB) failed to access its memory (EEPROM) after starting up.

The system received error information from the transistor PCB (or inverter PCB), indicating a problem with the inverter circuit.

The inverter output DC voltage is too high (over 415V for 3+ seconds) or the inverter input DC voltage is too high (over 425V) or too low (below 80V) for certain models. This can also occur after a momentary power cut-off.

An abnormal current value is detected at the IPM (Intelligent Power Module), potentially due to blocked heat radiation.

An error with the electric air cleaner has occurred, specifically after the air cleanness monitor protection operated 4 times.

The thermistor sensing the compressor temperature is detecting an abnormal reading.

The air clean operation signal was detected for 1 minute when the air clean mode was actually off, indicating an issue with the electric air cleaner power supply circuit.

When the system starts, the indoor unit (evaporator) and outdoor unit (condenser) are not communicating. This indicates a problem with the serial communication wiring.

During normal operation, the indoor and outdoor units failed to communicate for 10 consecutive seconds. This indicates a communication issue.

At system startup, the indoor unit (evaporator) and outdoor unit (condenser) are not communicating.

During operation, the indoor and outdoor units failed to communicate for 10 consecutive seconds.

The indoor unit (evaporator) is not communicating with the wired remote controller.