Mitsubishi Electric MSZ-FH Air Conditioners
41 fault codes documented
Compressor does not restart immediately — 3-minute time delay active
After the system turns OFF, the compressor will not restart for approximately 3 minutes. This is a built-in safety feature designed to protect the compressor from potential damage due to overload or rapid restarts. This is normal operation.
AIR PURIFYING lamp flashes 2 times — Air purifying power supply issue or front panel not closed
The AIR PURIFYING lamp indicates a problem with the air purifying power supply. This can be caused by the front panel not being firmly closed, or if the air purifying device is dirty or wet.
AIR PURIFYING lamp 2-time flash — Air purifying power control circuit error
The AIR PURIFYING lamp flashes two times, indicating that the AIR PURIFYING power control circuit on the indoor electronic control P.C. board is out of order.
AIR PURIFYING lamp 2-time flash — AIR PURIFYING power control trouble (normal troubleshooting)
During normal operation troubleshooting, the AIR PURIFYING lamp flashes two times. This indicates a problem with the AIR PURIFYING power control within the indoor unit.
AIR PURIFYING lamp continuously blinks — Protection activated due to wet air purifying device
The AIR PURIFYING lamp blinks continuously, indicating that a protection mechanism has been activated. This usually happens if the air purifying device was wet when an operation check was performed.
AIR PURIFYING lamp flashes — Air purifying power cannot be turned OFF
The indoor and outdoor units do not operate. This symptom occurs when the AIR PURIFYING power remains ON and cannot be turned OFF, even after attempting to disable it via the remote controller.
AIR PURIFYING lamp flashes and POWER lamp is lit — MXZ type multi-system operation mode conflict
In an MXZ type multi-system, the outdoor unit operates but the indoor unit does not. This occurs when indoor units are set to different operation modes (e.g., COOL/DRY/FAN vs. HEAT). The unit that started first has priority.
AIR PURIFYING lamp off — Front panel not closed
The lamp indicating the air purifying operation is not lighting up. This means the function is not active. This typically happens when the front panel of the indoor unit is not properly shut.
OPERATION INDICATOR lamp blinks — Multi-system operation mode conflict
In a multi-system setup, if you try to operate multiple indoor units with conflicting modes (e.g., some for cooling, others for heating) simultaneously, the unit that started first determines the mode. Other units cannot operate and their OPERATION INDICATOR lamp will flash.
POWER lamp flashes ON and OFF at 0.5-second intervals — Indoor/outdoor unit miswiring or serial signal trouble (normal troubleshooting)
During normal operation troubleshooting, the indoor unit's POWER lamp flashes ON and OFF at 0.5-second intervals. This typically signifies miswiring or a serial signal communication problem between the indoor and outdoor units.
POWER lamp flashes (0.5s ON/0.5s OFF) — Miswiring or serial signal error
The indoor and outdoor units do not operate. This indicates a problem with the wiring between the units or that the serial signal from the outdoor unit has not been received for 6 minutes. It can also occur if the indoor unit was previously connected to a non-low-standby-power model.
POWER lamp 0.5-second blink with beep — Air purifying device abnormality (recall mode)
When the unit is in air purifying power failure mode recall function, the indoor unit's POWER lamp blinks at 0.5-second intervals, with a beep at the same timing. This indicates an abnormal condition specifically in the air purifying device.
POWER lamp 0.5-second blink with beep — Indoor or outdoor unit abnormality (recall mode)
When the unit is in failure mode recall function, the indoor unit's POWER lamp blinks at 0.5-second intervals, accompanied by a beep. This indicates a general abnormal condition in either the indoor or outdoor unit.
POWER lamp 1-time flash — AIR PURIFYING power control failure (air purifying recall mode)
When in air purifying power failure mode recall function, the POWER lamp flashes once. This indicates that the AIR PURIFYING power cannot be turned OFF even when the AIR PURIFYING operation is turned OFF with the remote controller, or a specific voltage drop at CN1T1 (+)-(GND).
POWER lamp 1-time flash (0.5-second interval) — Room temperature thermistor short or open circuit (recall mode)
When in failure mode recall function, the POWER lamp flashes once every 0.5 seconds. This indicates that a short or open circuit has been detected in the room temperature thermistor during operation.
POWER lamp 11-time flash (2.5-second OFF) — Indoor fan motor rotational frequency signal not detected (recall mode)
When in failure mode recall function, the POWER lamp flashes eleven times, followed by a 2.5-second OFF period. This indicates that the rotational frequency feedback signal from the indoor fan motor was not emitted during 12 seconds of indoor fan operation.
POWER lamp 12-time flash (2.5-second OFF) — Indoor control system data read error (recall mode)
When in failure mode recall function, the POWER lamp flashes twelve times, followed by a 2.5-second OFF period. This indicates that the indoor control system cannot properly read data from the nonvolatile memory of the indoor electronic control P.C. board.
POWER lamp flashes 14 times — Other abnormality detected
The indoor fan motor turns OFF. This indicates that an abnormality other than those specifically mentioned has been detected by the system.
POWER lamp 14-time flash — Other outdoor unit abnormality (normal troubleshooting)
During normal operation troubleshooting, the POWER lamp flashes fourteen times. This indicates an unspecified abnormality originating from the outdoor unit.
POWER lamp flashes 2 times — Indoor coil or room temperature thermistor is faulty
The indoor fan motor turns OFF. This indicates that either the indoor coil thermistor or the room temperature thermistor has a short or open circuit, affecting temperature readings.
POWER lamp 2-time flash — Electrode (Spark discharge) error 1 (air purifying recall mode)
When in air purifying power failure mode recall function, the POWER lamp flashes two times. This indicates an abnormal electric discharge error where the voltage on the electronic P.C. board falls by 1.2V below the normal voltage (2.5V).
POWER lamp 2-time flash (2.5-second OFF) — Indoor coil thermistor short or open circuit (recall mode)
When in failure mode recall function, the POWER lamp flashes two times, followed by a 2.5-second OFF period. This indicates a short or open circuit in the indoor coil thermistor (main or sub) detected during operation.
POWER lamp 2-time flash — Room temperature or indoor coil thermistor trouble (normal troubleshooting)
During normal operation troubleshooting, the POWER lamp flashes two times. This indicates a problem with either the room temperature thermistor or the indoor coil thermistor.
POWER lamp flashes 3 times — Indoor fan motor rotational frequency signal missing
The indoor fan motor turns OFF. This indicates that the rotational frequency feedback signal is not being emitted during the indoor fan operation, suggesting a problem with the motor or its control.
POWER lamp 3-time flash — Abnormal electric discharge error 2 (air purifying recall mode)
When in air purifying power failure mode recall function, the POWER lamp flashes three times. This indicates an abnormal electric discharge error where the voltage on the electronic P.C. board falls significantly (0.4V / 0.5ms).
POWER lamp 3-time flash (2.5-second OFF) — Serial signal not received from outdoor unit (recall mode)
When in failure mode recall function, the POWER lamp flashes three times, followed by a 2.5-second OFF period. This indicates that the serial signal from the outdoor unit has not been received for a maximum of 6 minutes.
POWER lamp 3-time flash — Indoor fan motor trouble (normal troubleshooting)
During normal operation troubleshooting, the POWER lamp flashes three times. This indicates a problem with the indoor fan motor.
POWER lamp 3 seconds ON then 0.5-second blink with no beep — Outdoor unit abnormality (recall mode)
When the unit is in failure mode recall function, the indoor unit's POWER lamp stays ON for 3 seconds without a beep, then blinks at 0.5-second intervals. This specific pattern indicates an abnormal condition in the outdoor unit.
POWER lamp flashes 4 times — Indoor control system data read error
The indoor fan motor turns OFF. This indicates that the system cannot properly read data from the nonvolatile memory of the indoor electronic control P.C. board, which controls the indoor unit's functions.
POWER lamp 4-time flash — AIR PURIFYING power issue (air purifying recall mode)
When in air purifying power failure mode recall function, the POWER lamp flashes four times. This indicates a problem with the AIR PURIFYING power when the voltage on the electronic P.C. board falls significantly.
POWER lamp 4-time flash — Indoor unit control system trouble (normal troubleshooting)
During normal operation troubleshooting, the POWER lamp flashes four times. This indicates a problem with the indoor unit's control system, specifically relating to its electronic control P.C. board.
POWER lamp flashes 5 times — Outdoor power system overcurrent or start-up failure
The indoor fan motor turns OFF. This happens if the compressor stops due to overcurrent protection or start-up failure protection consecutively three times within one minute after starting.
POWER lamp 5-time flash — Abnormal electric discharge error 1 (air purifying recall mode)
When in air purifying power failure mode recall function, the POWER lamp flashes five times. This indicates an abnormal electric discharge error where the voltage on the electronic P.C. board rises above 3V.
POWER lamp 5-time flash — Outdoor power system abnormality (normal troubleshooting)
During normal operation troubleshooting, the POWER lamp flashes five times. This indicates an abnormality in the outdoor unit's power system.
POWER lamp flashes 6 times — Outdoor thermistors are faulty
The indoor fan motor turns OFF. This indicates that one or more outdoor thermistors have a short or open circuit during compressor operation, affecting temperature readings.
POWER lamp 6-time flash — i-see sensor poor contact or data loading failure (recall mode)
When in failure mode recall function, the POWER lamp flashes six times. This indicates either poor contact in the i-see sensor wiring or a failure in loading the corrected data of the i-see sensor.
POWER lamp 6-time flash — Thermistor trouble in outdoor unit (normal troubleshooting)
During normal operation troubleshooting, the POWER lamp flashes six times. This indicates a problem with a thermistor located in the outdoor unit.
POWER lamp flashes 7 times — Outdoor control system data read error
The indoor fan motor turns OFF. This indicates that the system cannot properly read data from the nonvolatile memory of either the inverter P.C. board or the outdoor electronic control P.C. board.
POWER lamp 7-time flash — Outdoor control system trouble (normal troubleshooting)
During normal operation troubleshooting, the POWER lamp flashes seven times. This indicates a problem with the outdoor unit's control system.
POWER lamp solid — Outdoor control system data read error (Outdoor unit not operating)
The POWER lamp lights up solid, and the outdoor unit does not operate. This indicates a problem reading data from the nonvolatile memory of the inverter P.C. board or the outdoor electronic control P.C. board.
Remote controller missing, failed, or batteries low — Cannot control AC
The air conditioning unit cannot be controlled using the remote controller. This situation occurs if the remote is lost, not working correctly, or its batteries are depleted. Emergency operation is available on the indoor unit itself.