Mitsubishi Heavy Industries R410A Systems

A communication error has occurred between internal components, likely between the indoor and outdoor units or control boards. This prevents proper system operation.

The system detected an issue during the auto-addressing process, or one or more units (indoor or outdoor) are still set to factory default addresses (48 or 49). Auto-addressing may not be possible on certain systems.

The system displays E14 and the LED flashes 3 times, indicating a problem with the control wiring between the master and slave units. This could be an incorrect DIP switch setting or an open circuit in the wiring.

A fault has been detected with the indoor unit's fan motor, preventing it from operating correctly. This can lead to poor airflow and inefficient cooling/heating.

The sensor within the remote controller has failed. This sensor is typically used to read the ambient temperature at the remote control's location, impacting temperature regulation.

There is an error related to the connection between the indoor and outdoor units. This indicates a problem in the communication or wiring that links these two main components.

This error indicates that an indoor unit has a duplicate address number (U00-U47) or there is an error in the outdoor unit's address setting. Each unit must have a unique address in a multi-system setup.

The anti-phase device has detected that two phases of the mains power need to be swapped, or the L2 phase of the mains power (primary side of contactor) has been detected as open. This is a critical power supply issue.

The current transformer (CT) on the L3 phase has detected abnormally low current, or no current at all. This indicates a power supply issue on the L3 phase.

The outdoor unit's heat exchanger sensor (ThOR) is detected as defective (open or closed circuit), or there is abnormally high pressure in the cooling circuit.

The discharge temperature is abnormally high, or the compressor discharge temperature sensor (THOD) is defective. High discharge temperatures indicate system strain.

The outdoor unit's heat exchanger sensor (ThOR) has an open circuit or a poor connection, preventing accurate temperature readings. This general error code encompasses more specific thermistor failures (E37-1 to E37-6).

The outdoor unit's heat exchanger thermistor (Tho-R1) has failed. This thermistor is critical for measuring the temperature of the heat exchanger, impacting unit operation.

The outdoor unit's heat exchanger thermistor (Tho-R2) has failed. This thermistor is critical for measuring the temperature of the heat exchanger, impacting unit operation.

The outdoor unit's heat exchanger thermistor (Tho-R3) has failed. This thermistor is critical for measuring the temperature of the heat exchanger, impacting unit operation.

The outdoor unit's heat exchanger thermistor (Tho-R4) has failed. This thermistor is critical for measuring the temperature of the heat exchanger, impacting unit operation.

The outdoor unit's heat exchanger thermistor (Tho-R5) has failed. This thermistor is critical for measuring the temperature of the heat exchanger, impacting unit operation.

The outdoor unit's heat exchanger thermistor (Tho-R6) has failed. This thermistor is critical for measuring the temperature of the heat exchanger, impacting unit operation.

The outside air temperature sensor (ThoA) is defective, either due to an open circuit or a poor connection on the outdoor unit PCB. This prevents the system from accurately reading ambient outdoor temperatures.

The compressor discharge temperature sensor (ThOD) has a defective resistance (open circuit) or a poor connection on the outdoor unit PCB. This sensor monitors the temperature of the refrigerant leaving the compressor.

The high-pressure switch (B3H or 63H1) has tripped, indicating abnormally high pressure in the refrigerant system. This could be due to an overcharge, closed service valves, or insufficient airflow over the condenser coil.

The power transistor for the inverter has overheated. This indicates a problem with the inverter board, often due to excessive load, poor ventilation, or component failure.

Abnormally high current has been detected in the compressor, indicating it is working too hard or experiencing an electrical fault. This is a protective shutdown.

The maximum number of indoor units allowed for connection to one outdoor unit has been exceeded. This is an installation configuration error.

A transmission error has occurred between the inverter and the outdoor unit's Printed Circuit Board (PCB), or there is a loose connection at the "Cal" point. This affects communication between critical components.

There is a conflict in address settings where automatic, manual, and/or remote control addresses are coexisting on one network. This leads to communication issues in multi-unit systems.

The inverter has detected an overvoltage condition. This means the incoming electrical voltage to the inverter is too high, which can damage components.

A fault has been detected in the DC outdoor fan motor. This prevents the outdoor unit from properly dissipating heat, leading to system inefficiencies or shutdowns.

The system has detected either a low pressure fault in the refrigerant system or a low voltage condition. Both can impair system performance and lead to protective shutdowns.

There is a fault with the inverter PCB itself, or the power transistor on the inverter board has overheated. Both indicate a serious internal electronic issue.

The outdoor unit has detected that the electrical phases are reversed. This indicates an issue with the power supply wiring to the outdoor unit.

The system has detected an open phase on the L3 power line, typically affecting the outdoor unit. This means there is a loss of power on one of the electrical phases.

This error indicates that the 63L connector, likely associated with the outdoor unit, is open or disconnected. This is often a wiring issue.

An open or disconnected 49C connector has been detected in the outdoor unit. This suggests a problem with a specific electrical connection.

A fault has been detected in the reverse phase detector circuit on the main printed circuit board (PCB) of the outdoor unit. This is an internal electronic fault.

An input circuit fault has been detected in the outdoor unit. This generally points to a problem with the electrical power input to the system.

This error means that two or more connectors, likely within the outdoor unit, are open or disconnected. This points to multiple wiring issues or a more general problem.

The system has detected an open phase on the L2 power line or an open 51CM connector. This indicates a power supply or connection issue on one of the phases.

The intake air sensor in the indoor unit, which measures the temperature of the air entering the system, is reporting an abnormal reading. This can lead to incorrect temperature control.

A pipe sensor, likely measuring refrigerant temperature on a pipe within the indoor unit, is reporting an abnormal condition. This affects the system's ability to monitor refrigerant flow.

This indicates a system communication error between components, similar to an E0 error. It means signals are not being sent or received correctly, impairing system control.

The drain sensor has detected an abnormal condition, usually indicating a problem with the condensate drain system. This could lead to water overflow.

The system's drain overflow protection mechanism has malfunctioned. This means the unit is unable to properly prevent condensate water from overflowing, which could lead to water damage.

An abnormality has been detected in the coil frost or overheating protection modes. This indicates the system is either freezing up or overheating, and its safety mechanisms are not functioning correctly.

An address system error has occurred, which typically happens in multi-unit systems where each unit requires a unique address for communication. This indicates a conflict or misconfiguration.

A general malfunction has been detected in the outdoor unit. This broad error indicates that a component within the outdoor unit is not operating as expected.

The system has detected excessively high pressure in the refrigerant circuit, triggering the high-pressure switch (63H) as a safety measure. This can lead to system shutdown.

The unit has performed a "direct cut" shutdown, indicating a protective measure due to an detected internal fault. This could be related to electrical stability or sensor readings.

The outdoor unit has detected an abnormally high discharge temperature. This often indicates the system is working under strain, possibly due to blockages or low refrigerant.

The inner thermostat (49C) in the outdoor unit has activated, likely due to an internal overheat condition. This triggers a safety shutdown to prevent damage.

The discharge thermistor, which measures the temperature of the refrigerant leaving the compressor, is either short-circuited or open. This prevents accurate temperature readings.

The system has initiated an overheat protection shutdown. This occurs when internal temperatures exceed safe operating limits, often due to restricted airflow or system strain.

The outdoor thermistor, which measures the ambient temperature, has a short or open circuit. This prevents the system from accurately sensing external conditions, affecting performance.

The compressor has drawn too much current, triggering an overload protection shutdown. This indicates the compressor is working too hard or has an electrical fault.

The compressor has experienced an overcurrent condition related to the terminal relay, causing a shutdown. This suggests an electrical issue with the compressor's starting or running circuit.

A high-pressure error has occurred, specifically indicating that a ball valve is closed, restricting refrigerant flow. This causes pressure to build up in the system.

The system detected excessive current drawn by the compressor during startup, causing a safety shutdown. This typically means the compressor motor is unable to begin operating.

The compressor experienced an overcurrent condition while running, leading to a safety shutdown. This suggests a mechanical problem or excessive load on the compressor during operation.

A fault has been detected in the current sensor, which monitors the electrical current within the system. This can lead to incorrect readings or safety shutdowns.

The system has detected abnormally low pressure in the refrigerant circuit. This usually points to a lack of refrigerant or a blockage.