Mitsubishi Electric FR-D700 Inverter

A voltage (or current) has been input to terminal 4 when the setting in Pr. 267 Terminal 4 input selection and the physical voltage/current input switch on the inverter are mismatched. This incorrect input configuration can lead to erroneous frequency commands, unstable operation, or potentially damage the analog input circuit if not corrected.

An error has occurred within the inverter's CPU or its peripheral circuits. This is a critical internal hardware fault that can lead to unpredictable operation, improper control, or complete shutdown of the inverter. Electromagnetic interference from nearby devices can sometimes trigger such faults.

The analog input bias and gain calibration values (C3, C4, C6, C7) have been set too close, potentially causing instability, inaccuracy, or an invalid range in analog input readings. This can lead to incorrect frequency commands or control signals, affecting system performance. The inverter output is not shut off.

This is a panel display code (specifically for FR-PU04/FR-PU07) that indicates a CPU fault (E.CPU) is active. The underlying issue is a communication fault of the built-in CPU, leading to inverter output stoppage. It signals a critical internal processing error that prevents normal operation.

This fault appears when there is a mismatch between the type of signal (voltage or current) being input to terminal 4 and the inverter's configuration settings. Specifically, it occurs if voltage (current) is applied while Pr. 267 (Terminal 4 input selection) and the physical voltage/current input switch are set differently. This can lead to incorrect speed commands or erratic operation.

This fault indicates that the brake transistor has detected an alarm condition, typically due to excessive regenerative energy from the motor. This usually happens during rapid deceleration or when driving high-inertia loads, leading to overheating of the braking components. Continuous overheating can damage the inverter's internal brake circuit and external brake resistor.

This fault activates when the inverter's output current surpasses the level defined by Pr. 150 (Output current detection level). It serves as a protective measure, indicating that the motor or load is drawing more current than configured, possibly due to an overload or incorrect parameter settings. Exceeding this limit can lead to inverter or motor damage.

This fault code signifies a detected malfunction within the inverter's internal safety circuit, specifically indicating an issue related to the CPU's safety monitoring functions. When triggered, it causes the inverter to shut off its output to maintain a safe state and prevent motor operation.

This fault occurs when an earth (ground) fault is detected on the inverter's output side, typically in the motor or its connecting cables, specifically during startup. This protective function, active when Pr. 249 is set to '1,' immediately trips the inverter to prevent damage. An unresolved ground fault poses an electrical shock hazard and can severely damage the inverter or motor.

This fault signifies a loss of one or more phases (R/L1, S/L2, T/L3) on the inverter's input power supply. This protection, which can be enabled by Pr. 872, stops the inverter to prevent damage to its internal converter section and DC bus capacitors. Continuous operation with an input phase loss can drastically shorten the inverter's lifespan. It may also trip due to large unbalanced phase voltages or if the load on the inverter is very light.

This fault occurs when the resistor within the inverter's inrush current limit circuit overheats. This typically happens due to frequent power ON/OFF cycles to the inverter, stressing the charging components, or an internal component failure. Prolonged overheating can damage the inverter's power supply section and lead to critical failures.

This fault indicates a loss of one or more phases (U, V, W) on the inverter's output side, typically between the inverter and the motor. This protective function, which can be enabled by Pr. 251, stops the inverter output to prevent motor damage from unbalanced current flow. Operating a three-phase motor with a phase loss can severely overheat and damage the motor windings.

An excessive current condition has been detected while the inverter is accelerating the motor. This can be caused by an abnormally high load, a short circuit between phases, or a ground fault on the inverter's output side, potentially leading to damage if not resolved.

This fault indicates that the inverter's output current has reached or exceeded approximately 200% of its rated value while operating at a constant speed. This is typically caused by sudden increases in mechanical load, a short circuit, or a ground fault in the motor or its cabling. Persistent overcurrent can lead to overheating and premature failure of inverter components.

This fault signifies that an external thermal relay (for motor overheat protection) or an internal motor temperature relay has tripped, causing its contacts to open. The inverter has stopped its output to protect the motor from overheating. This function is active only when the 'OH' signal (value 7) is set in any of Pr. 178 to Pr. 182 (input terminal function selection). Prolonged motor overheating can lead to winding insulation breakdown and motor failure.

This fault occurs when the inverter's output frequency drops to 1Hz due to stall prevention operation and remains at that level for 3 seconds, ultimately leading to an inverter trip. The display shows "OL" during active stall prevention. This indicates that the motor is experiencing a continuous overload condition that the stall prevention function cannot overcome. Sustained overload can lead to motor and inverter damage.

This fault indicates an error with the inverter's internal parameter storage device (EEPROM) on the control circuit board. This can be caused by a corrupted memory block or by an excessive number of parameter write cycles, which can wear out the EEPROM. A corrupted EEPROM can lead to incorrect operation, loss of critical configuration data, or complete inverter malfunction.

This fault indicates that the resistance of the PTC thermistor, connected between inverter terminals 2 and 10, has exceeded the threshold set in Pr. 561 (PTC thermistor protection level), causing the inverter to trip. This typically signals motor overheating due to overload. This protective function is active only when Pr. 561 is set to a value other than '9999'. Continued overload and overheating can severely damage the motor.

This fault indicates a loss of communication between the inverter and the Parameter Unit (PU) or another device via RS-485. This can be due to a disconnected cable, incorrect communication settings (Pr. 75, Pr. 121, Pr. 122), or excessive consecutive communication errors. Loss of communication will stop inverter output, potentially halting the connected process.

This fault signifies that the inverter has attempted to automatically resume operation a specified number of times (configured in Pr. 67) after a previous fault, but has failed to clear the underlying problem. The inverter will now trip to prevent further damage. This code indicates a persistent issue that needs direct investigation and manual intervention.

This fault code indicates a detected malfunction within the inverter's internal safety circuit. When active, it causes the inverter to shut off its output to ensure a safe state, preventing drive operation. This is a critical internal error.

One or more units (indoor or outdoor) are still addressed at 48 or 49 (factory setting). This prevents auto-addressing, which is only possible on a single KX2 system, if one or more units (either indoor or outdoor) are not set at 49.

This indicates an incorrect setting of DIP switches (SWS) on the indoor unit PCB when configuring a master/slave system. It also points to incorrect control wiring or an open circuit in the control wiring between master and slave units.

The indoor fan motor is faulty, preventing proper air circulation. This can lead to inefficient cooling/heating or system shutdown.

The sensor within the remote controller has failed, leading to incorrect temperature or operational readings. This affects the indoor unit's ability to control room temperature accurately.

This error indicates a problem with the connection or communication between the indoor and outdoor units. It prevents proper system operation and coordination.

There is a duplication of an indoor unit address number within the U00-U47 range, or an outdoor unit address setting error has occurred. This conflict prevents proper system communication and unit identification.

The anti-phase device has detected that two phases of the mains power need to be swapped, indicating a phase reversal. Alternatively, the L2 phase of the mains power (primary side of contactor) has been detected as open, leading to unbalanced power.

Abnormally low current or no current has been detected by the current transformer (CT) on L3. This indicates an open phase condition detected at L3 (secondary side of contactor), which can prevent the compressor from operating correctly.

The outdoor unit heat exchanger sensor (ThOR) is defective, indicated by an open or closed circuit resistance, or by a poor connection of the sensor connector on the outdoor unit PCB. This can also be caused by high pressure in the cooling system, impacting heat exchange.

The compressor discharge temperature is abnormally high. This can be caused by insufficient refrigerant, a defective compressor discharge temperature sensor (THOD), or other system issues leading to compressor overheating and potential damage.

The outdoor unit heat exchanger sensor (ThOR) is defective (open circuit resistance) or has a poor connection on the outdoor unit PCB. This error may also specify which particular thermistor (Tho-R1 to Tho-R6) has failed, leading to inaccurate temperature readings.

The outside air temperature sensor (ThoA) is defective (open circuit resistance) or has a poor connection on the outdoor unit PCB. This compromises the system's ability to accurately sense ambient conditions and adjust operation.

The compressor discharge temperature sensor (ThOD) is defective (open circuit resistance) or has a poor connection on the outdoor unit PCB. This can lead to incorrect discharge temperature monitoring, potentially causing compressor damage.

The high-pressure switch (B3H or 63H1) has tripped. This can be caused by a system overcharged with refrigerant, one or more service valves being shut, or insufficient airflow over the condenser coil, all leading to dangerously high system pressures.

The power transistor for the inverter has overheated, indicating excessive heat generation, potentially due to a fault or overload condition. This poses a risk to the inverter module's longevity.

Abnormally high current has been detected in the compressor, indicating a potential electrical or mechanical fault with the compressor, or system overload. This can lead to compressor failure if not addressed.

The maximum allowed number of indoor units connected to one outdoor unit has been exceeded, or an outdoor unit has reached its capacity limit. This leads to system communication issues and operational faults.

A transmission error has occurred between the inverter and the outdoor unit PCB, possibly due to a loose connection at the 'Cal' terminal. This disrupts critical communication and control signals.

There is a conflict of address settings, where a combination of automatic, manual, or remote control addresses coexist on the same network. This prevents proper system addressing and communication.

The inverter has detected an overvoltage condition, which could be due to an unstable power supply or a malfunction within the inverter itself. This protects the inverter components from damage.

There is a fault with the DC outdoor fan motor, which could prevent proper heat exchange in the outdoor unit. This leads to inefficient operation and potential system overheating.

This fault indicates a low pressure condition, low voltage detected within the system, or an inverter PCB fault. The manual lists these three distinct sub-causes for E49, any of which can lead to system malfunction.

The power transistor has overheated, indicating excessive heat generation, potentially due to a fault or overload condition. This protects the inverter from damage.

The suction pipe thermistor (Tho-S) is disconnected, which will prevent accurate temperature readings for the suction line. This compromises the system's ability to regulate superheat and optimize refrigerant flow.

This error indicates a disconnection or output error with either the low-pressure sensor (PSL) (E54-1) or the high-pressure sensor (PSH) (E54-2). This prevents accurate pressure monitoring, jeopardizing system safety and control.

The thermistor located under the compressor dome is disconnected, which will prevent critical temperature monitoring of the compressor shell. This can lead to undetected compressor overheating and failure.

The power transistor thermistor is faulty or disconnected (specific to FDCVA151-251 models), impacting temperature monitoring of the power transistors. This can lead to inverter damage from overheating.

This indicates a refrigerant leak or shortage of refrigerant (specific to FDCVA151-251 models), leading to insufficient cooling or heating performance. A low refrigerant charge can cause compressor overheating and damage.

The compressor has failed to start properly, which can be due to electrical issues, mechanical binding, or control problems. This prevents the system from generating cooling or heating capacity.

An error has occurred in detecting the compressor's rotational position, which is critical for proper inverter control. This can prevent the compressor from starting or running smoothly, leading to system shutdown.

The indoor unit has initiated an emergency stop, indicating a critical safety or operational fault. This requires immediate attention to prevent further damage or unsafe conditions.

The cumulative value of the electronic thermal O/L (overload) relay has reached 85% or higher of the Pr. 9 Electronic thermal O/L relay setting. This warning signifies that the motor or inverter is approaching an overload condition based on its thermal model. Continued operation without reducing the load could lead to an overload trip.

The external thermal relay connected to the OH signal has been activated. This indicates that the motor or connected equipment is experiencing an overload condition, potentially causing damage if not addressed. The inverter will not restart unless it is manually reset after the relay contacts return to normal.

This alarm indicates a problem with the inverter's cooling fan. It appears on the operation panel when the cooling fan stops due to an alarm condition or operates differently from the settings configured in Pr. 244 (Cooling fan operation selection). Insufficient cooling can lead to inverter overheating and potential damage to internal components.

The cooling fan is either at a standstill despite being required to operate, or its speed has decelerated significantly. This indicates a potential failure of the cooling fan, which is critical for dissipating heat from the inverter's internal components. Continued operation without proper cooling will lead to overheating and subsequent damage to the inverter.

The resistor of the inverter's inrush current limit circuit has overheated. This typically occurs due to frequent power cycling (ON/OFF) of the inverter, which causes the inrush current limiting components to work excessively, leading to thermal stress and potential failure. Overheating can degrade or destroy these components, preventing proper inverter startup.

The reset signal (RES signal) is ON, causing the inverter to immediately shut off its output. This indicates that a reset command has been issued, either manually through a control signal or automatically by the system, placing the inverter in a non-operational state.

The cumulative energization time has exceeded the value set in the maintenance output timer (Pr. 503 Maintenance timer). This is a warning indicating that routine scheduled maintenance is due based on operating hours. While not a fault that stops operation, ignoring it can lead to component degradation and potential future failures.

Parameter setting has been attempted in External or NET operation mode when Pr. 77 Parameter write selection is not '2', or when the command source is not the operation panel. This error prevents parameter changes under specific operating mode constraints, aiming to maintain system stability and prevent unintended modifications.

Operation has been attempted while the inverter's operation panel is locked. This is an error message preventing unintended changes or operations, but the inverter output is not shut off. It requires an unlock procedure to regain control of the panel.

The output current has exceeded the detection level set in a parameter. This functions as a protective measure to prevent overcurrent conditions that could damage the motor or the inverter's power components. Incorrect parameter settings can trigger this unnecessarily, or it could indicate an actual motor overload or short circuit condition.

The resistance of the PTC thermistor connected between terminal 2 and terminal 10 has reached or exceeded the Pr. 561 PTC thermistor protection level setting. This indicates an overheating condition, likely in the motor or associated equipment, which could lead to component damage if the load is not reduced.

A communication error has occurred between the PU (Parameter Unit) and the inverter, or the communication interval has exceeded the permissible time during RS-485 communication. This also triggers if the number of communication errors exceeds the retry limit. Loss of communication means the inverter cannot receive commands or send status, interrupting operation.

The 'STOP' button on the operation panel (PU) has been pressed during External operation mode. This warning indicates that the inverter has been commanded to stop via the parameter unit while in an external control mode. The inverter output is not shut off by this warning, but the operation will cease.

An abnormality has occurred in the component (control circuit board) where parameters are stored. This suggests a hardware issue with the inverter's non-volatile memory, potentially leading to incorrect operation, loss of critical settings, or failure to save new parameters. Frequent parameter writes for communication purposes can stress this component.

An attempt has been made to read or write a parameter that is restricted by a password. This security feature prevents unauthorized modification of critical settings, but the inverter output is not shut off. Access to protected parameters is denied until the correct password is entered.

The regenerative brake duty has reached 85% or higher of the Pr. 70 Special regenerative brake duty setting. This warning indicates that the regenerative braking capacity is approaching its limit. If deceleration demands continue to be high without sufficient energy dissipation (e.g., a braking resistor), it could lead to an overvoltage fault.

The inverter has failed to restart within the set number of retries after a preceding error or trip. This indicates a persistent underlying problem that the inverter's automatic recovery attempts could not resolve, requiring manual intervention to prevent further issues.

This alarm indicates that both safety input signals (S1 and S2) are in an open state, which triggers the safety stop function and causes the inverter output to shut off. This typically occurs as an intended safety action or due to a wiring issue, not an internal safety circuit fault.

The safety stop function has been activated, resulting in an immediate shutdown of the inverter outputs. This critical safety measure is typically triggered by an external safety device or a wiring issue across terminals S1 and SC, or S2 and SC, indicating an open circuit in the safety chain. If misconfigured or experiencing an internal failure, it can prevent normal operation or compromise machinery safety.

This fault occurs when the safety circuit input terminals (across S1 and PC, or across S2 and PC) are detected as open. This indicates a break in the safety loop, signaling a potentially unsafe condition and leading to inverter shutdown. It could be due to incorrect wiring, a fault in an external safety device, or an activated safety interlock.

The inverter's safety stop function has been activated, resulting in the immediate shutdown of outputs. This typically indicates that a safety condition has been detected by the system, often an open circuit on the safety input terminals (S1 and SC, S2 and SC), or potentially an internal failure if these inputs are correctly shorted and the drive remains enabled. This is a critical protective action.

The overcurrent stall prevention function has been activated. This warning indicates that the motor is encountering excessive current, possibly due to overload, insufficient acceleration time, improper torque boost settings, or mechanical binding. While a warning, prolonged activation can lead to motor or inverter damage.

The overvoltage stall prevention function has been activated, often during regeneration avoidance operation. This warning indicates that the DC bus voltage is exceeding safe limits, typically due to rapid deceleration or regenerative loads feeding energy back into the inverter. Sustained overvoltage can damage the inverter's internal components.

The voltage at the main circuit power supply has dropped below an acceptable operating level. This can be caused by issues in the incoming power supply line, insufficient capacity, or a fault within the power supply itself, leading to insufficient power for the inverter and potential damage if the voltage fluctuates excessively. The inverter output is shut off.

This error occurs when parameter writing is set to be disabled (via Pr. 77 Parameter write selection), when frequency jump ranges (Pr. 31 to Pr. 36) overlap, or when normal communication between the PU and inverter cannot be established. It prevents new parameter settings from being applied, potentially leading to incorrect operation if desired changes are not accepted.

Parameter writing has been attempted while the inverter is actively operating (STF/STR signal is ON) and Pr. 77 Parameter write selection is not set to '2'. This error prevents parameter changes from being applied while the motor is running, which could cause instability, unsafe conditions, or unexpected behavior if allowed.