Mitsubishi Electric PWFY Air Conditioners

This error indicates a serial communication failure between the main control board and the inverter (INV) board, specifically identified by detail code 01. This disrupts critical communication needed for compressor operation.

The unit detects a discharge temperature of 115°C (239°F) or higher multiple times (three detections within 30 minutes), leading to an abnormal stop. A preliminary error code will appear on the LED.

When the compressor starts from Stop Mode, if low pressure reads 0.098 MPa (14 psi) immediately before start-up, the operation stops. This indicates a problem with low pressure in the system.

The unit detects a pressure of 3.23 MPa (468 psi) or higher multiple times (three detections within 30 minutes) during operation, leading to an abnormal stop. A preliminary error code may appear on the LED for 30 minutes after each stoppage.

If a pressure of 0.098 MPa (14 psi) or lower is registered on the pressure sensor immediately before startup, it will trigger an abnormal stop, and error code '1302' will be displayed. This indicates an issue with low pressure impacting the high-pressure system.

The unit's flow switch has detected that the water flow rate to the unit is at or below the specified minimum, causing the unit to stop operation. This indicates insufficient water circulation.

The thermistor TH6, which monitors water temperature (inlet for BU), has detected a temperature of 85°C (185°F) or greater. This high temperature causes the unit to stop and enter a 3-minute restart delay mode.

The system detects conditions indicating that the water-source heat exchanger is freezing. This error is critical and requires immediate corrective action to prevent damage to the heat exchanger, refrigerant piping, or surrounding property. A normal power reset will not clear this error in newer versions (Ver 1.24 and later).

The system cannot determine the power frequency when the power is switched on. This indicates an issue with the power supply or related electrical components, such as wiring, coils, or the noise filter.

An error is detected in the PWM (Pulse Width Modulation) circuit on the INV (Inverter) board. This can lead to PAM (Pulse Amplitude Modulation) damage and usually requires replacing the INV board.

A DC bus voltage of 200V or less is detected during inverter operation. This can be caused by power supply environment issues, a voltage drop within the system, or faults in the noise filter or INV board.

The inverter detects a DC bus voltage of 380V or higher during operation. This often indicates an incorrect power supply voltage connection or an internal issue with the INV board.

An error is detected within the converter circuit on the INV (Inverter) board. This indicates a critical internal hardware fault, typically requiring the replacement of the INV board.

An overcurrent condition is detected while the power module error detection signal is output. This indicates a problem within the inverter's intelligent power module, often due to wiring issues, compressor failure, or the INV board itself.

An overcurrent of 34.5Apeak or 16Arms or above is detected by the ACCT sensor. This indicates a significant electrical overload, potentially from incorrect wiring, fan issues, compressor failure, or a fault with the INV board.

The unit has detected an issue with one of its temperature sensors (thermistor), indicating either a short circuit (very high temperature reading) or an open circuit (very low temperature reading). The specific code (e.g., 5102, 5103) indicates which sensor (TH22, TH13, TH23, TH11, TH6, TH8) is affected.

This error code indicates a detected issue with the heat sink temperature sensor (THHS). This could be due to a short circuit (indicating a high temperature) or an open circuit (indicating a low temperature), typically occurring either before or during the inverter's operation.

The unit's high pressure sensor (63HS) is detecting a pressure of 0.098MPa (14psi) or less during operation. This triggers an error stop and an anti-restart mode to protect the system.

The system detects an abnormal reading from the low-pressure sensor (4.06 MPa / 589 psi or above). The unit may continue operating by using other sensors as a backup, but this indicates a potential issue.

The system detects that the output current remains below 1.5 Arms for 10 seconds while the inverter is in operation. This indicates a problem with the ACCT sensor or inverter components.

An abnormal value is detected by the ACCT sensor detection circuit immediately before the inverter starts. This suggests an issue with the sensor, its wiring, or the compressor itself.

The self-diagnosis LED displays error code 7102, signaling a problem with the M-NET transmission line, which facilitates communication between system components. This error can stem from a short circuit or improper wiring.

The remote controller continuously displays "HO" or "PLEASE WAIT" and the air conditioning unit does not operate. This message should typically clear within 5 minutes after the unit is powered on.

The remote controller screen remains blank, and the air conditioning unit does not power on or respond to any commands. The power indicator light also fails to illuminate.