Mitsubishi Heavy Industries · Air Conditioners
Error E55, indicated by one flash of the outdoor unit's red LED, means the compressor under dome thermistor is disconnected. This sensor monitors the compressor's temperature for safe operation.
Click steps to track your progress.
Turn off the main power supply to the outdoor unit.
Locate the compressor under dome thermistor connection to the outdoor PCB and verify it is secure.
Ensure the connector is free from physical damage or corrosion.
This sensor is typically internal to the compressor area and difficult for a user to access.
Contact a professional technician for inspection and re-connection or replacement of the thermistor.