Mitsubishi Electric · City Multi Air Conditioning Systems
This fault signals an issue with the indoor unit's pipe temperature sensor (TH22). A defective thermistor or a connection problem can cause this, resulting in inaccurate pipe temperature readings.
Click steps to track your progress.
Turn off the power to the indoor unit at the circuit breaker.
Check the connector for the TH22 thermistor on the indoor unit to ensure it is securely connected.
Visually inspect the thermistor's lead wire for any visible damage.
Restore power to the unit. If the error persists, note the ambient temperature.
A technician would typically check the thermistor resistance at different temperatures (e.g., 0°C, 10°C, 20°C, 30°C, 40°C) against specified values (15kΩ, 9.7kΩ, 6.4kΩ, 4.3kΩ, 3.1kΩ respectively).