U3 - Discharge thermistor short/open in outdoor unit

What does U3 mean?

This error indicates that the discharge thermistor in the outdoor unit is either short-circuited or has an open circuit, leading to incorrect temperature readings.

• Faulty discharge thermistor sensor.
• Loose or damaged wiring to the discharge thermistor.
• Corrosion or poor connection at the sensor terminal.

Click steps to track your progress.

1. 1

   Turn off the main power supply to the air conditioning system at the circuit breaker.

2. 2

   A qualified technician should inspect the discharge thermistor and its wiring in the outdoor unit.

3. 3

   The technician will check the resistance of the thermistor and the integrity of its connections.

4. 4

   If the thermistor is faulty, it will need replacement by a professional.