8E — Ambient temperature thermistor (TH4) open/short

What does 8E mean?

This error indicates a problem with thermistor TH4, which measures the outdoor ambient temperature. The sensor or its wiring is either open (broken circuit) or shorted (incorrect resistance).

• Damaged ambient temperature thermistor (TH4).
• Loose or corroded thermistor connection.
• Faulty wiring leading to the thermistor.
• Thermistor physically damaged or obstructed.

Click steps to track your progress.

1. 1

   Turn off the main power to the outdoor unit by switching off its dedicated circuit breaker.

2. 2

   Locate thermistor TH4, typically exposed to ambient air, and inspect its wiring connections for damage or looseness.

3. 3

   Ensure the thermistor is not physically damaged or covered by debris.

4. 4

   Power cycle the unit by turning the breaker back on after inspection.

5. 5

   A service technician is usually required to test and replace the thermistor if it's malfunctioning.