th-21 — Room temperature sensor fault

What does th-21 mean?

The sensor measuring the room temperature is faulty. Set-point control by the thermostat will be stopped.

• Thermistor sensor is defective.
• Wiring to the sensor is damaged.
• Sensor connection is loose.
• Sensor is obstructed.

Click steps to track your progress.

1. 1

   Check the room temperature sensor and its wiring for damage or loose connections.

2. 2

   Ensure the sensor is not blocked by any objects.

3. 3

   Verify the sensor's readings or resistance.

4. 4

   Replace the sensor if it is defective.