Alarm 5209 - Temperature sensor TC1 fault

What does 5209 mean?

This alarm indicates a persistent failure of the heat carrier outlet sensor TC1. It is triggered after repeated errors or continuous open/short circuit conditions for 15 minutes, combining conditions for warnings 5207 and 5208.

• See possible causes for alarm codes 5207 and 5208 (Loose connection, broken or shorted sensor/cable, defective installer module).

Click steps to track your progress.

1. 1

   Note the alarm code 5209.

2. 2

   Contact a qualified Bosch Heat Pump installer or service technician.

3. 3

   The technician will inspect the sensor's connections and wiring, and replace the sensor or installer module if needed.