sensor fault BT25 — Heat medium return external sensor not connected or defective

What does 25 mean?

The BT25 sensor, monitoring the external heating medium return, is not connected or defective. This will block any external additives.

• BT25 sensor is disconnected or has loose wiring.
• Faulty sensor unit.
• Wiring or connection issues with the external additive system.

Click steps to track your progress.

1. 1

   Power off the Heat Pump at the main breaker.

2. 2

   Inspect the BT25 sensor connections for security and any damage.

3. 3

   Verify that the external additive system is correctly installed and connected.

4. 4

   Restore power to the Heat Pump and check if the alarm is resolved.

5. 5

   If the alarm remains active, professional diagnosis may be necessary.