F.25 - Safety switch-off: Flue gas temperature too high

What does F.25 mean?

The boiler has performed a safety shutdown because the flue gas temperature became too high, indicating a potential issue with the flue system or its safety components.

• Break in the plug connection for the optional flue gas safety temperature limiter (STB).
• Break in the cable harness.

Click steps to track your progress.

1. 1

   Press the reset button on the boiler display up to three times to try and clear the fault.

2. 2

   Contact customer service immediately. This is a critical safety fault related to excessively high flue gas temperature.

3. 3

   A qualified technician will need to check the plug connection for the flue gas safety temperature limiter and the cable harness for integrity.