Blocking fault 1/a/ (3/1/6) - Flue gas sensor temperature too high

What does 1/a/ mean?

The flue gas sensor has detected an excessively high temperature in the exhaust gases. This is a safety measure to prevent damage to the boiler. No heating operation or domestic hot water (DHW) will be available until the fault is cleared.

• High flue gas temperature
• Potential blockage in the flue system
• sensor malfunction

Click steps to track your progress.

1. 1

   Press the 'Reset' button on the BC10 basic controller to attempt a restart.

2. 2

   Check that the flue terminal outside the building is clear of obstructions like debris or bird nests.

3. 3

   If the fault reoccurs, contact a qualified service technician for an inspection of the flue system and sensor.