Fault F2 (Detailed 129) — Burner fault: fixed high limit switch open

What does F2 mean?

The burner is in fault mode because the fixed high limit switch has opened (activated). This safety switch trips when the boiler's internal temperature becomes excessively high, preventing damage.

• Fixed high limit switch open (activated)

Click steps to track your progress.

1. 1

   Check the heating system fill level and add water if necessary.

2. 2

   Check the circulation pump to ensure it is running and circulating water effectively.

3. 3

   Bleed air from the heating system to release any trapped air.

4. 4

   Inspect the fixed high limit switch and its connecting cables for any visible damage or loose connections.

5. 5

   Press the reset button R on your boiler.