F.24 - Safety switch-off: Temperature rise too fast

What does F.24 mean?

The boiler has performed a safety shutdown because the temperature in the system rose too quickly, indicating a circulation problem.

• The pump is blocked or has insufficient output.
• Air is present in the boiler or heating system.
• System pressure is too low.
• The non-return valve is blocked or incorrectly installed.

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

   Check the system pressure gauge and top up the system if it's too low, as per your boiler's user manual.

3. 3

   Bleed air from the heating installation and radiators if you suspect air is trapped in the system.

4. 4

   Contact customer service. This indicates a problem with water circulation, possibly due to a blocked pump, air, or a faulty non-return valve, requiring professional diagnosis.