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

What does F.24 mean?

The boiler has shut down because the temperature of the water is rising too rapidly. This indicates a problem with water circulation or flow within the system.

• Circulation pump is blocked or performing poorly.
• Air trapped within the boiler or heating system.
• System pressure is too low, impeding proper water flow.
• Non-return valve is blocked or incorrectly installed.

Click steps to track your progress.

1. 1

   Check the boiler pressure and top up the water if it is below 1.0 bar.

2. 2

   Bleed air from your radiators and heating system to ensure good water flow.

3. 3

   Press the fault clearance key on the boiler to reset it. If the fault reoccurs, contact Vaillant Service Solutions.