F.24
Temperature rises too quickly
The boiler has detected an abnormally rapid increase in water temperature.
What this code means
The boiler has detected an abnormally rapid increase in water temperature.
Possible causes
- Air in boiler
- Low system pressure
- Poor circulation
- Pump, valve or blockage problem
- Temperature sensor fault
Common symptoms
- F.24 displayed
- Boiler may shut down or lock out
- Heating may stop
Checks to make
- Check displayed system pressure
- If pressure is low, follow the appliance user instructions if competent
- Arrange heating-engineer diagnosis if the code remains
Safety
- Do not access internal boiler components. Gas and combustion work must be carried out by appropriately qualified personnel.
Model notes
Vaillant links this fault mainly with circulation, pressure and sensing issues.