Boiler displays F2 and shuts down shortly after ignition attempt
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Switch off power and isolate gas before opening the boiler. Gas work must comply with local regulations.
User-level checks:
- Confirm that other gas appliances in the property work correctly (to rule out a general gas supply issue).
- Ensure the boiler's gas isolation valve is fully open.
- Check that the condensate pipe is not frozen or blocked, as this can cause flame instability.
Technical checks (qualified engineer recommended):
- Inspect and clean the main burner on the Saunier Duval heat exchanger for debris or corrosion.
- Check the ionisation electrode position and wiring.
- Measure gas inlet and burner pressure and verify gas valve modulation using a manometer and manufacturer data.
- Test the gas valve coil resistance and replace the gas valve if out of specification.
Warning: Do not attempt to adjust gas valve settings yourself. Persistent F2 faults require a professional diagnosis.
Repair Difficulty
Required Part
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