Boiler will not ignite, display shows fault code 01, no heating or hot water

Safety first: Turn off the boiler and isolate the electrical supply at the fused spur. Close the gas isolation valve before removing any covers. Only Gas Safe registered engineers should work on gas-carrying components.

• Reset the boiler: Press the reset button as per the Vokera manual and observe if the boiler attempts ignition. Listen for the spark and gas valve click.
• Check gas supply: Ensure the gas isolation valve under the boiler is open and other gas appliances (e.g. hob) work correctly. If not, contact your gas supplier.
• Inspect flue terminal: From outside, make sure the flue is not blocked by debris, snow, or vegetation, which can affect combustion.
• Check condensate pipe: In cold weather, ensure the external condensate pipe is not frozen. Thaw gently with warm (not boiling) water if frozen.
• Engineer checks (do not DIY):
  • Remove the combustion chamber cover and inspect the ignition electrode and flame sensor for cracks, damage, or heavy oxidation. Clean gently with fine emery paper if lightly sooted.
  • Check electrode leads for secure connections to the PCB and no insulation damage.
  • Verify gas valve operation and inlet pressure with a manometer according to Vokera specifications.
  • Clean burner and injectors if blocked or heavily sooted.

If the fault persists after basic checks and reset, contact a Gas Safe engineer to test ignition components and gas valve.