Boiler locks out with code 01, burner does not ignite, red lockout light on control panel.

Safety first: Turn off electrical power to the boiler and close the gas isolation valve before removing any covers. Only a Gas Safe (or equivalent) registered engineer should work on gas-carrying components.

• Reset the boiler: Press the reset button as per the Biasi manual and observe if the boiler attempts ignition (you should hear the fan and clicking from the igniter).
• Check gas supply: Ensure the gas isolation valve under the boiler is open and other gas appliances in the property work correctly. If not, contact your gas supplier.
• Inspect ignition electrode: With power and gas off, remove the combustion chamber cover. Check the ignition electrode on the Biasi burner assembly for cracks, heavy carbon deposits, or damage. Clean gently with fine emery cloth and ensure the ceramic is intact.
• Check electrode gap and position: Compare the electrode position and gap to the Biasi service manual. The tips must be correctly aligned over the burner for reliable ignition.
• Inspect ionisation (flame) electrode: Clean the probe, check the cable and connection back to the PCB for signs of burning or loose terminals.
• Gas valve operation (engineer only): A qualified engineer should verify that the gas valve coil is energised during ignition and that inlet and burner pressures match Biasi specifications.
• If lockouts persist: Do not keep resetting. Contact a qualified boiler engineer to test ignition components, gas valve, and PCB.