Boiler does not ignite, display shows A01, no flame symbol, heating and hot water unavailable.

Safety first: Turn the boiler off at the control panel and isolate electrical power at the fused spur. Close the gas isolation valve before removing any covers. Only a Gas Safe (or equivalent) registered technician should work on gas components.

• Check gas supply: Ensure other gas appliances work. Verify the boiler's gas isolation valve under the unit is fully open (handle in-line with the pipe).
• Reset the boiler: Follow the Beretta user manual to perform a reset (usually press and hold the reset button for a few seconds). Observe if the boiler attempts ignition.
• Inspect flue and air intake: From outside, check that the flue terminal is not blocked by debris, snow, or nests. Do not insert objects into the flue.
• Check system pressure: Confirm the pressure gauge is typically between 1.0–1.5 bar when cold. If low, top up via the filling loop according to the manual, then reset and test.
• Electrode inspection (technician): Remove the combustion chamber cover. Inspect the ignition and ionisation electrodes for cracks, carbon build-up, or incorrect gap. Clean with fine emery cloth and refit or replace as needed.
• Gas valve check (technician): Verify the Beretta gas valve receives power during ignition and that inlet gas pressure and burner pressure are within specification. Adjust or replace the gas valve if faulty.