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

Safety first: Turn the boiler off with the main switch and, if you smell gas, close the gas isolation valve and ventilate the room. Do not use open flames or operate electrical switches. Contact your gas supplier or a qualified technician immediately.

Basic checks you can do:

• Check gas supply: Ensure the gas isolation valve under the Fondital boiler is fully open (handle in line with the pipe). Confirm other gas appliances (e.g. hob) work normally.
• Reset the boiler: Use the reset button or control knob as described in the Fondital user manual. Wait a few seconds and see if the boiler attempts ignition again.
• Check for air in gas line: After a gas interruption, several ignition attempts may be needed to purge air. Reset 2–3 times only; if A01 persists, stop and call a technician.
• Visual inspection (without opening sealed chamber): Through the inspection window (if present), check whether you see sparking during ignition. No spark suggests an ignition electrode or PCB issue.

Work for a qualified technician:

• Measure gas inlet and burner pressure and adjust or replace the Fondital gas valve assembly if out of specification.
• Inspect, clean, or replace the ignition electrode and cable and the flame detection electrode; check correct gap and positioning relative to the burner.
• Check wiring harness between electrodes, gas valve, and Fondital main control PCB for damage or loose connectors.
• Verify correct polarity and earth on the mains supply; incorrect polarity can prevent flame detection.