Boiler displays A07, no heating or hot water, fan may not start.

Safety: Turn off the boiler and do not attempt to operate it with a suspected flue fault. Risk of carbon monoxide exposure.

• Check flue terminal outside: Ensure the terminal is not blocked by vegetation, plastic bags, snow, or other obstructions.
• Visual inspection: Check that the flue is properly supported, not sagging, and that all joints appear secure. Do not dismantle room-sealed flues unless qualified.
• Technician – test fan operation: Verify that the fan starts and reaches correct speed. Replace the Beretta fan assembly if it fails to run or is noisy and slow.
• Technician – check flue thermostat/NTC: Measure resistance and continuity of the flue temperature sensor or thermostat. Replace if it trips prematurely or is open circuit.
• Flue system check: A Gas Safe engineer should inspect the entire flue route for blockages, incorrect slopes, or recirculation issues and rectify as required.