Emergency
E03 on Alpha CB24

Your boiler has detected an issue with the airflow or ventilation system, and for safety reasons, it has turned itself off to prevent harmful gases from escaping.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description

Flue thermostat or pressure switch fault

Engineer required

This is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

E02View →

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