C53 Emergency

Baxi C53 Fault Code

The Baxi C53 fault code means: your boiler has detected an issue with how the flue pipe or ventilation is configured, preventing it from safely exhausting gases outside.. It appears on 1 Baxi model in our database.

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 Types
Typical repair cost £120-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Baxi models that show the C53 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Baxi C53 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026