E:01.20 Emergency

Baxi E:01.20 Fault Code

Also written as E0120 — same fault.

The Baxi E:01.20 fault code means: your boiler has detected that the gases escaping through your flue are getting dangerously hot, so it has automatically shut down to prevent damage.. It appears on 8 Baxi models 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: Maximum flue gas temperature reached (> 140 Deg C)
Typical repair cost £150-300 (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 E:01.20 fault code

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

Source

Baxi E:01.20 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