06 High

Baxi 06 Fault Code

The Baxi 06 fault code means: your boiler has detected that the water returning from your radiators is either too hot or is not flowing correctly through the system.. It appears on 3 Baxi models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: CH Return Temperature
Typical repair cost £90-180 (including labour)

DIY fix possible

Check that all radiator valves (TRVs) are fully openEnsure there are no blockages or clothes covering your radiatorsCheck that your central heating filters are clean, if accessible

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Baxi models that show the 06 fault code

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

Source

Baxi 06 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