FLASH OFF ON High

Baxi FLASH OFF ON Fault Code

Also written as FLASHOFFON — same fault.

The Baxi FLASH OFF ON fault code means: your boiler has become too hot and has automatically shut down to protect itself.. It appears on 2 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: Overheat lockout
Typical repair cost £120-350 (including labour)

DIY fix possible

Locate the reset button on the front control panel.Press and hold the reset button for at least 5 seconds.Ensure your radiator valves are open and your system pressure is adequate if a gauge is visible.

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Baxi models that show the FLASH OFF ON fault code

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

Source

Baxi FLASH OFF ON 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 31 August 2026