On Off Flash Unknown

Baxi On Off Flash Fault Code

Also written as ONOFFFLASH — same fault.

The Baxi On Off Flash fault code indicates a fault on your boiler. It appears on 2 Baxi models in our database.

Technical description: Live & Neutral Reversed. Incoming Live and Neutral reversed.

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 On Off Flash fault code

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

Source

Baxi On Off Flash 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