How much does it cost to fix Baxi error code Lights: On, Flash, Flash?

Typical repair cost for the Baxi Lights: On, Flash, Flash fault is £120-350 including labour.

Lights: On, Flash, Flash High

Baxi Lights: On, Flash, Flash Fault Code

Q: What does the Baxi Lights: On, Flash, Flash fault code mean?

Your boiler has detected that it is heating up internally without enough water flowing through it, causing it to shut down to prevent damage.

Also written as LIGHTSONFLASHFLASH — same fault.

The Baxi Lights: On, Flash, Flash fault code means: your boiler has detected that it is heating up internally without enough water flowing through it, causing it to shut down to prevent damage.. It appears on 2 Baxi models in our database.

Technical description: Go to Dry-Fire section of the fault finding instructions.

Typical repair cost £120-350 (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 Lights: On, Flash, Flash fault code

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

Source

Baxi Lights: On, Flash, 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 27 April 2026