How much does it cost to fix Baxi error code Overheat Neon Illumination?

Typical repair cost for the Baxi Overheat Neon Illumination fault is £90-250 including labour.

Overheat Neon Illumination High

Baxi Overheat Neon Illumination Fault Code

Q: What does the Baxi Overheat Neon Illumination fault code mean?

Your boiler has switched itself off because it has reached a temperature that is too high, and it needs to be manually reset once it has cooled down.

Also written as OVERHEATNEONILLUMINATION — same fault.

The Baxi Overheat Neon Illumination fault code means: your boiler has switched itself off because it has reached a temperature that is too high, and it needs to be manually reset once it has cooled down.. It appears on 3 Baxi models in our database.

Technical description: Cut-out is indicated by illumination of the neon light on the control box. The overheat cut-off device is of the manual reset type.

Typical repair cost £90-250 (including labour)

DIY fix possible

Wait for the boiler to cool down completelyLocate the reset button on the control box under the boilerPress the reset button and check if the neon light goes out and the boiler restarts

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Baxi models that show the Overheat Neon Illumination fault code

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

Source

Baxi Overheat Neon Illumination 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