How much does it cost to fix Protherm error code neon 2 not lit?

Typical repair cost for the Protherm neon 2 not lit fault is £90-180 including labour.

neon 2 not lit High

Protherm neon 2 not lit Fault Code

Q: What does the Protherm neon 2 not lit fault code mean?

Your boiler has shut down because it has detected it is getting too hot, likely triggered by a safety switch to prevent damage.

Also written as NEON2NOTLIT — same fault.

The Protherm neon 2 not lit fault code means: your boiler has shut down because it has detected it is getting too hot, likely triggered by a safety switch to prevent damage.. It appears on 1 Protherm model in our database.

Technical description: Overheat cut off device tripped or thermostat, overheat cut off device faulty

Typical repair cost £90-180 (including labour)

DIY fix possible

Turn off the power supply to the boiler.Allow the boiler to cool down completely for at least 20 minutes.Locate the reset button (usually behind the small plastic cover or on the control panel) and press it firmly.Restart the boiler and check if the radiators are bled of air.

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Protherm models that show the neon 2 not lit fault code

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

40-50 CI Repair: £90-180

Source

Protherm neon 2 not lit fault code information on this page is sourced and cross-checked against the official Protherm service / installation manuals for each affected model.

Protherm 40-50 CI manual (PDF)

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026