BoilerFaultCodesIdeal Neon I3 Fault Code
Also written as NEONI3 — same fault.
The Ideal Neon I3 fault code means: your boiler has electrical power and is currently functioning normally, as this light simply indicates the mains power is switched on.. It appears on 7 Ideal models in our database.
Technical description: Mains electricity ON.
What causes the Ideal Neon I3 fault?
This is not a fault, but rather a status indicator showing that the boiler is successfully receiving electrical power from your mains supply. It confirms that the internal circuitry is live and the unit is ready to operate when there is a demand for heating or hot water. If the boiler isn't firing despite this light being on, the issue likely lies with your external thermostat or a different internal component.
DIY fix possible
Check if other control lights are flashing to indicate a real faultEnsure your room thermostat is turned up to call for heatNo action is required if the boiler is providing heating and hot water
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Ideal models that show the Neon I3 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal Neon I3 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026