Neon I3 Low

Ideal Neon I3 Fault Code

Also written as NEONI3 — same fault.

The Ideal Neon I3 fault code means: your boiler is receiving power and is in standby mode, waiting for a signal to provide heating or hot water.. It appears on 14 Ideal models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Mains electricity ON.

What causes the Ideal Neon I3 fault?

This is not actually a fault, but a status indicator showing that your boiler has successfully connected to the mains power supply and is functioning correctly. It means the system is currently in standby mode, simply waiting for your thermostat or programmer to tell it to start heating the radiators or water. If your home is cold while this is displayed, the issue is likely with your external controls or pump rather than the boiler itself.

DIY fix possible

Check that your room thermostat is turned up high enough to demand heatEnsure your programmer or digital timer is set to 'ON' or 'AUTO'Verify that the boiler's temperature control knob is not set to the 'Off' position

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

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 27 April 2026