Low
Neon I3 on Ideal Mexico Super 100FF / 125FF

Your boiler is receiving electrical power, and this light is simply a normal indicator that the mains switch is turned on.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Mains electricity ON

From this model's manual
Verified against the Ideal Mexico Super 100ff 125ff System 3 installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This indicator is not actually a fault, but a status light confirming that the boiler is successfully connected to your home's electrical supply. It stays illuminated as long as the mains power switch is in the 'on' position and the internal fuse is intact. If this light is off, it typically means there is a power cut, a tripped circuit breaker, or a blown fuse.

DIY fix possible

No action is required as this is a status light, not a fault code.If the boiler is not working despite the light being on, check that the thermostat is turned up.Ensure the programmer is set to 'On' or 'Auto'.

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