BoilerFaultCodesWhat the manual says
Manufacturer manualMains supply on PCB No.25B
What causes this fault?
This indicator is not a fault, but rather a normal status symbol showing that your boiler is successfully receiving electrical power from the mains supply. It indicates that the internal control board is live and ready to operate once there is a demand for heating or hot water. If the boiler isn't firing up, the issue lies with a different component or external control, as this light correctly confirms the power is on.
DIY fix possible
No action is required as this light simply confirms the boiler is switched onCheck other neon lights on the panel to see if a fault is indicated elsewhereIf the boiler is not firing, ensure the thermostat and timer are calling for heat
Avoid the next call-out bill
A cover plan would handle faults like Neon I3: no call-out fees, no surprise bills.
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Related fault codes
All 20 fault codes on the Classic FF 330
Seeing a different code? Every code this model can display, in one place.