Your boiler is working normally and is currently heating your home or water as requested.
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: Heating demand on boiler is OK
What causes this fault?
This is a status indicator rather than a fault, occurring when the boiler receives a signal from your thermostat or hot water tap to start heating. It confirms that the internal components are functioning correctly and that there is an active demand for energy in your home. There is no underlying issue to fix, as the light simply confirms the system is performing its job as intended.
This indicator is most frequently seen during autumn and winter when the central heating is used daily to maintain a comfortable temperature.
DIY fix possible
No action is required as this is a status indicator, not a fault.If the light is on but your radiators are cold, check that your room thermostat is turned up.Ensure your programmer or timer is set to an 'on' period.
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