Power on indicator (green) Low

Vaillant Power on indicator (green) Fault Code

Also written as POWERONINDICATORGREEN — same fault.

The Vaillant Power on indicator (green) fault code means: your boiler is receiving power and is currently switched on, which is the normal state for the unit to be in.. It appears on 1 Vaillant model 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: Illuminates when the electricity supply to the boiler is on, the main on/off control is set to position (I) and the internal boiler fuses are o.k.

DIY fix possible

No action is required as this simply confirms the boiler has electricity.If you have no heating or hot water, check your programmer or thermostat settings instead.

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Vaillant models that show the Power on indicator (green) fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vaillant Power on indicator (green) fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026