Power on indicator Low

Vaillant Power on indicator Fault Code

Also written as POWERONINDICATOR — same fault.

The Vaillant Power on indicator fault code means: your boiler is receiving electrical power and is currently in its normal standby state, ready to provide heating or hot water when requested.. It appears on 3 Vaillant 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: Ensures that the power to the boiler is on and illuminated.

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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Vaillant models that show the Power on indicator fault code

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

Source

Vaillant Power on indicator 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 7 July 2026