Flame indicator Low

Vaillant Flame indicator Fault Code

Also written as FLAMEINDICATOR — same fault.

The Vaillant Flame indicator fault code means: your boiler is working exactly as it should and has successfully lit the flame to heat your water or home.. 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: Illuminates as soon as the burner has ignited and the flame has been sensed.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vaillant models that show the Flame indicator fault code

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

Source

Vaillant Flame 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