Low
S.09 on Vaillant ecoTEC exclusive

Your boiler is currently performing a routine self-check to ensure it is burning fuel efficiently, and this usually only lasts for a few moments.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Product starts by fully calibrating the combustion regulation.

Engineer required

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

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Related fault codes

S.00View →S.02View →S.04View →

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