Low
S.04 on Vaillant ecoTEC exclusive

Your boiler is currently performing a routine self-test or measurement, which is a normal part of its operational cycle.

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 is ready for the measurement (Burner on - Heating mode).

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.03View →

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