Low
S.4 on Vaillant Atmomax

Your boiler is currently firing up to provide central heating and is functioning as normal.

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

Heat mode – burner on error

DIY fix possible

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

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Related fault codes

S.3View →S.7View →S.8View →

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