Low
S.04 on Vaillant Home System

Your boiler is working perfectly and is currently running specifically to provide heating for your radiators.

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

Display shows S.04 if the product is working correctly in heating mode.

DIY fix possible

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

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Related fault codes

S.03View →S.07View →S.08View →

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