Low
S.22 on Vaillant Home System

Your boiler is simply preparing to heat your hot water and is performing a quick internal check before it starts.

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

Hot water handling mode: Pump pre-run

DIY fix possible

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

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Related fault codes

S.20View →S.24View →

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