Low
S.21 on Vaillant ecoTEC plus Aquaplus

Your boiler is currently heating up the internal hot water storage tank, which is a normal part of its operation.

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

Fan running (store charging)

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.20View →

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