Medium
S.33 on Vaillant ecoTEC sustain

Your boiler is currently performing a safety check on its internal airflow system and is waiting for a pressure sensor to confirm it is safe to ignite.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Forced fan operation until the pressure monitor is switched

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.33View →F.32View →

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