High
S.97 on Vaillant ecoTEC Plus 840

Your boiler is currently performing an internal health check on its sensors and has temporarily paused heating and hot water to ensure everything is functioning safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Automatic test programme: Water pressure sensor, heating and hot water request blocked.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.22View →F.73View →F.74View →

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