High
F.68 on Vaillant ecoTEC plus Regular

Your boiler is struggling to maintain a steady flame, causing it to shut down for safety reasons to prevent unburnt gas from building up.

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

Unstable flame signal

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.61View →F.62View →F.67View →

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