High
F.27 on Vaillant ecoTEC plus Aquaplus

Your boiler has detected an internal failure that is preventing it from safely starting the fuel supply to create heat.

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

No demand to gas valve | Electronic board defective; Gas valve defective

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.28View →F.29View →

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