High
F.11 on Vaillant ecoTEC plus Aquaplus

Your boiler has detected an electrical fault with one of its temperature sensors, meaning it cannot accurately monitor the water returning to the system and has shut down as a precaution.

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

Short circuit - return-NTC (<130 °C) | NTC-plug shorted to casing, NTC 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.10View →F.12View →

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