High
F.85 on Vaillant ecoTEC exclusive

Your boiler is confused because its temperature sensors have likely been swapped or placed on the wrong pipes during installation or a recent repair.

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

Fault:NTCsfittedincorrectly Theflowand/orreturntemperaturesensorshavebeeninstalledonthe samepipe/incorrectpipe

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.84View →

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