Medium
F.84 on Vaillant ecoTEC plus System

Your boiler has detected an inconsistent temperature reading between the pipes, suggesting it is struggling to accurately measure how well water is circulating through your heating system.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Fault: Flow/return temperature sensor difference implausible

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.83View →F.22View →

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