Medium
FE96 on Alpha FMK

Your boiler is struggling to accurately measure the temperature outside, which can cause your heating to behave unpredictably or stop working altogether.

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

External sensor fault

Engineer required

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

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