Medium
E321 on Baxi Suprima 40

Your boiler is struggling to accurately measure the temperature of the water being heated for your taps, which usually means a sensor has failed.

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

Hot water negative temperature coefficient (NTC) fault.

Engineer required

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

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Related fault codes

E125View →E131View →E193View →

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