High
E04 on Ariston Clas One

Your boiler is struggling to accurately measure the temperature of the hot water it produces because a sensor is not communicating correctly.

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

Domestic Hot Water temperature probe fault (N.T.C. open or short circuit)

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

E05View →

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