High
28 on Ariston Clas HE 35

Your boiler has detected an issue with the sensor that tracks the temperature of the water circulating through your radiators, causing the system to stop heating safely.

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

Heating temperature indicator and diagnostic indicator

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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