High
3 01 on Ariston Clas HE 35

Your boiler's main internal computer has developed a fault and is unable to communicate with the rest of the system, meaning the boiler will not function.

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

Internal P.C.B. error

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

3 02View →3 03View →3 04View →

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