High
C0 on Keston System S40

Your boiler's internal memory chip hasn't activated correctly, meaning the central control unit doesn't recognize which model it is supposed to be operating.

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

Boiler Chip Card (BCC) activation fault

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

C2View →F9View →

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