High
C2 on Keston System S40

Your boiler's computer memory card has failed or is unreadable, meaning the system cannot talk to its internal controls to operate.

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) 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

C0View →L2View →

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