High Lockout
UA-65 on Daikin D2CND

Your boiler's main control board is currently unable to communicate with its internal memory chip and needs a software or hardware synchronisation.

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

Printed circuit board (PCB) requires a boiler chip card (BCC) update

What causes this fault?

This fault occurs when the boiler's main control board loses its connection to the memory chip that holds the unit's specific configuration settings. It is often caused by a temporary data glitch, a loose connection on the circuit board, or the memory chip itself becoming faulty and unable to send instructions to the boiler.

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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