High Lockout
A12 on Vokera Condexa Pro

Your boiler's computer memory has encountered a software error and can no longer communicate correctly with the main control board.

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

Incorrect EEPROM signature

What causes this fault?

This fault occurs when the boiler's internal memory chip loses its identity or fails to share the correct security handshake with the main control board. The most common reason is a physical failure of the memory component on the circuit board, often caused by an electrical surge or simple component degradation over time. Because the boiler no longer knows its own operating parameters, it shuts down as a safety precaution.

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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