A12 High

Vokera A12 Fault Code

The Vokera A12 fault code means: your boiler's computer memory has encountered a software error and can no longer communicate correctly with the main control board.. It appears on 1 Vokera model in our database.

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 the Vokera A12 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.

Typical repair cost £220-450 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vokera models that show the A12 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vokera A12 fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026