How much does it cost to fix boiler error code A12?

Typical repair cost for the boiler A12 fault is £220-450 including labour.

A12 High

Boiler Fault Code A12

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code A12 appears across 2 boiler brands and 10 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's computer memory has encountered a software error and can no longer communicate correctly with the main control board. (As reported on Vokera Condexa Pro)

Pick your boiler brand for the A12 fix

Ariston A12 9 models Vokera A12 1 model

Source

Information for the A12 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

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