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

Typical repair cost for the boiler BLOCK fault is £90-350 including labour.

BLOCK High

Boiler Fault Code BLOCK

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code BLOCK appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has encountered an unknown internal error and has shut down as a safety precaution to prevent damage. (As reported on Unical Alkon R 28 HE)

Pick your boiler brand for the BLOCK fix

Unical BLOCK 2 models

Source

Information for the BLOCK 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 7 July 2026