Boiler Fault Code F0 (242 - 256)

Also written as F0242256 — same fault.

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

Fault code F0 (242 - 256) appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's main electronic brain is failing to communicate properly, which means it has safely shut itself down to prevent further damage. (As reported on Worcester Bosch Greenstar 12i System)