Boiler Fault Code F0 (239)

Also written as F0239 — same fault.

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

Fault code F0 (239) appears across 1 boiler brand and 11 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's internal computer has suffered a critical failure and can no longer communicate with its own systems to safely run your heating or hot water. (As reported on Worcester Bosch Greenstar 12i System)