Boiler Fault Code 239 / F0

Also written as 239F0 — same fault.

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

Fault code 239 / F0 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's internal computer has detected a potential communication error with its safety circuits and has shut down to prevent unsafe operation. (As reported on Worcester Bosch Greenstar CDi Compact)