40 50 60 80 Medium

Boiler Fault Code 40 50 60 80

Also written as 40506080 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 40 50 60 80 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 is struggling to switch between heating your radiators and providing hot water, which may cause your taps to run cold or your heating to stay on constantly. (As reported on Chaffoteaux Serelia 24 MFFI)

Pick your boiler brand for the 40 50 60 80 fix

Source

Information for the 40 50 60 80 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