Fault 40 102 High
Boiler Fault Code Fault 40 102
Also written as FAULT40102 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Fault 40 102 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 lost connection with a temperature sensor, which means it cannot accurately monitor the water temperature to operate safely. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the Fault 40 102 fix
Source
Information for the Fault 40 102 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