BoilerFaultCodes 51123 Low
Boiler Fault Code 51123
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 51123 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning The system has detected that the wrong type of temperature sensor has been installed for your solar heating circuit. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the 51123 fix
Source
Information for the 51123 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