BoilerFaultCodes Fault 51 133 Low
Boiler Fault Code Fault 51 133
Also written as FAULT51133 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Fault 51 133 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 sensor has detected a communication issue with your solar heating system, meaning the solar panels aren't currently helping to heat your water. (As reported on Worcester Bosch Greenstar CDi Compact)
Pick your boiler brand for the Fault 51 133 fix
Source
Information for the Fault 51 133 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