BoilerFaultCodes 1-d1 Low
Boiler Fault Code 1-d1
Also written as 1D1 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 1-d1 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 Your boiler is reporting an issue with the solar panel temperature sensor, which usually means the system is detecting an unusual reading from your solar thermal panels. (As reported on Worcester Bosch Greenstar 8000 Life/Style)
Pick your boiler brand for the 1-d1 fix
Source
Information for the 1-d1 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