BoilerFaultCodes D1240 High
Boiler Fault Code D1240
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D1240 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 detected an electrical fault with the internal sensor that monitors the water returning to the unit, causing it to shut down to prevent damage. (As reported on Worcester Bosch GB162)
Pick your boiler brand for the D1240 fix
Source
Information for the D1240 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