BoilerFaultCodes ALL 26 Low
Boiler Fault Code ALL 26
Also written as ALL26 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code ALL 26 appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's temperature sensor responsible for reading your solar water heating system is not working correctly, which may prevent your solar panels from contributing to your hot water supply. (As reported on Sime Murelle Elite HE 35T System)
Pick your boiler brand for the ALL 26 fix
Source
Information for the ALL 26 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 7 July 2026