BoilerFaultCodes L 09 High
Boiler Fault Code L 09
Also written as L09 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code L 09 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 has encountered a computer or electronic communication error and has locked itself out for safety. (As reported on Ideal Logic Max Combi 2)
Pick your boiler brand for the L 09 fix
Source
Information for the L 09 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