BoilerFaultCodes 65 L....8..... High
Boiler Fault Code 65 L....8.....
Also written as 65L8 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 65 L....8..... 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 a problem with the fan that safely removes exhaust gases, meaning it will not fire up for heating or hot water until it is repaired. (As reported on Ideal Isar M30 / M100)
Pick your boiler brand for the 65 L....8..... fix
Source
Information for the 65 L....8..... 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