BoilerFaultCodes 68 H......4....... High
Boiler Fault Code 68 H......4.......
Also written as 68H4 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 68 H......4....... 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 that a sensor monitoring the temperature of the exhaust gases is not working correctly, causing the system to shut down for safety. (As reported on Ideal Isar M30 / M100)
Pick your boiler brand for the 68 H......4....... fix
Source
Information for the 68 H......4....... 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