BoilerFaultCodes 7 8 High
Boiler Fault Code 7 8
Also written as 78 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 7 8 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 is having trouble detecting the temperature of a key internal cooling component, which means it cannot operate safely and has shut down to protect itself. (As reported on Ideal Logic Air)
Pick your boiler brand for the 7 8 fix
Source
Information for the 7 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 7 July 2026