BoilerFaultCodes E00-688 High
Boiler Fault Code E00-688
Also written as E00688 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code E00-688 appears across 2 boiler brands and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is failing to detect that water is moving through the system, which means it cannot safely turn on your heating or hot water. (As reported on Ideal Mini HE)
Pick your boiler brand for the E00-688 fix
Source
Information for the E00-688 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 31 August 2026