BoilerFaultCodes E01---204 High
Boiler Fault Code E01---204
Also written as E01204 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code E01---204 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 detected a problem with the internal part that heats your water, often caused by a blockage or a faulty sensor, meaning you will likely have no hot water. (As reported on Biasi Riva Compact 24S)
Pick your boiler brand for the E01---204 fix
Source
Information for the E01---204 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