i01 Low

Boiler Fault Code i01

Also written as I01 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code i01 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 not actually broken; this code simply indicates it is currently in standby mode and waiting for a signal to provide heating or hot water. (As reported on Worcester Bosch Greenstar 12i System)

Pick your boiler brand for the i01 fix

Worcester Bosch i01 1 model

Source

Information for the i01 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