BoilerFaultCodes 2 03 Medium
Boiler Fault Code 2 03
Also written as 203 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 2 03 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 struggling to read the temperature of your hot water cylinder because a sensor connection has failed. (As reported on Chaffoteaux Talia Green System)
Pick your boiler brand for the 2 03 fix
Source
Information for the 2 03 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