ERROR CODE 3 High

Boiler Fault Code ERROR CODE 3

Also written as ERRORCODE3 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code ERROR CODE 3 appears across 1 boiler brand and 2 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 an issue with the air pressure or water flow sensors, preventing it from firing up for safety. (As reported on Ideal Icos HE)

Pick your boiler brand for the ERROR CODE 3 fix

Source

Information for the ERROR CODE 3 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