4 1 1 High

Boiler Fault Code 4 1 1

Also written as 411 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 4 1 1 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's internal safety sensor, which monitors the combustion process, is failing to communicate with the control board, causing the system to lock out for safety reasons. (As reported on Ariston HS Premium)

Pick your boiler brand for the 4 1 1 fix

Source

Information for the 4 1 1 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