StBY Low

Boiler Fault Code StBY

Also written as STBY — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code StBY appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is currently in standby mode and is working exactly as it should, waiting for a signal from your thermostat or hot water tap to start operating. (As reported on Atag Q 30CR)

Pick your boiler brand for the StBY fix

Atag StBY 3 models

Source

Information for the StBY 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