BoilerFaultCodes 129 High
Boiler Fault Code 129
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 129 appears across 1 boiler brand and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has stopped working because the fan responsible for moving air and removing exhaust gases inside the unit failed to start. (As reported on Atag Q 25CR)
Pick your boiler brand for the 129 fix
Source
Information for the 129 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