BoilerFaultCodes 122 Medium
Boiler Fault Code 122
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 122 appears across 3 boiler brands 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's secondary heating zone is failing to reach the required temperature, likely because the system is struggling to circulate heat to a specific part of your home. (As reported on Navien NCM 1130HH)
Pick your boiler brand for the 122 fix
Source
Information for the 122 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