BoilerFaultCodes 615 High
Boiler Fault Code 615
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 615 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's fan is failing to run correctly, which prevents it from safely venting gases, so the system has shut down to protect your home. (As reported on Navien NCB H)
Pick your boiler brand for the 615 fix
Source
Information for the 615 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