BoilerFaultCodes nF1 High
Boiler Fault Code nF1
Also written as NF1 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code nF1 appears across 1 boiler brand and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected trapped air inside it which is preventing it from starting up safely. (As reported on Viessmann Vitodens 200)
Pick your boiler brand for the nF1 fix
Source
Information for the nF1 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