How much does it cost to fix boiler error code 301?

Typical repair cost for the boiler 301 fault is £150-350 including labour.

301 Emergency

Boiler Fault Code 301

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code 301 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has automatically shut down because the internal engine head has reached an dangerously high temperature. (As reported on Navien NCM 1130HH)

Pick your boiler brand for the 301 fix

Navien 301 1 model

Source

Information for the 301 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 31 August 2026