How much does it cost to fix boiler error code 426?

Typical repair cost for the boiler 426 fault is £150-300 including labour.

426 High

Boiler Fault Code 426

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 426 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 is struggling to detect that the flue system is properly open, which prevents it from safely venting gases. (As reported on ECA FELiS FL 50 HM)

Pick your boiler brand for the 426 fix

ECA 426 1 model

Source

Information for the 426 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