How much does it cost to fix boiler error code 429?

Typical repair cost for the boiler 429 fault is £120-250 including labour.

429 Emergency

Boiler Fault Code 429

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code 429 appears across 2 boiler brands 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 has detected that the water pressure inside the system is dangerously high, which has triggered a safety shutdown to prevent internal damage. (As reported on ECA FELiS FL 50 HM)

Pick your boiler brand for the 429 fix

ECA 429 1 model Grant 429 1 model

Source

Information for the 429 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