How much does it cost to fix boiler error code BURNER Slow flash?

Typical repair cost for the boiler BURNER Slow flash fault is £250-450 including labour.

BURNER Slow flash High

Boiler Fault Code BURNER Slow flash

Also written as BURNERSLOWFLASH — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code BURNER Slow flash appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's electronic control brain is experiencing a internal fault and is unable to safely ignite the burner. (As reported on Grant Vortex Eco)

Pick your boiler brand for the BURNER Slow flash fix

Grant BURNER Slow flash 5 models

Source

Information for the BURNER Slow flash 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