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

Typical repair cost for the boiler Slow flashes fault is £180-£450 including labour.

Slow flashes Emergency

Boiler Fault Code Slow flashes

Also written as SLOWFLASHES — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Slow flashes 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 still sensing a flame even though it has tried to shut off the gas, which is a safety concern that requires a professional inspection. (As reported on Worcester Bosch Greenstar 25CDi)

Pick your boiler brand for the Slow flashes fix

Worcester Bosch Slow flashes 1 model

Source

Information for the Slow flashes 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