BoilerFaultCodes 5 pulses Low
Boiler Fault Code 5 pulses
Also written as 5PULSES — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 5 pulses appears across 1 boiler brand and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has been left in its internal testing mode, which is usually only used by engineers during a service or setup. (As reported on Worcester Bosch Greenstar 12Ri)
Pick your boiler brand for the 5 pulses fix
Source
Information for the 5 pulses 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