B.(1) High

Boiler Fault Code B.(1)

Also written as B1 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code B.(1) appears across 2 boiler brands 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 is failing to stay lit after you try to start it because the pilot light is going out as soon as you let go of the ignition button. (As reported on Potterton Kingfisher 2 RS60, RS80, RS100)

Pick your boiler brand for the B.(1) fix

Source

Information for the B.(1) 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