How much does it cost to fix boiler error code LOCKOUT: b?

Typical repair cost for the boiler LOCKOUT: b fault is £120-350 including labour.

LOCKOUT: b High

Boiler Fault Code LOCKOUT: b

Also written as LOCKOUTB — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code LOCKOUT: b appears across 1 boiler brand 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 switched itself off because it has gotten too hot, likely due to a blockage or a pump issue stopping the water from circulating. (As reported on Potterton Housewarmer)

Pick your boiler brand for the LOCKOUT: b fix

Potterton LOCKOUT: b 2 models

Source

Information for the LOCKOUT: b 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