How much does it cost to fix boiler error code Lt?

Typical repair cost for the boiler Lt fault is £150-250 including labour.

Lt High

Boiler Fault Code Lt

Also written as LT — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Lt appears across 2 boiler brands and 3 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 detect that you have turned on a hot tap, so it is not heating the water for your shower or kitchen faucet. (As reported on Baxi 130 HE (range))

Pick your boiler brand for the Lt fix

Baxi Lt 1 model Johnson Starley Lt 2 models

Source

Information for the Lt 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