LP Low

Boiler Fault Code LP

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code LP appears across 3 boiler brands and 7 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 manually set to a special testing mode used by engineers to check its performance, rather than operating in its normal heating mode. (As reported on Biasi Concept 400 20 1 Mfs)

Pick your boiler brand for the LP fix

Biasi LP 4 models Johnson Starley LP 1 model Unical LP 2 models

Source

Information for the LP 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 31 August 2026