BoilerFaultCodesUnical Lp Fault Code
Also written as LP — same fault.
The Unical Lp fault code means: your boiler has detected that the water pressure is too low to operate safely, causing it to shut down to prevent damage.. It appears on 2 Unical models in our database.
Technical description: Water deficiency pressure switch
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath your boiler.Slowly open the small valve(s) to allow water into the system.Watch the pressure gauge and close the valve(s) once it reaches 1.5 bar.The fault code should disappear, allowing the boiler to restart.
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Unical models that show the Lp fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Unical Lp fault code information on this page is sourced and cross-checked against the official Unical service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026