BoilerFaultCodesUnical 8 Fault Code
The Unical 8 fault code means: your boiler has stopped working because the water pressure is too low for it to operate safely.. It appears on 2 Unical models in our database.
Technical description: wATER DEFICIENCY Insufficient water pressure and consequent intervention of the minimum water pressure - pressure switch ( 13 ).
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath or near the boilerSlowly open the small valves on the filling loop until you hear water flowingWatch the pressure gauge until it reaches 1.5 bar, then close the valves completelyPress the 'Reset' button on the boiler to clear the fault
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Unical models that show the 8 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Unical 8 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