BoilerFaultCodesUnical 08 Fault Code
The Unical 08 fault code means: your boiler has detected that the water pressure is too low for it to operate safely and has shut down to avoid damage.. It appears on 2 Unical models in our database.
Technical description: Water deficiency
DIY fix possible
Locate the pressure gauge on the front of the boiler or underneath it.Find the filling loop, which is usually a flexible silver hose with one or two small black taps.Slowly open the taps until the pressure gauge needle sits between 1.0 and 1.5 bar.Securely close both taps and attempt to reset the boiler.
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Unical models that show the 08 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Unical 08 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