BoilerFaultCodesUnical BLOCK Fault Code
The Unical BLOCK fault code means: your boiler has encountered an unknown internal error and has shut down as a safety precaution to prevent damage.. It appears on 2 Unical models in our database.
Technical description: General block for unclassified anomalies.
DIY fix possible
Press the Reset button on the control panel to see if the error clearsCheck that your gas supply is turned on and other gas appliances are workingTurn the power supply to the boiler off and back on again after 30 seconds
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Unical models that show the BLOCK fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Unical BLOCK 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