BoilerFaultCodesSime ALL10 Fault Code
The Sime ALL10 fault code means: your boiler has detected low water pressure in the system, which means it cannot circulate water safely or effectively.. It appears on 1 Sime model in our database.
Technical description: Seek help and advice from a qualified engineer.
DIY fix possible
Locate the filling loop (usually two blue levers or a braided hose) under the boiler.Slowly open the valves until you hear water flowing and the pressure gauge reaches between 1.0 and 1.5 bar.Close both valves completely and press the reset button on the control panel.
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Sime models that show the ALL10 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Sime ALL10 fault code information on this page is sourced and cross-checked against the official Sime service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026