BoilerFaultCodesMain E10 Fault Code
The Main E10 fault code means: your boiler has stopped working because the water pressure inside the heating system has dropped too low.. It appears on 1 Main model in our database.
Technical description: System water pressure fault
DIY fix possible
Locate the external filling loop, which is usually a flexible metal or silver braided hose underneath the boiler.Open the two valves at either end of the loop slowly to allow water to enter the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone, ideally around 1.5 bar.Close both valves tightly and ensure the filling loop is disconnected if required.
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Gas Safe Register →Main models that show the E10 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main E10 fault code information on this page is sourced and cross-checked against the official Main service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026