BoilerFaultCodesMain E317 Fault Code
The Main E317 fault code means: your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.. It appears on 1 Main model in our database.
Technical description: System water pressure fault
DIY fix possible
Locate the filling loop, which is a silver braided hose with one or two small valves under the boiler.Gradually open the valves to let water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valves tightly and check the display to see if the error code clears.
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Gas Safe Register →Main models that show the E317 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main E317 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