BoilerFaultCodesPotterton E118 Fault Code
The Potterton E118 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 2 Potterton models in our database.
Technical description: System pressure low (<0.5 bar)
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the one or two taps/valves until you hear water entering the system.Watch the pressure gauge and close the taps once it reaches between 1.0 and 1.5 bar.
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Potterton models that show the E118 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton E118 fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026