BoilerFaultCodesIdeal E8 Fault Code
The Ideal E8 fault code means: your boiler has stopped working because water is not moving through the system properly or the pressure is too low.. It appears on 1 Ideal model in our database.
Technical description: water flow fault
What causes the Ideal E8 fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving through the unit quickly enough to safely carry heat away from the burner. The most common reasons are a failed internal pump, a build-up of debris causing a blockage in the pipework, or air trapped within the system. It can also be triggered if the system pressure has dropped too low for the pump to operate effectively.
This issue often surfaces during the first cold spell of autumn when the heating is turned on after being idle all summer, which can cause the internal pump to seize.
DIY fix possible
Check that the boiler pressure gauge is between 1 and 1.5 barIf the pressure is low, use the filling loop to top it upEnsure all radiator valves and boiler isolation valves are fully openReset the boiler once the pressure is corrected
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Gas Safe Register →Ideal models that show the E8 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal E8 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026