BoilerFaultCodesIdeal E0 Fault Code
The Ideal E0 fault code means: your heat pump has stopped working because water isn't flowing through the outdoor unit properly, and it has failed to start ten times in a row.. It appears on 1 Ideal model in our database.
Technical description: No Water Flow, through Outdoor Unit, 10 times in succession
What causes the Ideal E0 fault?
This fault occurs when the system detects that there isn't enough water moving through the outdoor unit to safely transfer heat into your home. The most common reasons are a blockage in the pipework, air trapped in the system, or a circulation pump that has seized up. Because the unit has failed to start ten times, it has locked itself out to prevent the internal components from overheating or freezing.
This issue often appears at the start of autumn when the heating is turned back on after a long summer break, as internal pump parts can become stuck during periods of inactivity.
DIY fix possible
Check that all radiator valves are fully openEnsure the system pressure gauge is between 1.0 and 1.5 barLook for any external valves on the pipework that might be closedClear any debris or blockages from around the outdoor unit fans
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Gas Safe Register →Ideal models that show the E0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal E0 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