BoilerFaultCodesIdeal E03 Fault Code
The Ideal E03 fault code means: your boiler has stopped working because it cannot safely clear waste gases through the ventilation pipe.. It appears on 6 Ideal models in our database.
Technical description: Fan or flue pressure switch failure
What causes the Ideal E03 fault?
This fault occurs when the boiler's safety sensors detect that the fan isn't moving enough air to safely vent exhaust gases out of the building. The most common reason is a mechanical failure of the fan motor or a blockage in the small plastic tubes that monitor air pressure. Without a clear path for waste gases to escape, the boiler automatically shuts down to prevent dangerous fumes from entering your home.
This issue can be more frequent during very windy weather, as strong gusts can sometimes create back-pressure in the flue that interferes with the pressure switch readings.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Ideal models that show the E03 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal E03 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