BoilerFaultCodesIdeal LED3 Fault Code
The Ideal LED3 fault code means: your boiler is stuck in its starting sequence because it cannot confirm the fan is working correctly to clear away waste gases.. It appears on 1 Ideal model in our database.
Technical description: Fan on
What causes the Ideal LED3 fault?
This fault occurs when the boiler's internal computer signals the fan to start, but fails to receive confirmation that air is moving through the system to safely clear waste gases. It is usually caused by a mechanical failure of the fan motor, a blockage in the flue, or a faulty sensor failing to detect the airflow.
This issue is slightly more common in autumn and winter, as debris like fallen leaves or nesting material can block the external flue pipe, preventing the required airflow.
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 LED3 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal LED3 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