L....8..... High

Ideal L....8..... Fault Code

Also written as L8 — same fault.

The Ideal L....8..... fault code means: your boiler has stopped working because the fan that removes exhaust fumes is not spinning correctly or communicating with the system.. It appears on 11 Ideal models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: FAN ERROR

What causes the Ideal L....8..... fault?

This fault occurs when the boiler's control board cannot confirm that the fan is spinning at the correct speed to safely clear exhaust fumes. It is usually caused by a mechanical failure of the fan motor, a loose connection in the internal wiring, or a fault on the main circuit board that prevents it from sending power to the fan.

Typical repair cost £220-£450 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ideal models that show the L....8..... fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal L....8..... 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