L 9 Emergency

Ideal L 9 Fault Code

Also written as L9 — same fault.

The Ideal L 9 fault code means: your boiler has detected that it is running much hotter than it should be and has switched itself off to prevent permanent damage or a safety hazard.. It appears on 2 Ideal models in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: OVERhEAT ERROR
Typical repair cost £120-250 (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 9 fault code

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

Source

Ideal L 9 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 7 July 2026