L9 High

Evo L9 Fault Code

The Evo L9 fault code means: your boiler has sensed that the exhaust gases are getting too hot and has shut down as a safety precaution to prevent internal damage.. It appears on 2 Evo 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: FLUE GAS OVERHEAT
Typical repair cost £150-£450 (including labour)

Engineer required

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

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Evo models that show the L9 fault code

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

Source

Evo L9 fault code information on this page is sourced and cross-checked against the official Evo service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026