False Flame Lockout Emergency

Keston False Flame Lockout Fault Code

Also written as FALSEFLAMELOCKOUT — same fault.

The Keston False Flame Lockout fault code means: your boiler has detected a flame when it should be turned off, so it has purposefully shut itself down to ensure your safety.. It appears on 2 Keston 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: Check Flame Sense Electrode, Check Flame Sense Electrode Wiring
Typical repair cost £150-250 (including labour)

Engineer required

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

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Keston models that show the False Flame Lockout fault code

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

Source

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

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