Flame Loss Emergency

Keston Flame Loss Fault Code

Also written as FLAMELOSS — same fault.

The Keston Flame Loss fault code means: your boiler has successfully ignited but is struggling to stay lit, so it has shut down as a precaution to prevent unburnt gas from accumulating.. It appears on 6 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: Boiler ignites for a short time and then extinguishes
Typical repair cost £150-350 (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 Flame Loss fault code

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

Source

Keston Flame Loss 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