F20 Emergency

Ferroli F20 Fault Code

The Ferroli F20 fault code means: your boiler has detected an issue with the air or exhaust system, meaning it cannot safely burn gas, and has shut itself down to prevent a safety risk.. It appears on 4 Ferroli 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: Combustion failure in the flue
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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Ferroli models that show the F20 fault code

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

Source

Ferroli F20 fault code information on this page is sourced and cross-checked against the official Ferroli service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026