How much does it cost to fix Ferroli error code F3?

Typical repair cost for the Ferroli F3 fault is £120-250 including labour.

F3 High

Ferroli F3 Fault Code

Q: What does the Ferroli F3 fault code mean?

Your boiler has switched itself off because it is detecting a blockage or a lack of water movement that is causing the internal temperature to rise too quickly.

The Ferroli F3 fault code means: your boiler has switched itself off because it is detecting a blockage or a lack of water movement that is causing the internal temperature to rise too quickly.. It appears on 8 Ferroli models in our database.

Technical description: Safety thermostat trips. Possible causes: Flow sensor not active; No system circulation.

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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Ferroli models that show the F3 fault code

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

Source

Ferroli F3 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 27 April 2026