F40 High

Ferroli F40 Fault Code

The Ferroli F40 fault code means: your boiler has detected that the water pressure level inside your heating system is currently too high or too low for it to operate safely.. It appears on 7 Ferroli 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: Incorrect system water pressure
Typical repair cost £80-150 (including labour)

DIY fix possible

Check the system pressure gauge on the front of the boiler.If the pressure is below 1 bar, locate the filling loop to top up water until the needle reaches 1.5 bar.If the pressure is above 2.5 bar, bleed a radiator elsewhere in your home to release excess pressure.

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Ferroli models that show the F40 fault code

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

Source

Ferroli F40 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