5 (Flashing) High

Ferroli 5 (Flashing) Fault Code

Also written as 5FLASHING — same fault.

The Ferroli 5 (Flashing) fault code means: your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.. It appears on 4 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: Insufficient pressure in Central Heating System
Typical repair cost £80-120 (including labour)

DIY fix possible

Locate the filling loop (a flexible silver hose) underneath the boiler.Open the small valve(s) on the loop to allow water into the system.Monitor the pressure gauge on the boiler until it reaches the green zone (typically 1.0 to 1.5 bar).Close the valve(s) tightly to stop the flow.

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Ferroli models that show the 5 (Flashing) fault code

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

Source

Ferroli 5 (Flashing) 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