BoilerFaultCodesFerroli LED 5 (Flashing light) Fault Code
Also written as LED5FLASHINGLIGHT — same fault.
The Ferroli LED 5 (Flashing light) 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.
Technical description: Insufficient pressure in central heating system
DIY fix possible
Locate the external filling loop (a flexible silver hose beneath the boiler connecting two pipes)Open the valves at both ends of the hose to allow water into the systemWatch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically 1 to 1.5 bar)Close both valves tightly and remove the hose if required by your specific model instructions
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Gas Safe Register →Ferroli models that show the LED 5 (Flashing light) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ferroli LED 5 (Flashing light) 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