4 (Flashing) Low

Ferroli 4 (Flashing) Fault Code

Also written as 4FLASHING — same fault.

The Ferroli 4 (Flashing) fault code means: your boiler is currently in standby mode and is simply waiting for a signal from your thermostat or hot water tap to start heating.. It appears on 3 Ferroli models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Central Heating standby

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 4 (Flashing) fault code

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

Source

Ferroli 4 (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 7 July 2026