High
LED 4 Flashing (DHW Mode) on Ferroli Falcon

Your boiler is failing to detect when you turn on the hot tap, meaning it cannot start the burner to heat your water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Flow Sensor fault

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

LED 1View →LED 3View →

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