Medium
FL on Biasi Advance 25C

Your boiler is notifying you that the water pressure has dropped too low and the system needs to be topped up.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Filling request: The boiler works regularly and the display shows all the icons, but the signal FL is flashing every 1 sec.

From this model's manual
Verified against the Biasi Advance 25c installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Locate the filling loop valves underneath the boiler.Slowly open both valves to allow water into the system.Close both valves tightly once the pressure gauge reaches between 1 and 1.5 bar.

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