BoilerFaultCodesIdeal F L Fault Code
Also written as FL — same fault.
The Ideal F L fault code means: your boiler has detected that there is not enough water circulating through the system to operate safely, which is usually caused by low water pressure or an air lock.. It appears on 1 Ideal model in our database.
Technical description: Pump dry run
DIY fix possible
Check the pressure gauge on the front of the boiler; if it is below 1 bar, use the filling loop to top it up to 1.5 bar.Ensure all radiator valves and boiler isolation valves are fully open.Restart the boiler by pressing the reset button once the pressure is corrected.
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Ideal models that show the F L fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal F L fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026