BoilerFaultCodesIdeal Ln Fault Code
Also written as LN — same fault.
The Ideal Ln fault code means: your boiler has lost its flame while running, meaning it is not getting enough gas or the spark is failing to keep the burner lit.. It appears on 5 Ideal models in our database.
Technical description: Flame Loss
What causes the Ideal Ln fault?
This fault occurs when the boiler successfully starts but then unexpectedly loses its flame while it is trying to provide heat or hot water. The most common reasons are a dirty or worn-out sensor that can no longer 'see' the flame, or an inconsistent gas supply that causes the burner to go out. It can also be caused by debris blocking the burner or a failing component that manages the electrical spark.
This fault can be more common during very cold snaps if the gas meter regulator freezes or if the increased demand for gas in the neighborhood causes a drop in pressure.
DIY fix possible
Check if your gas meter has credit (if on a prepayment meter)Check if other gas appliances, like a hob, are working to confirm gas supplyReset the boiler by turning the mode knob to 'RE' and then back to the desired settingEnsure the external condensate pipe has not frozen if it is winter
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Gas Safe Register →Ideal models that show the Ln fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal Ln 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 27 April 2026