BoilerFaultCodesIdeal L F (flashing) Fault Code
Also written as LFFLASHING — same fault.
The Ideal L F (flashing) fault code means: your boiler is failing to light the gas flame after three attempts, which means it has safely shut itself down to prevent a build-up of unburnt gas.. It appears on 2 Ideal models in our database.
Technical description: Boiler is not working for central heating or hot water but attempts to fire by going through 3 ignition attempts.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A cover plan would handle faults like L F (flashing): no call-out fees, no surprise bills.
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Ideal models that show the L F (flashing) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal L F (flashing) 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