How much does it cost to fix Ideal error code Fn?

Typical repair cost for the Ideal Fn fault is £100-£250 including labour.

Fn High

Ideal Fn Fault Code

Q: What does the Ideal Fn fault code mean?

Your boiler has lit correctly but the flame has gone out unexpectedly, often due to a temporary interruption in the gas supply or a blocked condensate pipe.

Also written as FN — same fault.

The Ideal Fn fault code means: your boiler has lit correctly but the flame has gone out unexpectedly, often due to a temporary interruption in the gas supply or a blocked condensate pipe.. It appears on 5 Ideal models in our database.

Technical description: Flame Loss

What causes the Ideal Fn fault?

This fault happens when the boiler successfully starts up, but the flame goes out shortly after because the system can no longer detect it. The most common reasons are a lack of gas entering the unit, a dirty sensor that can't 'see' the flame, or a blockage in the pipe that carries away waste liquid.

This fault is frequently seen during freezing winter spells, as the external condensate pipe can freeze solid and cause the boiler to shut down for safety.

Typical repair cost £100-£250 (including labour)

DIY fix possible

Check that your gas meter has credit and the isolation valve is open.Inspect the white plastic pipe (condensate) leading outside for signs of freezing or blockages.Restart the boiler by pressing the 'Reset' button.

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Ideal models that show the Fn fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal Fn 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