This fault can involve incomplete combustion and carbon monoxide.
If anyone in the property feels sick, dizzy or drowsy, or you can smell gas: open the windows, leave the building, and do not switch anything on or off. Then call the National Gas Emergency Service.
0800 111 999Ideal L6 fault codewhat it means and how to fix it
A flame is being detected when there should not be one. Turn the appliance off and call a Gas Safe engineer rather than resetting it.
Stop — this needs an engineer
Get a Gas Safe registered engineer to look at your Ideal L6
Gas Safe Register engineers only. No obligation.
What L6 means
L6 is false flame detection on an Ideal appliance, and the L prefix tells you it is a lockout that will not clear on its own. The appliance is reading a flame signal at a point in the cycle when the gas valve should be closed and the burner out. Two things produce that. The likelier is current leakage on the electrode or a control board fault — in other words a sensing circuit reporting something that is not happening. The more serious is that the reading is accurate, gas is still burning after the valve was told to shut, and the gas valve is passing. That is a genuine gas safety fault rather than an inconvenience. Nothing you can observe from outside the casing will tell you which of the two you have, and the appliance cannot tell you either. The proportionate response is to assume the serious one until an engineer proves otherwise, which means isolating the appliance rather than resetting it.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Current leakage on the electrode | Contamination, moisture, or a breakdown in the electrode lead creating a path that mimics a flame signal. The most common cause and the benign one. | Common |
| Gas valve passing | The valve not sealing fully when closed. Less common, and the reason this code is treated urgently. | Occasional |
| Damp inside the case | Water tracking across connectors after an internal leak, or condensation in an unheated garage installation. | Occasional |
| Control board fault | The flame detection stage on the board misreading its own input. Diagnosed once the gas side is proved sound. | Rare |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£110–£420
An electrode is £110 to £190 fitted. A gas valve is £280 to £420. Expect a diagnostic charge on top, because separating the two requires a flue gas analyser.
Typical UK prices including parts and labour, updated August 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Ideal Logic ignition electrode
175565£18–£42Authorised Ideal parts distributor
Price checked 5 August 2026
What other owners found
Nobody has shared what worked for them on this code yet. If you have had it, you would be the first — and it genuinely helps the next person.
Related Ideal fault codes
- L2Stop — call an engineerThe boiler failed to detect a flame during ignition and has locked out on the gas valve. Do not keep resetting it.Related: ignition and gas supply
- F2Get it checkedThe flame was lost during operation. Ideal direct you to check the gas supply first, and that is genuinely the right order.Related: ignition and gas supply
- LCUsually simple to fixYou have reset the appliance five times in fifteen minutes. This is not a fault in itself — it is the boiler asking you to stop.Related: ignition and gas supply
- EA 227Stop — call an engineerThe boiler tried to light and never detected a flame, so it has shut the gas off and locked out. This is the most common Worcester fault code.Related: ignition and gas supply
- E01Get it checkedThe appliance tried to light and could not confirm a flame, so it has locked out. In winter a frozen condensate pipe is the most likely reason.Related: ignition and gas supply
- F.28Stop — call an engineerThe boiler tried to light and failed three times in a row, so it has shut the gas off and locked out. Do not keep resetting it.Related: ignition and gas supply
Related guides
Common questions about Ideal L6
What should I do before I call anyone?
Cut the power at the fused spur and leave it cut — the L prefix is Ideal telling you they consider this a hard lockout rather than something the appliance should shrug off. Then find your guarantee paperwork. Ideal guarantees are among the longest in the trade, and calling an independent engineer while still covered can cost you the balance of it.
What should I tell the engineer?
Describe it as a false flame lockout and say the appliance is an Ideal showing L6. Ideal attribute this to current leakage on the electrode, so an engineer who knows the brand will know where to start rather than working through the possibilities on your time.
What does "current leakage on the electrode" actually mean?
Flame detection works by passing a tiny current through the flame itself. If moisture or carbon deposit gives that current an alternative path to earth, the appliance reads it as a flame even with the burner out. It is the electrical equivalent of a stuck sensor, and it is the benign end of the possibilities.
I kept resetting and now it shows LC instead. Have I made it worse?
You have not damaged anything — LC is just the reset counter tripping after five attempts in fifteen minutes. But it is the appliance making a fair point. Power off at the spur for a minute to clear LC, and then leave L6 alone until somebody has looked at it.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
- Trade body guidance
Checked by Technical reviewer (Gas Safe registration to be displayed on appointment) on 5 August 2026.