Ideal L2 fault codewhat it means and how to fix it
The boiler failed to detect a flame during ignition and has locked out on the gas valve. Do not keep resetting it.
Stop — this needs an engineer
Get a Gas Safe registered engineer to look at your Ideal L2
We do not pass enquiries to a repair firm, so there is no form here. Find a Gas Safe registered engineer through the Gas Safe Register, and ask to see their registration card when they arrive — it is the register, not the van, that tells you they are qualified.
What else is happening?
The right answer depends on what you can see. Pick the one that matches.
Choose the option on the left that matches what your appliance is doing, and the answer for that case appears here.
Other gas appliances have stopped working too
No gas is reaching the property, and the boiler is behaving correctly.
Check the emergency control valve at the meter and any prepayment credit, then call your supplier.
It is freezing and the boiler worked yesterday
A frozen condensate pipe is the most likely explanation.
Pour warm — never boiling — water along the external white plastic pipe and reset once.
You can hear it clicking and trying, then it gives up
The ignition is sparking, so the fault is downstream: either gas is not arriving at the burner or the flame is not being detected.
Book a Gas Safe registered engineer. Two resets maximum while you wait.
You can smell gas
Stop. Do not reset and do not touch any electrical switch.
Open the windows, leave the property, and call 0800 111 999 from outside. It is free and answered around the clock.
What L2 means
L2 is an ignition lockout. The boiler runs its start sequence — fan to speed, gas valve open, spark — then looks for an ionisation signal confirming a flame is burning. Without that signal it shuts the gas off, purges, and retries.
After the permitted number of attempts it latches L2. The lockout exists precisely so an appliance cannot keep introducing unburnt gas into a combustion chamber. That is why the reset limit matters more than the code itself: each reset starts a fresh set of attempts. In practice, the cause is usually either no gas reaching the boiler, or a flame sensing electrode too dirty to detect the flame it has just lit.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| No gas at the appliance | Empty prepayment meter, closed service valve, or a supply interruption. | Common |
| Dirty or worn ignition and sensing electrode | Carbon deposits drop the ionisation current below the detection threshold. Ideal electrodes are a routine service item. | Common |
| Frozen or blocked condensate pipe | Very common in the first hard frost, and it presents as a failed start. | Common |
| Gas valve fault | The valve is not opening, or is opening too slowly for the ignition window. | Occasional |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£120–£450
Time on site
1h 15m
Electrode £120–£200. Gas valve £280–£450. Frozen condensate costs nothing if you can reach it.
Typical UK prices including parts and labour, updated September 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 28 September 2026
Condensate trap and siphon
COND-TRAP£15–£38Plumbing merchant
Price checked 28 September 2026
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Ideal fault codes
- 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
- L FStop — call an engineerAn Isar, Icos, Mexico HE or Esprit has made three attempts to light and locked out; the LED window flashes L then F. Ideal permit one reset and a gas supply check, then an engineer.Related: ignition and gas supply
- L6Stop — call an engineerA flame is being detected when there should not be one. Turn the appliance off and call a Gas Safe engineer rather than resetting it.Related: ignition and gas supply
- F16Stop — call an engineerThe board has detected a fault in the gas valve or its wiring. Nothing here is for a householder to try; Ideal's checks cover the valve's supply and coil and end with replacing it.Related: ignition and gas supply
- F10Get it checkedThe spark generator on a Logic Combi2 — the unit that makes the ignition spark — has failed a self-check. Ideal's instruction is to check its wiring and, if that is sound, replace it.Related: ignition and gas supply
Own an Ideal boiler? Save it and its codes come first next time.
Related guides
Common questions about Ideal L2
What is the difference between L2 and F2 on an Ideal?
The letter is the state, not the severity, and it runs the opposite way to what most people assume. L is the latched one: the boiler has stopped and will stay stopped until somebody presses Restart. F is the same class of fault in a condition it can come out of by itself. Ideal prove the relationship in their own table by printing several faults in both columns — F04 and L04 are one flow thermistor, F05 and L05 one return thermistor. So an L2 is not a worse fault than an F2, it is a boiler that has given up. Tell the engineer which you are looking at, because a fault that keeps clearing itself and one that has latched point at different things.
How many times can I reset it?
Ideal have already answered that for you, twice over. The appliance makes five ignition attempts of its own before it declares this code, so by the time you see it, it has done what pressing Restart asks it to do five times without success. And your presses are counted too: five inside fifteen minutes produces L0C, which no further pressing will clear, because Ideal designed it to be cleared only by switching the electrical supply off and on. Two attempts is the sensible ceiling. Each one releases a little gas into a combustion chamber before the valve shuts, and the fault does not become less real for being cleared.
What does the repair usually cost?
An electrode is £120 to £200 fitted. A gas valve is £280 to £450. If it turns out to be your gas supply, the supplier deals with it at no charge to you.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
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
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.