L2 on a boiler means ignition lockout: the boiler tried to light the burner several times, failed, and shut itself down for safety. It's most common on Ideal boilers (Logic, Vogue, Exclusive, Independent). Check your gas supply is on (try the hob, check a prepayment meter has credit), look for a frozen condensate pipe in cold weather, then press reset. If L2 comes back, call a Gas Safe engineer.
An L2 code isn't dangerous in itself. It's the boiler doing its job: if it can't confirm a flame, it stops trying rather than letting unburnt gas build up. Most L2 lockouts in winter have a simple cause you can check in a few minutes. For other boiler problems, see our home heating guide.
What L2 means
When the heating or hot water calls for heat, the boiler opens the gas valve and makes a spark to light the burner. A flame sensor then confirms the burner has lit. If it doesn't detect a flame after a few attempts, the boiler locks out and shows L2.
Other brands use different codes for the same problem:
| Brand | Ignition failure code |
|---|---|
| Ideal | L2 |
| Worcester Bosch | EA (often with 227) |
| Baxi | E133 |
| Vaillant | F28 (failed to light) / F29 (flame lost) |
Is L2 on a boiler dangerous?
No, the lockout itself is a safety feature. The boiler has stopped because it couldn't light safely.
If you can smell gas, don't reset the boiler. Call the National Gas Emergency number on 0800 111 999 immediately, turn the gas off at the meter if it's safe to do so, open doors and windows, and don't use light switches, flames or anything that might spark.
The 5 most common causes of L2
1. A frozen condensate pipe (most common in winter)
Condensing boilers produce acidic water (condensate) that drains through a white or grey plastic pipe, often running outside to a drain. In freezing weather that pipe can ice up, the water backs up into the boiler, and it locks out. You may hear gurgling from the boiler.
2. No gas reaching the boiler
- Is the hob or gas fire working?
- If you have a prepayment meter, has the credit or emergency credit run out?
- Is the gas valve at the meter fully on (handle in line with the pipe)?
- Has there been work on the gas supply in your street?
3. A one-off hiccup
Boilers sometimes lock out once after a power cut, a dip in gas pressure, or a long period switched off. A single reset fixes it, and it doesn't return.
4. A faulty ignition or flame sensing part
If the ignition electrode, flame sensor or its lead is worn, dirty or damaged, the boiler may not light or may not "see" the flame. Engineer job.
5. A gas valve, fan or PCB fault
Less common, but a faulty gas valve, fan or control board (PCB) can cause repeated L2 lockouts. Engineer job.
How to fix L2: step by step
- Check for a gas smell. If you smell gas, stop and call 0800 111 999.
- Check other gas appliances. If the hob won't light either, it's a supply problem: check the meter, prepayment credit, or call your supplier.
- In freezing weather, check the condensate pipe (see below).
- Press the reset button on the boiler. On many Ideal models you press and hold it for a few seconds; your user manual shows exactly how.
- Wait a couple of minutes for the boiler to run through its start-up and try to light.
- If L2 returns, stop resetting. Repeated resets won't fix a faulty part. Book a Gas Safe engineer.
Make a note of the full code and any other symbols on the display, and when it happens (first thing in the morning, only on hot water, only in frosty weather). Engineers diagnose faster, and cheaper, with that information.
How to thaw a frozen condensate pipe
- Find the plastic condensate pipe: it usually leaves the boiler at the bottom and runs outside to a drain or soakaway.
- Feel along the outside section for the frozen part, usually the lowest point, a bend, or the open end.
- Pour warm (not boiling) water over the pipe, or hold a hot water bottle or heat pack against it. Boiling water can crack the plastic.
- Once the ice clears, reset the boiler.
- Long-term fix: ask an engineer about insulating the pipe, making the outside run shorter, or increasing its diameter so it's less likely to freeze.
Only thaw the pipe from the outside, at ground level. Don't climb ladders in icy weather, and don't remove any part of the boiler to get at the pipe.
L2 on an Ideal Logic, Vogue or Independent boiler
L2 is an Ideal code, and you'll see it across their popular ranges: Logic, Logic+, Vogue, Independent and Exclusive. Display styles vary between models, but the code means the same on all of them: ignition lockout.
On most Ideal combis the reset (or restart) is a button on the front panel. Ideal's user manual for your model shows exactly where it is.
Other common Ideal boiler codes: L1, F1, F2
If your Ideal boiler shows a different code, these are the ones householders see most:
| Code | What it usually means | What you can do |
|---|---|---|
| L2 | Ignition lockout: failed to light | Check gas and condensate pipe, then reset |
| L1 | Overheat or no water flow through the boiler | Check pressure, bleed radiators, reset; if it repeats, engineer (often the pump) |
| F1 | Low water pressure | Top up to 1–1.5 bar with the filling loop, then reset (how to) |
| F2 | Flame loss or ignition lockout (Ideal lists it like L2) | Same checks as L2: gas supply and condensate pipe |
| F3–F5 | Fan or temperature sensor faults | Engineer |
Ideal publishes the full list for each model in its user manuals, so check yours if you see a code not listed here.
When to call a Gas Safe engineer
- L2 comes back after one or two resets
- Other gas appliances work fine, and the condensate pipe isn't frozen
- You hear unusual banging, clicking without lighting, or smell burning
- The boiler is more than 10–15 years old and lockouts are getting more frequent
Typical UK costs: a call-out and diagnosis is around £60–£120; replacing an ignition electrode or flame sensor is often £80–£200 fitted; a gas valve or PCB is more, usually £200–£450.
FAQs
Can I reset an L2 code myself?
Yes. Pressing the reset button is designed for householders. Reset once or twice at most. If L2 keeps returning, there's a fault that needs an engineer.
Why does my boiler keep going to L2?
Repeated L2 lockouts usually mean a frozen condensate pipe (in cold weather), a gas supply problem, or a worn ignition electrode or flame sensor. If the pipe is clear and gas is reaching the boiler, it's an engineer job.
Does L2 mean I have no gas?
It can. A lack of gas is a common cause, so check your hob and prepayment meter first. But L2 can also happen with a perfectly good supply if the boiler can't ignite or detect the flame.
Is L2 the same on all boilers?
No. L2 is mainly an Ideal code. Other brands show ignition failure differently, for example EA on Worcester Bosch, E133 on Baxi and F28 on Vaillant.
How do I fix L2 on an Ideal Logic boiler?
Check other gas appliances work and any prepayment meter has credit, thaw the condensate pipe if it's frozen, then press reset. If L2 returns, an engineer needs to check the ignition electrode, gas valve and flame sensing.
What is the difference between L1 and L2 on an Ideal boiler?
L2 means the boiler couldn't light (ignition lockout). L1 usually means it overheated or detected no water flow, which often points to low pressure, air in the system or a pump problem.
Will L2 damage my boiler?
No. The lockout protects the boiler. But repeatedly resetting a boiler with a real fault isn't a good idea, so get it checked if it happens more than once.
- L2 = ignition lockout: the boiler couldn't light, so it shut down safely.
- Check for a gas smell first, then gas supply, then a frozen condensate pipe.
- Reset once or twice. If it returns, call a Gas Safe engineer.
- Thaw frozen condensate pipes with warm, never boiling, water.
