Written by Stephen Day
Gas Safe Engineer
Updated: 2nd February, 2026
What the Ideal L2 error code means and what to do when your boiler will not stay lit.
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A boiler error code is a fault message shown on the boiler display when the system detects a problem.
These codes are part of the boiler’s safety and diagnostic system. They help identify issues early and prevent unsafe operation.
Knowing what an error code means helps homeowners act quickly and confidently.
Recognising faults early can prevent minor problems from turning into expensive repairs. It also helps ensure the boiler continues to run safely and efficiently.
The Ideal L2 fault code means flame loss.
The boiler has tried to ignite or re ignite but cannot detect a stable flame. For safety, the boiler shuts itself down.
If you see the L2 fault code:
Reset the boiler once using the manufacturer’s instructions.
Check that your gas supply is working elsewhere in the home.
If the fault returns, arrange a professional inspection.
Do not keep resetting the boiler if the code persists.
Several issues can trigger an L2 fault.
Gas supply problems such as low pressure or interruptions can prevent ignition.
Faulty ignition leads or electrodes may stop the flame from forming or being detected.
Blocked flues or restricted air supply can interfere with combustion.
Frozen condensate pipes in cold weather can interrupt the ignition process.
Electrical or control board faults can also disrupt ignition.
The boiler fails to fire and provide heating.
The system resets and locks out repeatedly.
You may hear ignition attempts without the boiler lighting.
Heating and hot water may stop altogether.
Only very basic checks should be carried out by homeowners.
You can confirm other gas appliances are working.
You can check that the external flue terminal is not visibly obstructed.
You can perform a single reset following the manufacturer’s guidance.
Do not remove covers or attempt internal checks.
If the L2 fault repeats after a reset, professional help is required.
Gas appliances should not be dismantled or adjusted without proper training. Incorrect repairs can be dangerous and may invalidate warranties.
Yes. An Ideal L2 fault must be diagnosed and repaired by a Gas Safe registered engineer.
A Gas Safe engineer is legally qualified to work on gas boilers in the UK and will ensure repairs meet safety standards.
A typical diagnosis starts with checks on gas supply, ignition components, and the condensate route before testing the ignition sequence.
Repair costs depend on the cause of the fault and the parts required.
Costs vary by region, parts availability, and whether the issue is intermittent or constant.
Typical UK repair cost ranges for 2026
Type of repair | Typical range |
|---|---|
Minor adjustment or reset issue | £150–£200 |
Ignition related parts | £200–£300 |
More complex faults | £300+ |
An engineer should confirm costs before any work is carried out.
An L2 fault does not automatically mean replacement is required.
However, replacement may be worth considering if the boiler is older, breaks down often, or repair costs are becoming high.
The boiler is over 15 years old.
Breakdowns are becoming more frequent.
Repair costs are approaching half the cost of replacement.
Heating efficiency is noticeably poor.
There are ongoing safety concerns.
Most boilers last around 15 to 20 years with regular servicing.
As boilers age, efficiency drops and faults become more likely. At a certain point, replacing the boiler can be more reliable than continued repairs.
Regular servicing helps reduce the risk of faults like L2.
Servicing checks ignition systems, safety controls, and overall performance. Problems can often be identified before they cause a breakdown.
At iHeat, boiler servicing is carried out by Gas Safe registered engineers, with prices starting from £99.
An Ideal L2 error code can be worrying, but understanding what it means makes the next steps clearer.
Many cases can be resolved with a professional repair. Regular servicing can help prevent the fault from returning.
If the issue persists or the boiler is reaching the end of its life, replacement may be the more reliable long term option.
iHeat supports homeowners through repair advice, boiler servicing, and the installation of modern, energy efficient boilers using a simple online process.
Last updated: 2nd February, 2026
Written by Stephen Day
Gas Safe Engineer at iHeat
Stephen Day is a Gas Safe registered and FGAS certified engineer with over 20 years of hands-on experience in the heating, cooling, and renewable energy industry, specialising in boiler installations, air conditioning, and heat pump systems.
LinkedInArticles by Stephen Day are reviewed by iHeat’s technical team to ensure accuracy and reliability.
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