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What Is The Ideal Boiler L2 Fault Code? And How To Fix it


The L2 Fault Code is a serious one. You have to act fast. Usually, ideal boilers tend to shut down after displaying this frightening message. The fault code is mainly triggered by flame loss caused by several problems like:

  • A faulty ignition lead
  • Low gas pressure
  • A blocked condensate pipe
  • A faulty gas valve
  • A faulty flame sensor
  • Gas leaks

Unfortunately, the L2 Fault Code is one of those problems you can’t solve with DIY skills. You have no choice but to hire a Gas Safety registered engineer. For information purposes, we’ll dissect this problem further and tell you how it’s fixed.

Most owners tend to panic when their boiler forcefully shuts down after displaying the L2 Fault Code. There’s no need to worry. It’s a safety procedure that prevents the problem from worsening. We promise you, once a professional fixes it, your boiler will resume operations.

Causes of the L2 Fault Code

As expected, the professional engineer will first diagnose the boiler. Below are some of the problems your engineer will try to find.

A faulty ignition lead

A faulty ignition lead is the most notorious cause for flame loss in ideal boilers. It’s a crucial component necessary for igniting gas to produce the flames used in heating.

Once you turn on your boiler, the gas valve opens to release gas into the combustion chamber. Immediately, the ignition lead is supposed to react and spark a flame. If it doesn’t, then your boiler will quickly display the L2 Fault Code before shutting down. Gas accumulation is dangerous. That’s why your boiler refuses to work until the ignition lead is fixed or replaced.

But what causes the ignition lead to break down?

Leaks and loose connections are usually the culprits. If the ignition lead is faulty, the engineer will have to replace it.

On the other hand, if leaks are the primary cause, the engineer will inspect the entire system. Leaks are extremely dangerous. If you smell any gas, immediately turn off your boiler unit and call a Gas Safe engineer.

Low gas pressure

Low gas pressure can also cause flame loss which will, in turn, trigger the L2 Fault Code. Most of the time, low gas pressure is caused by a faulty gas meter, especially if it’s outside.

During the winter, temperatures can drop low enough to mess with your gas meter. If the meter is the issue, the engineer will most likely inspect the regulator. During harsh winters, the regulator tends to freeze and block.

The best solution is to lag the gas meter, and your boiler should resume operations. To prevent the problem from occurring in the future, the engineer might secure the gas meter in a box to protect it from the elements.

Low gas pressure can also be caused by outdated pipes (Especially if you’ve recently upgraded your ideal boiler to a much larger unit). If the pipes aren’t compatible, they might end up delivering less gas to your boiler that will, in turn, lead to flame loss. The engineer should be able to assess your system and advise on the necessary changes.

Blocked condensate pipes

Condensate pipes are also known as flues. Like gas meters, external condensate pipes are also prone to harsh winters and debris that cause blockages. It’s the main reason why the Heating and Hotwater Industry Council (HHIC) is tirelessly fighting against external condensate pipes. As per the new regulations, all condensate pipes must safely terminate internally into a soil stack that will absorb all waste.

Condensate pipes redirect waste products produced by the boiler in the course of its operation. If something blocks the condensate pipe, your boiler will immediately lockdown after displaying the L2 Fault Code.

If your condensate pipe is clogged by debris like leaves, the engineer will quickly remove the obstruction. Ideally, the condensate pipe should have a protective guard to prevent blockage. If yours doesn’t have one, the engineer will install it.

If your condensate pipe is frozen, the engineer will most likely thaw it with warm water. After that, the boiler should resume operations.

To avoid future condensate-related problems, you should consider switching to internal condensate pipes. Also, the engineer might opt to replace the condensate pipes or insulate them against the cold.

A faulty gas valve

The gas valve is also among the most crucial components of your ideal boiler. When you turn on your heating system, it’s responsible for releasing the gas necessary for combustion. For the boiler to work correctly, the gas valve has to release the right amount of gas. If it releases very little gas, the boiler won’t heat up. On the other hand, if it releases a lot of gas, the boiler will immediately lock down after displaying the L2 Fault Code. Boiler gas is explosive and dangerous. It’s even worse if the gas valve gets stuck and continuously releases boiler gas.

If that’s the case, the gas engineer will attempt to readjust the gas valve. Nonetheless, there are times when the engineer will have to replace the component. Depending on the installation company, gas valves can be costly. A new gas valve can cost around ₤300.

A faulty flame sensor

The Print Circuit Board controls most modern ideal boilers. The board is responsible for receiving and sending signals to and from other boiler components. It will immediately shut down your boiler if it doesn’t receive information from the flame sensor that a flame was lit. It does this to prevent gas buildup, which can be dangerous.

The engineer will test your boiler’s flame sensor to see if it’s functioning as expected. If it’s faulty, he will have to replace it.

Gas leaks

We touched on gas leaks when we talked about faulty ignition leads. Nonetheless, we feel the need to emphasize how dangerous they are. As the owner, it’s your responsibility to frequently inspect your boiler for gas leaks. If you smell even the slightest leak, you should completely shut down the boiler and gas supply before evacuating the house. Once you are outside, immediately get in touch with a certified Gas safe engineer.

Do I need a new Ideal boiler?

So far, we’ve proven that the L2 Fault Code is solvable. Not only can the gas engineer fix the problems, but he can also prevent them from happening again in the future. Nonetheless, there are some instances where replacing your ideal boiler will be the most reasonable and money-saving option. For example, if the repairs cost hundreds of pounds, your boiler’s warranty is void, and the boiler is old and worn out. In such a case, we advise you get a new one.


The Ideal L2 Fault Code is usually triggered by flame loss problems. Fortunately, most of them can be dealt with by a certified gas engineer.

Once again, we are reminding you that you are strictly advised against fixing the problem on your own. It’s dangerous. Only certified gas engineers are allowed to diagnose and fix the L2 Fault Code.

Need help with your Ideal boiler? Call us today. We are here for you.

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