What Does L2 Mean on a Boiler: Boiler Codes Explained


Sometimes life throws curve balls, such as a fault code on your boiler system. As most of us aren't plumbers or heating engineers, an L2 fault code can be very much a mystery at first sight.

To help you work out exactly what it is, we've created a quick guide on the L2 fault code on boilers, what it means, and how you can get your boiler back to normal in no time.

What is a boiler fault code?

In the unfortunate circumstance of your boiler no longer working or not functioning as it should, it will typically display a fault code. The fault code being displayed can then be used to identify the cause of the problem, which in turn prompts the necessary follow-up action.

When investigating a boiler fault code, it's important to bear in mind that codes vary according to the make and model of your boiler. Modern boilers like gas combi boilers can display many different codes and combinations, which all have different meanings.

If you do have the misfortune of having to deal with a fault code, then don't panic, as it is more than likely something that can easily be fixed with the right knowledge. Do note that only certified gas engineers should be fixing errors you can't solve yourself.

What does F2 mean on a boiler?

First and foremost, any boiler fault code could mean one of two things - either your gas boiler needs to be repaired, or it needs to be replaced. More specifically, an L2 fault code or ignition lockout error is related to an issue with your boiler that is causing the flame to go out. When this happens, your boiler locks and cannot be used until the issue is resolved.

Why does the L2 fault code occur?

Why does the L2 fault code occur

The L2 fault code typically occurs as a result of a gas supply issue or a particular component failing. If the error occurs during winter, it might mean that you have a frozen condensate pipe on your hands.

Here's a more detailed look at why the L2 fault code occurs.

1 - Low gas pressure

There are often instances in which large-capacity boilers don't have a sufficient gas supply. If this is the case, you can upgrade to a gas pipe that is larger in diameter to combat the low gas pressure.

You can also contact your gas supplier to query why you might be experiencing low gas pressure and then ensure that your property is receiving the required amount of gas.

2 - Flame sensor failure

A faulty flame sensor is one of the main reasons why the L2 fault code occurs on a boiler. When the boiler is controlled by a printed circuit board, if it doesn't receive an indication from the flame sensor that the flame is on, it will close the gas stream.

This then means that the boiler has lost its flame and thus can't operate. A flame sensor repair or replacement generally rectifies this.

3 - Faulty gas valve

A faulty gas valve is another common cause of the L2 fault code. The gas valve regulates the flow of gas to your boiler, so a faulty gas valve disrupts this. You'll probably have to replace the gas valve as the cost of repairing one can be quite expensive.

4 - Gas meter blockage

Your gas meter can also experience blockages, the same way your condensate pipe does. Boiler repair companies will lag the gas meter to provide extra protection. After this, your meter's regulator thaws, and the error code can be cleared.

5 - Condensate pipe blockage

Condensate pipes can freeze over during cold winter weather, and as a result, harmful gases can escape the system. These gases may be extremely dangerous. If you smell any gas coming from your boiler unit, then turn it off immediately and contact a Gas Safe Engineer.

How to fix the L2 fault code on your boiler

Whenever you're investigating a boiler fault code of any kind, you should always start with the simplest solution - switching it off and back on. If the error isn't cleared by that, then it may indicate a more serious problem.

If the L2 fault code is occurring because the condensate pipe is frozen, you may be able to fix it by carefully thawing it out the pipe with warm water.

Regardless of what you may think is causing the problem and whether you think you can fix it, it's best that you get in touch with a registered Gas Safe Engineer. While hiring a Gas Safe Engineer may sound expensive, it is probably the best solution to having your boiler fixed and for it to be fixed safely, as such operations can be dangerous if not done by a professional.

Lastly, if there are components in your boiler, such as the gas valve, that are failing or rapidly deteriorating, then getting a new boiler might be your best option. This isn't always the most ideal option, but it may be a more convenient and cost-effective long-term solution.

FAQs about L2 fault codes

What is a condensate pipe?

Condensate pipes are the pipes via which the boiler discharges wastewater from the condensing process.

What are the most common boiler problems?

With a boiler, you can expect to encounter the following problems:

Boiler leak

  • Low boiler pressure

  • Boiler kettling

  • Unusual noises

  • Hot water but no heating

  • Frozen condensate pipes

  • No responses to the thermostat

  • The pilot light switches off repeatedly

    These problems are precisely why it is always a good idea to invest in a boiler that is of high quality and is the right size for your home or commercial property. So, be sure to explore our range of boilers, from electric boilers to oil boilers.

    If you have a fault code chart and it indicates that the code in question should be looked at by a certified gas or heating system engineer, then it is advisable that you cease further use and enlist the services of a qualified professional.

    If you can't find your boiler's handbook or it didn't come with one, you may be able to find one from online resources.

    Are a boiler and a water heater the same thing?

    Despite the words often being used interchangeably, boilers and water heaters are not the same things. Boilers heat water rapidly to be used as hot water or for home heating. On the other hand, a water heater heats and stores water. The water that a water heater heats is kept at a consistent temperature until it is needed.

    What are the types of boilers, and which is best?

    What are the types of boilers

    There are three main types of boilers:

    Combi boilers - These are single units that generate all the heating and hot water for your home. There are no hot water tanks involved with this type of boiler. Combination boilers provide instantaneous hot water through an integral heating exchange. Traditional systems store hot water in a tank prior to use.

  • Heat-only - Heat-only boilers, also known as conventional or regular, directly provide heat to radiators and use a cylinder to provide hot water. They generally work via either an open-vented heating system or an open-vented system. You may also have heard of back boilers. Don't get too confused, though, as they are merely a type of heat-only boiler that is situated in a chimney breast with a fire on the front.

  • System - Like conventional boilers, gas system boilers use a hot water cylinder but are not open-vented, and some components that are typically found on the outside can be found in the boiler.

    As far as which is better, that depends on the needs of your household as some work better than others in certain regards. For example, system boilers are good for properties with high water demands, whereas a combi boiler is good for saving space. Always consult an expert first before buying a boiler.

    Should I switch my boiler off when I go on holiday?

    It's generally not advisable to switch off your boiler entirely when you go on holiday unless you have an old model with a gas pilot light, as they tend to consume large amounts of energy.

    Leaving your boiler on when you're away is beneficial as it means your house won't be unbearably cold when you return. Plus, it prevents any pipes from freezing in the event of there being a cold snap and you not being able to adjust the thermostat accordingly.

    The simple solution for when you go on holiday is to set your thermostat to the lowest temperature. That way, the boiler shouldn't turn off while you're off getting some much-needed rest. You can also set your heating on a timer to ensure it comes on regularly during the day.

    If you absolutely have to, pause the production of hot water through your boiler. This mainly applies if you have a separate water heater or water storage tank.

    Browse our range of boilers at PlumbNation

    If you do find a serious fault with your boiler and need to replace it, take a look at our boilers at PlumbNation.

    We supply a range of heating options, from gas boilers and radiators to heat pumps and underfloor heating systems.