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What to Do If Your Boiler Breaks Down

Author: Samuel Beckingham
Updated: Jan 30, 2024
7 minutes read
  • Common boiler breakdown issues
  • Gas, electric and combi boiler guidance
  • Prevent breakdowns with a regular boiler service

A boiler breakdown is never welcome, and it often sends you into panic mode. Without thinking clearly, and without any working mechanical knowledge, it can often seem hopeless. Fortunately, there are steps you can take to first identify if there’s an underlying issue. These simple checks can save you money on calling out an engineer.

This article will go through what steps you should take in the event of a boiler breakdown. From common issues that you can resolve yourself to significant issues that require professional input, you can find out what you should do here. A regular boiler service can reduce the chances of a breakdown, keeping it working efficiently and effectively, even during the winter months.

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Identifying a Boiler Breakdown

First things first, you should go through some checks to see if your boiler is actually broken. You may have noticed some or all of the following:

  • Strange noises

  • Higher than average heating bill

  • An orange-yellow pilot light

  • A high water pressure gauge

  • A water leak

  • The boiler not switching on

Depending on whether you have a gas, electric, system or combi boiler, some of these boiler breakdown indicators might not apply. Gas boilers, for example, should have a blue pilot light, so any change in colour is not normal. You should fix a leaking boiler as soon as possible. These can be caused by high pressure, damaged seals or pipework and loose connections.

If the solution isn’t obvious, you shouldn’t delay in calling in a professional. Any issue that can be easily solved yourself can save a hefty callout charge, which is why you should look at the first fixes you can do below.

First Fixes

Thermostat and Programmer

The very first thing to check with a boiler breakdown is that your temperature and timing settings are correct. The thermostat should be above room temperature and your programmer should show the correct time. If your programmer doesn’t require the central heating to be on, this could be why you don’t have any heat or hot water.

Consumer Unit

A power cut could have simply stopped your programmer from working or a fuse could have blown, shutting off the power to where your boiler is located. Similarly, if you’re on a prepayment meter, a boiler breakdown can simply be caused by running out of credit.

Gas Valve

Any gas boiler can be affected by a change in the gas supply. Double check that the emergency shut off valve hasn’t been knocked or is on. Gas boilers can stop operating if they notice an interruption in their supply. You can do a quick check of other gas appliances (if available) to see if they’re operating as they should.

If you’re having any issues, Gas Safe engineers can resolve this problem for you.

Water Supply

Boiler Breakdown Isometric

A boiler breakdown could simply be caused by the water supply being turned off. Any internal and external stopcocks should be checked.


Boilers can only operate within certain pressures. Anything outside this range is inefficient and potentially harmful to your system. Check the pressure gauge to see if the boiler breakdown is due to being too low or too high. Boilers with low water pressure can stop working, whereas boilers that fail to release excess pressure can be dangerous. The pressure gauge should be between 1 and 2 bars.

Repressurising a boiler can be done by following the instructions in the manufacturer’s literature.

Gas Boiler Breakdown Fixes

Gas Leak

If you smell gas, you should immediately call the National Gas Emergency Service on 0800 111 999. You will be asked to turn off the gas supply to your home (if possible), and an engineer will be with you in a couple of hours.


If you have a gas boiler, check the ignition. If it isn’t firing up or clicking noises can be heard, it might be faulty. If the boiler lights and then goes off again, this indicates a fault. Newer models feature boiler breakdown codes, which you can consult the manufacturer’s literature for.

Frozen Pipes

Gas Boiler Vector

Winter can see sub zero temperatures, especially in cold snaps. Older homes without proper pipe insulation are more prone to becoming frozen, causing a blockage and boiler breakdowns. If your pipes are exposed, you can try and warm them with hot water bottles or hot water, but this relies on you knowing where the water has frozen.

The best way to resolve frozen pipes is to call in a professional. A Gas Safe Registered engineer will be able to do this for you.

Electric Boiler Breakdown Fixes

There are fewer issues related to electric boiler breakdowns as they don’t have as many parts as gas boilers. Without a gas supply, it’s just the electrics and the water supply that you’ll need to check, as well as whether there are any leaks.

Make sure you do the following checks:

  • Thermostat and programmer settings

  • Power supply

  • System pressure

  • Water supply

  • Leaks

  • Frozen pipes

  • Boiler fault codes

If you still can’t ascertain the cause of your boiler breakdown, you should always call a professional.

Other Issues


If you’ve tried to unsuccessfully fire your boiler up and you’ve followed the steps outlined above, it could just need a reset. You might be locked out, have an error code or the boiler just doesn’t seem to want to come on. Find the reset button – using the manufacturer’s literature – and restart your system. If the boiler breakdown isn’t resolved with this trick, or you have to keep resetting it, it could be the sign of a bigger underlying problem. A professional should be called in at this point.

Fault Codes

Different manufacturers feature their own fault codes. Ideal boilers, for example, have two digit codes, such as F1 and L6. Baxi boilers, meanwhile, feature a letter followed by a few numbers, such as H.01-.18. The point is, there is no universal system in labelling these codes.

If you have a modern boiler, these fault codes are invaluable for identifying the issue with your boiler breakdown. Simply find them in the manufacturer’s literature. If you don’t have a physical copy, you can find the manual for your boiler on their website. Alternatively, their fault codes can be sought online.

Boiler Service Vector

Who Do I Call?

This can be one of the most frequently asked questions. After using the troubleshooting advice outlined above, any unresolved issues resulting from a boiler breakdown should be directed to the most suitable person. This depends on your situation, as outlined below.

Home Cover

If you benefit from a home cover package from your supplier or manufacturer, you should call them to come out and check any major or underlying issues. Any cover you have should come from a lender who is authorised and regulated by the Financial Conduct Authority.


A new boiler comes with a warranty that lasts for around ten years. Any issues that arise in this time can be directed to the manufacturer, no matter where their registered office is.


Your landlord or letting agent should always be your first point of contact for a boiler breakdown. They need to be made aware of any issues that could prevent the property from being habitable.


Gas leaks or dangers should always be reported to the National Gas Emergency Service by calling 0800 111 999. An emergency engineer will always be dispatched to deal with these issues, usually within a couple of hours.

You can see the typical months that people tend to report boiler breakdowns in the graph below. The winter months are more affected, and January has a high of over 15%.

Boiler Breakdown – Be Prepared

You never know how long you’ll be without heating in the event of a boiler breakdown. A home with elderly relatives or young children will be prioritised by heating engineers, but you should make sure you have some sort of back-up heating in case boiler repairs take a few days. Electric heaters can be useful, as can spare blankets and thick clothing. In an extreme scenario, friends or relatives should be sought for temporary accommodation.

Higher Heating Bill

If you’ve noticed a sharp increase in your heating bill, it might be something much simpler than a boiler breakdown. Typical advice for boilers is that they lose efficiency over time, which lowers their heating output per unit of power supplied. Eventually, a boiler takes much more fuel to produce the same amount of heat as it did when it was first installed. If you’ve noticed a steep climb in your heating bill, it could be an indication that you need a new, more efficient boiler.

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