Is there anything worse than waking up to a cold home, or discovering you have no hot water when you really want a shower or bath? Boilers are complex beasts, but there are things that you can check safely before you need to call out an engineer. If your boiler won’t ignite, follow this step-by-step guide to find out what you can do to get your home warm and toasty again.
Cover the basics
WAIT! Before you spend money on an engineer call out, it’s worth checking the basics first…
Check the gas
It’s best to test another gas appliance to see if the problem lies with your domestic gas supply or the boiler itself. Check a gas appliance, such as the hob. If your gas supply runs through a prepayment meter, you’ll need to make sure you have enough credit.
If you have no gas at all, then this indicates that the problem lies with your utility supplier, rather than your boiler.
Check your fuse box
If a switch has tripped in your fuse box, then it may impact your boiler. Check the switches are all in the right place to ensure this isn’t the problem with your boiler.
Has there been a power cut?
If your boiler is on a timer, then a recent power cut may have reset the boiler’s timings. If this is the case, consult the boiler manual and reprogram the times of your heating.
Check if your boiler is switched on
If your boiler doesn’t ignite, then the issue may be that the boiler isn’t switched on. You can check this by looking at the power supply to your boiler and making sure the home’s electricity supply is connected.
Check the display on the boiler; there should be a message or light which would indicate that the boiler is on.
If you have a slightly older boiler, you may be able to check the pilot light. This will be the blue flame under your boiler. If this will not turn on, then the boiler will not work. If your boiler is new, then you may not see a pilot light, though it should have a reset function. Follow the instructions in your boiler’s manual to reset it, and then see if it switches back on.
Another way to check your boiler is switched on is by adjusting the thermostat to higher than 21 degrees. Temperatures below this can stop your heating from coming on, so increase the heat to see if your boiler kicks into life again.
Potential issues that could cause your boiler not to start up
1. Gas valve
One of the most common reasons why a boiler fails to ignite is because of a problem with the gas flow into your boiler. There could be a blockage or damage which is impacting the gas flow.
How to resolve it: A Gas Safe Registered engineer will be able to check your gas supply and diagnose any issues for you.
2. Gas pressure
If there is too much or too little gas, then this can cause problems with your boiler. Your boiler is likely to display a fault code if the gas pressure is wrong.
How to resolve it: Ask a Gas Safe Registered engineer to test the gas pressure throughout your system.
3. Cold weather
If you find that your boiler fails to ignite in cold weather, then it may be that your condensate pipes are frozen.
How to resolve it: Even the most looked after boiler will struggle to function if its condensate pipe freezes. Luckily, it’s not a difficult job to put things right if it does happen. We’ve got a handy guide and video on how to thaw a condensate pipe, which will help you get your boiler up and running quickly and easily.
4. Low water pressure
A boiler will struggle to ignite (or won’t bother at all) if the water pressure is too low. You can check this by looking at the boiler display. The reading should indicate that the water pressure is between one and two bars. If the reading is lower than one bar, the water pressure is too low.
How to resolve it: You can try to repressurise the boiler by following the instructions in the boiler manual.
Need a manual? If you can’t find it, you may be able to download your boiler manual online.
5. Ignition lead
The ignition lead is vital for your boiler to ignite. If, when trying to ignite your boiler, you hear clicking noises, then a faulty ignition lead or electrode may be to blame. You may also find that the boiler can ignite, but then quickly goes off again. If you have a newer boiler, a fault code will typically appear.
How to resolve it: A Gas Safe Registered engineer will be able to test and replace these parts relatively cheaply.
6. The fan isn’t operating
Inside the boiler, there’s a fan which pushes harmful gases out of the boiler and into the flue. If the fan isn’t working, then the boiler will lockout and won’t ignite.
How to resolve it: Ask a qualified heating engineer if they can replace the fan in the boiler. If your boiler is old, you may be required to replace the whole unit.
My boiler still won’t start – Next steps
Due to the many safety devices on your boiler, there could be many reasons why your boiler won’t ignite. If you can’t see an obvious problem, then you will need a professional diagnosis.
IMPORTANT: As your boiler is a gas appliance, it’s essential to be safe when trying to resolve any issues. Remember, any work on the gas boiler itself MUST be done by a Gas Safe registered engineer; it’s against the law for anyone else to do this.
These engineers are experts when it comes to boilers and will know how to work safely with gas. Do not try to alter aspects inside the boiler yourself. If there is anything you are unsure about, it is best to seek the help of a professional.
Need a one-off boiler repair? You can count on our expert repairs team to get things working again in no time.