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Why Your Boiler Does Not Ignite?

In this article, we look at the causes of why your boiler won't ignite and offer some simple solutions before calling in the professionals.

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Why Your Boiler Does Not Ignite?

Reasons Why & How To Fix Them

You know it’s not going to be a good day when you wake up and your home feels much colder than usual or you jump straight into a cold shower without checking it’s warm first. So you look at your boiler and it’s flashing red at you, you check the error code and find that there’s a problem with the boiler ignition, but why?

If there is an issue with your boiler it will lockout as a safety precaution and won’t ignite until the issue has been sorted.

In this article, we will look at reasons why your boiler won’t ignite and steps you can take to diagnose (and hopefully fix) the issue before you need to call out a Gas Safe Engineer to take a look.

woman under blanket in cold home

Check The Basics First

Some of these suggestions may sound a bit obvious but you’d be surprised at some of the issues that many boiler installation companies have seen over the years, so it makes sense to just cross off the basics first before looking at more serious issues.

Check The Gas Supply To Your Property

If you have a gas boiler then it won’t be able to ignite without a gas supply. Check another appliance in your home that runs on gas such as a hob to ensure that the gas supply to your property has not been interrupted.

If you have no gas supply then you will need to contact your utility company and tell them about your cold shower experience, they will no doubt make it their top priority to get it sorted.

For homes with a prepayment meter, ensure that you have enough credit.

Check The Timer On Your Boiler

An easily overlooked issue is an out of sync timer or smart thermostat. If you use the timer on your boiler and there’s been a power cut in your area it can result in the timer getting out of sync and the heating won’t come on when you expect it to. Just check the dial on the boiler is set to the correct time.

Similarly, if you have a smart thermostat that loses connection to your internet, it could get out of sync, in the same way, the timer on your boiler can. Just check the settings on your smart thermostat to ensure the timing is correct.

Crank The Heating Up

It’s worth turning your heating up above 21 degrees Celcius to check your boiler is turned on, if the room temperature is below this then your boiler may be off because it isn’t cold enough for it to switch on. Turn your thermostat up and see if it kicks in.

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Check Your Fuse Box

The final basic check to rule out is a tripped fuse in your fuse box. Your boiler won’t ignite if it has no power supply. If any fuses have tripped turn them back on and try again.

If your boiler is flashing an error message at you then you know it has power, if the LCD screen is blank then there is a good chance it has no power.

Once you’ve established your boiler has a fuel and power supply we can look at some more likely candidates as to why your boiler won’t turn on.

lit gas hob with blue flame

Low Water Pressure

One of the more common reasons for your boiler locking out and not igniting is due to low water pressure. This is often caused by a small leak in your system, like a drip on a radiator, which over time will decrease your system pressure until it causes a lockout.

The ideal pressure level is between 1 – 1.5 bar (the green section on the pressure gauge on your boiler).

If you’ve recently had a boiler installed or recently bled your radiators then there is a good chance that you’ve released air from your system causing the pressure to drop. The good news is, that this is one you can fix yourself in just a few minutes without any technical know-how.

If there is a leak coming from your boiler or the pipes beneath the boiler then you will need a Gas Safe Engineer to take a look as there is a malfunctioning part. If the leak is coming from a radiator or radiator valve then you can re-pressurise the boiler but you will need to fix the leak or the system will continue to lose pressure.

Every boiler is different, so we recommend referring to your boiler manual if you have it, or searching for it online if you don’t. Some boilers have filling loops and some have internal filling keys, it’s the same principle to re-pressurise but slightly different methods are used.

  • Switch off your boiler and let it cool completely.
  • Find the filling loop (flexible silver cable) and make sure both ends are tight or you may have an internal filling key but it’s the same principle.
  • Open bath valves or turn your internal filling key to allow cold water into the system, this will re-pressurise the system.
  • When the gauge reaches 1.5 bar close both valves.
  • Remove the filling loop if it isn’t a permanent attachment.
  • Turn the boiler back on.

Once you’ve completed the steps above and the pressure has been increased, your boiler should now fire up and provide you with the warmth you deserve.

boiler pressure gauge

Frozen Condensate Pipe

Condensing boilers (any boiler installed after 2005) have a white plastic pipe coming out of them (you guessed it, the condensate pipe) which transports waste acidic water from your boiler outdoors to either a drain or a waste pipe.

In particularly cold weather, the water in this pipe can freeze. This will cause a backing up in the system as the water has no way out. The system will then lockout to prevent any harm from coming to the boiler.

Your boiler will then display an error code to inform you that you have a frozen condensate pipe. You may also hear a strange gurgling noise coming from your boiler.

This is another issue you can easily fix yourself by pouring some warm water on the frozen area of the pipe to melt the frozen water inside.

frozen condensate pipe

WARMZILLA

Gas Valve Fault

The gas valve in your boiler is responsible for controlling the flow of gas into your boiler. If you request a higher temperature, the gas valve will open and allow more gas into the boiler to be burned to heat your home.

If there is too much or too little gas being supplied your boiler will lockout for safety reasons. You should not attempt to resolve any issue linked to a gas valve yourself, you will need to call a Gas Safe Engineer. Gas valve issues can arise due to a blockage stopping the gas flowing or from a wiring malfunction. Usually, it’s an issue with the adjustment of the gas valve and it’s not a major job to fix and will cost in the region of £220.

If you have a boiler that is already over 7 years old and you’ve previously had issues with it then rather than continuing to sink money into it, it might be worth getting a quote on a new boiler.

Gas Pressure

We’ve already done a basic check to make sure your property has a gas supply coming into the property but your boiler will also lockout if the gas pressure is either too high or too low.

A Gas Safe engineer will need to test your gas supply to ensure you have the correct gas pressure.

In particularly cold weather the regulator on gas meters can freeze and this will affect your gas supply. This issue can be resolved by lagging your gas meter box.

Faulty Ignition Lead

If, when trying to ignite your boiler you can hear a clicking noise then you may have a faulty ignition lead or electrode. This is the part responsible for providing the spark that fires up your boiler.

This is something a trained engineer will need to take a look at, they’ll check the electrode and ignition lead with a multimeter to see if there are any issues. If there is a fault with your ignition lead then it will cost anywhere around £200 to fix.

Fan Malfunction

The fan within your boiler creates a draught which draws the harmful gases produced as a by-product of burning gas out through the flue in your boiler.

If there is a malfunction with the fan then your boiler will lockout as a safety precaution. You will need to call a Gas Safe Engineer to look at your boiler. If there is an issue with the fan on your boiler then you can expect to pay between £200 – £275, depending on the heating engineer and the area of the country you live in.

Pilot Light Has Gone Out

On older boilers, particularly back boilers, the pilot light might have gone out. You can try to relight the pilot light yourself but if the pilot keeps going out then there is likely an issue that will need to be looked at.

The jet for the pilot light has a very small aperture at the end, which can easily become blocked and require cleaning out. Again, you can do this yourself but we would recommend getting a Gas Safe Engineer out just to check that everything is in good order.

If you have an issue with a back boiler then we would recommend not spending any more on it. They are old, inefficient, and bad for the environment. Replacing an old G-rated boiler for a modern A-rated boiler can save you up to £310 per year on heating bills.

match lit for pilot light in boiler

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Other Possible Causes

There are any number of issues that could cause your boiler to fail to ignite. Above we have looked at the most common causes as to why your boiler might not switch on.

If you have gone through the issues above and ruled them out then it might be time to call in a professional and get them to check over your boiler. You shouldn’t take any chances when it comes to gas boilers, it’s illegal for anyone other than a Gas Safe Registered Engineer to work on a boiler.

To help you identify the issue with your boiler you will often be given an error code that you can look up in the boiler manual to see exactly what is causing the issue with your boiler. if you can’t find the code in the manual, look it up on the internet.

REMEMBER – NEVER UNDERTAKE ANY REPAIRS ON YOUR BOILER!!

If you still don’t have an answer to your question and need help and support, contact a trusted gas certified boiler installer who will be happy to help!

It always pays to do some research when buying a new boiler so be sure to take a look at our Heating Shop to get some help and support!

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