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Why does my pilot light keep going out?

Reasons why a pilot light might keep going out or doesn’t ignite at all 

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What Is A Pilot Light?

The pilot light is a small burner that keeps the main burner alight in order to keep the water inside the system heated; newer boilers won’t have a pilot light as they rely solely on electronic ignition. Pilot lights can switch off for a number of reasons, sometimes it’s as simple as a draught in the boiler room and in other circumstances it may be a more complex component that is faulty e.g. a thermocouple.

Identifying the issue is the pilot light

The first sign of a pilot light malfunction would be a lack of heating and hot water output, as the boiler wouldn’t be able to heat anything without a sufficient fuel source being burnt. If your system isn’t producing any hot water or heating you can check to see if the pilot light is on by going to your boiler. The boiler case should have a glass panel somewhere on the case, if you look through this glass panel you should easily be able to see a blue flame (this is the pilot light). When a blue flame isn’t present it means the pilot light has gone out and if there is a flame but it’s a different colour there is still an issue with the pilot light. Please note that you shouldn’t remove the boiler casing or open the door unless your user manual advises it is safe to do so. It may be illegal to remove the casing without the correct qualifications depending on your model of boiler, as the casing may be purely for decorative purposes or may be integral to gas components of your system.

A boiler pilot light ignited

What is causing the pilot light to malfunction?

A draft / breeze

Once the pilot light going out has safely been identified as the cause of your boiler system not working, you can now test a few things to see what is the underlying problem making it go out. The most straightforward root of this problem would be a continuous draft in your boiler room getting behind the boiler case and blowing it out. You can rule this out by going into your boiler room when there is some wind and feeling for a draft. Upon locating the source of the draft you will need to fill the gap that is letting the draft enter the room, once this has been done the pilot light will need to be relit. To find out how your pilot light is ignited consult your user manual which should detail the process and if it is safe to do so yourself. Never attempt to ignite your pilot light without checking the user manual beforehand, as mentioned previously this may need to be performed by a qualified engineer for it to be done safely and legally.

A gas supply issue

Now drafts have been discussed, the next step would be to check your gas supply. To check the gas supply you can either test other gas appliances to see if they’re working or locate your gas stopcock to see if it is switched on. The gas stopcock is otherwise known as your main gas valve and provides all the gas to your property, if this is switched off then it would explain the pilot light being off also. Gas stopcocks are always located next to your gas metre so they are easily found in the event of an emergency, commercial properties may have a more complex interlock system. In the event your gas stopcock is switched off, you should always find out why this has been done by contacting anyone that has been in your boiler room recently to check if this was done as a safety precaution. If not this may have been knocked accidentally when tending to the gas metre; you can switch it back on once you have confirmed it wasn’t switched off for a reason.

A loose stopcock

Another factor that may cause your gas supply to be interrupted is a loose lever, the more often levers are used the more slack they become and are prone to falling into the off position. This can happen either on the stopcock by your metre or on the supplier’s end, if it is your stopcock you will want to contact an engineer to prevent this continuously happening. The supplier’s stopcock will be located before the gas metre on your property and unless it is an emergency situation, shouldn’t be touched by anyone without the correct qualifications to do so. Once the gas supply has been restored you then need to reignite the pilot light, as mentioned previously you need to ensure the process is safe and legal for you to do so.

A build up on the gas nozzle

Other things that may be causing the pilot light to continuously go out aren’t easily fixed and would definitely need a Gas Safe registered professional to attend the property and resolve. Pilot lights will have a gas nozzle supplying itself, over time these can develop a build-up of carbon which will restrict the gas flow. Carbon deposit build ups will stop the pilot light igniting all together or change the colour of the flame to orange or possibly even another colour. To have the gas nozzle cleaned you will need to call out an engineer as this will involve conducting work on the gas components of your boiler, which is illegal to do without being on the Gas Safe Register.

A malfunctioning thermocouple

The other part which may cause your pilot light to turn off is the thermocouple, this detects any temperature changes with the pilot light and is known to malfunction over time. When a thermocouple isn’t working correctly it won’t detect the temperature changes, meaning it won’t detect if a pilot light has gone out and won’t switch it back on. A faulty thermocouple is potentially dangerous as it may continuously let off gas which is why a boiler will often shut down if it detects a problem with the pilot light. Again, this is a problem that needs to be fixed by an engineer for it to be done following the correct safety precautions and legal regulations.

If your boiler still isn’t turning on or heating up despite the pilot light being ignited, then click here for other reasons why a boiler might not be turning on.