Boiler Pilot Light Gone Out or No Flame, Causes And How To Fix

James Elston
Written by James Elston
Updated on 29th November 2023
Posted on 28th November 2023
Has Your Boiler Pilot Light Gone Out? – Causes And Fixes

Boiler Pilot Light Gone Out or No Flame: Causes and Solutions

One of the most common issues with boilers is when your boiler pilot light goes out. Although many different things can cause this, several common problems are quite easy to identify.

Most of the time, the boilers in our homes operate in the background, and years can pass without us having to inspect them for a burning pilot light for instance.

It can be challenging to identify the issue and work out how to fix it when something goes wrong.

This guide will look at these common causes and show you how to relight your pilot light if it goes out.

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What Is A Boiler Pilot Light & Why Is It Important?

The boiler pilot light is an important element of older boilers that needs to stay lit for the boiler to function. Its purpose is to ignite the gas supplied to the boiler, which provides your home with heat and hot water.

Keeping your pilot light lit is essential to ensure your boiler works properly and remains safe. The pilot light should constantly be burning; if it goes out, it must be dealt with immediately.

There are two types of boiler pilot lights. These are automatic pilot lights and manual pilot lights. Before you assess why your pilot light keeps going out, you’ll need to know which type of pilot light you have.

  • A manual pilot light: Inspecting the gas control knob is the easiest way to tell if your pilot light is manual. There should be three different settings: ‘ pilot’, ‘on’, and ‘off’. If your gas control knob has these settings, your pilot light is probably manual.
  • An automatic pilot light: A label on the front of your boiler should indicate it has an automatic pilot light.
  • If there isn’t a label on the front of the boiler, you’ll need to look at the gas control knob. If your pilot light is automatic, there should be just two settings, ‘on’ and ‘off’.
  • You should never try to light an automatic pilot light manually.

How To Tell If Your Boiler Pilot Light Has Gone Out

If you’ve noticed your boiler isn’t working correctly, it could be due to several issues unrelated to your pilot light. Considering this, you should inspect your boiler first to check that the pilot light has gone out – a straightforward procedure.

Follow these steps to help you identify the issue:

Boiler Pilot Light Burning - Call a Gas Safe Registered Engineer
  • Open the cover panel on the front of your boiler.
  • You should see a small flame. If you do, this means that the pilot light is still lit. If you can’t see a flame, the pilot light has gone out.
  • When your pilot light is functioning properly, the flame will be blue. If not, this may be a sign of a faulty pilot light.

It’s important to note that if you can smell gas fumes, you should contact your utility company immediately and ask them to turn off your gas supply. You should then get in touch with a Gas Safe registered engineer to inspect the boiler.

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The Main Reasons Your Pilot Light Keeps Going Out

There are many reasons your pilot light may have gone out and your boiler is not firing up, including some rare problems you won’t be able to identify yourself. In these cases, you’ll need to ask a registered Gas Safe engineer to identify the issue for you.

However, there are several common causes you should be able to spot yourself.

Dirty pilot orifice

If the flame coming from your pilot light is yellow and weak instead of blue, this probably means the pilot light orifice is dirty, and this dirt can prevent the flame from properly enveloping the thermocouple.

If you clean the dirty pilot orifice and the flame is still weak and yellow, this could indicate a gas leak. If this is the case, you should immediately contact a Gas Safe registered engineer.

Faulty or broken thermocouple

Another common reason your pilot light keeps going out is a broken or faulty thermocouple. The thermocouple is also known as the flame sensor. It’s a safety mechanism consisting of a copper rod which makes direct contact with the continuously burning flame of the pilot light.

If it senses that your pilot light has gone out, it will automatically turn off the gas to prevent gas from building up inside your home, leading to carbon monoxide poisoning.

When a thermocouple is faulty or broken, it can start to malfunction, and this means it may close the gas valve for no reason, which will, in turn, cause the pilot light to go out.

If you suspect the thermocouple in your boiler is broken or faulty, you should call a Gas Safe Registered Heating Engineer to inspect it.

Strong draughts

If your pilot light keeps going out, but you can relight it quickly, the issue could be strong draughts, potentially from the boiler flue or similar areas. Another telltale sign is if the light seems to go out during windy weather.

If your pilot light is affected by draughts, then the set-up of your boiler may need to be reconfigured. Again, the best way of going about this is to contact a Gas Safe engineer to take a look.

Faulty gas regulator

A malfunctioning gas regulator could also cause issues with your pilot light. If the regulator in your natural gas meter is faulty, this will affect your boiler and all of the other gas appliances in your home.

A malfunctioning gas regulator means your boiler isn’t supplied with the right amount of gas for the pilot light to stay lit. If several of the gas appliances in your home are experiencing issues, this is probably the cause.

Once you’ve identified a faulty gas valve, you should call your gas supplier and an engineer, and in the mean time, why not see how much a new boiler cost if your old boiler is starting to break down, it may be time to buy a new one to save on energy bills and repairs in the long run.

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How To Relight Your Boiler Pilot Light

Manual pilot light

  • If your boiler has a manual pilot light, you must turn the gas control knob to the ‘off’ setting rather than ‘on’ or ‘pilot’. Turn off any other gas appliances in your home.
  • Next, ensure that your thermostat is on the lowest setting.
  • Once you’ve turned the boiler off, it will release gas fumes into your home. Allow between 10 to 15 minutes so that all gas fumes will dissipate.
  • After the gas has properly dissipated, you will need to locate the panel or cover on the boiler and take it off.
  • Now, turn the gas control knob from ‘off’ to ‘pilot’ and press it down. This allows gas to flow into the boiler’s pilot light hole. Press the gas control knob and hold a lighter or lit match over the pilot light hole. Hold the knob down until the pilot light burns with a blue flame, which usually takes a minute.
  • If the pilot light goes out again when you release the knob, it has failed to reignite, and you’ll need to repeat the above steps.
  • If you repeat the steps and the pilot light goes out again, you should turn the gas off and contact an engineer.

Automatic pilot light

  • Firstly, you need to turn the boiler off using its electrical switch. If you can’t find this electrical switch on the boiler, you’ll have to locate the breaker panel and turn off the breaker switch.
  • Then, remove your boiler’s panel or cover.
  • Make sure that the gas control knob is turned off.
  • Your boiler will release gas once it’s turned off. Wait for around 10 to 15 minutes for the gas to dissipate.
  • Once the fumes have dissipated, turn the gas control knob back on.
  • Next, turn the electrical switch or breaker switch back on. You should then be able to hear a ‘click’, indicating that the automatic starter is igniting the pilot light.
  • If the clicking noise doesn’t stop or the pilot light fails to reignite, you’ll need to turn the gas off again. You should then contact a Gas Safe registered heating engineer to inspect the boiler.

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Can an unlit pilot light be dangerous?

If the pilot light in your boiler has gone out, you must turn off the gas as quickly as possible. This is because the gas supplied to your boiler won’t be burned off. The gas can then leak into your home, leading to carbon monoxide poisoning or explosions.

How much gas does a pilot light burn?

On average, a pilot light will burn around 600 BTUs of gas in an hour. That works out to around 14,400 BTUs daily and 432,000 BTUs monthly. One therm of gas equates to 100,000 BTUs of heat, which means that the average pilot light will burn around 4.3 therms of gas a month.

Can I clean a pilot light myself?

It’s relatively simple to clean a pilot light yourself if you notice that the orifice is dirty. Firstly, you should clear any debris and buildup away using a wire brush or a paper clip. Then, blow away any soot or other dirt by using compressed air.

If the pilot light is still yellow or weak after you’ve cleaned it, you will need to contact an engineer to inspect it.

Final Thoughts

If your boiler pilot light has gone out, it’s most likely due to one of the common causes discussed in this guide. Luckily, it’s reasonably straightforward to relight it yourself. However, many issues causing your pilot light to go out are too complex to tackle on your own and should instead be fixed by an engineer.

Remember, if you suspect a gas leak, you should turn off the gas immediately. You should call your gas supplier and an engineer as quickly as possible. In addition, get a Boiler Cover & Service Plan.

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Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 28th November 2023

James Elston is our resident boiler replacement and heating expert here at Boiler Central. With over 20 years experience in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutions. This can be from simply procuring the latest best combi boilers, to reviewing and ensuring that Boiler Central maintains the highest standards across our boiler installation company.

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