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Why Your Boiler Pilot Light Keeps Going Out

If your existing boiler is a little old, it will likely feature a pilot light. The pilot light should hold a continuously burning flame and must stay lit to ignite the gas and provide you with heating and hot water. But when your boiler pilot light goes out, your appliance won’t function properly. 

Read on to discover the possible reasons why your pilot light keeps going out, how you can relight it, and what to do if it doesn’t stay lit. 

Common reasons why your boiler pilot light won’t stay lit

Below is a list of reasons why a boiler pilot light can keep going out and won’t stay on. 

1. Your pilot light is exposed to a draught

Is your boiler positioned in a draught? If this is the case, a draught might be the reason your pilot light won’t stay lit. Draughts can come through windows and under doors if your property isn’t draught-proof. 

A quick and effective way to check for draughts is to light a candle close to your pilot light to see whether it blows out. If the candle blows out, chances are your boiler is exposed to a draught, which should not affect the pilot light. The only thing you can do is contact a Gas Safe registered engineer to check your boiler.   

2. The pilot light orifice is dirty

Your pilot light will struggle to hold a flame if the opening has a build-up of dirt. The pilot light should be a bright blue colour – but will be a weak yellow or orange colour that continually extinguishes itself when the pilot orifice is dirty.

Only a qualified Gas Safe engineer should deal with your gas appliances, so you’ll need to call out a professional to take a look at your boiler.  

3. Your gas regulator is faulty

When the regulator in the natural gas meter outside your home is faulty, it will impact the flow of gas to your appliances, including your boiler, and prevent the pilot light from staying lit. The easiest way to determine whether the gas regulator is faulty is to check the other gas appliances in your home. 

If you believe you have a malfunctioning gas regulator, you must contact your utility company as soon as possible to resolve the problem. 

4. The thermocouple is faulty or broken

Also known as the flame sensor, the thermocouple detects when your pilot light is lit and shuts off the gas valve when the pilot goes out. Like other parts of your boiler, the thermocouple can wear out over the years and eventually need replacing. 

The thermocouple is next to the pilot light on your boiler and is inexpensive to replace. We recommend you get a Gas Safe registered engineer to check the thermocouple and determine whether you need a replacement, which they can install for you.   

How to relight your boiler pilot light

First, you need to find the user manual that came with your boiler and look for instructions on relighting your pilot light. Don’t panic if you can’t find your manual. You can usually download a copy for free from the manufacturer’s website. 

Alternatively, you can read our step-by-step guide on relighting a manual or automatic pilot light below. 

How to relight a manual pilot light on your boiler

If your boiler has a manual pilot light, you can follow these instructions to relight it:

  • Turn the gas control knob on your boiler to the ‘off’ position and wait 10 to 15 minutes to allow the gas fumes to disappear.
  • Turn down the thermostat to its lowest setting.
  • When the gas fumes are gone, you can remove your boiler’s cover or panel.
  • Turn the gas control knob to the ‘pilot’ position, then press it to release gas into the pilot light hole.
  • Light a match and hold it at the tip of the pilot light hole whilst pressing down the knob. Keep doing this until the pilot light is lit, then carefully blow out the match away from the pilot light. 
  • Continue to press down the knob for another minute until the flame turns blue.
  • Release the knob – the pilot light should continue burning. If the pilot goes out after releasing the knob, you should repeat the above steps one more time. 

What to do if the manual pilot light doesn’t stay lit

If you fail to relight the pilot light after two attempts, turn the gas control know to the ‘off’ position and call a Gas Safe registered engineer to look at your boiler. 

How to relight an automatic pilot light on your boiler

If your boiler has an automatic pilot light, you can follow these instructions to relight it:

  • Switch off your boiler at the electrical switch, usually located somewhere on your boiler. However, you may need to find the breaker panel before flipping the breaker switch to the ‘off’ position. 
  • Remove your boiler’s cover or panel.
  • Turn the gas control knob on your boiler to the ‘off’ position.
  • Wait 10 to 15 minutes for the gas fumes to dissipate.
  • Turn the gas control knob to the ‘on’ position. 
  • Turn the electrical switch or breaker to the ‘on’ position. You should then hear a clicking sound, which is the sound of the automatic starter igniting the pilot light. 

What to do if the automatic pilot light doesn’t stay lit

If your automatic pilot light doesn’t ignite after 30 seconds or the clicking sound continues, turn off your boiler and the gas control knob before contacting a Gas Safe registered engineer to identify the cause of the problem.