Pilot light keeps going out? What it means & what to do

A pilot light that keeps going out can leave your home without heating or hot water, and repeated failures should not be ignored. The issue is usually found on older boilers with a standing pilot light, while many modern boilers use electronic ignition instead and may display a fault code or need a reset.

What a recurring pilot light problem means

The pilot light is a small, continuously burning flame that ignites the main burner when your boiler needs to produce heat. If it goes out, a safety device should stop the gas supply to the main burner, helping to prevent unburnt gas from building up.

An occasional outage may be caused by a draught or temporary interruption to the gas supply. However, if you have to relight the boiler regularly, there may be a fault with the pilot assembly, flame sensor or another internal component. Do not remove the boiler casing or attempt to adjust gas controls yourself.

Common causes homeowners can recognise

Draughts around the flue area

Strong draughts can disturb the pilot flame, particularly if the boiler is near an outside door, window or an exposed flue terminal. Blocked or damaged flue components can also affect safe operation, so never cover, alter or obstruct the flue. A Gas Safe registered engineer should inspect anything connected with the flue or combustion system.

A dirty pilot assembly

Dust, soot or debris around the pilot assembly can prevent the flame from burning steadily. The flame may appear weak, yellow or uneven rather than small and blue. Cleaning internal boiler parts is not a suitable DIY task, as the engineer may need to check combustion and gas safety afterwards.

A worn thermocouple or flame sensor

The thermocouple, or a similar flame-sensing device, confirms that the pilot is alight. If it is dirty, misaligned or failing, it may shut off the gas even when the flame appears to be burning. Replacement and testing must be carried out by a Gas Safe registered engineer.

Gas supply problems

A low or interrupted gas supply can extinguish the pilot light. Check whether other gas appliances are working, but do not interfere with the meter, pipework or boiler controls beyond the instructions in your appliance manual. If several appliances are affected, contact your gas supplier or seek professional advice.

• Check whether your cooker or other gas appliances are working normally.

• Make sure boiler ventilation openings are not blocked by boxes, furniture or stored items.

• Read the boiler manual for the approved relighting procedure.

• Stop immediately if you smell gas, feel unwell or hear unusual noises.

Safe steps before calling an engineer

First, check the manufacturer’s manual to confirm that your boiler has a standing pilot light and to find the correct relighting instructions. Some older appliances require a control to be held down for a short period, but you should only follow the exact procedure provided for your model.

Do not repeatedly try to relight the boiler if the flame will not stay on. Avoid removing the casing, cleaning the pilot with tools, changing settings or replacing a thermocouple yourself. These actions involve gas or combustion components and should only be completed by a Gas Safe registered engineer.

If you have a modern boiler without a permanent pilot light, the relevant step may be to use the reset button instead. Read our guide to the boiler reset button for general guidance, and check the boiler fault codes page if your display shows an error.

Gas safety warning

If you smell gas, do not attempt to relight the pilot. Extinguish naked flames, avoid electrical switches, leave the property immediately and call the National Gas Emergency number on 0800 111 999 from a safe location. Do not return until you have been advised that it is safe to do so.

Answers to common questions

Is it dangerous?

A single extinguished pilot light is not automatically dangerous because the boiler’s safety device should stop the gas supply. Repeated outages, a yellow flame, soot, unusual smells or signs of scorching need prompt attention, particularly if the appliance is old.

Can I relight it?

You may be able to relight an older pilot light if the manufacturer’s instructions clearly permit it and there is no smell of gas. If it goes out again, stop using the boiler and arrange an inspection rather than continuing to reset or relight it.

Why does it happen more often? Frequent outages can result from a deteriorating thermocouple, a dirty pilot assembly, changing draughts or an unreliable gas supply. The pattern can worsen as an older component wears out, so a professional diagnosis is the safest solution.

Get help with an unreliable boiler

A pilot light that repeatedly goes out is a clear reason to arrange a boiler inspection, even if the appliance starts working again temporarily. Westhill Boiler Services can investigate the cause safely and advise on suitable boiler repairs.

For reassuring, professional help, call Westhill Boiler Services on 01224548803. Always use a Gas Safe registered engineer for work on gas appliances.