What to do if your boiler won’t ignite

Are you struggling to get your boiler pilot light to ignite? Can’t get any heating or hot water? Here we’ll explain some simple things you can try if your boiler won’t turn on.

Boiler pilot light keeps going out

One reason why you might not be getting any heating or hot water is if there’s no pilot light on the boiler or the boiler pilot light keeps going out.

The pilot light is used to ignite the gas, which heats the water in your boiler and fires up your central heating. If the pilot light has gone out, you’ll need to reset it following your manufacturer’s instructions.

Newer boilers will have an ignitor, whereas an older boiler pilot light may require you to light a match for ignition.

If you still can’t light your boiler, there could be debris blocking the jet. Boiler pilot light jets are relatively cheap to replace but can also be removed, cleaned and re-installed. Your heating engineer will be able to advise you on the best course of action and replace the jet accordingly.

Check for draughts

It may sound unlikely, but a draught could be blowing out the pilot light on your boiler. Check for potential draughts by lighting a candle and seeing if it blows out. Draughts often come from poorly sealed windows or under doors.

The problem can be solved by draught-proofing your property and ensuring the cover on your boiler is properly secured.

Adjust the pilot light valve

Is the flame on your pilot light present but weak? Refer to the manufacturer’s instructions to locate the screw on the pilot light valve. This can be used to adjust the flame. Following the instructions, turn the screw until the flame is blue and crisp.

Pilot light on boiler not firing up still? If you’ve tried reigniting the pilot light, you’ve checked for draughts, and you’ve adjusted the pilot light, then, unfortunately, the problem could be a little more serious.

Faulty thermocouple

If you still can’t ignite the pilot and your boiler won’t turn on, there could be a problem with the thermocouple, i.e. the sensor that opens up the gas valve when the pilot light ignites. It’s essentially a safety device to ensure gas does not leak out from your boiler when there’s no pilot light present.

If the problem’s the thermocouple, you’ll need it to get it looked at and potentially replaced by a Gas Safe registered heating engineer.

Problem with the gas valve

Your boiler won’t turn on if there’s a problem with the gas valve. This is the part that controls the flow of gas to your boiler. If more heat is needed, the valve opens up to provide more fuel. The same goes for hot water.

However, if the gas valve is blocked, seizes up or the connections are damaged, it can’t do its job correctly and therefore, could be the reason your boiler won’t ignite. In most cases, your boiler will shut down to prevent the danger of it from being supplied with too much or too little gas.

Unfortunately, a faulty gas valve isn’t likely to be something you can identify yourself and repair work will require the expertise of a Gas Safe registered engineer. The gas engineer will be able to correctly adjust or replace the valve to get your boiler back in working order.

Blocked burner

If carbon gets clogged up in your boiler’s burner, your appliance may run inconsistently or stop working altogether.

Hiring a heating engineer to clear out the carbon should fix the issue. Although, if your burner is at the end of its life, you will need to consider a replacement.

Burner replacements aren’t cheap, but you may be able to claim on your boiler insurance or warranty. If your boiler is old and out of warranty, you may want to consider a new boiler installation instead.

Boiler not heating water?

If your boiler pilot light is working, but you’re not getting any hot water, it’s worth checking the gas supply and water supply are both switched on. Accidents happen, and sometimes they get switched off. Turning them back on could save you the cost and inconvenience of calling out an engineer.

Reset your boiler – It’s also worth trying to reset your boiler – providing there is a switch on the outside you can access. Follow your manufacturer’s instructions for guidance. Never remove the casing as this is Gas Safe registered engineers’ territory only. Interfering with the internals of your boiler could potentially put you and those living in your property at risk.

Check thermostat settings – It may be worth checking your thermostat settings, just in case there’s been a power cut or your device has been knocked. Turn the thermostat right up to see if you get any hot water. If it works, go back and reset your thermostat to its normal setting.

Check clock/timer – If the clocks have recently gone back or forward, your clock or timer could be wrong. This may be the reason you’re not getting any hot water.

Noticed an orange or yellow pilot light?

If your boiler is igniting, but you notice an orange pilot light or yellow gas pilot light, it could be producing carbon monoxide. This is an odourless, poisonous gas that can be fatal.

The pilot light on your boiler should be crisp and blue. If it’s any other colour, turn off your boiler and contact a registered Gas Safe engineer to inspect it.

Expert boiler advice from Hometree

We hope this guide has helped you ignite your boiler pilot light and access the heating and hot water you require.

Got boiler care with Hometree? Give us a call if you can’t reignite the pilot light on your boiler. If we can’t help you over the phone, we’ll send out one of our Gas Safe registered engineers to inspect your boiler and carry out the necessary repairs.