Boiler not working? Try these 5 things before calling in an engineer

Isn't it always the way? The boiler works like a dream all year round then breaks down just before Christmas/when the weather turns cold. But before you call in an engineer, here's what to do

Mending a boiler
(Image credit: Shutterstock)

Why does the boiler always break down at the least convenient time (when you're on holiday during a heatwave for example)? Why does it ALWAYS stop working just when you're about to fill the house with guests or when it's freezing outside? 

Often, calling out an engineer is the only option. However, there are some steps you can take to get it going again yourself – with a little know how (which we're about to give you). 

Need a new boiler? Don't miss our essential boiler guide to picking the right one.

1. Is the boiler simply switched off?

If your boiler's timer is out of sync or has gone off altogether, it won't work as it should. Don't rule out that there could have been a power cut while you've been asleep or out that you've not noticed. If so, it might just be a case of switching it back on (there should be an obvious button on it to do this, but check the manual if not). 

Not this? Move on to tip 2.

2. Is the electricity on? Is there a gas supply?

The boiler might run on gas but it needs electricity to run. So, first off, is the electricity supply okay? You can check this on your fuse box – it might be the only switch facing downwards. Or perhaps you're on a prepayment meter? Are you in credit?

Next, check the gas supply to the house: if the gas hob or gas fire is working, it's not a problem with your supply.

Both of those coming up blank? Move on to tip 3.

3. Does turning up your thermostat kick it into action?

If you can't work out why the heating isn't coming on, perhaps your thermostat is set too low. Try notching it up above 21ºC to see if the heating kicks in – if not move on to tip 4.

4. Is the boiler pressure high enough?

This is NOT technical we promise! Look at the front of your boiler: the pressure gauge should show more than one bar – if it doesn't this might be why your boiler isn't working. 

In this case, you'll need to top up the water pressure – you can do this by opening the two valves below the boiler to increase the pressure to between one and one-and-a-half bar. Turn them off afterwards so you don’t over-pressure the boiler. Your boiler manual can be helpful for this.

Not this? Try tip 5.

5. Back to the boiler control panel: press reset

Get that manual out again to find the reset button. If yours is an old boiler that has a pilot light, you'll need to make sure it's on; if it's off, light it, following the instructions on the manual. Can't find the manual? A quick web search with the model and make of the boiler should help. 

Not this? NOW you can call the engineer.

Lucy Searle

Lucy is Global Editor-in-Chief of Homes & Gardens having worked on numerous interiors and property titles. She was founding Editor of Channel 4’s 4Homes magazine, was Associate Editor at Ideal Home, before becoming Editor-in-Chief of in 2018 then moving to Homes & Gardens in 2021. She has also written for Huffington Post, AOL, UKTV, MSN, House Beautiful, Good Homes, and many women’s titles. Find her writing about everything from buying and selling property, self build, DIY, design and consumer issues to gardening.