A guide to your boiler

Some combi boilers have so many features they can be hard to understand. With our easy to use guide to boiler care, you can start recognising and using the heart of your central heating system – putting you in control of your energy.

In this article, we’re taking you through some of the most common dials and controls on gas-powered boilers and what they do. If you’re in any doubt about changing controls on your boiler don’t hesitate to call a professional plumber as you could cause some damage.

Different types of boiler

By far the most common way to power central heating in your home is with a gas-powered boiler. These come in a variety of different types but the most common are combi, conventional and system boilers. Check out our guide to boilers and how they work.

Pressure gauge

Your central heating is a closed system – meaning it recirculates the same water around the pipes and radiators in your home. That water expands when it heats up, so one of the most important things to look at on your boilers is the pressure gauge. This will show you (in the measurement metric ‘bar’) how much water pressure is in the system. Too much and you could risk pipes or parts of your boiler bursting. Too little and your boiler won’t be able to circulate enough hot water to your radiators – especially to those higher or further away from the boiler.

When your heating has been on for some time, and the water in the system has expanded, you should see this pressure gauge rise towards a mark. This mark will be the optimal pressure setting for your system.

If it is too low, your central heating won’t be working as well as it should.

This could be because:

  • Your radiators have air in them. This is fairly common and can be solved by bleeding the radiators. You can check by feeling the tops of your radiators – if some of them aren’t as hot as the bottom part, that could mean you have air in the system.

  • There’s a leak in your central heating somewhere. This needs to be diagnosed and fixed as soon as possible by a professional.

If it’s too high, it means your system is too full. Try bleeding some water out of your radiators to bring the pressure down. If you're not sure how to bleed your radiator, always ask a professional.

Power switch/button

There will be a way to turn your boiler on and off – that could be a switch or a button. Generally, boilers are designed to stay on for long periods, so you shouldn’t have to use this. However, if you’re going away for a long time you might want to stop your boiler from coming on at all, and this power button is the most effective.

Central heating dial

You can control how hot your boiler will make the water in your central heating system. Generally, this will be set quite high, as you’ll have thermostats around the house controlling when the boiler turns off and on or when the radiators take hot water in.

There’s usually one of these for hot water – you should see a picture near the dial showing which is which.

In most cases, you won’t need to touch these.

Eco button

Some boilers, like the Worcester-Bosch Greenstar 30CDi (combi), have an ‘eco’ button. When this is pressed (the light is on) your boiler won’t preheat the water in your hot water pipes.

Although this means you’ll have to wait a short while until you have hot water from your taps you’ll only use gas when you need it.

Upgrading your boiler

If your boiler is getting on a bit, a newer boiler is likely to be more energy-efficient, quieter, more reliable and have more features.

Take a look at our Boiler Replacement service.

Protection for your central heating

Should anything happen to your central heating it’s good to know that help is at hand. There are lots of different plans out there. View our guide on how to choose the best one for you.

Could your boiler do with a service? 

It’s important to get your boiler serviced regularly to check for any worn parts or potential problems. View our complete guide on gas boiler services.