How to bleed a radiator
By Tom Drake | 3rd October 2024 | 4 min read
Bleeding your radiators is an important part of central heating maintenance that will keep your system working at its best. Over time, air can become trapped inside radiators which will prevent water from circulating. Bleeding your radiators will remove this trapped air.
How to bleed radiators:
2. Fit the bleed key
Locate the bleed valve on your radiator. The bleed valve is a small metal square inside a white round nut that will usually be located on the side of your radiator. If you’re unsure whether you've found the bleed valve, all you need to do is check if your bleed key fits.
Why do I need to bleed my radiators?
When there's air trapped in your radiator and the water can’t circulate properly, your room will take longer to warm up. This means higher energy usage and as a result, higher bills.
How often do I need to bleed my radiators?
It’s a good idea to bleed your radiators once a year when you turn your heating system back on after the summer months. Bleeding your radiators at this time will ensure your system is working efficiently through the coldest months of the year.
How do I know if I need to bleed my radiators?
If your radiators are cold at the top but warm at the bottom, this will usually mean you need to bleed your radiators. As water is heavier than air, the trapped air will always be at the top of the radiator. This prevents warm water reaching this part of the radiator so it will feel cold.
Gurgling or banging noises coming from your radiators are also a good indicator that there’s air trapped in the system. Lastly, if you’ve noticed a general drop in the performance of your radiators over time, it’s likely they need to be bled.
Other heating issues
If your radiator is cold at the bottom, take a look at our guide to fixing that issue, or if you’ve bled your radiators and you’re still not getting the best heating performance, it might be time to invest in new radiators.
