Bind – Gas Safe Registered Boiler Engineers, Somerset & Wiltshire

Boiler Installation | Boiler Servicing & Repair | Central Heating Installation | Smart Thermostats


If you’ve been feeling a bit chilly lately, even with the heating turned up, and your radiators aren’t quite doing their job, it might be a good idea to bleed or flush them. As the UK winter approaches, our radiators become essential companions, but if they’re not pulling their weight, this blog post is here to guide you. We’ll explore common issues and handy tips forradiators not warming up to bring back that cosy warmth to your home.


Radiator Cold at the Top?

One of the possible reasons for a radiator not heating up is that there is air trapped inside it. Air can block the flow of hot water to the top of the radiator, making it feel cold or lukewarm. This can happen when the central heating system is refilled or when there is a leak in the pipework. To fix this issue, you need to bleed your radiator, which means releasing the trapped air from the bleed valve.


Bleeding Radiators Top to Bottom

Bleeding your radiators is a simple and effective way to improve their performance and efficiency. However, you need to follow the right order and sequence to ensure that you remove all the air from your heating system. The general rule is to start from the lowest radiator in your home and work your way up to the highest one. This is because air tends to rise to the top of the system, so you need to release it from the bottom first. You also need to start from the radiator that is furthest away from the boiler and move towards the closest one. This is because the boiler pumps the water to the radiators, so you need to release the air from the end of the circuit first.
To bleed your radiator, you will need a radiator key, a cloth, and a container to catch any water that might drip.

1. Turn on your heating system and identify which radiators need bleeding by feeling the top and bottom of them. If the top is cold or much colder than the bottom, it means there is air trapped inside.
2. Turn off your heating system and wait for the radiators to cool down.
3. Locate the bleed valve on the radiator that is lowest and furthest from the boiler. It is usually a small metal square inside a round nut on the side of the radiator.
4. Get your cloth to hand, and place the container on the floor below the bleed valve to catch any water that might drip.
5. Fit the radiator key to the valve and turn it anti-clockwise until you hear a hiss of air. Keep turning or wait until water starts to come out, then close the valve by turning it clockwise.
6. Repeat the process for the next radiator that is higher and closer to the boiler, until you have bled all the radiators in your home.
7. Check the pressure of your heating system and top it up if needed – usually between 1-2 bars.
8. Turn on your heating system and enjoy your warm and cosy home.

Read our blog If you still have issues with boiler pressure dropping or if you’re having further issues with cold radiators it might be time to call your local heating engineers for a service/repair.


Radiator Hot at the Top and Cold at the Bottom

Another possible reason why your radiator is colder at the bottom is that there is sludge build-up at the bottom of it – doesn’t sound good, does it?

Sludge is a mixture of rust, dirt, and impurities that can accumulate inside your radiators over time. It can block the flow of hot water to the bottom of the radiator, making it feel cold or unevenly heated. This can happen when the water in your heating system is:

a) not treated with an inhibiter or serviced.
b) when the radiators are old and corroded.
c) you don’t have a magnetic filter fitter – learn more about this by reading our blog

To fix this issue, you need to flush your radiator, which means removing the sludge from the inside of it. While this is not difficult, it does take some time and effort and might be better reserved for a heating engineer who can powerflush your entire system more effectively.

To flush your radiator, you will need a correctly sized spanner, a hosepipe, and a container to catch the dirty water.

1. First, you need to turn off your heating system and isolate the radiator by closing the valves on both ends of it – one side usually has a small white cap on it, remove the cap.
2. Then, you need to loosen the nuts that connect the radiator to the pipework and carefully detach the radiator from the wall.
3. Next, you need to take the radiator outside or to a suitable place where you can flush it with a hosepipe. You need to insert the hosepipe into one of the openings of the radiator and turn on the water until it runs clear. You might need to shake the radiator or turn it upside down to dislodge the sludge.
4. Then, you need to repeat the process for the other opening of the radiator.
5. After that, you need to reattach the radiator to the wall and the pipework and reopen the valves.
6. Finally, you need to check the pressure of your heating system and top it up if needed.


Bind – Local Boiler Engineers and Heating Repairs, Somerset & Wiltshire

If you need any further assistance or advice, please do not hesitate to contact us at Bind. We carry out heating repairs and boiler installation in Frome, Somerset and Wiltshire and can help you with any heating issues you might have. We offer free quotes, competitive prices, and high-quality service.


Need a new boiler or a boiler replacement?

Fear not, Bind’s next-day boiler installation provides homeowners with a quick and super-simple solution to their heating needs, without the hassle of waiting weeks to get a new boiler installed. We offer some amazing new boiler deals, after-sales boiler servicing and system checks too!