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Why Are My Radiators Not Working

  • Posted by:
  • Admin
  • Tags:
  • central heating, radiators, central heating issues
  • Posted date:
  • 03-10-2021
Why Are My Radiators Not Working

Why are my radiators not working? We look at what to do when your radiators won't heat up. Find out what to do if you have cold radiators.

What to do When Your Radiators don't Heat Up 

In the winter months, when you need your radiators most, it can be a significant issue when they fail to heat up properly. 

Thankfully, if you find that your radiator not working or is cold, there are a few things you can do to get your home warm again as quickly as possible. 

In most cases, the issues facing your radiators or central heating system are easy to solve, so there is not too much to worry about.

Check for Problems with Your Central Heating & Boiler 

This first step will help you identify any serious radiator problems if they are there. 

Starting from the beginning, checking that your boiler and central heating system is operating properly will allow you to determine why multiple radiators aren't working. 

If every one of your radiators is cold, this suggests it is a problem with the entire system, rather than just one radiator.  

Assessing your heating system and the boiler will also allow you to discern anything unusual with these elements, for example, if they are making strange noises or not producing any hot water. 

If you find any of these significantly strange things going on with your boiler or central heating system, you should contact your local heating engineers and arrange for them to diagnose the problem.

Why Are My Radiators Not Working?

Check for Trapped Air  

If you find that only one or a couple of your radiators is not heating up properly, this is most likely caused by trapped air in the system. 

This trapping of air is especially common after you have turned your heating off through the summer, turning it on suddenly in the winter. A sure sign of this is the bottom of the radiator being warm while the top is cold.  

An easy fix to help release this trapped air from your radiators is to bleed them. Using a radiator key, you can unscrew the bleed valve slightly until there is a hissing sound and release the trapped air. After the hissing noise stops and water begins to flow out of the radiator, the trapped air has escaped, and you can close the valve again. Your radiator should now be able to get nice and warm again.

Check Your Radiator Valves

Check Your Radiator Valves 

If you have released the trapped air and your radiator isn't heating correctly, or you still have entirely cold radiators when they are cold at the top as well, then there could be an issue with the radiator valves. Checking these valves is the next step to take to get your heating system running smoothly again.  

Essentially, there are two valves at either end of your radiator, which should be open. Additionally, if you have a thermostatic valve, which allows you to control the radiator's temperature, ensure that this is turned up high enough.  

Another common cause of your radiators not working correctly is your thermostatic valve becoming stuck. However, this is not something you should attempt to fix yourself. It is far safer to have an experienced and skilled heating engineer to attend to the problem. They can assess the damage and replace the valve when necessary.

Do you Need Powerflushing? 

If none of the previously mentioned solutions appears to help your radiators get back to working order, you may need to consider power flushing. This is the process of removing a build-up of sludge and debris from your radiators. 

This sludge naturally builds up in your central heating system and can prevent it from heating your radiators properly.  

A key sign you could need to power flush your system is that your radiators are cold at the bottom but getting hot at the top. This suggests that the sludge builds up at the bottom of your radiators, preventing the hot water from travelling freely. 

A Gas Safe registered engineer can flush out this sludge and help your central heating system to operate correctly again. 

Ask a Professional Heating Engineer 

If you have tested all of these possibilities and can not figure out what is wrong with your radiators, getting in contact with a professional engineer is the best option. 

No matter the issue, experienced heating or boiler engineers can diagnose the problem, fix it and provide expert advice on preventing similar issues in the future.  

It would be best not to fix the issue yourself, as the complexity and danger of mending heating systems require expert knowledge and skill. 

Therefore, arranging for a professional to come and fix the problem is your best option.

Do You Need Powerflushing?

Why is my radiator cold at the bottom? 

If you find that one or more of your radiators is cold at the bottom but warm at the top, this is a clear sign that there is a build-up of sludge and debris blocking the free-flowing of warm water through the system. 

This debris can also contain oxidised rust or dirt that is caused by the corrosion of your pipework. Of course, if you live in an area with a lot of hard water in its utility system, limescale is also a possible cause of blockages in your radiators.  

If you find that only one radiator suffers from a blockage, you can remove it and clean it out entirely. An engineer can take it from your wall and hose out the debris before refitting it. 

If the problem extends throughout your whole heating system, power flushing is the best option. An engineer will put a high force of water through the system that will dislodge the sludge and debris, freeing the system.

Why Is One Radiator Cold When The Heating Is On?

Why is one radiator cold when the heating is on? 

If just one of your radiators is cold while the others are working perfectly, this is most likely caused by trapped air or a stuck thermostat valve. 

Thermostatic radiator valves (TRVs) control the flow of hot water through the radiator, so when it becomes stuck, it cannot open and allow the water to flow.  

To loosen this stuck valve, remove the head to reveal the pin underneath, which you should be able to press in with your finger. When you lift away from it, the pin should rise on its own to where it was. 

If the pin does not move back or is already depressed when you remove the head, this fault is likely the source of the issue. You can try to free the pin with pliers, but do not use too much force.

Why are my downstairs radiators cold? 

If it is only your downstairs radiators that are cold, this could be due to balance issues. Hot water naturally rises upwards through your system, so if only the upstairs radiators receive this heat, you need to address this imbalance. 

To do this, close the lockshield on the upstairs radiators (the small valve on the opposite end to the thermostatic valve) and then open them a quarter of the way. This will encourage the heat to flow back downstairs.  

If this does not work, you may need to rebalance the entirety of your central heating system. This can be done yourself, but contact your local professional heating engineer if you are unsure of what to do. They will remedy the problem, offering free quotes for any work you need before being called out.


We offer services to both domestic and commercial customers in Uppingham, Oakham, Stamford and Rutland. Our charges are highly competitive and realistic. If you are experiencing problems with your central heating - Please contact us.