<iframe src="https://www.googletagmanager.com/ns.html?id=GTM-MH5676" height="0" width="0" style="display:none;visibility:hidden"></iframe>How to fix a cold radiator | Local Heroes

How to fix a cold radiator

Posted on 2/1/2020

During the colder months, a nice warm radiator is like your best friend, but if one or more of your radiators won’t warm up, it can become a pain. So what can you do to fix it? Should you call an engineer immediately or can you investigate the issue yourself?

Here’s how to identify what’s causing the problem and how to fix it.

Check your central heating system and hot water pump

You’ve probably already thought to do this, but it’s worth making sure it’s just one radiator not heating up and not all of them. If none of them are turning on, there could be a problem with your central heating system.

Take a look at your system and check your heating is actually working. Is it making a funny noise? Do you have no hot water? If your answer is ‘yes’ to either of these, call in a professional right away.

A common problem is with the hot water pump. It could be that yours is broken or just on a low setting, preventing hot water from reaching your radiators furthest from the boiler.

First, check your pump is making a noise to show it’s working. Or, if it’s on a low setting, try turning it up one notch to see if that helps.

Check your thermostat

Another obvious one, but if your heating’s on but none of your radiators are warming up, do just check your thermostat is turned up to the right temperature! If it’s been turned down low for any reason, whether it’s because you’ve been away or your kids have been meddling with it, turn it back up to about 180 – 200 and see if that does the trick.

Check the valve

If it’s definitely just one radiator that won’t heat up, you should make sure that both valves either side of it are open to allow hot water through it. Try turning the thermostatic valve (the one with numbers) to its maximum setting to see if it brings the radiator to life. If the pipe leading into the valve is hot and the radiator immediately next to the valve is still cold, it’s likely it’s the valve that’s the problem.

If you can’t turn one or both of the valves, they could be jammed, which can happen if they’ve been off for a while. Try turning them both using a cloth for extra grip. If they still won’t budge, call in a professional.

Check for trapped air and bleed your radiators

If you’ve checked the valve and you’re still seeing no results, your system might have trapped air.

If you’ve just turned on the heating after a long time off, such as the summer, air can become trapped in your radiators. This can cause them to warm in patches, usually hot at the bottom and cold at the top.

How to bleed your radiators

First, grab a bucket to catch any water that might leak out. It’s often quite brown in colour, so cover any surfaces you think it might come into contact with. Use a radiator key (you can buy one at any hardware store) to slowly unscrew the bleed screw until you hear a hissing sound, which is air escaping from the system. As soon as the hissing stops and water appears, tighten the bleed screw again. Your radiator should soon function normally.

Read a full guide to bleeding your radiators

Powerflushing your system

If none of the above works, your system might need to be powerflushed.

Powerflushing is the process of removing dirt and debris from within your central heating system. If after bleeding you’ve noticed that your radiators are still warm at the top but not the bottom, this might be because of dirt in your system.

Ask a professional

Of course, it could be that the one radiator not heating up is the only one in your home with dirt in it.

In this case, a professional might advise you that it’s cheaper to simply replace it rather than pay for your system to be powerflushed.

In short, if you’re not sure what to do next, it’s always a good idea to ask a professional first. Get in touch with a Local Hero that lives nearby and they’ll be able to help.

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