- 1. Air pockets in the radiator
- 2. Radiator thermostat not working properly
- 3. Sludge, debris or blockages
- 4. A radiator leak
- 5. Diverter valve fault
- 6. An issue with the central heating controls
- 7. Boiler pressure is too low
As the nights continue to get darker and the weather drops to minus figures, there is one thing most rely on – central heating. If you turn on your radiator only to find that it is stone cold, even after 20 minutes or so, it can be incredibly frustrating and worrying, especially as the thought of an expensive repair bill enters your mind. There are many different reasons why your radiator may have stopped working. Experts at the leading heating and utilities company in Scotland, Skills Training Group, have shared several reasons why this may be the case.
The first thing households need to do is determine whether the issue is with one radiator or multiple – this will help get to the bottom of the problem. The pros said: “Establishing that you have one radiator not working with cold pipes can lead you to do several quick checks. Some of the issues may require professional assistance, yet it could be that the issue is straightforward, meaning you can easily fix it yourself.”
1. Air pockets in the radiator
If households have noticed that their radiator is cold at the top, yet there is some heat at the bottom, this is “a big indicator” that the issue is simply air in the system, according to the experts. They said: “When this happens, the air takes the space designed for the hot water, preventing correct circulation in the radiator.”
To fix this issue households will need to bleed their radiator. To carry out the “simple task”, unscrew the bleed screw using a radiator key until you can hear the air hissing out. Keep going until water appears. When you notice water, tighten the bleed screw. After the air has been removed, look at the pressure in the boiler system to ensure it is still within the limits.
2. Radiator thermostat not working properly
The issue could simply be that the valve for thermostatic radiator control has switched from being set on a temperature to being turned off. The heating gurus said: “If a higher temperature has been selected, it would not be unusual for the valves to have seized in a closed state.
Radiator not working
“This is something you can quickly check by taking off the top cover from the valve. A knurled nut is usually used to secure the valve, and you can undo this with your hand. Make sure you don’t undo any of the other nuts on the valve, though, or you could find yourself with water pouring out everywhere!”
After removing the cover from the valve, check that the centre pine can be freely moved up and down by a few millimetres. If this is not possible, this means that the pin has seized. The pros advised: “Try tapping it gently to free it. If you are unable to do this, you need to substitute the valve in its entirety. We always recommend getting a professional to do this.”
3. Sludge, debris or blockages
On a rare occasion, Britons may notice that their radiator is cold at the bottom, yet hot on the top. The experts said: “This is an indication that you have debris, a blockage, or most likely, sludge, which has accumulated in the radiator. Hot water is not able to circulate because of the build-up at the bottom of the radiator.”
The “most efficient and safest way” to deal with this problem is to seek professional help, according to the pros. When you do this, they will provide what is known as a power flushing service. Power flushing is the process of removing debris and sludge that has become stuck in your central heating system over time “preventing it from functioning correctly”.
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Other signs that one may need a power flushing service is if some rooms are colder than others, the central heating takes quite some time to warm up, and households find that they have to bleed their radiators frequently. For those who have no or limited hot water, this could also be a sign of sludge build-up, although there are other potential reasons for this problem.
4. A radiator leak
This can be frustrating, as it could mean that “you’re going to have to replace your radiator”. However, external sealers and leak sealers could assist, depending on the extent of the problem. Unfortunately, leaks tend to be caused by corrosion, which may mean your system is poorly maintained and needs to be cleaned out and protected. This is the worst-case scenario, though.
The experts noted that a radiator leak from the location where a thermostatic radiator valve connects to a pipe or radiator, or a leak from the pipe joint, may just mean that the nut has gotten loose. They said: “Therefore, merely turning it with a monkey wrench could be sufficient to rectify the problem.”
Nevertheless, if you have noticed that there is quite a lot of water coming through the pipework, “it is evident that a leak is the problem” and you are advised to call a professional.
Female hand with rag cleaning water from heating radiator leak
If all or several radiators aren’t working, the pros advised: “Firstly, check your heating is switched on! Yes, we know it sounds obvious, but you would be surprised by how many people panic, assuming their radiators are broken when all they needed to do was flick a switch.”
5. Diverter valve fault
If the controls are not working correctly and the pressure is correct, yet there is still not any flow, it could indicate that there is an issue with a diverter valve. The diverter valve fault controls the flow of warm water to either your heating or taps. It will prioritise heated water to run to your taps, meaning if you switch your heating on and require warm water from your tap, the valve is going to move the feed to the tap first.
The experts warned: “If you are getting hot water to your taps but not to your radiators, this could be an indication that the diverter valve fault is stuck. This is not something that you should try to fix yourself. You need to get in touch with an experienced engineer who is Gas Safe registered.”
6. An issue with the central heating controls
Although this problem is rare, it can happen. Issues with the controls mean that your boiler may be working as it should be, and the pressure is within the limits, yet the radiators are not turning on. This could be a problem with the electronic control panel that operates the timing of your central heating and signals to your boiler.
turning the boiler down
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To see whether this is the problem, the experts instructed: “Check that the timing control is set correctly. Choose the ‘on’ demand to make sure that it heats your radiators.
“Beyond this, you are not recommended to change the control panel settings or try to discover the faults. You could end up making the problem much worse and more expensive by doing this. Instead, simply contact a professional who has the experience to get to the bottom of the issue.”
7. Boiler pressure is too low
Combi boilers work on a closed-loop system, and they are kept at the pressure of between one and two bars. If your boiler is not properly pressurised, the boiler will not provide the needed hot water to warm your house. You can find out what the pressure is visually, either via the head of the cylinder, which tends to be located in the airing cupboard or by looking at the front of the boiler.
Should you discover that the pressure is too low, the heating experts said that you can turn the top-up valve to increase the water pressure, as this will enable the required amount of water to get in. You do need to be careful, though, as you don’t want too much water to get into the system.
Keyword: ‘You can easily fix it yourself!' Why your radiators are not working properly - how to fix