There can be different causes which contribute to a radiator not working as expected. With some guidance, a homeowner may be able to resolve some of the problems. A series of logical checks set out in this guide can help determine the cause. Once, the home owner determines the cause, they can then work on fixing the issue.
Step 1: Check all the radiators in your home or property
First, take a simple step of checking if this is an isolated incident. You can determine this by checking all other radiators in the property. By checking all of the radiators you can tell where the source of the problem is. If it is one radiator then it might be the radiator which is faulty. If there are multiple radiators with issues, it could be a problem with the system. It might be trivial but it is common that the heating isn't working at all. Once you have turned your heating on at the thermostat check if your radiators are still cold. If they are still cold something could be blocking the water supply. Make sure to check that all radiators are on at the thermostat and at that radiator. If you have hot water but none of the radiators are working it could be that there is a problem with the termastat. If you have no hot water at all then it could be a problem with your boiler. At this point you should not be conducting anywork you are not confortable with. Also, only registered gas safety engineers should work with gas systems, Gas Safety Regulations 1998
Standalone Cold Radiators
If you have a cold radiator but all others are working there are some quick checks you can undertake.
If the radiator has no heat at all, first, check if the valve on the radiator is not set to off. The valve can usually turnable by hand. First try turning the valve, then check if the radiator heats up. If the valve is too stiff to move, or if it does turn but the valve does not open it could be that the valve has broke. A broken valve may need replacing by a professional.
Once you have checked the valve, confirm that the radiator is warming up. You may discover that it is heating up at the bottom but staying cold at the top. This is a typicall sign that there is air in the pipes. Having air in the radiator is a common problem. Air in the system stops circulation and prevents the full radiator heating up. It is easy to fix this problem. A professional or a homeowner if they feel confortable can fix this problem. If you attempt this yourself make sure to cover yourself as hot air or water could emit from the radiator.
you fix air in a radiator by bleeding the radiator. You bleed a radiator by loosening the bleeding screw at the top of the radiator. To loosen the screw you should use a bleeding key, ensure that you have the correct key as you may blunt the screw. In this case the screw may get stuck.
The heating should off and the radiator let to cool. Open valve by turning with the key, as it loosens air will escape from the radiator. You should take care with this, if the heating as recently been on the air may be hot. After the air has escaped the water will start to flow out. Once water starts to escape, you should close the valve by tightening it with the key. Now there is no air in the radiator the water can flow to the top and heat the full radiator. Also, ensure the pressure is within the boiler limits.
Sludge of Congestion
If the radiator is still cold at the top, or if cold in other areas then something could be preventing the flow. If a radiator heats up at the top yet stays cold at the bottom its likely something has block the flow. This heating sludge. It's normal for a system to accumulate limescale, rust or dirt over time. Eventully, this builds up in to a thick sludge. Heating sludge usually accumulates at the base of a radiator. When this happens the sludge prevents heat flowing and stops the rest of the radiator heating up.
It is important to note, sludge may only occur in one radiator. As a radiator is part of a circuit it will prevent the flow from reaching other radiators after it in the circuit.
In this situation the system needs to be power flushed. Seeking professional assistance to flush the sludge is the safest option.
A proffesion connects a pump, and flows a chemical through the system to decompose the sludge. They may apply a substance to help prevent future rust. They may disconnect the radiator and flush the individual radiator if the build up is too great. After they reove the sludge the water should be able to flow through. The chemicals used to break down the sludge will be drained from the system. They will reconnect the system, check the pressure, then confirm the heating works.
Unfortunately, flushing the radiator may not solve all problems. If the sludge has built up too much, it may not be possible to flush the system. In this case you will likely need a new radiator.
It's common for a radiator to last 5 years or more without problems if you take care of your heating. If your heating is new and having problems it's best to contact the manufacturer or installer.
Why you shouldn't ignor cold or faulty radiators
If a radiator isn't working correctly you may leave your heating on longer to allow your property to heat up. Doing this may increase energy costs. Also, it can mean that faults such as sludge can occur more frequent as you are overusing your radiators.
Also if a faulty radiator is not treated. You will not be able to flush the sludge as it becomes to thick and you will need to replace the radiator or boiler.