Column Rads Guide to
Radiator Troubleshooting

For the most part radiators in your home need very little on-going maintenance and will typically work for years without much intervention. However, as with most things in life, occasionally a radiator can go wrong and problems can occur. Because the radiator in the home is generally off for a large portion of the year, such as through the summer months, it is common for any problems to crop up just as soon as you actually need your radiator to heat your room.

This guide has been put together to give you some advice on how to trouble shoot and solve some of the common problems that may occur with your hot water radiator.

Cold Radiators

One of the most common problems that affects a radiator is that it is not producing any heat and it is cold. In these situations, the very first thing to check is if it is a solitary problem with one radiator in your home or if there is a problem with all the radiators. If all the radiators in your home are cold then most likely it is not the radiator that is at fault, instead the issue lies somewhere else. It is highly unlikely for all your radiators to break at once, so you can start to look at other issues.

It is possible that someone has turned off the valves leading to all the radiators, therefore shutting them all off, so this is worth checking to ensure that this is not the case. It is also worth checking to ensure that your hot water and boiler are switched on and are working. Again it is common to simply turn off the heating completely through the summer and then forget about turning it on again in the colder months. Again, is the thermostat set at the correct temperature or has it been switched off or turned down? Sometimes the most obvious and simplest thing is the cause of the problem.

If checking the valves, thermostat and boilers didn’t help resolve the radiator heat issues, then it might be time to call a professional in. If you are not trained in boiler servicing or repair you can make some costly and potentially dangerous mistakes and it’s just not worth the risk to try to fix something that you are not that experienced with.

Is the Problem With Just One Radiator?

If you find that most of your radiators are working and it is just a solitary unit that is not producing any or adequate heat, then you can be fairly sure that the problem lies within the radiator itself.

In this situation the first thing to check is whether the entire radiator is completely cold or whether there is some heat being generated.

If the radiator is completely cold, then the first thing to check is whether the valves on both sides are switched to the open position. As we’ve mentioned earlier in this article the most common reason for a cold radiator is because it is switched off at the valve. If both the valves are open, then the next thing to check (if your radiator is fitted with one) is if the thermostatic valve is working correctly. An issue that can occur over time is that the valve pin can become a little stuck and if this is stuck in the off position then the radiator will not generate any heat.

The way to fix this is to initially remove the thermostatic valve head to check whether the pin is stuck. You can remove the head mechanism from the thermostatic value either by unscrewing by hand (if it is loose enough) or using some plyers or grips to loosen the head from the valve.

Radiator Valves

Once the head is off the thermostatic valve then you will see a metal pin within the valve. This should be in the fully up position and you should be able to press it down and move it freely back and forth. If the valve is in the down position, or is stuck in the half way position then you have a sticky valve and this will need to be repaired. In some situations, simply ‘freeing’ up the valve with a tap of a hammer, or by moving it gently up and down with plyers may be enough to fix the problem. Remember to reign in the brute force! Tap and not hit is the key phrase here. If the valve is truly stuck, then you may need to replace the valve. Whilst this job is fairly straight forward, some people may wish to get a plumber in to do the job at this point.

Radiator is Just Warm at the Bottom

If your radiator is only warm at the bottom, then the most common problem is that the radiator has air in it and it needs to be ‘bled’. Bleeding a radiator is simply the process of letting the trapped air escape from the radiator. Cold spots on the radiator are normally caused by this trapped air. It’s fairly common to have to bleed a radiator from time to time, therefore it is a good idea to learn how to do it since calling out a plumber to fix this common and simple issue is not very cost effective.

Typically, you will need to use a radiator key to bleed the radiator. A radiator key is a small tool that has been specifically designed to make bleeding a radiator easy. These can be purchased here at /radiator-air-vent-key

This key will fit the small valve that is located at the top of the radiator. Some valves are designed to use a socket or a screwdriver. Use which ever tool is appropriate for your own system.

Radiator Key

How to Bleed a Radiator

To bleed a radiator, firstly ensure that the heating system is switched off. This is an important step because the heating system contains hot water and if you try this process when the heating is on then there is a possibility of burning yourself. Don’t forget to allow enough time for the heating system to cool down. Your radiator may not be that hot, but the water inside it most likely is!

When you bleed a radiator to let the air escape from the system you will also likely release some hot water along with it. The best way to deal with this is to have a bowl and old cloth handy to mop up any drips. Some water will most likely be released from the system so if there any perishable or electrical items in the vicinity then this is the time to move them.

Slowly open the valve, counter clockwise with the radiator key. You should hear a hissing sound as the air escapes from the system. Eventually some water will start to be released and this is your cue to tighten up the valve again, with a clockwise turn of the key.

When you release water from the system you may end up lowering the overall pressure in the system which means you may need to add more water to the boiler. This might need to occur during or even after the bleeding process. If you’re unfamiliar with how to do this or how your specific system works, then it might be worth calling for an expert to help you. Sometimes it can also be a good idea to bleed all the radiators in your house at the same time since if one radiator is having a problem it can have a knock on effect to the other radiators too.

Bottom of the Radiator is Cold

If the bottom of the radiator is cold but the top is warm, then this might be indicative of a more serious issue with this one particular radiator.

Generally, when this situation crops up it means that there is a layer of sludge within the radiator and that it will need to be cleaned out or even in some cases replaced. If you are confident with your plumbing skills, then it is possible to carry out this job yourself. However, it should be noted that to clean out the radiator it will need to be disconnected and removed from the wall. Since radiators are filled with water this means that quite a lot of water will be released as the radiator is removed. Towels and mops will be required to keep the water at bay.

Firstly, at this point it might be a good idea to get a plumber in to clean out your radiator using a professional tool called a power flusher. For those who would still prefer to do the job themselves the process then the first thing to do is to isolate the radiator from the rest of the system. This is done by switching off the valves at both sites of the radiator. Then using your bleed key, you need to open the air vent at the top of the radiator until the water stops dribbling. This means that the radiator is then isolated correctly at the valves. At this point, remember to close the air vent again.

Place all your towels under the radiator and then slacken off the nuts on the inside of the valves that attach the radiator to the valves. Some water may drip out at this point. Once the nuts are loose then flip the radiator down on the floor, so the top is resting on the ground, whilst it’s still attached loosely to the valves. This can help reduce the water spillage. When the radiator is in this position you are now free to remove the nuts completely and lift off the radiator, upside down so as not to spill the water that is still inside it. For large radiators this might not be possible as they will be heavy, so a good number of towels may be required! In addition, this trick might now work depending on how the pipes and the radiator fit together. In these instances, a radiator drain kit might be worth investing in since they are pretty cheap.

Next step is to find an appropriate place to empty out the radiator. A bath would suffice or a garden ideally since you will need access to a hose and water supply to carry out the next step. Once the radiator is clear of water then you will need to attach a garden hose to the water inlet valve and turn on the water to blast out any sludge that is inside. It can be a good idea to do this via both connector holes to ensure all the sludge is removed. Once this has been done to your satisfaction then you will need to reverse the process to re-attach it to your wall. Don’t forget to bleed to the radiator as it will be full of air.

My Radiator is Leaking

If your radiator is leaking, then the solution is dependent on where the leak is coming from. If it is coming from one of the valves or one of the connectors, then it might be possible to tighten up the connections with a wrench to fix the leak.

If the water is coming from the radiator itself then you will need to isolate the leak by turning off the valves to minimise the discharge and either repair or replace the radiator or call in an expert for help.

My Radiator is Noisy

Generally clanking pipes or noisy radiators are caused by pipes or fitting that has not been given enough room to contract and expand as the heating system heats and cools. If this is the case with your heating system, it might be worth getting a plumber in to help diagnose and resolve the issues. In some instances, plastic piping can help because of the flexibility that plastic has over copper. In other cases, some basic adjustments can be made to the system to help reduce the noise.

How to Clean a Radiator

Generally cleaning a radiator is fairly straight forward. For those who are looking to maintain their radiators in tip-top condition it is possible to follow the same steps for clearing out the sludge in a radiator (see Bottom of the Radiator is Cold, above) though it is generally not worth the hassle doing this until there is a problem, since removing the radiator from the wall can in itself cause issues.

For general spring cleaning the best way to clean a radiator is firstly to vacuum it regularly to keep it as dust free as possible. It is best to clean the radiator of course when it is switched off since you’re going to have to get up close to the heat.

Use a dust cloth and push through the grooves and gaps in the radiator to brush off as much dust as you can. Then you can simply use soap and warm water to wash the radiator and clean it. Remember to dry off the radiator with a dry cloth to avoid any potential for corrosion.

Next Steps & Finding a Professional to Fix Your Radiator

If these common faults and issues do not cover your particular issue or do not help rectify the situation with your heating system, then it might be time to call out a professional to look into the problem further. Generally, most issues with a faulty radiator can be resolves fairly quickly and cheaply, however if the problem lies with the boiler then there may be a more serious problem that will need to be dealt with.

If it is a radiator from ColumnRads, you can of course contact us for more info. All our products are guaranteed for a minimum of 1 year (radiators 10 years, copper tube 25 years) but many offer longer warranties from the manufacturer, which you may need to register for.