Are you having trouble with your radiators?

As winter starts to bite and the big central heating turn on begins, your boiler starts to work its hardest. This is the time when it’s common occurrence to start experiencing various problems with your radiators.

It may be annoying not getting the full heat benefit you need, but the good news is that in my experience, there’s usually an easy enough fix for these problems, and you may not even have to call in an expert.

Below, I’m going to talk you through five main symptoms and fixes for radiators failings to heat properly.

Symptom 1: Radiator is hot at the bottom but cold at the top

The Cause: This is one of the most common problems you’re likely to encounter, and is caused by trapped air in the top of the radiator, stopping the hot water from circulating properly.

The Fix: Firstly, turn off the boiler so you don’t draw any more air into the system. Now, bleed the radiator using your radiator key, and put a cloth under the end of the radiator that you are working on.

Air should begin to hiss out, until you see water squirting into the cloth in your hand. At this point, you can close the valve up nice and tight, checking to ensure there are no leaks.

Symptom 2: Radiator is hot at the top but cold at the bottom

The Cause: If you are wondering why your radiator isn’t heating at the bottom, the chances are it could be full of silt or sludge, stopping the radiator from getting hot.

The Fix: This is usually a simple enough case of cleansing and flushing the system, however, if your radiator has any signs of corrosion or rust around the ends, it’s probably wise to just replace it entirely.

To cleanse and flush it, drain the system, remove the radiator from the wall and flush it out. You can also buy various chemical sludge removers and system cleaners if you think your whole system may be affected. Refill the radiator, test it, and add some corrosion inhibitor to stop rust.

Symptom 3: A single radiator is cold/not working

The Cause: If just one of your radiators is not playing ball, it could be down to either a faulty or jammed valve, or alternatively a blocked pipe could be the culprit.

The Fix: Check all of your valves, especially your thermostatic radiator valves (TRVs) as they can easily jam. Turn all the other radiators off to try and force the heat through, and see what happens.

If you have a blocked pipe, I’d recommend calling in the professionals, as it may require flushing or cutting out and replacing any faulty pipework.

I was once called to a job where the upstairs radiators had been turned off for a number of years, as the rooms were not used. The pipe leading to the radiators had sludged up and stopped the radiators receiving any heat.

Symptom 4: All radiators are not working

The Cause: This could be down to one of three possible causes:

• A faulty motorised valve
• A fauly pump
• A problem with your boiler

The Fix: I’m afraid that for this one, you really need to call in a Gas Safe registered engineer as this usually signifies a more serious problem.

Symptom 5: A lukewarm radiator

The Cause: When this happens, it usually means there’s a restricted flow, which could have been caused by a kinked pipe that may have been bashed, or faulty TRV.

The Fix: It’s possible that the TRV pin could be stuck, so unscrew the head and try pushing down on the exposed pin. It should move down and then spring back up – if this doesn’t happen, it may just need replaced.

Close all the other radiators to try force heat through and see if that makes any difference. If all else fails, call in the experts. It’s very possible that a valve or piece of pipework may need replaced. Another explanation is that the radiator may need flushed.

In the past, I’ve been called out to customers whose radiator hadn’t been heating, and they had been airing it to check if this was the problem. However, we found the TRV was jammed as it had been turned to the ‘off’ position for two years since the children left home.

Check your room thermostat/temp control

Remember, you will likely have a room thermostat which tells the boiler to come on and switch off when the room reaches the correct temperature.

There is also a temperature control on the boiler which controls the temperature of the water going through your radiators. If this is turned down low, the radiators will not get as hot as you might need them to in the depths of winter.

It’s also worth bearing in mind that if you have a very large radiator in a small room fitted with a thermostatic radiator valve, it will cut off once the room comes up to the correct temperature. So, the radiator may only just be warm, but this is adequate for the room.

Conclusion

As we start to use our heating more and more, we also start to notice any problems with our radiators. Fortunately, there’s usually a quick enough fix, that may mean you won’t actually have to call a heating engineer (but sometimes it is unavoidable).

The above symptoms and fixes should be able to help you with some of the most common radiator issues. Don’t forget to check your room thermostat, as that tells your boiler to come on and switch off when the room reaches the correct temperature.