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Why is Your Radiator Cold at the Bottom?

There is nothing quite as nice to waking up to a comfortable and warm home in the morning when it’s cold outside. The problems begin in the day when you wake up to a chilly house and realise that the radiators are not as efficient as they should be and are no longer warming up.

When you find your radiator hot at the top but cold at the bottom, you have a problem in your heating system. Of course, there are plenty of reasons that this can happen and yet no matter how hard your heating system is working, you will find that you need to give your radiators some attention from time to time to keep them warm – as they should be! When you neglect your radiators and their maintenance, you will find that they take longer to heat up and they will remain cold at the bottom and hot at the top.

If you have ever wondered “why is my radiator cold at the bottom?” you’re in the right place. Your radiators need a little TLC and so in this article, we’re going to talk you through the reasons that your radiator is cold at the bottom.

What Can Cause A Radiator To Have A Cold Bottom?

When you notice that your radiator is hot at top cold at bottom, there is a chance that there is a blockage in place that is preventing the flow of hot water to the bottom of the radiator. Most people are unaware that debris can be collected in a radiator, but this debris is made up of sludge, rust, dirt and other bits of muck that collect over time in the metal pipes. Metal pipes inside radiators degrade over time when they are constantly subjected to the onslaught of hot water and oxygen, and the rust breaks off after it occurs. This is then carried around your radiators and into the pipes, and blocks up the flow of water through the radiator. When you are living in a hard water area, you may find that you are dealing with limescale build up in the radiators, too. These can all cause blockages in your radiators and the smallest blockage can quickly turn into a larger one, causing the radiator to remain only warm at the top.

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A radiator that is cold at the bottom but warm at the top shows that there is an interruption in the flow of hot water through the system. If you are dealing with just one radiator in the house with this problem, you can remove the radiator and clean it throughout. This should help you to remove the blockage and you can use a garden hose to remove the dirt and then refit it to the wall with the water flowing through it properly. However, if the problems with radiators in your home happen to more than one, you should ensure that the whole system flushes out.

It is well known that central heating sludge is the main cause of a radiator hot at top cold at bottom. This sludge is made up of limescale, dirty water and incorrectly placed filters. It can take years for sludge to build up and cause serious issues in your radiators, and even those in soft water areas can be affected by limescale in the radiators of the home. It takes longer in soft water areas to notice a blockage compared to hard water areas, but nevertheless, they can still be affected. Dirty heating water, as mentioned, is made up of rust in the towel rails and radiators that circulate. The sludge you get is thick, black and dirty and it settles right at the bottom of the radiators, causing them to be cold at the bottom. The sludge circulates around the heating system and gets into the radiator valves, pipe work and bottoms of radiators, which leaves it blocked from receiving the hot water. As the heat rises, the radiator will get hot at the top, but there’s nowhere for the hot water to go at the bottom of the radiator – and this causes the main problem.

What Won’t Help

When it comes to having a radiator hot at top and cold at bottom, you need to learn what not to do so that you can get rid of the problem.

When you notice a cold patch at the bottom of the radiator, you are likely to immediately turn to the thermostat as if the problem is that your heating is not on a high enough setting. Instead, you will find that this won’t help the cold patches in the radiator at all – it’ll just push the heating bill through the roof as you heat only the top of the radiator and leave the bottom cold. Cranking up the thermostat will also put your boiler to work even harder than usual. The pressure you put onto your boiler can end with you needing to replace it as it overworks, and that’s just not ideal!

You want to return balance to your radiators instead of trying to push more hot water through them without checking whether there is a blockage in the first place. You need to fix the problem and we’ve got some suggestions for you!

What Will Help

The radiators can eventually make a problem for your boiler, but there are a number of things that you can do to clear out the muck and get the radiators back to the efficiency.

You can’t just wait for the sludge to rectify on its own. The longer the problem is left behind, the worse the problem gets and the more sludge accumulates. The radiators can eventually make a problem for your boiler, but there are a number of things that you can do to clear out the muck and get the radiators back to the efficiency that they once had. You may not need to call out a heating engineer, but that doesn’t mean that you should rule it out.

Firstly, you must determine which of the radiators in the home are the problem. The best way to do this is to turn the heating on for all of the rooms, and then you can move to the room to discover which radiators are hot at the top and cold at the bottom. There are some cases where it’s just one radiator in the home that is the problem, but in other cases, you will find that it’s more than one radiator. If there is just one radiator with a blockage, you might find that all of the other radiators in the home do not heat up as a result.

Also read: How To Bleed a Radiator Without a Key

Next, you should dose your central heating system with a central heating system inhibitor. Your boiler warranty should have thi written into it as otherwise, you may find that your warranty is void! The inhibitor can help your central heating system to break off the loose rust and limescale within the system and get rid of them. Once you have done this, you can then flush out the system. You won’t necessarily need a full flush to get rid of the sludge build up in the system, but you just need a hose to get rid of the heating sludge in its majority.

A manual flush can be completed with the help of a plumber, but you can bleed your radiators yourself if only one of the radiators is affected. In fact, this could be the solution that restores efficiency to the house. It doesn’t take much to do this, thankfully, as all you will need is to isolate the radiator, turn the valve to zero and close the lockshield at the opposite side with a spanner. Use a bucket or towels beneath the radiator so that you can prevent any spills and mess on the floor. When you turn the nut slightly, water can drip out and you can then use a bleeding key to allow the air to start flowing through the radiator. Water will pour from the loosened radiator nuts, and that’s where the towels come in!

Once the water has drained properly, you can undo the valves and remove the radiator from the brackets. A garden hose is sufficient enough to wash through the sludge and flush it out. Keep this up until the water runs clean, and then place the radiator onto the brackets of the wall once more. You can then tighten the nuts and valves to close it off. Water will start to fill the radiator immediately, so ensure that you have the bleed key ready as you see water start to move through it. It should repressurise itself if there is a conventional feed and expansion system, but this should help your radiator to remain hot all over!

Lastly, you can prevent that blockage from happening again once you have cleared it properly. You can use a good scale reducer to catch the limescale that the inhibitor breaks off, and you can use a boiler filter for other deposits such as dirt and rust that break off. This junk will be caught and stored in the system and you can ask a heating engineer to properly empty the filters in their next visit.

Get Professional Help

To be able to help your blockage in your radiators, you can call for professional help from Aquatek today. You can feel comfortable in your home first thing in the morning once again!

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