Why is bottom of radiator cold

A radiator that is cold at the bottom is usually caused by a build up of sludge in the system. This sludge is mainly composed of rust and dirt particles which accumulate from internal corrosion.

As the sludge is heavier than water, it settles at the bottom which prevents water and heat flow to the bottom of the radiator. To fix a cold radiator bottom, you will need to flush the sludge clogging up your radiator:.

For a full explanation of how you can flush the sludge out of your radiator, check out our guide. If Radiator sludge is making your home colder and creating an inefficient flow, that means you're paying more for heating than you have to. Radiator sludge can damage your boiler which can mean the longer you put off cleaning out your radiator, the bigger the problems can become.

Radiators are naturally warmer on top than the bottom, but some radiators more than others. For example, 'convection radiators' focus on convection heating which is when heat rises and pushes cool air downwards.

This cool air is then heated and the cycle continues. All radiators use a combination of both convection heating and simply 'radiating' their heat out. No matter how high you turn the thermostat up when a radiator is cold at the bottom, it simply won't work. This will just put additional strain on the boiler putting it at risk of running into a fault. Radiators that are cold at the bottom need quick attention.

You have a couple of options including a powerflush or chemical flush. Both of these must be carried out by a heating engineer. A powerflush involves a chemical being circulated around your heating system at a high pressure.

This process will free any blockages to allow the hot water to flow efficiently and effectively — allowing your radiators to heat up properly. To perform a powerflush, a heating engineer will connect a pump to the central heating system.

This pump will push a chemical through the pipework and radiators at high speed to break down and remove the sludge. A descaler and corrosion inhibitor should also be used to remove limescale and prevent rusting in the future. Depending on how extreme the blockage is, the engineer may also need to use tools on the outside of the radiators to dislodge pieces. When they've finished they will dispose of the contaminated water.

And, having measured the temperature of your radiators before they started work, will show you the improvement after the powerflush. A powerflush is well worthwhile if your radiators are cold at the bottom as you'll benefit from:.

If you think your central heating system could benefit from a Powerflush, contact us today and we'll find you free, no-obligation quotes from up to 3 Gas Safe registered engineers in your area. A chemical flush involves chemicals being circulated around the heating system but not at a high pressure like a powerflush.

As the chemicals flow through the system, they remove any build-up of dirt, limescale and debris. The chemicals can be left for an hour or as long as a week in some cases. Once the chemicals have done their job, the system is then flushed to refill it with clean water and a rust inhibitor. While it isn't recommended and, for the best results, we highly recommend hiring a professional, it's possible to flush the heating system yourself. Essentially, flushing the heating system yourself involves removing each radiator from the wall one-by-one.

You then take them outside to clear out any sludge by running clean water through it. Prevention is far better than the cure. Once the blockage has been cleared from the radiator, it's a good idea to take steps that will prevent it from happening again.

This could include:. A central heating inhibitor is a chemical which can be added to your system to prevent the buildup of limescale and sludge. It does this by coating the system to keep the water running through smoothly.

Scale reducer is a very good idea for homes in hard water areas, as limescale is much more likely to form a blockage in a heating system. These bubbles rise to the top, stopping the hot water from being able to fully circulate your radiator.

The good news is that this is also one of the easiest things to fix if you know for sure that this is the issue. To check, turn your central heating on and adjust your radiator valves to their maximum heat setting. You might also hear a gurgling noise coming from them. Take a look at our guide on how to bleed a radiator to easily fix this issue yourself.

It might sound unpleasant, but sludge in your radiator and central heating system is a common occurrence. The combination of water and metal often results in limescale and rust which can build up over time. If it gets really bad, it can settle at the bottom of your radiator and cause a blockage. This stops the hot water from being able to circulate, creating cold patches at the bottom of your radiator. You can help protect your radiator from a build-up of sludge by using a radiator inhibitor regularly.

This is a chemical that you pour into your central heating system to help break down sludge and prevent a blockage from occurring. However, if you already have a blockage on your hands, a bottle of inhibitor probably won't be enough. If you are certain which radiator is causing the problem, you can try removing the sludge yourself. To do this, try the following steps:. For more help on how to remove a radiator, our guide to replacing a radiator has a step-by-step guide.

So long as you have already checked that the valves are fully open and the boiler is at the right pressure, it could be that a blockage in a different radiator or elsewhere in the system is stopping the hot water from reaching your new one.