Is your radiator cold at the bottom? This is often caused by a blockage within your radiator. If not managed, then it could result in more serious issues, such as leaks. Our experts identify the signs and causes of your radiator being cold to the touch at the bottom, as well as solutions to fix the problem.
The causes of a cold radiator
Cold radiators occur due to a restriction in the flow of hot water. If your radiator is cold to the touch at the top and hot at the bottom, the most common cause for the problem is trapped air in the system. However, when your radiator is cold at the bottom and hot at the top, it is unlikely to be a trapped air issue and is more likely to be due to sludge build-up, as the sludge blocks the flow channels in the system. When a flow channel is blocked, it doesn’t let water pass through which will end up leaving your radiator cold in certain areas.
If you suspect your radiator isn’t working properly, contact an installer who can help you find the cause and rectify the problem.
How to fix your cold radiator
Fixing your cold radiator can be done easily by a professional via a simple step-by-step process that should get your system working again.
Here’s what to expect when your installer arrives to fix the issue:
Switch off the heating
As radiators can become quite hot, it is important to make sure they are fully switched off and cooled down before starting. This reduces the risk of scalds, as radiators can get very hot when left on. Switching the central heating off before fixing also reduces pressure in the system, as well as preventing any leaks from occurring. By turning the heating off before your installer arrives at your property and reducing multiple risks, this can help to speed up the repair process.
Lay sheets under the radiator
It is important to lay a sheet underneath the radiator as a safety precaution as system water leaking from the radiator can damage your flooring.
Switch off the radiator valves
Next, the installer will make sure that all radiator valves are closed so that once the radiator is drained, it will not refill and leak . There are three main valves to switch off in a radiator. These include:
Thermostatic radiator valves (TRV) - These are usually located on one side of your radiator at the bottom. Their purpose is to control hot water flow into the radiator. They often have a numbered dial that controls the temperature.
Lockshield valve - This is on the other side at the bottom (opposite side to TRV). Its purpose is to balance the system by controlling how much water leaves the radiator. It rarely needs adjusting, as this is set by a professional during the installation process.
Bleed valve - Typically located at the top of the radiator, on one side. Its purpose is to release trapped air from the system and is essential during the bleeding process.
Valves should be switched off 30 minutes to 1 hour before fixing. This gives the radiator time to cool completely so it can be handled safely but also allow the system to depressurise (no trapped air or water left in the system).
Flush the radiator
Flushing your radiator will remove any sludge and debris that has built up over time.
When the installer flushes your radiator, it should allow the system to evenly circulate the hot water flow, as no flow channels are being blocked. There are two methods the installer can do to flush your radiators.
1. The system is connected to a powerful flushing pump and is connected to the full system. The high power flow of water will remove debris and blockages effectively.
2. Each radiator can be removed from the wall and flushing water through it using a hose pipe. Often a partly full radiator is turned up and down to dislodge any sludge.
Both methods are effective but to be sure that the system is clean, your installer can check the water with an electronic meter that shows the amount of dissolved solids. This indicates that the water is clean when compared to the tap water and there is little difference.
Switch on valves
Once the radiator has been bled and flushed, the installer will reopen the TRV and lockshield valves to allow water to flow through the system again.
Switch heating back on
Once the valves have been reopened, it is safe to turn the heating back on to see if the problem has been resolved.
What to do if you’re still having problems?
If you have more questions about why your radiator is cold to touch at the bottom or require help to fix it. Contact one of our Glow-worm Energy Club installers so that the matter can be fixed quickly and efficiently.
