Is your central heating system dropping pressure? You might have a hidden leak!

How to find and fix a radiator leak

Coming home to a patch of wet carpet or a pool of water underneath a leaking radiator is possibly one of the most frustrating things that can go wrong around the house. Luckily, fixing a leaking radiator can be relatively easy. In this blog, we are going to explore the causes of radiator leaks and learn how to identify the source of a radiator leak and fix the issue in five easy steps. So, let’s get into it.

Why is my radiator leaking?

Before you are able to effectively fix your leaking radiator, you need to understand the cause of the leak. There are a number of potential causes for a radiator leak.

Damaged or loose valves

The most common cause of a leaking radiator is a damaged, loose or faulty valve. 

Over time, your valves undergo some wear and tear, and when the valve’s seal deteriorates, it allows water to escape. The more damaged the valve is, the worse the leak will be. To replace the damaged valve, you will need to contact an experienced plumber. This will ensure that the valves are replaced correctly and no leaks are present.

In some cases, the valve may have become loose and therefore needs tightening, rather than replacing.

Rusted radiator

Another common cause of a leaking radiator is that it has become rusted and corroded over time. This corrosion can cause small holes in the radiator pipes and body, causing a leak. If the leak you found near your radiator is muddy brown in colour, it is likely that rust is the cause of your issue.

How to fix a leaking radiator in 5 steps

When you know the cause of your radiator leak, you will be able to locate the source and start the process of repairing it. Here, we are going to run through five easy steps to locate the source of your leak and fix it.

#1 – Find the source of the leak

If you’re aware that the cause of the leak is a loose or faulty valve, you may have already located the leak. However, if you can’t pinpoint the source, you will be unable to repair it. The best way of doing this is to turn your heating off and wait for your radiator to cool down (you don’t want to burn yourself!), before drying your radiator completely with an old towel.

Once the radiator is dry, wipe a piece of clean, dry paper towel over the radiator, focusing on areas that are most likely to leak – the body, control valve and connector pipe. When the paper becomes wet when wiping it over your radiator, you’ve found the source of your leak.

#2 – Drain the radiator

Now you’ve found the source of the leak, you can begin the repair process. If you need to replace the radiator valve or you may need to access internal parts of the unit, you will need to drain your radiator.

To drain your radiator:

  • Turn your radiator off and allow it to completely cool down. This will probably take anywhere between 30 minutes and an hour
  • Close the control valve. If you have a thermostatic valve, take note of its setting to ensure it is correctly restored
  • Find and close the lockshield valve – it is located on the bottom of your radiator
  • Making sure there are buckets in place to collect the water, use an adjustable spanner to remove the control valve from your radiator
  • Release the bleed valve using your radiator key to release air from the radiator and allow the water to drain

#3 – Fix the leak

How to fix the leak depends on where the leak is and what caused it.

A pinhole leak

A pinhole leak is a slow leak caused by tiny pin-sized holes in the body or pipes of the radiator. These leaks are typically caused by corrosion within your system, and can develop over time. Another cause of pinhole leaks is a buildup of debris within the water pipe.

Unfortunately, the best way to get rid of pinhole leaks is to replace your radiator, which of course requires a gas-safe engineer or plumber to do so.

A leaking radiator valve

If you found the cause of your leak to be the radiator valve, there are two main culprits behind this. It could either be caused by a loose gland nut, or deteriorated spindle packing in the valve itself.

To fix a loose gland nut, simply remove the valve cap from the control valve and locate the gland nut (around the spindle). Tighten it with a spanner, before replacing the valve cap.

If the radiator valve has deteriorated, it will need replacing. This is best done by a professional in order to reduce the chances of it leaking in the future.

#4 – Turn the radiator on and check for further leaks

Once the leaks have been found and fixed, you need to check that the repairs have worked and that there aren’t any more leaks that were missed originally. 

Ensure all the valve connections are tightened and that the valves are open to allow water to flow through the unit. Turn your central heating back on, and check for any more signs of a leak.

#5 – Call a professional

Unfortunately, a lot of the time, a leaking radiator will need to be repaired (or replaced) by a professional engineer in order to prevent it from happening again.

The cost of this may vary depending on what needs to be replaced. Most of the time, radiator parts are fairly cheap. However, if the full unit needs to be replaced, this cost can get quite pricey.

How Harmuns can help

If your radiator has been fixed but you still suspect a leak in your central heating system, you may need a more in depth leak detection service. At Harmuns, we find and fix the leaks your plumber can’t. If your heating engineer suspects a leak but can’t find it, give us a call!

We’ll send a skilled, gas-safe engineer to address the problem as quickly and efficiently as possible. Using various detection equipment, including moisture meters, thermal imaging cameras, and trace-gas systems, they will locate the source and rectify the leak.

You may not require our services immediately, but you may do in the future. Save our number to avoid unnecessary panic: 01753 378569.

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About Harmuns

We are a specialist non-invasive pipe and water leak detection company here to fix your problems. We find hidden leaks on central heating systems, water mains and hot & cold water supply within the property.

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We are not an emergency plumber. If you have a visible leak, please contact your local plumber.