What can cause a radiator to leak?

What can cause a radiator to leak?

Water can cause a lot of damage if it's left to its own devices in the wrong places.

So, if you discover that one of your radiators is leaking water, it's important to dry the damp patch quickly and to establish where the leak is coming from.

In this article we'll look at the most common reasons why your radiator might be leaking and what you can do to fix the situation.

A leaky radiator valve

In the vast majority of cases, the reason there is a wet patch underneath your radiator is because you have a faulty radiator valve.

If the internal workings of the valve start to wear out, the valve will not be watertight and water will start to leak out.

Usually water leaks out of a faulty valve when it is halfway open. You can check to see if it is indeed a problem with the valve by turning it to the off (closed) position.

Dry off the water with a towel to see if the area around the valve remains dry. Then open the valve again and see if water leaks out. If so, then it's likely you need to replace your valve, which is fortunately a fairly easy job.


A rusted and corroded radiator

Over time, there will be a certain amount of corrosion that occurs inside radiators.

This is especially the case if you have very old radiators and you have not been regularly topping up your chemical inhibitor levels. (Chemical inhibitor is a liquid you can add to the water inside your central heating system that helps to stop internal corrosion.)

If the corrosion gets really bad, it can cause holes to appear at the bottom of your radiator. These holes normally start very small, so you can usually notice a small amount of brownish water leaking out before it becomes an emergency situation.

However, the brown, rust-filled water that leaks out can cause stains on your carpet and is a frustrating problem.

Normally, if you've got a hole in the bottom of your rad, the best thing to do is to replace it with a brand new one.

Loose or damaged spindle

There is a joint that connects the main body of the radiator to the radiator valve called a spindle. This can often be the source of water leaking from a radiator.

This is often sorted out by simply tightening the gland nut, which may have come loose over time.

If water is still leaking out then wrapping some PTFE tape around the spindle is another common fix for this problem.

Radiator still leaking?

If none of the suggestions above relate to the leak in your radiator, or you've tried fixing the problem and water is still leaking out, then it's time to get a professional in.

Water leaking out of your radiator can cause a real mess if untreated, so it's important to get a plumber round as soon as possible to get the problem sorted out for you.


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Ben Clarke

I have over 10 years of experience researching and writing about a broad range of heating-related subjects. I understand the significance of home heating and strive to provide you with high-quality radiator content in an easy-to-understand manner.