How/when to bleed your radiator

Date published: 6th April 2013

If your radiators stop heating up as they should, it’s easy to think the worst – your boiler has broken down. But don’t panic – there are lots of other reasons why they might be losing power and the most simple of all is also the most common – they just need to be bled.

Bleeding a radiator is a really simple job that you don’t need a whole lot of training to do. Once you know what you’re doing you’ll be able to do it in less than five minutes – it really is a piece of cake.

You’ll know if they need to be bled because your radiators will be warm at the bottom and cold at the top.

Bleeding a radiator has the added bonus of making your heating system more efficient and therefore economical so if any of your radiators aren’t behaving themselves it’s time to investigate.

Why do they need to be bled?

It’s really just air that is blocked somewhere within the radiator. By bleeding it, you release the trapped air and let new air circulate. It happens from time to time, but if it is happening very regularly then it might be time to call an expert in as there may be an air pressure problem somewhere else in the system.

There are plenty of well-trained and fully qualified plumbers in Plymouth but always try bleeding your radiator first before you call one – you could save yourself an unnecessary call-out fee.

When do they need to be bled?

Only if your radiator starts to lose heat. As the old saying goes ‘if it ain’t broke don’t fix it’!

And how do I do it?

Simple! It’s really easy so don’t be worried. All you need is a radiator key, a jug and an old cloth. (If you don’t have a radiator key you can pick one up really cheaply from a hardware store.) Be careful though – the water that comes from the radiator is likely to be hot, if not scalding, so make sure you protect yourself against burns by wrapping your hand in an old cloth. Follow these easy steps and you won’t go far wrong:-

1.      Turn off your central heating – this will stop more air from entering the system

2.      Locate the bleed valve – this will be a small red handle on one side of the radiator

3.      Put a cloth down – just to make sure you don’t stain your carpets with dirty water

4.      Find the bleed valve – this is a small hole at the top of one side of the radiator

5.      Bleed using the radiator key – twist the key in the valve and gently turn anticlockwise

6.      Let air hiss out – only tighten the valve again once water dribbles out (do this quickly!)

7.      Turn the heating back on – give it ten minutes and see if the radiator is working again

If that doesn’t fix the problem then it’s time to call someone out.

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