Tips GB

How to bleed a radiator

By Maha

Updated: October 20th, 2021

The secret to a toasty home? Learning how to bleed your radiators.

If you’re one of the 85% of UK households with gas central heating, you may already have heard of ‘bleeding radiators’ before.

And if you haven’t, don’t worry, it’s not exactly as gory a process as it sounds.

What does it even mean?

Bleeding a radiator means letting out any air bubbles trapped within it.

Why? Trapped air leads to inefficiency and cold spots in a radiator by preventing heat from circulating within.

The good news? There’s no need to recruit professional plumbing services for this task. You can learn how to bleed a radiator yourself.

Not only will your home be deliciously toasty, you can save money on energy bills as your efficient radiator won’t need to be on for as long.

Let’s get to the how

What you’ll need

  • Radiator key
  • Cloth
  • Bowl

So far, so simple.

1. Start by turning on your heating to assess which of your radiators need bleeding

First, turn on your central heating and wait till all your radiators are fully heated. Once all radiators are completely hot, take a stroll around your home and check them all individually. You want to assess whether all parts are warming up equally.

If you hit upon any cool spots, especially at the top of the radiator, you’ll know it’s time to let the bleeding commence.

2. But first, make sure you turn off your central heating

Switch off your heating so your skin isn’t in contact with radiators for too long  – they can get hot enough to burn.

3. Release the air

Next, attach your radiator key (which should come with your unit) to the valve at the top of the radiator.  If you’ve misplaced this, you can easily find one at your local DIY store or use a screwdriver with a flat blade.

Use a dry cloth to hold your key, and turn it anti-clockwise (slowly). Keep another cloth handy for any dripping from the radiator.

Hear a little hiss? That’s the sound of gas leaving your radiator.

4. Close the valve

Once all the gas has left the radiator, you’ll need to close the valve quickly to stop trickles of liquid from coming out.

5. Check the pressure gauge

Almost there…

Take a peek at the pressure gauge on your boiler next. If the pressure is looking low, you can return it to a normal level by using the ‘filling loop’ tap or lever on the boiler.

6. Run a test to finish

Finish off by running a quick test to check that all your bleeding efforts haven’t been in vain. Turn your heating back on and check for any cool spots when the radiators should be fully heated.

Aaaand… you’re done.

When to call a plumber

So, as proud as you should be for your foray into the world of plumbing, there are times when only expert plumbing services will do the trick. Hire a plumber in the below instances:

If your bleeding process hasn’t solved the problem

Radiator still not heating up efficiently after going through all the steps above? Find professional plumbing help to investigate.

Keep an eye out for any signs of more serious problems with your radiator as well, such as rust or leakage.

If your boiler itself is leaking

Avoid trickier issues by having your boiler serviced, at least annually.

Need to find a plumber in London? Connect with trusted and rated local plumbers with Airtasker



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