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Tips for new homeowners: How, when and why you need to bleed a radiator

As a new homeowner there are a million and one things you’re now responsible for remembering, from which day the garbage is collected, when the house insurance is due, and how often you should mow the lawn.

Owning your first home can be daunting. As well as remembering some of the everyday things listed above, you are now also responsible for maintaining and improving your home as well as fixing things when they go wrong – which they inevitably will.

radiatorYour central heating system is possibly one of the most important systems in your home, and as anyone who has experienced a couple of days without heat during a bitter winter will tell you, it’s well worth investing a bit of time and energy into making sure it’s running smoothly and will be ready to go when you need it.

For anyone with gas central heating, bleeding radiators is one of those household chores that should be completed regularly, although often gets overlooked due to our busy and stressful lives.  Those with electric radiators do not need to worry about this annual household chore.

Here are some helpful hints and tips to help you understand how, when and why you need to bleed your radiators:


All radiators should be bled regularly as the heating and cooling of hot water naturally releases air bubbles that remain in the coils. Once a year, just before the time you need to turn the heating on is usually the best time to take care of this job.

It’s very easy to tell when a radiator needs bleeding as the top section will remain a lot cooler than the bottom, or it may not be providing any heat at all.

Larger houses that use a considerable amount of hot water every day may need its radiators to be bled more often than a smaller house.


Trapped air or gas prevents hot water from heating your radiator fully. The process of your water heating up and then cooling down creates tiny air bubbles, which cause the trapped air.  This air isn’t dangerous, but over time the air will build up and will prevent your radiator from working as well as it should do or may heat unevenly or not at all.


Bleeding a radiator is quite a simple task when you know how.  You will need to find or invest in a bleed key (also known as a radiator key) and two old pieces of cloth to catch any drips.

Step 1 – Turn on your heating

Check each radiator once your heating is on to establish any immediate issues.  Turn your heating off again before you start to bleed any.

Step 2 – Bleed the radiators

  • Situated at the top of the radiator will be a valve
  • Attach the radiator key to the square piece in the centre of this valve
  • Hold the key with one of the cloths, and have the second cloth ready to catch any drips
  • Slowly turn the radiator key clockwise
  • If gas or air is escaping you will hear a hissing sound
  • When there is no more gas, liquid will come out and the valve must be quickly closed again

Step 3 – Check the pressure

Check the pressure in your boiler hasn’t dropped too low as a result of your actions.  If it has then top it up using the filling loop on your boiler.

If in doubt, there are many professional plumbers around who will be able to do this for you for a small charge.






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One Response to Tips for new homeowners: How, when and why you need to bleed a radiator

  1. Kristin Wheeler (@MamaLuvsBooks) January 14, 2014 at 9:52 pm #

    Great tips! I’ll be sure to pass these on. It’s been a brutal winter.

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