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How to Bleed a Radiator

Bleeding a Radiator: Why It’s Important and How You Should Do It

A full working central heating system is essential to any home especially in the colder seasons, but not a lot of homeowners understand the importance of bleeding their radiators regularly to ensure their efficiency and keep energy costs down. To add to that, having your boiler serviced annually will help to keep your central heating system healthy and well-maintained.

But what exactly does bleed a radiator mean and how is it done properly?

What does ‘bleeding a radiator’ mean?

Before you learn how to bleed a radiator, you should know what bleeding means, which is simply letting trapped air from inside the system out. When air is trapped, it keeps water from heating the radiator, thus resulting in cold spots. It’s very important to bleed your radiator to make them last longer, keep your home properly heated and avoid costly energy bills in the long run.

When bleeding a radiator is necessary

The easiest way to determine if your radiator needs bleeding is to simply touch its upper section. If it’s cooler than the bottom part of the radiator, then it’s time to think about bleeding your radiators.



when bleeding a radiator is necessary - image for post


How to bleed a radiator properly:

  • To get started, you’ll need two things: a radiator key that you’ll use to open the radiator vent valve and a cloth or towel for drips.
  • To bleed your radiator, simply follow the bleeding radiators sequence, which begins with turning your heating system on to warm up the radiator and push the unwanted air out.
  • Check every radiator for cold spots and listen for gurgling sounds. Make sure to use thin gloves to avoid burning your hands, as some radiators will tend to be hotter. Those with the most issues have to be bled first.
  • Turn your central heating system off just before you begin bleeding to avoid scalding yourself and flooding water on your floor.
  • Layout your old towels around the radiator to catch any drips of discoloured water while bleeding your radiator, this will help save time in cleaning the area later.
  • Use a radiator key to open the bleed valve at the top of the radiator. Turn the key counter slowly clockwise until you hear a hissing sound, which means that the air is escaping. Air could be hot and contain hot water so make sure you keep a good distance. If you don’t have a key any flat head screwdriver will do.
  • Turn the key halfway and hold it until the air stops coming out. If you see only water is dripping out, that’s a sign that bleeding is complete. Turn the key clockwise to re-seal the radiator but make sure not to over tighten it.
  • Repeat the process on all your radiators.
  • We advise you to start your bleeding from the ground floor and work your way up to the second floor, as the air rises through the system.

To complete the bleeding operation, you must re-pressurise your heating system until the needle gauge is facing green. If it’s on yellow, then you have to re-pressurise by locating the central filling loop connected to the radiator. Turn the tap slowly while adjusting the pressure.

Below is a quick recap of the steps to bleed the radiator:

1. Prepared a radiator key and some old clothes or towels
2. Turn your heating on
3. Check which radiator needs bleeding by feeling for the cold spots and listen for gurgling sounds
4. Turn your central heating off before bleeding the radiator
5. Put some old towels under the radiator to catch the dripping water
6. Use a radiator key to open the bleed valve at the top of the radiator
7. Bleed the radiator as mentioned above
8. Repeat the process on all your radiators
9. Make sure to start from the ground floor and work your way up
10. Check the pressure on your central heating

To keep your home heating up more efficiently and to save on your energy bill, we suggest that you have your boiler serviced regularly to maintain the health of your central heating system.

Want to see it in action? Below is a Wickes video to show you how to bleed a radiator:



When is the best time to bleed your radiators?

The best time to bleed your radiators are at the start of the Autumn season when the weather is starting to turn colder, as you would like the central heating to be on more frequently.

If you are at all uncertain about how to bleed your radiators, you should speak to a qualified local Gas Safe Registered professional such as a plumber or a Heating Engineer.

What is the ideal temperature for your home?

According to the expert, keep your room temperature on a warm but not too high temperature can save you some money. Areas such as kitchen, hallway, and storage room are recommended between 16°C to 18°C, whereas the lounge should be around 20°C to feel warm and cosy. For bathroom and children bedrooms are best to set at around 23°C to 24°C.

Any Questions? Get in Touch!

We hope you have enjoyed reading our post; if you have any questions on your central heating problems, or would like to book an annual boiler service, simply give us a call on 07771 956641, our gas safe registered heating engineers are here to help you with your enquiry. Alternatively, you can also send us a message via our online contact form.

Harman Heating is a family run plumbing and heating company for over 25 years, based in Northampton, we cover the area in and around Northamptonshire, including Northampton, Wellingborough, Rushden, Sywell, Overstone, Kettering, and all surrounding areas.