Bleeding a radiator describes the process of removing trapped air from within the central heating system. It ensures that the system is up to full operating capacity, which can also increase efficiency. It is generally recommended that for most modern central heating systems, your boilers should be bled around twice a year. This ensures your system will be running at its maximum potential and not inefficiently heating your home.

Within this article, we’ll cover everything you need to know about bleeding your radiators. This will include how you can tell when your boiler needs bleeding, a step-by-step guide to perform the process yourself, as well as some advice for troubleshooting inefficient heating systems


How do I know when my boiler needs bleeding?

Whilst it is recommended that you bleed your boiler twice yearly, there are some symptoms that could indicate that you might need to do it sooner. Understanding these problems will ensure you can keep your home warmer and reduce your bills.

  • Your radiator is cold at the top

This is a quick and easy sign of air in your central heating system. Just by feeling sections of the radiator, you will be able to identify if there is a temperature difference between the top and bottom of your radiator. This contrast in temperature indicates that the air in the system is preventing hot water from flowing throughout the entire radiator. This is a telltale sign that your radiator requires bleeding.

  • The whole radiator is cold

Again, just by touch, you can infer that your radiator needs bleeding. It is recommended that you allow the central heating system to fully warm up before concluding that your radiator is cold. If surrounding radiators in adjacent rooms have become warm and the highlighted radiator has not, there is likely air in the radiator that needs to be bled.

  • Rattling radiators

Perhaps one of the most apparent indicators of air within your radiator is an audible gurgling or rattling noise coming from within your pipes or radiators. The noise often sounds like a boiling kettle and occurs as the heating has been turned on. Once again, the sound is an indication of air within the heating system, bleeding the radiator in close proximity to where the sound originates is the most effective solution to release this air.


How to Bleed a Radiator

Bleeding your radiator is a simple household task that doesn’t typically require the services of a plumber or gas safe engineer. Following our step-by-step guide provides enough detail to be able to bleed your radiators with ease.

What You’ll Need

  • A radiator key OR flat head screwdriver
  • Jug
  • Cloth
  • Safety-gloves

The equipment required to bleed your radiator can be found around the home. Radiator keys can be substituted for a flat-head screwdriver or can be purchased for just a few pounds at most local DIY stores.

Step-By-Step Guide for Bleeding your Radiators

  • Turn your central heating on

Before determining whether or not your radiators need bleeding, it is important to assess which radiators hold built-up air. Ensure that before deciding which radiators to bleed, you wait for the heating to fully circulate your home.

  • Identify cool spots

Once your radiators are fully heated you can assess the temperature of your radiator from top to bottom.  However, it is vital that you take caution during this action. If your radiators are too hot, you can wear thin gloves to prevent injury or discomfort. Identify whether any of your radiators are cooler at the top or aren’t as warm as others.

  • Turn off heating and wait for it to cool

It is highly important that you allow a considerable amount of time for your central heating to cool down. If you attempted to bleed your radiators before allowing the central heating to cool, you could scold yourself with steam and boiling water escaping from the radiator.

  • Protect the area surrounding your radiator

With a cloth or towels, create a protective area surrounding the radiator to prevent water from reaching the carpet or walls. You can also use a jug or bowl to catch excess water that escapes from the radiator.

  • Open the radiator valve

Using your radiator key or flathead screwdriver, release the valve on your radiator. The valve typically requires turning once or twice anti-clockwise. You will know when the valve is open once you hear a hissing. This sound indicates the air escaping your central heating system.

  • Close the valve

Your radiator should only require bleeding for 20-30 seconds, depending on how much air has built up in your system. Once the hissing sound starts to gurgle, or water begins to escape from the valve, you know it is time to close it. This can be closed by turning once or twice clockwise, in an opposite fashion to how it was opened.

  • Turn the heating back on

After bleeding the radiators in your home, it is a good idea to turn the heating back on to check a couple of things. The first is to ensure that your boiler pressure isn’t too low. Occasionally, allowing too much water to leave the central heating system can create lower pressure. This will require you to repressurise the system. Secondly, if your boiler pressure is correct, check whether your radiators are fully heated.

After allowing the heating system to fully circulate your home, you should check that the radiators are fully heated. If cool spots persist, this could be an indication of more complex problems. Whilst bleeding your radiators can be done without the help of an expert, you could require the services of a gas registered engineer to diagnose and resolve the problem. The team at Boiler Hut are certified and determined to help you heat your home, visit their website to receive professional assistance with your boiler.


Final Thoughts

Cold or noisy radiators could be a sign that air has accumulated within your central heating system. The air gathers within the top sections of your radiators, preventing them from efficiently heating your home. Bleeding your radiator is a quick and simple fix for this problem, allowing you to complete the task without the help of a boiler expert. In addition to some simple preparation, bleeding your radiator should only take around 30 seconds. After this, your home should heat far more efficiently.

If any problems persist after bleeding your radiator, this could be an indication of more complex problems. Under these circumstances, you’ll likely require the services of a gas safe engineer. Boiler Hut can supply you with certified engineers across the UK in order to provide peace of mind and a fully functioning boiler.