How to Bleed a Radiator - Household Maintenance Tips | Warrantywise

Why do I need to bleed my radiators?

If you find that your central heating hasn’t been making your house as toasty and warm as it used to, or your radiators make strange gurgling sounds when you turn your heating on – it may be time to bleed your radiators.

Over time, radiators can develop ‘cold spots’ which are essentially trapped pockets of air in your heating system which prevent hot water from filling your radiators.

Thankfully, there’s an easy solution to this problem and you can do-it-yourself at home like Anthea – check out her video or follow the simple steps below. Let’s get your house nice and cosy again!

What do I need before I start?

The only tool you’ll need is a radiator key (available at most DIY stores) or a flathead screwdriver if your radiators are quite modern.

It’s also a good idea to grab some towels or cloths to catch any drips of water that come out of the radiators (the water is often discoloured, so if you’ve got light carpets – this will save you a lot of cleaning time later on!).

Toolbox with cloth and radiator key


Anthea's step-by-step guide...

  1. The first step is the easiest – turn your heating off. That’s it!
    Once your radiators are completely cold to the touch, you’re ready to start the process of restoring your heating to its former glory! We advise that you bleed all the radiators in your home to ensure optimum results. It’s best to begin on the ground floor with the radiator that’s furthest away from your boiler, then move to the upper floors of your home.

  2. Next, you’ll need to identify the bleed valve – it’s at the top of the radiator on one of the ends and looks like a round hole with a square inside it. This is where you’ll be releasing the trapped air from and potentially some murky water, so it’s best to get your towels down at this stage!

    man holding radiator key next to radiator

  3. Then you simply pop the radiator key into the square in the middle of the bleed valve (or if you’re using a screwdriver – put the blade into the groove) and turn slowly anti-clockwise, one quarter to a half turn, to open the valve.
    Be careful not to open the valve fully or you’re likely to end up wearing the contents of your radiator! You should start to hear a hissing sound and some water may begin to drip from the radiator valve as the trapped air is released and replaced with the water from your heating system.

  4. Keep holding the valve open until you notice more water than air coming out. Eventually, water will start to squirt out of the bleed valve which means you’ve released all the trapped air in the radiator. At this point, you can re-tighten the valve by turning clockwise until there are no leaks.

    man bleeding radiator with water coming out

  5. You can then repeat this process on each of the radiators in your home to make sure you get rid of all the air in your heating system and keep it running as efficiently as possible.

Once you’ve bled all of your radiators, it’s important to check your boiler pressure. Bleeding your radiators will release a lot of pressure from your heating system, which may prevent the heat from reaching some of your radiators (after all your hard work!).

If you’re worried about the potential costs of boiler failure and repairs, purchasing high-quality boiler cover can provide peace of mind. Warrantywise Home Cover includes a comprehensive annual boiler service which includes efficiency testing, pressure testing, bleeding radiators and much more.

Visit our Warrantywise Home Cover page for more information.