As the cold weather sets in and you swap your summer shorts for woolly jumpers, it’s time to prepare your home for winter! During the summer months many radiators and home heating systems are ignored as we bask in the warm weather, but do you know how to bleed a radiator?

Before you begin to rely on your heating in winter, it’s best to check if your radiators need some TLC – not only to ensure they are working efficiently but help save you money too. If they need bleeding, they will have air trapped inside and will prevent the warm water from circulating around. This will result in your radiator not working effectively and therefore taking a lot longer to heat, and your bills ultimately higher – and no one wants that! If you notice your radiator making odd noises like clanking, gurgling, or banging then this is an obvious sign that you need to let the trapped air out.

So, if you want to ensure that your house remains toasty, cosy, and efficient, now’s the time to learn how to bleed your radiators. Follow our simple steps below to ensure they aren’t costing you money.


How To Bleed A Radiator

 You will need:

  • A radiator key or flathead screwdriver
  • A rag
  • Thick gloves
  • Container


 Step 1: Turn on your heating

First, turn on your heating and then go round and ensure that your radiators are turned up fully. Once all of your radiators have warmed up, then you can move onto the next step.


Step 2: Touch your radiators and feel for cold spots

Next, put on a thick pair of gloves. They should be thick enough so that you can’t hurt yourself when you touch the radiators but thin enough so that you can feel the heat coming through from them. Once you have your gloves on, go around your house and touch each radiator all over to find any cold spots.

You are checking for; cold spots, gurgling noises, a radiator that takes a long time to heat up or the top of a radiator feeling a lot colder than the bottom of a radiator.


Step 3: Diagnose which radiators to bleed first

You should check all of your radiators at the same time as one may need to be bled more than another. If some are significantly worse than others, simply bleed the radiators on the ground floor first, starting with the ones the furthest from the heater and then do the top floor.


Step 4: Switch off your central heating

Keep your radiator intake valves open but ensure that you have turned off your heating system fully before bleeding your radiators.


Step 5: Let your radiators cool down

Put your gloves back on and then re-check your radiators to see if they are still warm. Don’t attempt to check them when they are still warm. If you do, you could be at risk of burns as hot water can leak from the valve.


Step 6: Locate the bleed valve

To bleed a radiator, you first need to locate the valve. It will be at the top of the radiator, on either the left or right corners there will be a valve that looks like a round hole with a square in it. This is where you will be releasing all the air and water.


Step 7: Preparation

First things first, put the old rags down around the radiator in case water escapes. You can also put down some containers in case a lot of water is released, and you need to catch it quickly. Ensure that you have a correct radiator key or a flathead screwdriver to open your valve.


Step 8: Loosen the valve

Attach the radiator key or flat screwdriver into the valve by inserting it into the square groove. Turn the bleed screw anti-clockwise for one quarter to a half turn. That should be enough to open it but never open it fully or water will pour out. You should be able to hear the air hissing out as it escapes.


Step 9: Listen to the air and wait for it to stop

Keep listening to the air and wait for it to stop hissing. After the air has been released there may be a little of water escaping that you can just catch in the container or rag. Keep watching and catching the water until it comes out in a steady stream rather than in little bursts. This is the sign that the air has been released.


Step 9: Close and secure the bleed valves

Next, use the key or screwdriver to tighten the bleed screw in a clockwise direction. Then use a towel to dry the pipes to avoid any future rusting. If you notice any rust on your pipes, you can read our guide on how to remove rust.


Step 10: Turn on the heating

Finally, once you have bled all of your radiators and closed the valves securely, you can turn the heating back on. Using your gloves, go round and check the radiators and make sure that they feel hot all over. If you feel cold patches you may need to repeat the process again.


Step 11: Check the boiler pressure

You will also need to check the boiler is still showing its recommended heating pressure level (normally 12 to 15 psi). As you have released excess air from the radiators, the overall pressure of your heating will be lowered and if this occurs, heat may not be able to warm the upper floors of your house. If your pressure is low, you can top up the pressure by using the filling loop on your boiler.


Pro Tip:

If your radiator valves have been painted over and therefore more difficult to turn or remove, then you can apply WD-40 Multi-Use Smart Straw to unstick the valves to enable you to turn them.

Now that you know how to bleed a radiator, why not find some more DIY guides such as; our guide on removing rusted boltsHow To Protect Your Locks From Freezing In Winter, How to Clean & Degrease Tools, or How To Remove Chewing Gum From Carpet.