If you have gas central heating, radiator maintenance is an essential job to keep your system running efficiently. Radiators warm up the room in which they are installed by warming up the air in close contact with the radiator.
Knowing how to bleed your radiator can increase the energy efficiency of your heating, keep your boiler running efficiently and save you money on your heating bills.
When should you bleed a radiator?
If there are just one or two radiators in your home that are taking longer to warm warm up, this is a classic sign that you may need to bleed your radiators.
Radiators need bleeding when trapped air has displaced the hot water that would normally heat up the radiator. When this happens, you’ll find that the top section of your radiator is a lot cooler than the bottom section. This indicates that the trapped air has risen to the top and is preventing the hot water from circulating effectively, so the radiators aren’t getting as hot as they should be.
In this scenario, you need to bleed your radiators to get rid of the trapped air because you’re likely to be using more energy to heat your home. When you bleed the radiator, the air gets released and the hot water will be able to flow freely. Air is expelled from the radiator through a small air-release valve located at the top and to one side of the radiator.
Where to Start When Bleeding a Radiator
If your house is a 2-floor story building, begin the process by bleeding the downstairs radiators first. B
Before you start work, make sure that the central heating is off and your radiators have completely cooled. This is important because some water pumps will actually suck more air into the radiator if they are turned on while you open the bleed valve.
How to Bleed a Radiator
Tools You’ll Need
You will need a radiator key, old cloths or towels or a container for any water that comes out of the radiator. Place the towels placed around the radiator bleed valve to prevent damage to your flooring. You can find a radiator key in any DIY shop if you don’t have one.
- Switch on the central heating. Turn on the central heating and ensure that all of the radiators are fully turned up.
- Identify which radiators need bleeding. Determine all of the radiators that need bleeding by feeling them for cold patches.
- Switch off your central heating. This is really important. Keeping the central heating on while bleeding radiators can lead to boiling water squirting all over you. Make sure the radiators are cold to the touch before you start working on them.
- Set down the cloths. Put down the cloths or towels beneath the radiator to catch any spillage from the radiator.
- Look for the bleed valve. At one end of your radiator, you’ll see a slot known as the bleed valve that the radiator key fits into. (It looks like a round hole with a square inside.) This is what you’ll need to turn in order to release the air and water from the radiator. Put your container on the floor beneath this area so that you can catch any water that is released in the process.
- Use the key to turn the bleed screw anti-clockwise. Holding your towel or cloth below the bleed valve (to catch any spillage) turn the key anti-clockwise. One quarter to a half turn is enough. Don’t open the valve fully or water will pour out once the air is released. As the air escapes, you should hear a hissing sound which means that the built-up air is being released. As soon as the hissing air stops a steady stream of water will escape from the radiator. At this point, the radiator is fully bled.
- Use the key to re-tighten the bleed screw. Don’t tighten the screw too tightly to avoid damaging the valve. Wipe up any water on the radiator to avoid rusting then move on to the next radiator, repeating the previous steps.