How to Bleed a Radiator

Now that it’s winter, temperatures are dropping and will continue to drop, radiators are important to keep the house warm and homely. If the radiator in your home feels cold when you have the heating on, it probably means it’s time to bleed your radiator. When your radiator is not heating up it’s often because your radiator may contain trapped air that’s blocking its normal flow. The trapped air causes the radiator to circulate hot water less effectively and so less heat is emitted, meaning it will take longer to heat your home.

The bad thing about leaving your radiator if it needs bleeding is that you’re probably using more energy and therefore your energy bill will be higher than normal.

Its important to know that if all the radiators in your house are cold, it probably isn’t a case of just bleeding your radiator. This probably means you have a larger problem with your heating system.

Bleeding your radiator is a job you can do yourself, and we are going to tell you exactly how.

7 steps to bleeding your radiator

1: Turn on the central heating - Turn your central heating on and wait for your radiators to reach their maximum heat.

2: Diagnose the problem – Its normal for radiators to need bleeding every now and then. Signs such as the radiator taking a long time to heat up, or the radiator is colder at the top, are both signs your radiator needs bleeding.

3: Check all radiators – Assess each radiator in the house by touching the top and bottom, if the heat seems to be inconsistent then it is recommended to bleed that radiator.

4: Turn off your heating – Its really important to make sure the heating is turned off during the bleeding process. If you don’t turn the heating off this could cause a lot of water on the floor.

5: Release the trapped air – To release the trapped air you will need a radiator key and two rags. If you don’t have a radiator key, you can find them in most DIY stores. At the top of the radiator there is a valve, this is where you put the radiator key. As the air starts to escape, you should begin to hear a hissing noise. Use the rags to a) catch water drips and B) to protect your hands and arms. Twist the radiator key slowly anti-clockwise and this will release the air.

6: Shut the valve – Make sure to shut the valve quick enough so the water doesn’t go everywhere. Once air starts escaping, water will begin travelling to the whole of the radiator so if you don’t close the valve, water will leak. 

7: Check the pressure – After bleeding the radiator, check the pressure gauge on your boiler. If its too low after bleeding, you will need to rebalance the pressure. Use your boiler manufacturers manual for instructions on how to do this. If the pressure is normal, switch your heating on and check there are no more radiators with cold areas.