How to bleed a radiator
Does your radiator feel cold at the top and warm at the bottom? If so, it's likely that the problem is being caused by air that has been trapped in your radiator.
Does your radiator feel cold at the top and warm at the bottom? If so, it's likely that the problem is being caused by air that has been trapped in your radiator. Luckily, you should be able to fix the problem yourself by bleeding your radiator.
Bleeding a radiator is a fairly simple, safe and quick process. Basically it just means opening a small valve on your radiator to allow any trapped air to escape. Just follow our simple instructions below for a quick fix:
Turn off central heating
Before you bleed your radiator, it's very important that you turn off your central heating at the main controls.
This will prevent more air from entering the system. When turning off the radiator valves remember to count how many turns are needed to turn them off, one of the valves will be the lock shield valve. This is used to balance the system so opening or closing it too much will result in the system not being balanced correctly and one or more radiators won’t work properly.
Find the bleed valve
Find the bleed valve; this usually has a small red handle and is located on one side of the radiator.
Protect the area
Place a cloth or a small bowl underneath the bleed valve to catch any leaking water. Also, wrap your hand in a cloth to shield your hand as any water that escapes from the radiator may be very hot.
Find the bleed key
Your radiators should have come with a small bleed key (or radiator key). If you can't find the bleed key you should be able to buy a replacement at your local DIY store.
Bleed the radiator
First you'll need to locate the bleed valve. This will be a protrusion at the top of one side of your radiator. To bleed your radiator, insert the bleed key into this valve and carefully turn it anticlockwise (usually a quarter or half turn will do the trick). The air trapped in your radiator will start escaping with a hissing sound. When water begins to dribble out out the valve you will know that all the air has been purged from the radiator.
Re-tighten the bleed valve
Once water dribbles out of the valve you should tighten the valve back to it's original position. Use the cloth to clean up any spills (be careful, though, as the water can be scalding hot).
Turn the heating back on
Don't forget to switch the central heating back on once you've finished bleeding the radiator. Check on your radiator after a couple of hours to ensure that the radiator has a uniform temperature all over it's surface area and that there's no more water leaking from the bleed valve. Problem solved!
Remember, if you're ever in doubt of your DIY abilities it's best to call in an engineer to fix the problem for you.