How do I bleed a radiator?

If you've noticed that your radiator isn’t warm all over and has some cold spots, it's likely that it isn't working very efficiently. The result is that your system will be working harder and costing you more in heating all without your home feeling the full benefit.

The solution can often be simple. Air, trapped inside the radiator will need to be let out  - or bled. Bleeding a radiator is an easy and quick job that you can do yourself leaving your radiators work properly and your home warmer as a result.
 
How to bleed a radiator
First of all, you will need a radiator key (or a flat-head screwdriver), a cloth or towel.
 
Turn on your central heating 
Make sure that your radiators are on so that there is pressure in your system. This helps the air out to get out.
 
Check which radiators need bleeding
Go around your home and feel the tops of each radiator. If you find cold spots, you'll have identified a radiator that needs bleeding.
 
Turn off your central heating
Now turn off your heating and let the radiators cool down. If you do this when your radiators are hot, you could scald yourself with the hot water.

Bleed the radiators
Once your radiators have cooled down look for the valve at one end of the top of your radiator. Attach the radiator key (or flat head screwdriver) to the square part in the centre. Hold the key with a cloth and slowly turn the key anti-clockwise for about half a turn. Listen out for a hissing sound as the air leaves the system. Turn the key to the closed position once the hissing stops or when water starts to leak out. Don’t over-tighten the valve as this could damage it.
 
Check the pressure on your boiler
Check the pressure on your boiler gauge. If the pressure is too low, you’ll need to top up the water using the lever or tap on your boiler. Follow the manufacturer’s instructions on how to re-pressurise your boiler.
 
Turn the heating back
Turn the heating back on and let the radiators heat up. Check the radiators that you bled. Hopefully you will no longer have any cold spots. Also check that the valves are not leaking.
 
What if I still have cold spots?
If, after turning the heating back on, you still find cold spots, you may need to bleed some radiators a couple of times to complete the job. If you’ve done this and the radiators are still not heating properly, it’s time to call in some professional help. It could be that there is a build-up of rust or sludge in your central heating system which will need to be determined by a plumber.
 
Arco's heating engineers are all Gas Safe registered plumbing and heating specialists. Should you have any issues with your plumbing or are looking to service your boiler, give us a call. We cover all areas in and around Havering including, Romford, Collier Row, Hornchurch, Upminster and beyond.
 
Call us now on: Martin: 07977 229 134 | Craig: 07970 296 171

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