My Radiator Isn’t Working! How to Bleed a Radiator

So you’ve been informed that your plumber has balanced your system (always step one when your new radiator isn’t heating up, and especially if you fitted without plumbing assistance), and yet it’s still not heating up properly. At this point you might be tempted to throw in the towel and check your warranty, but to save even more hassle you might actually need that towel.

What does “Your radiator needs bleeding” actually mean?

If you imagine that a radiator is just a set of pipes that water is pushed through, it’s logical that it would work at its best when these pipes are cleared. Now having physical blockages within your radiator is very highly unlikely, but if you imagine for instance a spirit level, and then imagine that the liquid that surrounds the air bubble is warm, like the water in a radiator, it stands to reason that the air bubble would not heating up the same.  This is what we mean by “air in the radiator”, and as such “bleeding” is the process of removing the air in order for the radiator to be able to heat evenly.

The Fiddly Bit

The solution for this is pretty simple, but make sure you do it safely:

  1. Turn off your boiler – IMPORTANT. We don’t want and scalded hands.
  2. After waiting for your system too cool off, locate your bleeding valve. All radiators should have one. Not the same thing as the radiator valves which turn it on/off, up/down.
  3. Take the aforementioned (preferably old) towel and place bunched underneath the valve.
  4. Insert your radiator bleeding key (usually sold separately) and turn slowly.
  5. You should hear air escaping from the hole in the valve, confirming the air hypothesis. Keep bleeding the air until water begins to appear from the hole that the air was escaping from. This is why the towel is in place.
  6. The air is now out of your radiator, but make sure you lock the radiator valve back in place or the water will just keep coming!
  7. If water was the first thing to appear from your radiator and not air, then your radiator probably didn’t need to be bled and you should assess your options, such as checking your valves are in good condition.

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