top of page
  • Writer's pictureBen Blyth

How to bleed your radiators

There are some telltale signs that indicate your radiators may need bleeding:

  • Warm at the bottom, cold at the top. - This may be one (normally the highest radiator or towel rail on the system) or multiple radiators.

  • Gurgling or bubbling sounds in your radiators or pipes.

If you are experiencing this on your heating system, it's a simple fix you can do yourself.

So, how do you bleed your radiators?

What you need:

  1. Radiator bleed key

2. A small cloth or rag - No picture available - sorry for any inconvenience.

Bleed keys can be bought on Amazon or at any hardware stores for a couple of pounds.

They are also issued free of charge to all households in the "Stuff draw". It's never been proved how they get there but they always do.

How to bleed your radiators:

1. Attend problem radiator - Go to the offending radiator and insert the key as shown. On older radiators the bleed valve may be on the rear of the radiator (run your fingers along the back at the top and you can normally feel it). On a towel rail the valve is normally on the top of one of the sides (some have a silver cap on that can just be gently pried off.

2. Insert the bleed key - On the valve you've inserted the key into there is a small hole that lets the air out. Have the cloth/rag in your other hand and hold next to this (if unsure, keep it near the valve).

IMPORTANT NOTICE - If you have white/cream carpets, luxury wallpaper that only an ex Prime Minister would think is reasonable - you may want to put a towel down under where you are working as a small amount of water may come out.

Slowly turn the key anti-clockwise to crack the valve open - This may require a small amount of force. It shouldn't require brute strength - if it does, abandon the job, have a cup of tea and contact us here - don't risk snapping the bleed valve as that becomes a much messier job. Once you've cracked the valve open (don't unscrew it all the way, a 1/4 or 1/2 turn should be enough, you should hear a slow hissing sound - that's the air leaving your system. (top tip - as soon as you hear this, gently close the valve again so you know how far you've got to go to shut it off). Hold your cloth by the valve and as soon as you see water come out, shut the valve and that's the job done (you can often tell when water is about to come out as the sound changes).

3. Repeat - Not quite cup of tea time yet. Almost though - Repeat this on all radiators you have an issue with (it's often only one) - in the event the air stops but no water comes out, go to the next step then start the process again.

4. Final step - You may need to top up the pressure in your boiler. If you have a sealed system (a combi boiler or a boiler with an unvented cylinder is a sealed system - If you've water tanks in the loft coming down to your cylinder you don't need to do this step) you may need to add some pressure back to your boiler. To do this, go to your boiler or filling loop (if it's not next to your boiler and top the pressure back up (make sure you have closed all bleed valves first) to around 1.2 Bar.

Some boilers may have an error message on after the pressure has dropped. If this doesn't reset itself, just reset your boiler manually to clear it.

Hopefully this helped. If you need a local plumber in the Exeter, Exmouth and Budleigh Salterton area, contact us here. Fully Gas Safe registered we can deal with any plumbing, heating or boiler faults.

Recent Posts

See All


bottom of page