How to Remove an Airlock from a Heating System

Hi people, this article will inform you with the help of our amazing video instruction guide to remove an airlock from a radiator. Watch the video below and if you need a guide in black and white, then read on!


How do I know my radiator has an airlock?

If you have tried all the other guides on our website and your radiator is still not getting hot, it can be an airlock. Sometimes if you feel the pipes going to the radiator one may be hot but there is no flow into the radiator. This is a classic sign of an airlock.


How do I remove an airlock from the radiator?

Firstly take a deep breath because this can be tricky without a basic grounding in plumbing knowledge. You’ve been warned!

  1. Turn off the heating system.

  2. Latch open any motorised valves.

  3. Turn off the problem radiator at the lock-shield end and the TRV end.

  4. Use a radiator bleed key to dissipate any pressure from the rad via the air bleed point.

  5. Remove the whole radiator bleed point. Use a towel to catch any drips – there will be a few!

  6. Attach a hose where the air bleed was. You may need a 1/2″ adapter. If you need to take the air bleed to your local plumbers merchants and they’ll help you out.

  7. Run the hose outside. (obviously!)

  8. Open the TRV end and flush through. You should hear some air globbing through. It doesn’t take much to cause a blockage. Count to 10 and close the TRV.

  9. Repeat at the lock-shield end.

  10. Close both the valves and remove your hose.

  11. Re-install the bleed point and close it. Turn on the TRV and lockshield.

  12. Top up the heating system/re-pressurise.

  13. Turn on the heating system and admire your work. Make sure the motorised valves are unlatched.


If that didn’t work, close all other radiators in the house and try to force the heating water though with the pump. This doesn’t always work though. Good luck!


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