How to Bleed a Radiator
Quick Answer
Turn off the heating, use a radiator key to open the bleed valve, release air until water appears, then close the valve.
How to troubleshoot How to Bleed a Radiator
A radiator that is cold at the top but warm at the bottom has trapped air. This guide covers bleeding the radiator to restore full heat.
Step-by-Step Fix
- Turn off your central heating and allow radiators to cool completely.
- Place a towel or small container underneath the radiator bleed valve.
- Insert a radiator bleed key into the valve and turn it counter-clockwise slowly.
- You will hear a hissing sound as air escapes.
- Wait until water begins to trickle out steadily.
- Turn the key clockwise to close the valve tightly.
- Check the boiler pressure and top up if necessary.
Common Error Codes
| Code | Meaning | Resolution |
|---|---|---|
| No water comes out | Valve blocked or boiler pressure low | Check pressure and repressurise if needed. |
| Water splutters | Air still trapped | Continue bleeding until a steady stream of water appears. |
Frequently Asked Questions
Do I need to turn the heating off before bleeding?
Yes, to prevent burns and ensure the system is not under excessive pressure.
What if I don't have a radiator key?
A flat-head screwdriver can fit some bleed valves, but a key is recommended.