How to bleed a radiator

A radiator that is warm at the bottom and cold at the top, or that gurgles, contains air. Bleeding fixes it in a few minutes.

What you need

A radiator key (or a flat screwdriver, depending on the model), a cloth and a small container.

The steps

1. Turn the heating on so the radiators are warm, then turn it off and wait half an hour for them to cool slightly.
2. Find the bleed valve, at the top of the radiator, on the side opposite the tap.
3. Place the cloth and container underneath, then open the valve a quarter turn: air escapes with a hiss.
4. Close it as soon as water flows steadily, without bubbles.
5. Repeat for each radiator, starting on the lowest floor.

After bleeding

Check the boiler pressure on its gauge: it is usually between 1 and 2 bar, depending on the model. If it is too low, top up the water following the boiler's instructions.

If the radiator stays cold after bleeding, or you need to bleed very often, tell your manager: a circulation problem or a leak may be the cause.