How to Bleed a Radiator Step by Step

If the top of your radiator is cold but the bottom is warm, trapped air is likely the cause. Bleeding radiators is a straightforward task when done carefully.

Turn heating off first. Use a radiator key slowly and keep a cloth ready to catch small drips.

When hissing stops and water flows steadily, close the valve. Repeat around the home and recheck boiler pressure afterwards.

If cold spots remain at the bottom, sludge may be present and professional cleaning could be needed.