What you need
- A radiator key (cheap from hardware shops)
- An old towel or cloth
- A small bowl or tray
Steps
- Find the cold radiators. With the heating on, feel each radiator. Any that are cold at the top and warm at the bottom have air trapped inside.
- Turn the heating off and wait for the radiators to cool, so you do not release hot water.
- Find the bleed valve. It is a small square-headed valve at the top corner of the radiator.
- Hold the cloth under the valve and turn the key anticlockwise about a quarter turn. You should hear air hissing out.
- Close the valve as soon as water starts to come out, turning the key clockwise. Do not overtighten.
- Check the boiler pressure. Bleeding lets air out and can lower the pressure. Top it up if needed. See why boiler pressure drops and how to top it up.
Turn the heating back on and check that the radiator now heats evenly.
Still cold? It may not be air
- Cold at the bottom, warm at the top: usually sludge built up in the radiator, which needs a flush.
- Cold all over: the valve may be stuck, or the system needs balancing.
- Several radiators cold, or a boiler fault code: the cause may be the boiler or pump.
- A radiator that leaks from a valve or joint: turn off its valves and call a plumber.
If bleeding does not fix it, see our radiator repair service in Edinburgh or the boiler service.
More boiler guides
- How Much Does a New Boiler Cost in Edinburgh?
- Boiler Grants in Scotland: Who Is Eligible?
- Who Can Install a New Boiler in Edinburgh?
- Should a 20-Year-Old Boiler Be Replaced?
- Combi, System or Regular Boiler: Which Is Right for Your Edinburgh Home?
- Why Does My Boiler Keep Losing Pressure?
- Boiler installation in Edinburgh
- Boiler service in Edinburgh