Have you got a radiator feeling cold at the top and warm at the bottom. You probably need to bleed the radiator. If you don’t keep your radiators full of water, it can result in corrosion and ultimately a blocked system. You’ll need a radiator key which you can pick up for a few pennies at most ironmongers. A cup to catch drips and a rag to clean up is also helpful.

What the video below doesn’t say is that if you have a closed system like a combi boiler, after you bleed the radiator you should check the pressure on the boiler gauge and let some more water in via the fill valve. That’s probably a separate video though.