The most common cause for radiators failing to heat up is trapped air. You can tell this is the case if your radiator is hot at the bottom but cold at the top; in this case, you’ll need to bleed your radiators. The process is simple, simply use your radiator key to unscrew the bleed screw at the bottom of your radiator enough to cause a hissing sound. This is the sound of the trapped air escaping; once the noise stops, screw the bleed screw back in place. If this still doesn’t fix your radiator’s problem, one of our plumbers would be happy to assist you further. Don’t hesitate to get in touch with our team.