A steam radiator can be noisy, with a loud banging noise being heard. This is usually caused by the movement of the radiator’s release valve. When the hot steam enters a part of the radiator system where colder air is present, it creates an area of pressure. This pressure is not reduced until the temperature stabilizes. The pressure is exerted on the release valve, and on the sides of the pipes, which results in a loud banging noise. Also, if the feed pipe is not angled properly, water can become trapped in the pipe, which is boiled on contact with the steam, and results in a loud noise. Raising the angle of the pipe slightly may correct the problem.