Radiators use water heated by your boiler to warm the air in a room. In order to do their job effectively, radiators must always be free of air and full of water.
Check for cool spots on your radiators, particularly towards the top. It could mean that air is trapped inside. To release the air, wait until the radiator is cold, then use the special key to turn the air release vent.
If you have a sealed heating system (with no water tank), check that the water in the system is at the right pressure, topping up the levels if necessary. Your installer should have shown you how to do this. Alternatively, watch the Worcester Bosch YouTube video.
Keep the areas around your radiators clear of furniture and long curtains to ensure the heat is not blocked. If a radiator is fitted to an outside wall, a sheet of reflective foil on the wall behind it will reduce heat loss through the wall.
If your radiators feel excessively hot and the boiler keeps turning on and off, the temperature of the water going to your radiators may be set too high. This wastes energy and reduces the boiler’s efficiency. Adjust the temperature using the central heating control dial or adjustment switches on your boiler.
If you decide to turn off individual radiators, for example in rooms that are not being used, this might affect the overall heat output. Radiators in adjacent rooms may have a slightly lower temperature.