The ideal temperature for a central heating boiler depends on several variables, including the weather and personal preference. There is no single temperature that you should set your central heating boiler at, but it is recommended to adjust the boiler temperature to keep it within a specific temperature range to prevent the boiler from overheating. The recommended temperature settings for heating water are typically within the range of 120-160 degrees Fahrenheit for low-temperature settings and 180-200 degrees Fahrenheit for high-temperature settings. For a modern combi boiler, the recommended output temperature for the radiators is 75°C, and for the water, it is between 50°C and 60°C. The maximum temperature that is recommended for the radiator output is 80°C. If you want the temperature to be warm, it is best not to exceed 200 degrees Fahrenheit, as the boiler will start to overheat, which can cause it to leak or burst. The temperature settings of your hot water cylinder will likely remain within the same temperature range year-round, and the best temperature for your hot water cylinder is between 140-150 degrees Fahrenheit. It is important to note that adjusting the radiator and water temperature on a modern boiler system is quick and simple, and it is recommended to adjust the boilers high/low temperature settings as the weather gets warmer and colder.