What is a control on a boiler which controls temperature of water in boiler that is operated by boiler temperature and outside air temperature is called?

The control on a boiler that regulates the temperature of the water based on both the boiler temperature and the outside air temperature is known as an "outdoor reset control" or "weather-responsive control." This system adjusts the boiler's water temperature to optimize efficiency and comfort, taking into account the changing outdoor conditions. By modulating the water temperature, it helps maintain consistent indoor temperatures while reducing energy consumption.