What method is typically used to control the burner operation in a steam boiler?

The typical method used to control burner operation in a steam boiler is modulating control. This approach allows for continuous adjustment of the fuel and air flow to the burner, which helps maintain the desired steam pressure and temperature. By modulating the input, the system can respond to variations in steam demand more precisely than other control methods. This means that the burner can operate continuously at various levels, rather than being limited to just an "on" or "off" state, promoting efficiency and reducing wear and tear on burning components.

In contrast to modulating control, fixed control does not allow for adjustments based on varying load demands, which can lead to excessive fuel consumption or inefficient operation. On/Off control can manage the burner operation by simply switching it on when demand is high and off when it’s low, but this method can lead to cycling, resulting in less efficient burner operation and potential temperature fluctuations. Pressure control, while important in a boiler operation to maintain specific pressure levels, typically works in conjunction with the actual control method, rather than as the primary means of controlling burner operation. Therefore, modulating control provides the most effective and efficient means for managing the burner in a steam boiler context.