On a steam boiler with single element feed water control, what is the measure variable?

In a steam boiler with single element feed water control, the measured variable is the boiler water level. This system relies on monitoring the water level within the boiler to regulate the feedwater supply. The control mechanism ensures that the water level remains within safe operating limits, as maintaining the proper water level is critical for safe and efficient boiler operation.

When the water level drops too low, the control system will increase the feedwater flow to elevate the water level back into the desired range. Conversely, if the water level is too high, the system can alter the flow to maintain equilibrium. Other variables, such as feedwater pressure, feed water flow, or steam flow, may influence or be related to boiler operation but are not the primary measured variable in this control strategy. Understanding the role of the water level in this context is essential for effective boiler management and safety.