Which device controls and monitors the water level in a boiler?

The device that controls and monitors the water level in a boiler is the Water Level Control Transmitter. This instrument is crucial for maintaining safe operating conditions within a boiler system. It continuously measures the water level and relays this information to the control system, which can then make necessary adjustments to the feedwater supply.

In the context of boiler operations, maintaining the correct water level is vital for preventing issues such as water carryover or insufficient water for steam generation. The Water Level Control Transmitter ensures that the boiler operates within its designed parameters, which in turn maximizes efficiency and safety.

Other devices mentioned, while related to boiler operation, serve different functions. The Feedwater Control Valve manages the flow of water into the boiler but does not directly monitor the water level. The Level Measurement Sensor is part of the overall system that measures levels but may not provide direct control. The Pressure Relief Valve is a safety device designed to prevent excessive pressure build-up but is not involved in monitoring or controlling water levels. Therefore, the Water Level Control Transmitter stands out as the key device responsible for both monitoring and controlling the water level in a boiler system.