Which device is responsible for monitoring and controlling boiler water levels?

The water level gauge is the device specifically designed to monitor and control the water levels in a boiler system. Its primary function is to provide a visual representation of the water level within the boiler, indicating whether the water is at a safe operating level. Maintaining the correct water level is crucial for the safe and efficient operation of a boiler, as too low a level can lead to overheating and potential damage, while too high a level may cause carryover of water into the steam system.

By providing real-time insights into water levels, the water level gauge allows operators to make informed decisions regarding water feed and overall boiler management, ensuring operational safety and efficiency. Other devices listed, such as the blow-off valve, pressure relief valve, and thermostat serve different purposes within the boiler system, such as pressure management and temperature control, but do not specifically manage water levels.