New York Low Pressure Boiler Certificate of Fitness (COF) Practice Test

What device indicates the water level of a steam boiler?

1. Pressure gauge

2. Gauge glass

3. Photoelectric cell

4. Aquastat

The correct answer is: Gauge glass

The gauge glass is the correct choice for indicating the water level of a steam boiler. It serves as a visual reference that allows operators to clearly see the water level inside the boiler at any given time. This visibility is crucial because maintaining the proper water level is essential for safe and efficient boiler operation. If the water level is too low, it risks overheating and damaging the boiler, while a water level that is too high can lead to operational issues. In contrast, the pressure gauge measures the pressure within the boiler system, which is important for understanding the operating conditions but does not indicate the water level. The photoelectric cell is typically used for different applications, such as detecting the presence of liquid but is not designed for measuring water levels directly in a steam boiler context. An aquastat is primarily used to control the temperature of water and may signal when to turn a heating element on or off, but it does not provide a direct visual indication of the water level. Thus, the gauge glass is specifically designed for this purpose, making it the best answer.