How can the proper function of the gage glass be ensured on a boiler?

The proper function of the gage glass on a boiler is critical for ensuring safe and effective operation. The gage glass must accurately reflect the operating water line because it provides a direct visual indication of the water level within the boiler. Accurate water level readings are essential for the safe operation of the boiler, as insufficient water can lead to overheating and potential damage, while too much water can result in operational inefficiencies and risks.

To maintain the integrity of the gage glass, regular maintenance and inspection are necessary to ensure that it remains free from obstructions, scaling, or other issues that could affect its accuracy. This means that while calibration and protection from sunlight can aid in maintaining the gage glass, the primary function is to provide an accurate visual representation of the water line.

Thus, the critical nature of option B emphasizes that without an accurate reflection of the operating water line, the boiler's safety and performance cannot be guaranteed.