What might indicate a problem with the gauge glass if it is not displaying the correct water level?

The indication that a problem with the gauge glass might exist when it is not displaying the correct water level can indeed be attributed to a closed upper connection. The gauge glass relies on a clear path for water to rise and fall in response to the changing water level in the boiler. If the upper connection is closed, it prevents water from entering that section of the gauge glass, leading to inaccurate readings. This is crucial for operators who must rely on the gauge glass to monitor water levels for safe boiler operation.

When the gauge glass is functioning correctly, it should provide a direct visual representation of the water level within the boiler. Any obstructions, such as a closed upper connection, will result in deceptive readings, which can have serious implications for safety and operational efficiency. Regular checks of the gauge glass, including both connections, are essential to ensure accurate monitoring of the boiler water level.