If the water level in a steam boiler is below the gauge glass, what should be the immediate action?

In the event that the water level in a steam boiler is below the gauge glass, the immediate action should be to shut down the boiler. This is crucial because operating a boiler with insufficient water can lead to severe complications, such as overheating and damage to the boiler's components, including the heating surfaces.

When the water level is below the gauge glass, it indicates that the boiler may be at risk of running dry, which can cause the metal to overheat and possibly lead to a boiler explosion or catastrophic failure. Shutting down the boiler prevents further operation and allows for a safe assessment of the situation, ensuring that the operator can take the necessary steps to address the low water level issue safely.

While adding water or inspecting for leaks can be part of the corrective actions after safe shutdown, these should not be done while the boiler is still operational and in an unsafe condition. Increasing the temperature in such a scenario would also be inappropriate as it would exacerbate the risk of damage. Therefore, immediate shutdown is the most responsible and safety-oriented action to take in this situation.