What is the normal operating water level (NOWL) significant for?

The normal operating water level (NOWL) is significant primarily for maintaining adequate water for steam production. This is crucial because a sufficient water level allows the boiler to generate steam effectively, ensuring that the system operates within its designed parameters. If the water level drops below the NOWL, it can lead to incomplete steam generation and potentially cause the boiler to overheat, as the exposed heating surfaces may not be adequately cooled by the water. This not only affects the efficiency of the steam production but also poses risks to the integrity of the boiler itself.

While preventing overheating of the boiler and ensuring efficient fuel combustion are important, they are secondary outcomes of maintaining the correct water level. Similarly, reducing the risk of water hammer relates to the dynamics of steam and water flow within the system, but it is not the primary function of the NOWL. Overall, the emphasis is on ensuring that there is enough water to produce steam reliably and safely.