When should water gauge glasses be checked for satisfactory operation after light-off?

Water gauge glasses should be checked for satisfactory operation after light-off at 100 to 200 psig. This pressure range ensures that the system is operating within parameters where the water level and gauge functionality can be accurately observed without being affected by fluctuations or instability that might occur at lower pressures.

Checking at this specified pressure range allows for a reliable assessment of the gauge's performance, confirming that it accurately reflects the water level in the boiler. This is critical for safe operations, as an inaccurate gauge can lead to serious consequences, including equipment damage or failures.

The selection of 100 to 200 psig aligns with standard operating procedures, emphasizing the importance of maintaining compliance with safety regulations and ensuring proper system oversight during critical initial operation phases following light-off.