How many visible gage cocks must be present along the length of the water glass?

In a high-pressure boiler system, the water glass is an essential component that provides visual indication of the water level within the boiler. The presence of gage cocks along the length of the water glass is crucial for ensuring accurate monitoring and maintenance of the water level.

Having three visible gage cocks is the standard requirement, as it allows for adequate monitoring of water level under various operational conditions. These gage cocks serve different functions, such as checking the water level directly, ensuring that the glass itself is functioning properly, and providing points for drainage or flushing to avoid any build-up of mineral deposits that could obstruct visibility.

This setup is designed to enhance the safety and functionality of the boiler system, ensuring that operators can effectively manage the boiler's water level and prevent potential hazards associated with low or high water levels.