Steam boilers that are not filled all the way to the top with water and have a glass sight gauge mounted on the side to indicate the water level are typically what type of boiler?

• A. Steam
• B. Hot water boiler
• C. Electric boiler
• D. Condensing boiler

Answer: (A)

Steam boilers rely on a defined water level that leaves space above for steam to form. A glass sight gauge lets the operator see exactly where the water level sits, ensuring there’s enough water to produce steam without flooding the steam space. If the boiler were filled to the very top, there would be no room for steam, which can lead to poor steam quality or equipment damage.

Hot water boilers are designed to circulate heated water and are typically operated with the boiler more full, without the same need for a visible steam level. Electric and condensing boilers describe other types of heating designs that don’t depend on a visible water line for steam generation. The presence of a sight gauge and the partial fill indicate a steam boiler.