A scotch marine boiler can be easily recognized because it ______.

A scotch marine boiler can be easily recognized because it ______.

• A. Is externally fired
• B. Is internally fired
• C. Has no water level gauge
• D. Uses electric heating

Answer: (B)

The main idea here is how the furnace is arranged inside the boiler. A Scotch marine boiler is a fire-tube boiler with the furnace located inside the boiler shell, so it is internally fired. This internal firebox means the combustion occurs within the main pressure vessel, and the hot gases pass through the tubes submerged in water to transfer heat. That internal firing distinguishes it from externally fired designs, where the furnace sits outside the boiler shell. Also, Scotch boilers are not electric-heating systems, and they do have water level gauges, so those options don’t fit either.

The main idea here is how the furnace is arranged inside the boiler. A Scotch marine boiler is a fire-tube boiler with the furnace located inside the boiler shell, so it is internally fired. This internal firebox means the combustion occurs within the main pressure vessel, and the hot gases pass through the tubes submerged in water to transfer heat.

That internal firing distinguishes it from externally fired designs, where the furnace sits outside the boiler shell. Also, Scotch boilers are not electric-heating systems, and they do have water level gauges, so those options don’t fit either.