A mandatory (code required) control that is installed on all hot water and steam boilers

A mandatory (code required) control that is installed on all hot water and steam boilers

• A. Low water cut off
• B. Automatic air vent
• C. Expansion tank
• D. Backflow preventer

Answer: (A)

The safety device that must be on all hot water and steam boilers is the low-water cutoff. It monitors the water level inside the boiler and, if the level drops too low, it automatically shuts the boiler down to prevent dry firing. When a boiler fires without enough water to absorb the heat, components can overheat, warp, or even fail catastrophically, so codes require this control as a critical safety measure on both hot water and steam systems. This is why it’s the best answer: it directly prevents the dangerous condition of operation with insufficient water. Other devices serve important purposes—automatic air vents release trapped air, expansion tanks accommodate water expansion, and backflow preventers protect the potable water supply—but they are not the mandatory safety control that prevents a boiler from firing when water is low.

The safety device that must be on all hot water and steam boilers is the low-water cutoff. It monitors the water level inside the boiler and, if the level drops too low, it automatically shuts the boiler down to prevent dry firing. When a boiler fires without enough water to absorb the heat, components can overheat, warp, or even fail catastrophically, so codes require this control as a critical safety measure on both hot water and steam systems.

This is why it’s the best answer: it directly prevents the dangerous condition of operation with insufficient water. Other devices serve important purposes—automatic air vents release trapped air, expansion tanks accommodate water expansion, and backflow preventers protect the potable water supply—but they are not the mandatory safety control that prevents a boiler from firing when water is low.