What is the main function of the Automatic Feedwater Control Valve?

• A. To maintain boiler water level at Normal +1-1 inch
• B. To regulate boiler steam pressure
• C. To control fuel flow to the burner
• D. To isolate the feedwater system

Answer: (A)

The main idea is that keeping the boiler water level steady is essential for safe and efficient operation. The automatic feedwater control valve modulates how much feedwater is added to the boiler based on the level in the steam drum. When the level drops, the valve opens to feed in more water; when the level rises, it closes to reduce incoming water. This keeps the level near the normal setpoint, typically within a small band like plus or minus one inch, so the tubes don’t overheat and steam quality stays good.

This valve isn’t primarily responsible for setting or maintaining steam pressure, nor does it control the fuel to the burner or serve as an isolation valve for the feedwater system. Those are handled by separate controls or valves.