The Automatic Feedwater Control Valve maintains boiler water level at Normal plus/minus 1 inch. This tolerance is described as which option?

The Automatic Feedwater Control Valve maintains boiler water level at Normal plus/minus 1 inch. This tolerance is described as which option?

• A. Plus or minus 1 inch
• B. Plus or minus 2 inches
• C. Plus or minus 0 inches
• D. Plus or minus 3 inches

Answer: (A)

This question is testing how tolerance around a setpoint works in boiler level control. The stated tolerance—Normal plus or minus 1 inch—means the water level is allowed to vary by one inch above or below the Normal target and still be considered acceptable. So the acceptable range is from Normal minus 1 inch to Normal plus 1 inch. The Automatic Feedwater Control Valve maintains the level within that band by adjusting how much feedwater is added. If the level drifts below Normal, the valve opens more to increase water; if it drifts above Normal, it reduces feedwater to bring the level back down. Other options describe wider or zero tolerance, which do not match the given specification: a looser tolerance would allow more deviation, while zero tolerance would require the level to stay exactly at Normal.

This question is testing how tolerance around a setpoint works in boiler level control. The stated tolerance—Normal plus or minus 1 inch—means the water level is allowed to vary by one inch above or below the Normal target and still be considered acceptable. So the acceptable range is from Normal minus 1 inch to Normal plus 1 inch.

The Automatic Feedwater Control Valve maintains the level within that band by adjusting how much feedwater is added. If the level drifts below Normal, the valve opens more to increase water; if it drifts above Normal, it reduces feedwater to bring the level back down.

Other options describe wider or zero tolerance, which do not match the given specification: a looser tolerance would allow more deviation, while zero tolerance would require the level to stay exactly at Normal.