Which of the following is NOT a characteristic of a thermal expansion feedwater regulator?

The characteristic that does not apply to a thermal expansion feedwater regulator is the adjustment of flow based on pressure differentials. A thermal expansion feedwater regulator primarily operates based on temperature changes in the system rather than adjusting flow in response to pressure differences.

These regulators rely on a thermostatic element that senses the temperature of the feedwater. As the temperature changes, the regulator adjusts the flow of water to maintain the desired temperature in the system. This functionality is crucial in applications where maintaining the correct temperature is essential for efficient operation.

Additionally, thermal expansion feedwater regulators are designed to control feedwater supply automatically, ensuring that the system operates smoothly and maintains performance without the need for manual intervention. Therefore, options that pertain to temperature control and automatic operation align with the characteristics of a thermal expansion feedwater regulator, while pressure differential operation does not.