Question 267General Subjects - Assistant Engineer

The correct answer is B) 6.0 psig. For a pneumatically operated, diaphragm actuated control valve with a linear response, the pilot pressure is directly proportional to the valve position. Since the position indicator is calibrated in percentage, and it shows the valve to be 75% open, the corresponding pilot pressure would be 75% of the full pressure range, which is 3 to 15 psig. Calculating 75% of the pressure range (15 - 3 = 12 psig) gives a pilot pressure of 6.0 psig. The other options are incorrect because they do not represent the proportional relationship between the valve position and the pilot pressure for a linear response control valve.