Question 169Steam Plants - 1st Asst/Chief

The correct answer is A) manually controlled feed water regulator. In the event of a pneumatic control system failure, a multi-element feed water regulator is designed to operate as a manually controlled feed water regulator. This means that the regulator can be manually adjusted to maintain the desired feed water pressure and flow, rather than relying on the automatic pneumatic control system. The other options are incorrect because: B) a constant-pressure regulator maintains a fixed outlet pressure regardless of flow rate, C) a thermo-hydraulic feed water regulator uses thermal and hydraulic principles to regulate feed water, and D) a constant-volume feed water regulator maintains a fixed volume of feed water flow, which is not the intended function of a multi-element feed water regulator in the event of a pneumatic control system failure.