What is letdown v. total condensing?

• A. Let down exhaust to the lower pressure steam; total condensation condenses steam to liquid and returns to boilers
• B. Let down condenses steam to liquid; total condensation vents steam to atmosphere
• C. Let down uses a turbine to generate power; total condensation uses a boiler
• D. Let down increases pressure; total condensation decreases temperature

Answer: (A)

The main idea here is the difference between reducing steam pressure for use and returning steam as condensate. Letdown is the process of dropping steam from a high-pressure line to a lower-pressure system so that it can be used at the lower pressure. In a total-condensing setup, all of the steam that leaves the low-pressure side is condensed back into liquid water in a condenser, and that condensate is returned to the boiler as feedwater.

So the correct description aligns with letting the exhaust go to the lower-pressure steam system, and having total condensation turn that steam into liquid and return it to the boilers. The other descriptions mix up what happens: letdown isn’t about condensing steam, isn’t about using a turbine or boiler for the process, and doesn’t increase pressure. Likewise, total condensation doesn’t vent steam to the atmosphere; it condenses it and recycles the water.