Which of the following will NOT lead to flooding out the plant in a recirculated system?

In a recirculated system, flooding occurs when there is an excess of liquid in the system that cannot be vaporized properly, leading to operational issues. Choosing a change in the suction pressure setpoint by 2 PSI as the option that will not lead to flooding is understandable for several reasons.

Firstly, minor adjustments in suction pressure, such as a change of 2 PSI, often do not have a drastic impact on the overall liquid handling capabilities of the system. The system typically has built-in tolerances and operational ranges that accommodate such small fluctuations without causing significant issues.

On the other hand, the other options present scenarios that can create an imbalance in the liquid and vapor phases, leading to potential flooding. Over-adjusted metering valves can restrict or improperly regulate the flow of refrigerant, leading to excessive liquid buildup. Mis-managed liquid delivery, especially when compressors are off, can result in an accumulation of liquid in the evaporator, overwhelming the system’s ability to vaporize it. Similarly, setting thermostats to temperatures that are unachievable under existing conditions can result in system behavior that fails to adequately manage phase changes, creating conditions conducive to flooding.

Overall, the limited impact of a minor change in suction pressure make it the least likely cause