In enthalpy-based economizer control, what problem most commonly reduces performance?

• A. Too many sensors.
• B. Sensors that do not work properly.
• C. Inaccurate temperature setpoints.
• D. Infrequent maintenance.

Answer: (B)

Enthalpy-based economizer control depends on accurate readings of outdoor-air conditions to decide whether bringing in outside air is beneficial. When sensors are not working properly, the enthalpy (and thus the comparison between outdoor air and return air) becomes unreliable. The controller may falsely think outdoor air is more favorable than it actually is, causing the economizer to open when it shouldn’t, or it may close it when outdoor air would have been advantageous. This misreads lead to energy waste, humidity control problems, and reduced ventilation performance, which is why faulty sensors are the most common factor that degrades performance.

Other issues can contribute, but they don’t repeatedly undermine the system as often. Too many sensors can complicate signals but doesn’t inherently degrade the control logic. Inaccurate temperature setpoints affect comfort more directly than the fundamental ability to economize. Infrequent maintenance matters, yet the core reliability problem is sensors that fail or drift, because the economizer’s decisions hinge on those measurements.