Which event would indicate that the cooling tower is not being air-cooled effectively?

• A. Higher return water temperature
• B. Lower return water temperature
• C. No change in temperature
• D. Decreased head pressure

Answer: (A)

Cooling towers remove heat from system water by letting it air‑cool and then returning cooler water to the equipment. The temperature of the water as it comes back to the system shows how well that heat rejection is working. If the cooling tower isn’t air‑cooling effectively, it won’t remove as much heat, so the water returning to the system stays warmer than it should. That higher return water temperature means the chiller or condenser has to work harder, signaling reduced cooling performance. In contrast, a lower return water temperature means the tower is doing a good job cooling the water, and no change would suggest the performance is unchanged. A decreased head pressure doesn’t directly indicate poor air‑cooling of the tower; it points to different refrigerant or system issues.