Which characteristic is true about chilled water pump lines?

Chilled water pump lines being insulated is a characteristic that is true and essential for their operation. Insulation is crucial as it helps to minimize heat gain from the surrounding environment into the chilled water being transported. This ensures that the cooling efficiency is maintained, prevents condensation on the pipes, and protects them from temperature fluctuations that can lead to energy losses. Properly insulated chilled water lines also help in reducing noise and pipes sweating, which can lead to water damage and safety concerns.

In contrast, uninsulated lines would allow for significant thermal exchange, which is not desirable in cooling systems. Larger diameter lines are typically associated with specific application requirements, and while they can be larger than condenser lines in some cases, this is not universally true. As for the material composition, while some chilled water lines might use plastic, they are often more commonly made from metal due to factors like durability and pressure handling requirements. Therefore, insulation is the defining and correct characteristic of chilled water pump lines.