What advantage does a 4-pipe hydronic heating/cooling heating system have over a 2-pipe hydronic heating/cooling system?

Correct Answer: Option C — A 4-pipe hydronic heating/cooling system allows simultaneous heating and cooling of different zones, whereas a 2-pipe hydronic heating/cooling system does not.

A 4-pipe system utilizes separate supply and return lines for both hot and chilled water. This configuration allows for simultaneous heating and cooling in different zones, providing superior comfort control compared to 2-pipe systems, which are limited to either heating or cooling mode for the entire circuit.