What type of pump is invariably used as a circulator in a hydronic heating system?

Correct Answer: Option C — Centrifugal pump

Centrifugal pumps are standard for hydronic heating because they provide the continuous, high-volume, low-pressure flow required to circulate water through closed-loop piping. Their simple design, lack of internal valves, and ability to handle varying system resistances make them ideal for maintaining consistent thermal distribution throughout the vessel's heating circuits.