Ace the InterNACHI HVAC Exam 2025 – Heat Up Your Career with Confidence!

In closed boiler systems, the circulation of water is essential for the efficient transfer of heat throughout the system. Circulators, or pumps, are used to move the heated water from the boiler to various heating elements, such as radiators or underfloor heating systems, and then back to the boiler to be reheated. This continuous loop ensures that the building is maintained at the desired temperature, making circulators a critical component.

While other features like expansion tanks, venting, and safety valves are important for overall system safety and functionality, the presence of a circulator is necessary for the core operation of a closed boiler system. An expansion tank helps manage pressure changes, venting is often required for the safe escape of combustion gases in certain systems, and safety valves prevent excessive pressure build-up. However, without a circulator, the system would not effectively circulate hot water, rendering it incapable of providing the necessary heating performance.