Which system characteristic is specific to low-pressure hot water systems?

Low-pressure hot water systems are primarily characterized by their reliance on gravity for the circulation of water. In these systems, water flows from the storage tank to the taps and heating elements due to gravitational pull, which is essential for ensuring that hot water reaches various outlets in the system.

This method of operation minimizes the need for additional mechanical components like pumps, making the system simpler and potentially more reliable, particularly in residential applications where high water pressure is not necessary. The use of gravity also allows for easier installation without the complexity and power requirements that come with electric pumps.

When comparing this characteristic to other options, reliance on gravity differentiates low-pressure systems from those that require electric pumps, which indicates active circulation or pressurized flow. Similarly, feed tanks are commonly used in high-pressure systems to maintain adequate water levels, and high water pressure systems are designed to deliver water using pressurized flows, which is not a feature of low-pressure systems. Understanding these distinctions is crucial for effective application and maintenance of plumbing systems.