Minnesota Special Engineer Boiler License Exam Practice 2025 – Complete Preparation Guide

An expansion tank is used to accommodate the expansion and contraction of water volume due to temperature changes within a heating system. When water is heated, it expands, and in a closed system, this expansion can create pressure that may exceed safe operating limits. The expansion tank provides a buffer zone where this excess water flow can go, preventing excessive pressure build-up that could otherwise damage the system or cause safety issues.

This is particularly important in systems where water is heated and contained, as the variations in temperature can lead to significant changes in volume. The expansion tank allows for these changes by acting as a cushion, effectively maintaining the integrity and safety of the heating system.

In summary, the expansion tank's primary purpose is to handle the physical changes in water volume, ensuring smooth operation and preventing potential hazards associated with excessive pressure.