An expansion tank installation is the addition of a second tank to catch expanded water in a hot-water system. This relieves the amount of thermal pressure within the hot-water system, preventing the emission of dangerous gases or ruptures within the tank or pipes.
The purpose of a hot-water tank is to heat water. When water is heated, it expands. As water expands, water pressure builds. This pressure, if not alleviated, can cause the hot-water system to become unstable and dangerous. It can also cause severe damage to the system and its components. The expansion tank serves as a holding bin for expanded hot water and provides a stable environment for the water to properly cool.