What is the primary purpose of an expansion tank in a plumbing system?

The primary purpose of an expansion tank in a plumbing system is to allow for expanded water volume after heating. When water is heated, it expands, which can increase pressure within a closed system like a hot water heater. An expansion tank is specifically designed to accommodate this increased volume, providing a space for the expanded water to go. This helps to maintain stable pressure levels within the plumbing system, preventing potential damage to pipes or fixtures that can occur due to excessive pressure.

The design of expansion tanks enables them to absorb the pressure fluctuations that result from thermal expansion. This not only protects the integrity of the plumbing system but also enhances the efficiency and lifespan of water heating appliances. By having an expansion tank in place, homeowners can avoid issues related to overheating and over-pressurization, leading to a more reliable hot water supply.