An expansion tank, also known as an expansion vessel, is a small tank used to protect closed water heating systems and domestic hot water systems from excessive pressure. When water is heated, it expands and increases the pressure within the tank and plumbing system. The expansion tank is designed to handle the thermal expansion of water as it heats up in the water heater, preventing excessive water pressure. The tank is partially filled with air, whose compressibility cushions shock caused by water. The excess water enters the expansion tank, and within the tank, there is a pressurized air bladder that absorbs the additional water by expanding and contracting. The key features of an expansion tank include:
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Diaphragm: The tank has a rubber diaphragm separating the water from the air pocket.
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Types: There are different types of expansion tanks, including bladder tanks and diaphragm tanks.
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Location: An expansion tank is installed directly above a water heater on the cold water inlet.
Expansion tanks are beneficial to your homes plumbing system and are now required by code. They prevent leaks caused by pressure buildup, provide a second layer of security alongside the water heaters pressure relief valve, save money caused by water damage or pipe bursts, are inexpensive to purchase and install, and take up little space.
