When the water tank is heated its volume will expand significantly and the overflow will spill into the expansion tank, which is attached to the water supply pipe and prevents the water pressure of the main water tank from getting too high..The expansion tank’s purpose is to protect your house’s water system from excessive pressure, which can cause damage to fixtures, your water heater, lines, and or fittings. Inside, the tank has a rubber diaphragm at around the mid point of the tank pressurized air goes below the diaphragm in the bottom half of the tank, and water flows in and out of the top half of the tank..An expansion tank or expansion vessel is a small tank used to protect closed water heating systems and domestic water systems from excessive pressure. The tank is partially filled with air, whose compressibility cushions shock caused by water hammer and absorbs excess water pressure caused by thermal expansion..Some manufacturers may even void your water heater warranty if you have a closed plumbing system but don’t have an expansion tank for your water heater. You see, expansion tanks work like shock absorbers on your car. They absorb excess water pressure, protecting your water heater from damage and early failure..Your expansion tank can be anywhere on your plumbing system and does not need to be installed in close proximity to the water heater. It is most commonly installed using a “T” at the cold inlet to the water heater..Thermal expansion of heated water may occur wherever water is heated in a closed system when the boiler water is isolated from the public water supply by a one way valve, such as a feed water pressure reducing valve, backflow preventer, check valve, etc. ..Thermal Expansion in a Water Heater. By Aaron Stickley The only truly effective solution is to install a water expansion tank that provides the extrae for .The water heater expansion tank prevents fluctuations in water pressure by serving as a receptacle for excess water volume created when heating water..That is an expansion tank installed on the water supply pipe to the water heater. Its purpose is to deal with thermal expansion of water as it heats up in the water heater to prevent water pressure from getting too high..
Water heater expansion tanks are used on closed plumbing systems. As water heats and expands, the expansion tank prevents pressure from causing damage..Why does the water heater in my new house have another small tank hanging off the side of the pipe above it?That is an expansion tank installed on the water supply pipe to the water heater..