An expansion tank can protect your water heater from excessive pressure. The tank is a small tank that protects hot waster systems from building up excessive pressure. It is partially filled with air and cushions shock caused by water hammer and absorbs excess water pressure caused by thermal expansion. The modern expansion tank is a small container or tank divided in two by a rubber diaphragm. One side is connected to the pipe work of the heating system. The other side, the dry side contains air under pressure. This system can alleviate water hammer- the sound caused when water in motion in your water pipes is forced to stop or suddenly change direction. Call De Hart Plumbing if you would like more information on an expansion tank , 785-341-4193. De Hart Plumbing, serving Manhattan Kansas, Junction City Kansas and Wamego Kansas.