Your water heater is a pretty simple appliance. Newer styles have some interesting features but the old cylinder water heater is still what is most widely used in the U.S. today. The tank is the inner shell of a water heater. It contains a water protective glass liner that holds the water. The exterior of the tank is covered in an insulating material. Water enters the water heater through a dip tube at the top of the tank and travels to the bottom of the tank where it is heated. Electric water heaters have heating elements inside the tank to heat the water. Gas water heaters use a burner. There is an anode rod suspended in the water heater to help retard corrosion. Other parts of your water heater are a drain valve located near the bottom of the exterior housing to allow draining when repairs are needed, a pressure relief valve to keep the pressure inside the water heater within safe limits and thermostat which is the temperature control device. Your water heater is the most neglected appliance in your home till it stops working. De Hart Plumbing Heating and Cooling serving Manhattan Kansas, Junction City Kansas and Wamego Kansas and some outlying areas.