electric water-heater tank 
Mechanism cutting off the flow of electric current when the temperature of the water exceeds a set value.
Pipe through which water escapes when maximum pressure is exceeded.
pressure relief valve
Device for lowering the pressure inside the tank by releasing excess hot water.
Device for emptying water from the tank.
Point where the hot-water tank connects with the household circuit.
Device that senses changes in temperature and automatically switches the upper heating element on or off.
Outlet pipe for hot water flowing into the hot-water circuit.
Inlet pipe for cold water to the tank.
Material placed between the tank and the outer walls of the hot-water tank in order to reduce heat loss.
Insulated reservoir in which hot water is stored; it is usually cylindrical and enameled or glazed.
lower heating element
Coated electric resistor immersed in the lower part of the tank to heat the water.
Device that senses changes in temperature and automatically switches the lower heating element on or off.
upper heating element
Coated electric resistor immersed in the upper part of the tank to heat the water.
Magnesium-coated electrode protecting the tank from the corrosive effects of the water.