Tank-type water heaters # Electric water heater

In household and commercial usage, most water heaters in North America and Europe are of the tank type. Also called storage water heaters, that has the cylindrical tank to heat and keep the water and stores the hot water ready for use. These may use electricity, natural gas, propane, heating oil, solar, or other energy sources but most of people used electricity ,natural gas and now solar energy is quite popular in many country.

Electric water heater

How an electric water heater works

1. When power is initially turned on to the unit, the upper element is energized and heats the water in the upper third of the tank.

2. When the upper third of the tank is heated to the temperature set on the upper thermostat, power is switched to the lower heating element. The lower element continues to heat until the water temperature in the lower portion of the tank is heated to the lower thermostat setting.

3. As hot water is drawn from the top of the tank, the dip tube delivers cold water to the bottom of the tank.

4. Eventually the cold water mixes with the hot, lowering the temperature to below the lower thermostat setting and the bottom element is energized.

If enough water is drawn to cool the upper third of the tank, the upper thermostat will send power to the upper element first. When the upper third of the tank is heated, power will again be switched to the lower element. It will be the circuit like this again and again that make the water continuously hot all the time.

Source : http://www.whirlpoolwaterheaters.com/how/

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