The water coming into your home makes a journey through a system of pipes which is usually cold or cool, depending on the time of year. To have enough warm water to take a hot shower, hot bath, use the dishwasher or your washing machine, you need a water heater. Water heaters are familiar fixtures in most homes. They typically look like big, tall, cylinder, metal drums, filled with water and equipped with a heating mechanism on the bottom or inside. Newer styles are different as they lose the tank completely in favor of water-on-demand.
Parts of a Hot Water Tank
Tank - The inside of a water heater is a heavy metal tank containing a water protective liner that holds 40 to 60 gallons (151 to 227 liters) of hot water at around 50 to 100 pounds per square inch (PSI). The exterior of the tank is covered by an insulating material and a decorative outer shell.
Dip tube - Water enters the water heater through the dip tube at the top of the tank and travels to the tank bottom where it's then heated.
Shut-off valve -The shut-off valve stops water flow into the water heater. It's a separate component from the heater located outside and above the unit.
Heat-out pipe -Suspended toward the top of the tank's interior, the heat-out pipe allows the hot water to exit the water heater.
Thermostat - This is the thermometer and temperature-control device. This controls the temperature of the water inside the tank. Some electric water heaters have a separate thermostat for each element. It's usually located underneath a protective cover plate and has a knob or dial you can turn to set the temperature.
Heating mechanism - Electric water heaters have heating elements inside the tank to heat the water.
Drain valve - Located near the bottom of the exterior, the drain valve makes it easy to empty the tank, remove sediment or move the tank to another location.
Pressure relief valve - This safety device keeps the pressure inside the water heater.
Sacrificial anode rod - Made of magnesium or aluminum with a steel core and is suspended in the water heater tank to help with corrosion.