Most U.S. homes have a water heater and a traditional tank model in particular. These systems store and heat water in a tank that holds about 50 gallons on average. Let’s explore some of the key components that make the magic happen.

Dip Tube

The typical water heater tank is much taller than it is wide, and the cold water inlet is at the top of the tank. That could foster a scenario where cold water accumulates near the hot water outlet. The dip tube prevents this. It’s a tube that extends from the inlet to near the bottom of the tank. That way, the cold water entering the system goes directly to the bottom.

Sacrificial Anode Rod

Limescale and corrosion are big concerns with water heaters. Rust can undermine the inner tank walls and other components. Scale can promote that rust, and it can also build up in the tank. By doing so, it serves as an insulator and increases pressure. The sacrificial anode rod slows the rate of this accumulation through electrolysis. The anode rod itself will eventually rust. That’s why a plumber must check it annually and replace it as needed.

Temperature-and-Pressure Relief Valve

Pressure can build up within a water heater tank. It can make the heating uneven and decrease system efficiency. High pressure can also promote leakage and, in rare cases, even cause an explosion. A temperature-and-pressure relief (TPR) valve prevents this. When pressure is high enough, the TPR valve opens, and a small amount of water flows out and exits the home via a drainage line.

Heating Element or Burner

Electric water heaters typically have two heating elements: one for the upper tank and another for the lower. These are electric coils that heat the water directly. Fuel-burning water heaters have a burner within a sealed combustion chamber below the tank. Heat from the burner enters through the bottom and rises through the tank.

Thermostat

The thermostat is what lets you set the temperature of your hot water, and it directly controls the heating elements or burner. Electric models usually have two, one for each element.

Ignition System

Manufacturers have largely phased out pilot light systems. Nowadays, gas models usually have an electric ignition system to start the combustion process as needed. Heating elements draw electricity directly, so electric models don’t need an ignition source.

Flue

Gas water heaters generate toxic gases as a byproduct of combustion. A flue is what channels those gases outside the home. A water heater can lose heat through this process. This is why high-efficiency models often have a heat exchanger dedicated to the ventilation system.

Do you have additional questions about how water heaters work? Call Evenflo Plumbing in Corvallis, OR, or contact us online.