How a Water Heater Works

If you are hoping to better understand how a water

heater works in order to fix it in the future or if you

are simply curious this article will go through the

basics. While there are a number of different designs

of water heaters the most used the iconic cylinder

shape that you will find the basement or garage of

your house. The system used in these cylinders is

actually very simple.

1. Incoming Water Water is fed into your house through plumbing. The

water can come from your own well or the town

watershed. Either way it flows through the pipes, passing the shut-off valve and enters the water heater

where it sits. The heater is constantly full of water waiting to be used.

2. Heating the Water The cold or cool water will enter your water heater through the dip tube through the top of the tank and

travel down to the bottom. At the bottom of the tank the water will come into contact with the heating

mechanism. Electric water heaters will have heating elements inside of the tank (usually in the form of

wired coils around the pipes) while gas water heaters will have a burner and chimney system (the

burner is placed directly below the cold water at the bottom of the tank).

On the outside of a tank there is a thermostat which is set to the desired temperature (recommended

tempertatures are between (120-180 degrees Farenheit).

The thermostat is usually located below a protective cover

plate and has a knob you can turn to set the temperature.

The thermostat also measures the current heat of the

water. The heating mechanism will stay on until the water

reaches the set level. The pipe entering and existing the

water heater is an elongated U-shape. As the water heats

up it will naturally raise to the top of the tank above the

colder, denser water. This principle of heat rising is the

base principle of how the heater works and it is how the cold

water and hot water are separated. As the water heats up it

continues up the water heater eventually reaching the heat-

out pipe on top of the tank (these pipes should be marked so

you don’t accidentally burn yourself). The water leaving the

water heater through this pipe is the hottest the water in

the tank will ever be.

3. To Your Shower The hot water will sit on top of the water heater until you wish to use it. The water in the heater is also

pressurized so when you release the spout upstairs in the house the water pressure will push the hot

water up and out of your showerhead. If you are constantly requiring hot water you will find that the

water heater will not be able to heat up the cold water fast enough to keep up with demand (you might

need a larger heater). The water heater design is very simple and rests on the principle of hot water

rising above cold, dense water. If you are interested in creating a self-sustaining water flow in your

house look into groundwater mapping and installing your own well. Good luck in your future repairs.

Photo Credit: Christopher, smynsbrg