­Basically, a dishwasher is a robot that cleans and rinses dirty dishes. Humans have to load the dishes, add detergent, set the proper washing cycles and turn it on, but the dishwasher accomplishes a whole series of functions by itself. A dishwasher:

  • Adds water
  • Heats the water to the appropriate temperature
  • Automatically opens the detergent dispenser at the right time
  • Shoots the water through jets to get the dishes clean
  • Drains the dirty water
  • Sprays more water on the dishes to rinse them
  • Drains itself again
  • Heats the air to dry the dishes off, if the user has selected that setting

­In addition, dishwashers monitor themselves to make sure everything is running properly. A timer (or a small computer) regulates the length of each cycle. A sensor detects the water and air ­temperature to prevent the dishwasher from overheating or damaging your dishes. Another sensor can tell if the water level gets too high and activates the draining function to keep the dishwasher from overflowing. Some dishwashers even have sensors that can detect the dirtiness of the water coming off the dishes. When the water is clear enough, the dishwasher knows the dishes are clean.

In this article, we'll discuss exactly how a dishwasher gets the job done, how to use one properly and what features to look for when buying a dishwasher.

Inside a Dishwasher

­Although dishwashers are watertight, they don't actually fill with water. Just a small basin at the bottom fills up. There, heating elements heat the water to 130 to 140 degrees Fahrenheit. Then a pump propels the water up to the water jets, where it is forced out and sprayed against the dirty dishes. Think about a garden hose with no nozzle - if you put your thumb over the end of the hose, decreasing the space for the water to come out, it sprays out more forcefully. The dishwasher's jets work on the same principle. The force of the water also makes the arms that hold the spray jets rotate, just like a lawn sprinkler.

When the washing and rinsing is finished, the water drains down to the basin again, where the pump propels the water out of the dishwashe­r. Depending on the type of dishwasher, the drain water might go right into the pipes under your sink, or travel up a hose into your sink itself.

The final step in a wash cycle is optional - the dry cycle. The heating element at the bottom of the dishwasher heats the air inside to help the dishes dry. Some people just let them dry without heat to save energy.

Dishwashers are not very mechanically complex. In the next section, we'll take a look at the main parts of a basic dishwasher.