How Small Dishwashers Work

Small Dishwashers: The Basics

Small dishwashers work the same as any conventional-sized dishwasher. Water from a faucet or spout is heated then it is pumped into the main cavity then sprayed through rotating spray arms. Soap is introduced causing your dishes to get cleaned. That’s the sweet and short version, but if you continue to read on, you will find a more detailed explanation.

Small dishwashers are not very complicated mechanically. The main components that facilitate its operation are the pump, motor, spray arms, and a control panel. Depending on the model, the control panel will provide controls set the  water, heat, rinse, and drying cycles of your unit. Each of these cycles are as follows:

Pump

Typically a small dishwasher has a motor and pump assembly. The pump pushes water into the sprayer arms (see video below).

During your dishwasher’s drain cycle it also pushes the water out and into the drain. The motor is located behind a panel on the underside of the dishwasher.

Motor

You might find you have a reversible motor, depending on your dishwasher model. Your dishwasher may have a reversible installed. If this is the case, it will be in the center at the bottom with the shaft pointing upwards.

The pump assembly sits on top of the motor which is located underneath the dishwasher. As the water is pumped into the spray arms it turns in a clockwise direction, the motor turns counter-clockwise to allow your dishwasher to drain.

Spray Arms

The spray arms contain small ports (jets) where the water is forced through. As the water enters the spray arm rotates to build up pressure before the water exits. This pressurized hot water shoots up into the cavity where it mixes with the detergent that has been released from a dispenser and begins cleaning your plates.

Control Panel

In addition to the pump and motor, switches, valves, timers, and solenoids are installed in order to run the dishwasher. The timer is located behind the control panel at the top of the dishwasher or behind a lower panel.

The timer will either be mechanical or electric with an LED display. The primary function of the timer is to trigger the operation of the pump, motor, switches, valves, timers, and solenoids at a specific time and for a set period of time.

In addition, the control panel also has a selector switch to choose the temperature, wash, rinse, and drying cycles. Each cycle selected also selections the time the dishwasher runs.

Water Cycle

For most small dishwashers, a faucet adapter is provided so that you can hook up your inlet and return lines to your kitchen sink. If you happen to purchase a unit that does not have an adapter for your dishwasher, you can buy one online or at your local home appliance store.

The washing process starts by drawing in cold water from its inlet hose. The water passes through the water inlet valve to fill the tub.  As the water fills the washer’s tub, a float switch activates to close the valve once it reaches the right level.

Heating Cycle

Hot water is supplied by a tube connected to the water inlet valve. As the water is drawn, it is heated up by a heating element. The heating element is located at the bottom of the unit. The timer receives s a signal from a thermostat the prescribed temperature is reached. As this occurs, the water inlet valve opens to let the heated water to be pumped to the spray arms. In the video below you can see the spray arms distributing the heated water:

Rinse Cycle

After the washer has completed the wash cycle, the dirty water is drained through the drain line, and clean water is pumped back in to rinse the dishes. Depending on the particular model, the rinse cycle may go through more than once. This ensures more thorough cleaning.

Dry Cycle

Unfortunately, many small dishwashers do not have a drying cycle. Most models require that you open the door to facilitate drying. On the SPT countertop dishwashers, a rinse aid feature is incorporated so that you can add a chemical product such as Cascade or Jet-Dry, that helps your dishes dry faster.  If you have ever use RainX for your windshield, it’s the same concept.

As we have noted previously, the model that you purchase may vary in the number of features offered, but overall, they will all operate as we have described in this short guide. You can find out more about the different countertop dishwashers in our review section of the site.