How Does A Top Load Washing Machine Work?

How Top Load Washing Machine Works
Dorann Weber/Getty Images

The invention of the automatic washing machine freed women from grueling, back-breaking labor. As the models progressed, the task of laundering clothes became much more simple. Today, washers can be found in a variety of sizes, colors and styles. While front load washers with a horizontal axis are making an inroad in sales in the United States, the vertical axis top load washer is still the industry leader.

It is the combination of the mechanical energy of the washer's agitator, the thermal energy of temperature of the water and the chemical action of the detergent that cleans clothes.

How Does A Top Load Washing Machine Work?

While design features and cycle offerings on washers vary from manufacturer to manufacturer and all across price ranges, the basic workings of top load washing machines in the United States are the same.

There are two components in every washer - the control system and the mechanical system. The control system consists of the control boards, load size selector (pressure switch), the water temperature selector, timer and the lid/locking switch. The mechanical system is composed of the motor, transmission, clutch, inner and outer wash tubs, agitator, pumps, water valve, suspension system and a belt or motor coupling.

There are now two types of top loading washers on the market:  Standard and high-efficiency.

  • Standard top load washing machines in the United States, Canada and Australia use a center agitator with propeller-like paddles to move clothes through the water from the top of the washer to the bottom. The top to bottom agitation continues for the length of the wash cycle forcing water and detergent through the fabrics to loosen soil. In Asia, top load washer washers use an impeller agitator without the center post.
  • High-efficiency top load washers are much more like their front load washer cousins. They have a drum rotating around a horizontal axis like a front loader, but there is no front door. They have a liftable top load lid like a standard washer. These machines operate and spin just like a front-loader and use half the amount of water required for a standard washer. The advantages of a top load high-efficiency washer is they do not require the folding rubber bellows seal that can trap moisture and soil and cause odors. The top load design has a pair of symmetrical bearings rather than a single bearing on one side, reducing wear and tear.

For both types of top loading machines, after the user selects the load size, water temperature and type of cycle, the outer tub is filled with water. In a standard washer, the water fully covers the clothes and floats them in the basket (unless the washer basket has been overstuffed). The agitator then moves the water and the clothes to provide the friction necessary to loosen the soil. A high-efficiency washer uses much less water (about 40 percent less) and does not completely cover the clothes at first. The agitator draws the clothes into the water during the washing cycle.

Typically, the motor that powers the gearbox drives the agitator to move or spin in one direction. The water pump motor also spins one way as it recirculates the detergent-laced water. That same pump motor switches direction to pump or remove the water during the spin cycle. Top load washers have actually become more mechanically simple as manufacturers have developed new designs. However, the electronic controls have been much more complex. No longer can single control parts be replaced. The entire electronic control panel must usually be replaced with one component fails.

Thanks to the vertical design, top load washers allow laundry product dispensers for detergent, bleach and fabric softener to operate through gravity and centrifugal force. On a front loader, the dispensers must be opened by a solenoid valve.

The vertical design also makes it much more simple to move water in and out of the washer than the action in a front loader. Because of gravity and drain location, top load washers do not typically hold water that can cause mold and mildew odors. Cleaning maintenance for a top load washer is quite simple.

By understanding the basics of a top load washer, you can better diagnose problems and even make repairs. If you need a user or repair manual, you can find it here and replacement parts here.