It's frustrating when a front-load washing machine overflows, especially when you don't know why. If this happens, pause the cycle to contain the damage and stop the wash tub from filling until you can troubleshoot the problem. A number of issues can cause the washer to overflow the machine.
Use only high efficiency (HE) detergent with front-load washing machines. Ordinary detergent is made to produce lots of suds, which a front-load washing machine can't handle. A front-load washing machine uses a lot less water than a conventional top-load washer. If you put regular detergent into a front-load machine, it creates too many suds and prompts the water valve to fill the machine with more water to flush out excess suds, all of which can overflow the machine. Follow the directions on the panel of HE detergents for detergent measurements based on load size.
Stuck Water Valve
The water valve is controlled by the pressure switch and control panel. Once the machine reaches a certain water level, the pressure switch triggers the control panel to shut-off the water valve. However, if the water valve sticks, water continues to flow into the tub and can overflow the machine. At this point, however, the water pump should turn on and begin to pump water from the tub to the drain line. You might hear water running into the machine and the pump pushing it out simultaneously. Contact a washing machine repair technician to replace the water valve.
The pressure switch or water level switch monitors the water level in the wash tub. The pressure switch is attached to a tube that extends along the side of the wash tub. As the tub fills with water, air in the tube rise to the top. After the tub reaches a certain water level, the air pushes up toward the top of the tube and activates the pressure switch that sends a signal to the control panel to shut-off the water valve. However, if the tube is kinked or cracked, it's unable to detect the amount of water in the tub and as a result fails to force air pressure to activate the pressure switch, thus the tub overflows. Turn off the washing machine and contact a washing machine repair technician to replace the broken tube.
Defective Pressure Switch
Over time with repeated wash cycles, it's possible for the pressure switch to wear. A worn pressure switch is unable to send a signal to the control panel to close the water valve. Consequently, the washer might incorrectly think that it needs to continue filling the tub with water to the point that it overflows. Consult a washing machine repair technician to inspect the water level control system for problems and make needed repairs.