A dishwasher uses a combination of mechanical and electronic components to sense when it is completely drained. The process typically involves the following steps:
Drain Pump: The dishwasher is equipped with a drain pump responsible for removing water from the dishwasher's interior. When the dishwasher is running, the drain pump expels water through a drain hose, directing it either to a drain pipe or a sink. The pump's job is to evacuate all the water used during the wash cycles.
Float Switch: Inside the dishwasher's tub, there is a small, dome-shaped device known as the float switch. The float switch is typically made of plastic or styrofoam and is buoyant. It moves up and down depending on the water level in the dishwasher.
Water Level Sensor: The dishwasher has a water level sensor that detects the position of the float switch. The sensor measures the resistance or conductivity of the circuit, which changes depending on whether the float switch is up (indicating a full dishwasher) or down (indicating an empty dishwasher).
Control Board: The signals from the water level sensor are sent to the dishwasher's control board or electronic control unit (ECU). The control board is like the brain of the dishwasher, responsible for interpreting sensor data and controlling the various cycles and functions.
Logic and Algorithms: The control board uses pre-programmed logic and algorithms to analyze the data from the water level sensor. It determines if the dishwasher is fully drained and ready to move on to the next phase of the wash cycle or if more draining is required.
End of Cycle: Once the control board confirms that the dishwasher is completely drained, it signals the end of the wash cycle. At this point, the dishwasher's heating element may turn on to help dry the dishes or prepare for the next cycle if it's a multi-cycle dishwasher.
It's important to note that different dishwasher models may use slightly different technologies and sensors, but the general principles of using a float switch and water level sensor to determine drainage status are common across many dishwasher designs. The integration of electronic controls allows for efficient and automatic operation, making dishwashers a convenient and time-saving appliance in our daily lives.