Kitchen Large Electric Appliances - Washer will not stop filling with water!

I have a Kenmore Series 80 washer (model 110.28802890) that does not stop filling with water during the rinse! It overflowed once. Pulling out the control knob or moving to off does not stop the flow! The only way is to unplug the machine and turn the water connections off on the wall. Assuming the machine is not recognizing the water level. Bad sensor?

If your saying.
With the washer unplugged, and just by turning on the water supply the machine starts filling.
Then the fill valve is stuck open, for the price its best to replace it.

We think it ran through the Wash cycle okay (the overflowing water was clear). When it got to Rinse, the control knob did not advance any further and the water kept coming in to the basket till it overflowed. That sounds like the machine is not getting the message to shut the water off. At that point the only weay to stop the water was to turn off the water spigots on the wall. I unplugged the washer just to be safe. Does that help any? Thanks!

Ken

This is how most level control switches work.
The water level switch has a tube that connects to the lower part of the tub, as the water fills the tub air pressure builds up in the tube (from the weight of the water) that plugs in the back of the water level switch.
once the pressure reaches a set point a switch inside the level control sends power to the timer.
The timer will not advance if there is a problem with the level switch.

The tube may have come loose.
or the diaphragm in the switch may have a small hole.

Thanks for the very detailed response!