How does a Washing Machine Know When to Stop Filling? (Easy Explanation)
Could it be that the washing machine has some magical powers to know when to stop filling with water?
Otherwise, how does a washer know that it needs to stop filling?
You have thought about this question because your washing machine has at some point overfilled and spilled, and you wondered why it didn’t stop filling when it was supposed to.
Or like me, you are generally curious about how appliances work.
Well, there is no magical phenomenon that tells a washing machine when to stop filling.
It’s just science and we are going to explain it to you today.
And if your washing machine ever does not stop filling with water, there is a problem!
Here is how a washing machine knows when to stop filling:
Washing machines have a water level switch that controls the amount of water that enters the washer. The water level switch is a pressure switch that has two sets of contacts, one that sends power to the inlet valve to fill the washer, and another that sends power to the motor after the tub is fully filled.
In this article, we are going to explain in detail all you need to know about washing machines filling with water including which parts of a washer are responsible for it.
Table of Contents
What is a water level switch and where is it located?
The water level switch is a round plastic switch component that has a rubber tube connected to it that runs down at the site of the washing tub.
Its function is to send power to the water inlet valve and the temperature timer for the tub to be filled with water to a specific level during a wash cycle. And again, send power to the motor to start the cycle after the washer has been appropriately filled.
The level to which water fills the tub depends on different factors such as load size, and wash settings chosen.
It is important to know where you can locate the pressure switch is located on the washing machine so you can always check to see if you suspect that it may be faulty.
The location of the water level switch may be slightly different depending on the brand and model of the washing machine.
In order to locate your water level switch, you can always refer to the user manual.
However, in general, you will find the pressure switch as described below;
In top load washing machines, the water level switch is usually located on the control panel right behind the water level selector control/knob.
In front load washing machines, the water level switch is usually mounted on the upper cabinet frame and can be accessed by taking off the top panel.
How does the water level switch work?
As described above, the water level switch has a long and hollow plastic tube that contains air and runs down the side of the tub.
When your washing machine is filled with water, the hollow tube is also filled.
As the water goes into the tube, it pushes air inside to the top of the tube.
The water will rise up to the level suitable for the cycle and the air pressure in the tube causes the switch to send a signal to the main control to stop the filling.
The water level your top load washing machine fills up to depends on the settings you choose during the start of your wash cycle.
And the setting will usually be based on the size of load, fabrics, etc.
You can raise or reduce the water level in top load washing machines by resetting your washer for larger load size or to a smaller load size respectively.
As for other front load washing machines, they have a sensor that automatically determines the load size and chooses the optimum amount of water based on the load.
Then again, the pressure switch gets activated in the same as in top load washing machines.
Washing machine load sensor
You may ask, what is the load sensor in a washing machine and how does it contribute to the filling?
The load sensor on a washing machine is a component that senses the size of the load when you load your washer in order to determine the adequate amount of water that can efficiently run the wash cycle.
Not all washing machines have load sensors.
Semi-automatic washers and other older washer models do not have load sensors.
However, many modern front load and top washing machines have load sensors that effectively determine optimum required water quantities termed High Efficiency(HE) washers.
How does a washing machine fill with water?
Aside from knowing how a washing machine knows when to stop filling, it can also be good to know how a washing machine gets filled with water in the first place.
The mechanism by which a washing machine is filled with water.
Washing machines have an inlet valve behind them that controls the entry of water into the washer. The inlet valves open a close to allow water to enter by receiving electronic signals from the washer anytime you start your washing machine.
There are two opening ports with a seal/gate on the valve which accommodate cold and hot water supply and are closed by default.
When you start your washer, it sends alerts to a solenoid that controls any of the gates to either close or open the seal/gate.
Depending on the wash temperature settings you choose, one or both of the seals will be opened to allow water to enter your washing machine.
How long does a washing machine fill for?
There is no fixed duration for filling a washing machine. However, a wash cycle will usually take a few minutes to fill with water. It depends on the washer settings that you choose and the water quantity that is required for your load size.
Read also: Why do European Washing Machines take Longer? (5 Strong Reasons)
How much should a washing machine fill with water?
A washing machine should not be filled to the brim with water as that may your clothes to not clean properly and in some cases may cause spillage.
Your washer should only fill to a maximum of about ¾ the capacity.
Washing machines with a capacity of 4 cubic feet and below fill with an average of 9 gallons of water per load. Washers with a capacity between 4 and 5 cubic feet will use an average of 16 galls of water per load. 5 cubic feet and above capacity washers will use an average of 201 gallons of water per load.
We have explained in detailed and simple language how a washing machine knows when to stop filling with water.
As you have discovered, it’s no magic at all.
It knows by the water level switch sending electronic signals to the washer to open and close the inlet valves through which water enters the washing machine.