How to replace the pressure switch in a washing machine?

What is a pressure switch in washing machines?

A pressure switch in a washing machine is a device that detects and measures the pressure of water within the machine. This switch is responsible for monitoring the water level and communicating this information to the control board.

It plays a key role in ensuring that the machine operates correctly and safely by controlling the fill and drain cycles.

It also regulates the amount of water entering the machine according to the specific requirements of a selected wash program.

How does the washer’s pressure switch work?

The pressure switch is connected to a chamber through a hose or a tube.

When the water starts filling the washtub, the air present in the connected chamber is pushed up from the chamber towards the switch through the tube.

As the water level rises and fills up to a certain level, the air is pushed to the switch, and this is how it activates.

Finally, the switch passes a signal through the electrical wires to alert the control board to start the selected cycle.

In simple terms, the pressure switch works like a trigger that starts the washing process once enough water has been added to the machine.

Likewise, it also helps to drain the water from the washing machine once the cycle is complete.

What happens if the pressure switch wears out?

The water pressure switch is used to sense the water level in the tub and tell the washer when to stop filling.

A faulty or worn-out pressure switch will not allow water to enter, preventing the washer from starting due to a lack of water.

Also, it may not send the stop signal and continue filling even if the drum is full, causing an overflow.

Another problem that you may face is slow filling, which would significantly extend the time it takes to complete a cycle.

Common symptoms of a faulty pressure switch

A faulty pressure switch in a washing machine can cause several symptoms, including the machine not starting or completing a cycle, overflowing, stopping in the middle of a cycle, displaying error codes, making unusual noises, inconsistent water levels, and longer wash cycles.

Some of these symptoms may also be caused by other issues, so it’s best to have a professional diagnose the problem.

How to replace the pressure switch in a washing machine?

Step 1: Disconnect the washing machine from the power source

First, disconnect the power supply to the washing machine, this can be done by unplugging it from the wall outlet or by turning off the circuit breaker.

Step 2: Locate the pressure switch

Grab the user manual of your washing machine model and locate the pressure switch.

This will ensure that you will detach the right access panels from the washing machine to locate and remove them.

In general, the pressure switch in the top loader is located at the interior of the washer’s rear panel or under the control panel. For front-loaders, you should be able to find it under the top panel.

That being said, in some washing machines, a pressure switch is located behind the water dial or knob on the control panel.

Whereas, some washing machine models may have it fixed near the water inlet valve at the back top of the machine or simply at the side frame of the top panel.

So, the location of the pressure switch may vary from brand to brand, model, and design of the washing machine.

Step 3: Remove the access panels

Once you have determined the location, start by removing the required access panels.

For washers that have a pressure switch located at the top panel (at the backside), you can take off the machine’s top panel, this will usually give you instant access to the pressure switch instantly.

For washer models that have the switch located behind the water settings knob or dial, just pull the knob and twist it with your hands, and then proceed to remove the top panel.

You will need screwdrivers or nut drivers to unthread the retaining screws or nuts from the panels.

You may also need a putty knife to pry out some holding tabs of the top panel.

Just check the user manual to find the exact location of the pressure switch.

Step 4: Remove the pressure switch

Once you have found the pressure switch, use a Phillips head screwdriver to remove the two screws that hold it in place.

Now, carefully pull out the pressure switch and disconnect the running wires that are attached to it.

Simply pull the wire harness carefully and hold the pressure switch in one hand.

Next, gently pull the small hose using the other hand and keep it aside.

Step 5: Test the pressure switch

It is always better to have the pressure switch tested before replacing it in your washing machine.

You can use a multimeter to test for continuity between the two terminals on the pressure switch.

Testing the Pressure Switch in a Washing Machine:

What you’ll need

• A multimeter
• Pressure switch

Instructions to test the pressure switch in a washing machine

Step 1: Setting up the multimeter

Grab your multimeter and turn the dial to the lowest setting for measuring resistance in ohms.

Step 2: Testing the common terminal

Touch the black lead from the multimeter to the common terminal on the pressure switch.

Then, touch the red lead to the normally closed terminal.

Now, check the display on the multimeter; it should show a reading close to zero ohms.

Step 3: Testing the air pressure tube

Listen closely as you blow air into the attached air pressure tube; you should hear a clicking sound, and the terminals should no longer show electrical continuity on the multimeter’s screen.

Step 4: Testing the normally open terminal

The next step is to keep the black lead on the common terminal and the red lead on the normally open terminal.

Repeat the process of blowing air into the pressure tube. The display of the multimeter should not show continuity until you have blown air into the pressure tube.

The Results

Incorrect results from the pressure switch during this test indicate that it is broken (non-functional), thus, requiring a replacement.

Step 6: Install the replacement switch

Before you install the replacement switch, you should clean any debris out of the housing (areas around the pressure switch).

Also, make sure to blow air with your mouth into the hose that connects the pressure switch to clear any clogs.

Now, start by reconnecting the wires to the new pressure switch and pushing the small hose back into place properly.

Screw the replacement pressure switch back to its housing and reassemble the access panels by reversing the steps.

Make sure to reassemble the lid or access panels carefully and reconnect the power to the washing machine.

Step 7: Run a test cycle

You can either run an empty cycle or add a small load of laundry to ensure the pressure switch is doing its job of filling the washer and running the machine like before.

Final Thoughts

A pressure switch in a washing machine plays an important role in the overall operation of the machine as a whole, and if the switch breaks down, it can prevent the washer from operating normally.

A malfunctioning pressure switch can also lead to several problems, some of which may sound confusing, making it difficult to determine the actual cause of the issue.

This is because the symptoms that arise from a faulty pressure switch can be similar to many other problems, such as a malfunctioning drain pump or a clogged drain line.

That being said, changing a pressure switch is a fairly simple job that you can do yourself with a few basic tools and the user manual for your washing machine model.

If you suspect that your pressure switch is faulty and you aren’t confident enough to have it replaced yourself, then it is important to have it checked by a qualified technician.