How Does a Pressure Transducer Work?: A Basic Technical Explanation

A pressure transducer is the component inside some washing machines that detects water level in the tub. It’s similar to a water level pressure switch but works differently to detect and communicate the tub water level to the main electronic control board in the washer.

In this article, we’ll reveal how this electronic water level detector works.

The Role of a Pressure Transducer in Your Washer

The pressure transducer in your washer detects water level in the tub and converts the water level reading to a digital signal that it transmits through wires to the main electronic control board in the washing machine.

The main control board uses the water level pressure transducer signal to detect when the tub is full. When the tub is full, the control continues to the next step in the wash or rinse cycle to tumble or agitate the clothes.

How a Pressure Transducer Works

Here’s a basic explanation of how a pressure transducer works to detect water level in the washer tub:

• The water level pressure transducer detects air pressure exerted through an air tube connected to the bottom of the washer tub to determine water level.
• Air pressure in the tube increases directly proportional to the water level in the tub.
• As the washer tub fills with water, air in the sensor tube exerts pressure on a diaphragm that moves a metal rod or core inside a coil in the transducer to convert the air pressure (water level) to a digital frequency signal that is transmitted to the main electronic control board in the washer.
• The control board detects the digital frequency signal from the pressure transducer and shuts the water valves to end the filling process when the control detects that the set water level has been reached in the washer tub.

In this manner, the water level pressure transducer helps the washer’s electronic control board precisely control water level in the machine’s tub.

What Can Go Wrong?

While the water level pressure transducer is an accurate and reliable component, failures in the water level sensing system do occasionally occur.

Because a water level pressure transducer transmits a frequency signal to the control board, the internal logic in the control board will detect problems with the signal and display an error code on the control panel when a failure occurs.

When you see an error code on your washer, look up the code on our washer error code charts and follow the troubleshooting recommended to fix the problem.

Here are some common pressure transducer failures that you may face:

Air Tube Leaks or Connection Problems

The water level pressure transducer depends on the air tube for accurate measurement of the water level in the tub.

Damage or a loose connection in the air tube that causes an air leak will prevent the pressure transducer from accurately detecting water level in the tub.

Unplug the washer and check the air tube for damage and replace the tube if you find cracks, tears or damage.

Reconnect the air tube if the find it loose or disconnected at the bottom of the tub or on the water level pressure transducer.

Wiring Failure

The washer electronic control board depends on wiring to detect signals from the water level pressure transducer.

Loose or disconnected wires will typically cause the control to display an error code on the display. For example, LG washers will display the PE error code when the pressure transducer wire harness is damaged or disconnected.

Unplug the washer and check the pressure transducer wire harness connections on the electronic control board and the pressure transducer.

Reconnect any loose wires and replace any broken wires.

Failed Pressure Transducer

Although rare, pressure transducers sometimes fail due to internal wiring problems or an internal circuit board failure.

When this happens you’ll need to unplug the washer and replace the water level pressure transducer.

The water level pressure transducer is incorporated into the electronic control board on common Kenmore, Whirlpool, Amana and Maytag top-load washers. To replace the pressure transducer on those models, you’ll need to replace the entire electronic control board.

Here’s a DIY video that shows how to replace the control board in those machines:

If you’re unable to resolve an issue with the water level pressure transducer on your own, schedule washer repair service and we’ll send a Sears Home Services technician to your home to fix the washer.

The pressure transducer plays a critical role in washer operations. Understanding how it works and how to troubleshoot common problems will help you keep your washer running smoothly.

When your washer breaks down, keep in mind that Sears Home Services is always standing by with the best washer repair technicians in the business.

Trust us to help you keep your washer and all of your home appliances in top shape.

A misreading pressure transducer can disrupt your washer’s fill levels, causing underfilled or overflowing cycles. If recalibrating sensors doesn’t fix the issue, it might be time for front load washing machine repair. Certified technicians will ensure your washer’s electronic sensors accurately gauge water levels.