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LG PRESSURE SENSOR OPERATION

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Hi,

 

I am a seasoned service tech and was wondering if anyone knows the actual testing and operation of the LG washer pressure sensor. I have taken it apart and unlike most pressure switches there is a round magnet that passes between 2 small capacitors. I have checked on my meter and the best thing that I can figure out is that there is a small millivolt produced when the magnet passes by the capacitors. This obviously is very different from your standard bellows pressing a switch. ANyone with any info for testing and readings or if you know exactly how this works let me know.

 

Thanks

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Central, any particular model or part number?

Edited by PDuff

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The Water Level Frequency Sensor operation is based on the displacement of the *coil* attached to the diaphragm.

 

When the *coil* raises or lowers---it changes the electronically resonant characteristics of the oscillator circuit.

 

The water level is measured by the Main Board---by frequency readings.

 

I've never had a failed Water Level Sensor.

 

It is best tested while on the washer---by using the TEST MODE.

 

On most LG washers---the Test Mode is enabled by pressing and holding the SPIN SPEED and SOIL LEVEL buttons---and then pressing the POWER button (release all 3 buttons and wait for the door to lock).

 

Press the START / PAUSE button 4 times at one second intervals (Prewash Cold Water Fill)

 

The display read-out on the Control Panel will show the *frequency*

 

Empty---the frequency read-out should be about 255

 

A tub full of water should show a frequency of about 214 (depending on model number)

 

 

Some of the errors that can be displayed---relating to water fill are...

 

IE error:

 

Little or no water---usually caused by a failed Water Valve

 

FE error:

 

Too much water (overflow detected)---Can be a failed/stuck open Water Valve or blockage in the black air tube which is connected to the Water Level Frequency Sensor. Disconnect the tube from the sensor---and blow air back into the tub to clear obstruction.

 

To test the Water Level Frequency Sensor outside of the washer...

 

Use a test meter to check the ohms between pins 1 and 3 (should have between 21 & 23 ohms).

Edited by john63

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Hey thanks a million for the information. Yes I had read the ohms on the outside pins at 22 ohms on the new switch, but the old one read nothing. Makes total sense now looking at in given the magnet passing over to change the frequency. Thanks again!

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You're welcome:)

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