Whirlpool Duet Washer F5 Error Code

[TechnicianBrian]

Model #GHW9100LW2, this washer would start to fill with water, but would begin beeping and then display an F5 error message. This is a code I would see every so often years ago when these units were new to the market, so I was rather surprised to see this one pop up. The reason for most of these codes back then was a loose wire harness, but this time, this one was actually broken.



A temperature sensor is employed in many washers with electronic controls to better determine and control the temperature of the wash and rinse water. The sensor used is called a thermistor which has the ability to change in resistance as it changes in temperature. Often called an NTC for Negative Temperature Coefficient, these semi-conductor components will decrease in resistance as the temperature applied increases. By passing a small current through the thermistor circuit, the control board can very accurately determine the temperature of the water within the tub.


Thermistors can be easily checked by reading the resistance between the two terminals and observing the change. Some tech sheets will have a temperature/resistance chart to verify the accuracy of the thermistor at various temperatures. But usually the heat from your hand will be enough to see an NTC thermistor decrease in resistance. As long as you are reading a change in resistance as heat is applied, the thermistor should be good. Measuring an open or short, would be an indication of a failed thermistor.

Now back to the problem at hand. A quick look at the tech sheet for this particular model reveals the details behind the F5 error.

WATER TEMPERATURE SENSOR ERROR
If during the water heating step in the wash cycle, the water
temperature sensor (NTC) value is out of range, the 'F/05' error code will be displayed.

Using my meter, I did a check of the thermistor in this unit and found it indicating an open circuit which explains the reason for the F5 error. I removed the old component by simply pulling it out of the tub, and installed the new thermistor. There are no clips or screws holding these in place, only the rubber gasket, and some water will leak out once it has been removed, but not much so don't panic. Installed the new thermistor and once I reconnected the wire harness, the washer began working properly again.

[JWWebster]

Brian are these same thermisters used in their fancy dryers as well?

[TechnicianBrian]

Hey JW,

Nope, different thermistors, but the concept is the same.  As temperature goes up, the resistance goes down. 

Brian