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FIXED KRSC503ESS01 Kitchenaid side by side - icing on refrigerator side evaporator coil

plainv7

Premium Member
Joined
Sep 9, 2019
Messages
11
Location
MidwestUS
Model Number
KRSC503ESS01
Brand
KitchenAid
Age
1-5 years
I also have a one year old KRSC503ESS01 with seemingly the same problem. The freezer side appears fine, the fridge side evap coil was completely iced up--and had probably been so for more than several days. I removed the fridge coil cover and completely thawed the evap coil out. When I plugged it back in, the fridge coil fan did not run. I checked the voltage to the fan, it was 14v at the connector, but it did not run when I reconnected it to the wiring harness in the fridge. I ran step 3 of the service diagnostics mode and the fan worked in both O3 and O4 modes. However, when I plugged the fridge back in the after being opened and warmed up inside, the fan and the compressor did not come on--despite the inside temp being 45+F--until about 10-15 minutes later. That seems too long a time. I have left it to run to see what the refrigerator temperature equilibrates to overnight.

Step 2 of the service diagnostics returned an O1 (pass) for the RC thermistor (which I assume is not the same as the evap fan thermistor). Do I need to measure its resistance directly or can I trust the diagnostics?

Can you help with instructions for how to test the evap fan thermistor without cutting its wires (there is no connector within the fridge) and the only connection, I assume, is on the main controller board in the back.

Thanks&Regards. PS
 

Jake

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Hi, I moved your post to your own thread.

Ok, the evaporator coil in the refrigerator section does not have a defrost heater, it defrosts per that fan motor.

Here's the parts diagram:

#4 is your evaporator fan motor thermistor in refrigerator section. That could be bad and causing that fan motor not to run when it should be running.

You'll need to ohm test that thermistor.

Here's that thermistor for your model:
W10316760 Thermistor


To test it, unplug the refrigerator from the wall outlet first, then you ohm it with a multimeter, you put the thermistor in cup of ice water for 5 minutes and it should read about 8.7 K ohms.

Yes, you can ohm test it from the control board.

#30 is your control board here:

Its located in the back of your refrigerator in the control box #32. Unplug your refrigerator first before ohm testing it.

Remove the P8 connector on the control board and ohm test between P8-1(orange/black wire) and P8-2(black wire).

Let us know how it goes.

Jake
 

plainv7

Premium Member
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Messages
11
Location
MidwestUS
After running (mostly empty) for 18-24 hours the inside temp was 36-37F°. Minimal frost of the evap fins. The evap fan appears to still be functioning.

Connector P8 on my control board W11172798 is R-BK-3-4-5-6-R-BK. The resistance between pins 1 & 2 (thermistor RC evap) according to the wiring diagram) was 0.48 kΩ at about 36-37°F.

Connector P5 (R-BK-BK-BK), pins1-2 (thermistor RC) read 7.1 kΩ, also at about 36-37°F.

It looks like the thermistor on the refrigeration evaporator coil is bad. I'll replace it tomorrow and let you know.
 

Jake

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plainv7

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Messages
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Location
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I removed the old evap thermistor and confirmed that it was faulty (0.5 kΩ @ 32°F).

The new evap thermistor measured 8.4kΩ @ 32°F and about 4 kΩ @ about 72°F.

Before, the evap coil had iced up substantially (I should have taken a photo...) and the inside temp was in the low 40s when set at the factory default of 37°F. It has now been running for a few hours with the new thermostat and appears to be back down in the mid-30s. Fixed! Thanks for the help Jake.

This part should have lasted much more than a year, if not the lifetime of the refrigerator--which should not be a harsh environment for a thermistor.

I did not have to replace the evaporator fan, the other possible cause of this failure.
 

Jake

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Excellent, glad to hear the new thermistor fixed it. (y)

Thanks for the update!

Jake
 

plainv7

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Messages
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Location
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To make sure I installed the new thermistor in the right place, I reviewed the pictures I had taken of the coil before I started. I then noticed that the refrigerator had been manufactured with the evaporator thermistor incorrectly located on the input (high pressure) side of the coil.

I also added a couple of zip ties to ensure that it was in good contact with copper tubing and packed the two crimped connections with silicone grease and wrapped them with teflon tape.
 

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plainv7

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One more note: the faulty thermistor passed the test (status O1) in the service diagnostic mode (step 2). Apparently, since it was neither shorted or open, the control board did not recognize it as failed--registering too low. I wonder if the part was out of spec from the get go?
 

Jake

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Great photos, thanks for posting them for others to view as well. (y)

One more note: the faulty thermistor passed the test (status O1) in the service diagnostic mode (step 2). Apparently, since it was neither shorted or open, the control board did not recognize it as failed--registering too low. I wonder if the part was out of spec from the get go?
That's a good question, if you still have the old thermistor you can retest it again. Put the thermistor in cup of ice water for 5 minutes and it should read about 8.7 K ohms.

Jake
 

plainv7

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Location
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Original thermistor at 32°F shows 0.96 kΩ. Not surprising considering the room temp resistance measurement--and out of spec for the operating range of the fridge. The control board, sees a higher voltage, thinks that the refrigerator side (RC) is (much) warmer that it really is and stretches out the adaptive defrost cycles resulting in an iced up coil. Looks to me that the control panel is not programmed to check the voltage, only test for open, shorted, or a completed circuit. How difficult would it be for it to qualify the thermistor voltage, or compare it to the RC thermistor, too?


1568747616394.png
 

Jake

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Original thermistor at 32°F shows 0.96 kΩ.
That's bad.

The refrigerator thermistor ohms the same way, about 8.7 K ohms at 32 degrees Fahrenheit

Jake
 

plainv7

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Location
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The refrigerator coil, refrigerator evap coil, and freezer coil thermistors are all now the same part, W10316760, for many Whirlpool dual evaporator refrigerator/freezers.
 

Jake

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Yes, you are correct, I forgot to mention that they all use the exact same part number W10316760, and they all ohm test the same way.:)

Jake
 

plainv7

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Now I have to do something about the freezer door wires before they fray or break. They looked problematic to me when pulled out the wiring diagram and diagnostic sheets from the front grille--and I easily confirmed it by the many observations on this forum. Thanks again for the help.
 

Jake

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Glad to help.:)

Jake
 

PCT

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Colorado
I have the same refrigerator with the same problem. Last year the thermistor was professionally replaced, then they replaced the whole fan assembly too. Soon thereafter, frost started accumulating behind the crisper again. The tech said he was all out of ideas but he did eventually program in some new setting that he said might help prevent the problem. Nope. Currently I have to unplug and defrost the refrigerator at least every 3 weeks to get rid of the frost behind the crisper and ultimately the refrigerator compartment temperature starts creeping back up again to the point where food gets spoiled. No other real symptoms except the freezer section appears to have more condensation than normal.

Hey Jake (or any other knowledgeable folks) please help me with any other advice or suggestions. Can provide photos etc. as necessary. The refrigerator is out of warranty and it's getting darn near unusable!

Also as a bonus the wiring harness at the bottom left foot of the freezer door is partially cut due to poor manufacturing/installation, so now the ice maker auger motor won't run. The tech said I have to replace the whole door for $1000. Good times.
 

Jake

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Hi,

You have the same exact model number KRSC503ESS01? Please make sure that's very important. The model number tag is located inside the refrigerator section on the upper walls or ceiling.

If so, here's our main thread on this problem:

Do exactly what I said in post #3 and post your results here.:)

Also as a bonus the wiring harness at the bottom left foot of the freezer door is partially cut due to poor manufacturing/installation, so now the ice maker auger motor won't run. The tech said I have to replace the whole door for $1000
Nope, just add some extra wire and solder the wires back together.:)

Here's our main thread on that:

Jake
 

PCT

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Location
Colorado
Hey Jake, thanks for your quick reply. Looks like I have a KRSC503ESS00. I will read up on the main thread and follow the instructions in post #3.
 

Jake

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Ok great!

Yes, let us know what you find.

Jake
 

plainv7

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Location
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I've researched the door wiring on this model, and other Whirlpool refrigerators with in-door icemakers and water dispensers, and it seems like it's not a question of if, but when it will fail. This is the wiring as it currently is (below); the fridge is a little over a year old.

I expect that Whirlpool is well aware of the freezer door wiring problem; have they changed anything in the design to address it? It does not seem so. Should I be splicing some extra wire into the harnesses, now, before they fail?

krsc503ess01_freezer-door-hinge&wiring.jpg
 
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