Whirlpool WRF560SEYM04 Fridge Defrost problems

[nilesr1996]

I am having defrost problems with my WRF560SEYM04 30" french door fridge. The freezer evaporator is icing up regularly. It completely ices over the evap thermistor. I used diagnostic mode and manually triggered the defrost heater. I smelled plastic burning and once I took off the evaporator cover it looks like the heater has drooped and the ends have melted holes in the sides of the liner, but the holes look too big to have been made completely by the melting. Are those holes supposed to be there? There is a link to photos below. It looks like maybe they bring air in from the fridge section. If the holes are supposed to be there, and have just been made bigger, how can I be sure that the liner won't melt further? I metered the evap thermistor and I think the cold and room temp values were in range (though I didn't write them down so I am not positive)

I can bend the heater back into shape, or should I replace it? 

I have purchased a new control board. Even though I can trigger the defrost cycle from diagnostic mode this could still be my issue, right?

What should I do to make sure the defrost heater doesn't melt the liner any more? 

Is there anything I should to about the melted liner?

Melted Liner photos

 

Thanks in advance!

[Vance R]

It is hard to tell from your pictures but those could be tha air returns from the refrigerator section.  The hole are right at the styrofoam blocks for the evaporator to control airflow.  Would suggest replacing the thermistor on the evaporator as the board use that information to control defrost. It still could be the board but the thermistor is less expensive or you could just replace both since you already have the board.

[Rob Gabbard]

Doesn't look like the liner is actually melted. A further back picture of the entire evaporator might help as well. The heating element picture on the right bottom side looks seated properly. I agree with Vance, look at the thermistor first. Much cheaper option than board. 

[worx appliance service]

cracked liners WILL cause repeated drain issues

[nilesr1996]

Thanks all! The thermistors don't fault in service mode - but I does that only flag if there is a dead short? 

I don't see thermistor values on the copy of the tech sheet I got off servicemanuals.net. What should I be getting?

As an aside, I purchased the service manual as well and what I was sent was "Job Aid - W10444924 (R-114)" which is for a 36" fridge with dual evaporators. Is there another manual that is closer to this model?

Here's a photo wider angle photo, but I had already removed and bent the heater back into shape a little.

https://imgur.com/d8g7muS

And another of the hole

https://imgur.com/a/FVLHTXs

 

[Vance R]

19 minutes ago, nilesr1996 said:

does that only flag if there is a dead short?

Short or open will set a flag so it still could be out of spec. whirlpool does have alot of information out there on thermistors. The tech sheet has no valves for them. You can google some info on whirlpool thermistors. Whirlpool doesn't have a service manual for every model. 

[nilesr1996]

Quote

 

Glad you agree that those holes could be returns. It looks that way to me too. I asked on another forum and was told no way.

The thermistor meters at 23k ohms at 33 degrees and 8.8k ohms at 60 degrees. The googling i've done seems to indicate that 8.8k is in spec for closer to 32 degrees. So definitely seems bad, but seems like the misreading is in the wrong direction?

[Vance R]

Since there is no reliable sheet may just want to try replacing the thermistor.