Thread: Defrost Cycle Not Working

Hi,

The condenser is frosting up about every two days

Evaporator.
Condensor is the hot tubing.

As a precaution I have replaced the bi-metal

If the defrost thermostat/bimetal checks ok, heater ohms/checks ok....the bimetal should be ok since it is new....the board is normally automatically changed out.

Defrost control board

jeff.

Jeff,

You are correct. I'm sorry about the error on my post. We are talking about the evaporator instead of the condenser. I know electronics pretty well but very little about refrigeration. Thanks for the input. I'll order the board directly. I had pretty much eliminated the other possibilities for the trouble but needed a little encouragement. I wish I had a diagram of the electronic control board for the defroster. I would like to know logically why the board worked when the bi-metal was bypassed with the jumper and wouldn't work through the bi-metal even though it's resistance was less than one ohm when operated. One thing I did discover during my career in electronics was that logic circuits don't always behave logically! Thanks again for the advice.

Mike

One thing I did discover during my career in electronics was that logic circuits don't always behave logically!

jeff.

After 8 months of manually defrosting my freezer as I tried to find this trouble, it's finally fixed. I eventually replaced the ADC as someone had suggested. I was hesitant as the unit was expensive. My resolve was well deserved as this did not fix the problem. I managed to get some additional information on a website about the ADC (automatic defrost control) board. I found out that is was an adaptive defrost control board that has a microprocessor in it. This control board monitors information from several locations to determine the time elapsed between defrost cycles. There is a brown lead that on one end attaches between the defrost thermostat and the defrost heater. The other end is attached to the ADC at one of the monitor terminals. The ADC is in the refrigerator section and the defrost components are in the freezer section. They are connected together through a harness and connectors on each end. This harness is put in place at the factory and foam is injected between the inside and outside shell of the refrigerator. It is not accessible. After several trouble shooting attempts, I found that the brown lead in the harness was going open momentarily. This made the ADC think that the defrost thermostat had opened, consequently the ADC removed the voltage to the defrost circuit. I had to bypass the harness and run a wire from the defrost thermostat/defrost heater connect point to the ADC monitor lead point through the return vent between the refrigerator/freezer sections. This has fixed the trouble and all is working well.

Mike

"I found that the brown lead in the harness was going open momentarily"

How did you determine that this brown wire was somehow disconnecting itself during a defrost? I have a similar issue and I just replaced the control board.
Before I send it back for another one I would like to make sure that its not something like you ran into.

Did you solder the new wire in place?

Hear is a photo of mine. There seems to be more than one brown wire, which one is it?

http://img706.imageshack.us/img706/2819/img1311oq.jpg

Originally Posted by RAJOD

"I found that the brown lead in the harness was going open momentarily"

How did you determine that this brown wire was somehow disconnecting itself during a defrost? I have a similar issue and I just replaced the control board.
Before I send it back for another one I would like to make sure that its not something like you ran into.

Did you solder the new wire in place?

Hear is a photo of mine. There seems to be more than one brown wire, which one is it?

http://img706.imageshack.us/img706/2819/img1311oq.jpg

Hi,

Model#?
Where is my Model Number? | Appliance Aid

jeff.