Kitchen Large Electric Appliances - Refrigerator Defrost Question

I have 7 year old Kenmore/Frigidaire top freezer refrigerator. It been really hot lately, compressor runs about 90% of the time but does maintain
35F in fresh food compartment as long as evaporator is frost free. Problem is that evap coils keep frosting over and I have to defrost these manually. I have replaced defrost timer and checked the heater/thermostat circuit(measures 33ohm )to be good. Is it possible that the excessive on-duty cycle produces frost faster than system can remove it? Have any experts seen a problem like this?
Thanks , in advance
George Raetz

Confused. Fresh food compartment should be 40 degrees. You say you get 35 but it's still not cold enought?

After I manually defrost the evaporator the fresh food part will measure 33F-40F. After a few days the evaporator accumulates frost and fresh food temp climbs to 45F or more.

You say you tested the timer and defroster. Then turn the timer to defrost, and watch (frost melt) the defrost cycle yourself. Then report what you believe the problem is.

I rotate the timer to defrost position, makes a distinct click. Next, I remove the back cover of freezer compartment, there is a thin layer of frost on the coils, with a few lumps in the corners. (This is about 12-14 hrs since I thouroughly defrosted the unit with a hair dryer). The defrost heater glows red hot, and after a few minutes all frost is gone. Heater shuts off after a few minutes, assumably from the defrost thermostat. :wall:
So, I put everything back together. I can only think of two causes: (1)Bad defrost timer, it is new but to make sure I mark the shaft location,after about an hour it turns about 1/8 turn so it appears good. (2) other possibility is a flakey connection somewhere which would cause an intermittent problem.

Thank was a clear description of what you saw, thus thanks. However, your description sounds like a normal operational unit. What exactly is the complaint?

make sure the gaskets are good
make sure the lights go out when you close the freezer door.
make sure the condender is clean
make sure the condenser fan is working.
Make sure the drain pain in the freezer where the defrost water goes is not clogged.


As lugnut said it looks and sounds normal with respect to the coils and defrosting. However it is running too long. It is running practically all the time it is not defrosting.

In order for it to satisfy the 35 degrees in the fresh food compartment it is possibly making the freezer colder[compressor run longer] than it should be. Turn down[warmer temp] the cold control a little and see if that, combined with the stuff listed up above, will help.

Someone in another NG suggested that the defrost thermostat may be intermittentlysticking open and it should be replaced. So I did that, and the problem seems to be fixed.
Thanks for the help,
George

Since this is a topic about Kenmore refrigerator, I will ask my question here. Today, my parents told me that the 5yrs old side-by-side refrigerator is not cooling anymore. The fan on the back of the refrigerator is on, but I dont think the compressor is on. I took the front cover off and vacummed the inside of it. I'm thinking about testing the defrost timer of it. Can someone tell me where is it? I checked behind the grill, and saw a metal box with a knot on it. It only turn one way. Do I have to check the back of the refrigerator?

The box:
http://xs.to/xs.php?h=xs41&d=05325&f=kenmore01.jpg

in the back?
http://xs.to/xs.php?h=xs41&d=05325&f=kenmore02.jpg