TFX20KJB running warm

smoky66

Member
Joined
Jun 9, 2019
Messages
5
Location
Wisconsin
Model Number
TFX20KJB
Brand
GE
Age
More than 10 years
Both the freezer and fresh food compartments on our unit are running warm. I see a lot of ice buildup in the lower freezer compartment. After a bit of reading I suspect the heating element on the defroster might be bad, or perhaps it could be a faulty defrost timer? I have a meter, how can I test these to determine if they are bad? Thanks for any tips.
 

smoky66

Member
Joined
Jun 9, 2019
Messages
5
Location
Wisconsin
I looked a little closer just now and found the condenser to be completely covered with years of dust. I cleaned the condenser and manually advanced the defrost timer, the compressor and fan shut off as expected but I didn't hear any sounds or see any indication that the frost was melting. I'm going to go ahead and order a new defrost timer and defrost heater. Will report back if this solves my problem.
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
100,762
Location
McMullen Valley, Arizona
Hi,

When you turned your defrost timer into the defrost cycle and the heating element didn't come on, then you either have a bad defrost thermostat or bad heating element.

I'd ohm test the defrost heaters first, normal would be under 30 ohms on the heaters. Just take the wires off the heaters first. Of course unplug your refrigerator first thing.

Here's the video link that shows you how: Defrost Heater Ohm Testing Video

If your defrost heaters are good, you can ohm test the defrost thermostat, while its frosty and it should read 0 ohms, or you can put it in a glass of ice water, waiting at least 5 minutes before ohm testing it.

Here's the video link to ohm test the defrost thermostat: Defrost Thermostat Ohm Testing Video

Here's the defrost thermostat for your model:
Defrost Thermostat


Jake
 

smoky66

Member
Joined
Jun 9, 2019
Messages
5
Location
Wisconsin
I replaced the defrost heaters, defrost thermostat and the defrost timer today. Before defrosting with a hairdryer I noticed the lower third of the freezer coils were solid ice and the upper coils were not frost covered. I tried to manually get the heater coils to fire by advancing the timer with no luck. Then I bypassed the thermostat and the heater coils fired up and melted the remaining ice chunks. So I guess my defrost thermostat isn't getting cold enough to allow the heater coils to get voltage. I will leave it overnight and check in the morning. I left the back cover off for now so I can observe the evaporator coil and check temps with my laser temp gun.
 

smoky66

Member
Joined
Jun 9, 2019
Messages
5
Location
Wisconsin
Checked this morning at the fridge is quite a bit cooler than it had been. Fresh food 45 and freezer 30. Seems it's slowly getting cooler. I replaced the back cover to improve airflow and will monitor temps over the next 24 hours. One thing I notice is the drain line seems to be clogged. Would a clogged drain line be relevant to the symptoms I described? Thanks for any guidance.
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
100,762
Location
McMullen Valley, Arizona
I replaced the back cover to improve airflow
Yes, that's very important to do.:)

Would a clogged drain line be relevant to the symptoms I described?
No, but it does need to be cleaned out.:)

If it still is not below 10 degrees in the freezer by morning, then you most likely have a sealed system problem. You can confirm that by removing the evaporator cover and looking at the frost pattern on the coils, normal would be a thin layer of frost on all the coils from top to bottom.

Jake
 

smoky66

Member
Joined
Jun 9, 2019
Messages
5
Location
Wisconsin
Thanks for the reply Jake. Do you know how cold the defrost thermostat has to get before it will pass current to the heaters?
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
100,762
Location
McMullen Valley, Arizona
It will say on the side of the defrost thermostat, They usually begin with "L", this defrost thermostat I believe is L55 which would be 55 degrees.

Jake
 
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