Kenmore Upright Freezer 253.22042410 Defrost Not Defrosting at the bottom?

[BillHammer]

Every few months for the past year now, a smooth, clear layer of ice 1/8" to 1/4" builds up on the bottom of my freezer. It starts in the back, freezes the drain area all across the back, and drain line freezes solid then creeps forward. I've cleaned it completely out including the drain line center back, got rid of all the ice, then it happens again. Rest of the freezer does not ice up. What is going on? It didn't used to do this.

-Bill

[citizenX]

That's a pretty common issue. Sounds like the drain line is clogged and/or frozen up and the defrost water is just building up instead of running to the pan underneath. Get the ice out to where you can access the drain and run some hot water down the drain to thaw it out. Get a piece of hose or something and blow down through the drain line to clear any gookus out. You may need to access the drain tube from behind the unit as well. That said, sometimes those drain lines just like to freeze up regardless. If that happens, you can wrap a piece of copper wire (stripped electrical wire) and wrap it around the defrost heater and run it down the drain tube. That will help to transfer heat into the drain line to keep it thawed out. More than likely though, there is probably just some crud in there clogging the line, but you'll have to thaw out the ice first then go from there. 

[BillHammer]

Drain line was blown down and scoured clear the last time, checked from front and back. Nothing there but ice. This unit is 7 years old and never did this until recently. Why would it start to freeze over now? Could there be a problem with the defrost? Also can you tell me where the defrost heater line is so I can try your wrap trick?

[citizenX]

Over time, moisture can get into the insulation from leaking in around the drain tube and cause it to freeze up, without an actual drain tube obstruction.  You can also have too cold a temp set and it can cause the drain to freeze up. The defrost system is designed to clear ice/frost from the evaporator coil, not the drain. So, if the evap coil is defrosting and the unit is cooling properly then the defrost is working normally. 

The defrost heater runs down the sides and along the bottom of the evaporator. You can clear away a few of the fins above where the drain inlet is if needed to make room and just wrap the copper wire around the heating element. If the wire trick doesn't stop it from freezing, there are after-market drain heater kits you can wire in, but the wire usually does the trick. 

Just for reference, the defrost heater is #14 in this image. 

Edited March 11 by citizenX

[BillHammer]

Perfect, thanks!