Question about Sub-Zero 632 / S
The evaporator coil behind the cover on the back
wall inside the freezer will ice up under normal conditions. Every 8 to 10
hours for around 20 minutes the defrost timer (or in most newer models the electronic
adaptive defrost control) will turn the defrost heater on to
melt the built up ice. There is a defrost thermostat which prevents the heater from
overheating the freezer by breaking the heater circuit when the temp reaches
close to 32 degrees F. The entire cooling system shuts off during the defrost
cycle and starts back when the timer advances through the cycle.
If this ice is not melted it will continue to build up until the air can’t flow over the coil to circulate the cold air through the freezer and into the fridge. The temperature change in the fridge is usually noticed first followed by the freezer.
If the defrost thermostat is bad it can prevent the heater from coming on OR it won’t turn the heater off when it gets too warm. It is clamped to the evaporator coil at the top to sense the temp. If it appears to be misshapen it is bad.
With an ohm meter it should show continuity when cold and none when warm.
You can also bypass the thermostat to see if the heater comes on then. If it does then you know the thermostat is bad and needs replaced.
The defrost heater is located on the evaporator. It is in a tube which is at the bottom and can also go up the sides of the evaporator. On some types you can see a burnt spot if it’s bad. With an ohm meter it should show continuity from end to end when disconnected from the wiring in the freezer. You can also test the wiring for voltage when it’s in the defrost mode.
If you have a defrost timer you can test it. It can be located under the fridge behind the kick panel on the front. Some are in the fridge with the controls at the top. You can turn the defrost timer till it clicks and everything shuts down. The heater should now come on. If it does, replace the timer because that means the timer is not running. If it doesn't, check the heater and defrost thermostat. Turn the timer again till everything starts back up to end the defrost cycle.
If you have an adaptive defrost control instead of a timer, replace it if the heater and thermostat test good. It is located in the fridge with the controls in some models and on the back in others.
Posted on Nov 16, 2009
Testimonial: "Thank you very much for the detailed troubleshooting. I would not have known where to start. I appreciate you sharing your knowledge. "
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
unplug 24 hrs with doors open plug in again if it works better you have a defrost problem. it may be the defrost termination switch.. burned out element or bad timer
Posted on Aug 03, 2009
It takes time for the temp to adjust(up to 24hrs) If the door is open a lot(looking into the box) or the door gasket is bad this will contribute to your problem. Are you sure the thermometer is good that you are checking the machine with. The thermistor could be bad as well(the control that senses the actual temp
Posted on Nov 03, 2009
Check out these tips...they can help you figure out whats going wrong...
Refrigerator not Cooling or Fridge not Cooling
How to Defrost Refrigerator Defrost Timer Problem
Water Running in Refrigerator from Freezer
Posted on Aug 12, 2010
Tips for a great answer:
Feb 05, 2015 | Refrigerators
Aug 21, 2011 | Amana ARB224RCC Bottom Freezer...
Jun 08, 2011 | Refrigerators
May 17, 2011 | Kenmore Top Freezer Refrigerator
Many times a freezer and/or refrigerator do not work right because of a dirty condenser coil...there are also many other things that can go wrong.
If you are hearing a clicking or buzzing then check out the last two tips.
If your refrigerator is running but warm, then...
Check out these tips that I wrote about that... it is a great place to start trouble shooting your unit...and something that you can do rather then calling a repair person to do a simple thing for you...
Refrigerator Condenser Coil Cleaning Refrigerator Repair
Refrigerator Troubleshooting Refrigerator Compressor
Refrigerator Compressor Start Capacitor and Start Relay
Nov 20, 2010 | Amana ATB1935HR Top Freezer Refrigerator
Oct 31, 2009 | Whirlpool 21.0 cu. ft. Top Freezer...
Sep 23, 2009 | Amana ASD2625KE Side by Side Refrigerator
Oct 03, 2007 | Kenmore 50522 / 50524 Side by Side...
656 people viewed this question
Usually answered in minutes!