HI. There are two causes here, in this situation. The most common will be a faulty defrost timer, or adaptive defrost control board. The defrost mechanism will vary form unit to unit. Most newer units will be equipped with an defrost control board. This will be located in the control housing, just above the heat shield, in the upper right had side. Older models will have a standard defrost timer mechanism. If this device fails, the evaporator heater Assembly will not receive the command to defrost the coil, on time. The easiest way to isolate the cause, will be to test the heater element. If the element is functional, the defrost timer/board, will be the culprit.
Defrost heater assembly test procedure:
The defrost heater is usually located at the back of a side by side freezer or under the floor of a top freezer. It will be necessary to remove obstructions such as the contents of the freezer, freezer shelves, ice-maker and the inside rear or bottom panel of the freezer, to access.
The panel may be held in place by retainer clips or screws. Remove the screws or depress the retainer clips with a small screwdriver. On some older top freezers it is necessary to remove the plastic molding to access the freezer floor. Removal of that molding can be tricky, so try not to force it, if possible. If you decide to remove it, you do so at your own risk. it will break, if forced. Warm it first with a warm towel, or hair dryer, set to low heat.
There are three primary types of defrost heater elements; exposed metal rod, metal rod covered with aluminum tape or a wire coil inside a glass tube. All three elements are tested in the same way.
The heater is connected by two wires. The wires are connected with slip on connectors. Firmly pull the connectors off of the terminals (do not pull on the wire). You may need to use a pair of needle-nose pliers to remove the connectors. Inspect the connectors and the terminals for corrosion. If the connectors are corroded they should be replaced.
Test the heating element for continuity using a multimeter. Set the multimeter to the ohms setting X1. Place a probe on each terminal. The multimeter should display a reading somewhere between zero and infinity. Because of the number of different elements we cannot tell what your reading should be, but we can be certain of what it shouldn't be. If the reading is zero or infinity the heating element is definitely faulty, and should be replaced.
NOTE::----(If indeed the heater and defrost board are functioning as designed, the culprit will then be the actual defrost thermostat. This may or may not be attached to the heater assembly. In some cases, the entire heater Assembly will need to be replaced along with the thermostat.)
Hi, In this post we will talk about one of the most common problems with your kitchen refrigerator - the freezer looks fine but the refrigerator part is warm.
Before we go further let me explain the basic performance of the refrigerator.
Your refrigerator could be made by Whirlpool, GE, Frigidaire, kenmore or Maytag - it does not matter.
The cooling coil (aka evaporator coil) is located in the freezer behind the back panel.
The evaporator fan is distributing the cold air through the cooling coil into the freezer and, through the damper control, into the refrigerator, causing the refrigerator to cool down as well.
If anything goes wrong with the cooling coil in the freezer, wrong temperature in the refrigerator is more visible and gets your attention first due to a very big temperature difference in the freezer (normally -5°F to 6°F) and refrigerator (36°F to 40°F).
So the problem as it looks to you is: the freezer is fine but the refrigerator is warm.
Well, the cause of this problem could be very different and now we will go over the first one - a faulty defrost system.
As the evaporator coil cools down, the frost builds up on the coil.
If it does not defrost periodically then the excess frost will block the air flow though the cooling coil, affecting proper distribution of the cold air and causing an increase in the temperature (the fresh food compartment first).
The classic defrost system (we are not talking now about refrigerators operated by electronic devices) consists of three parts: the defrost timer which calls for defrost on certain time intervals, the defrost heater which should melt the frost and the defrost thermostat which senses the cooling coil temperature and operates with the electric current to the defrost heater.
The first and most important sign of a faulty defrost system is a frost build up on the back panel in the freezer.
How to find out which part of the defrost system is bad?
Based on my own experience, I would recommend the following procedure:
1). Locate the name plate with the model number of the refrigerator.
2). Type the model number in the search box, click the "search" button and you will be directed to the break down diagrams.
3). Using the break down diagrams, locate the defrost timer.
4). Using a flat screwdriver, slowly turn the shaft in the middle of the defrost timer clock wise until it clicks to switch from the cooling cycle to the defrost cycle.
5). Wait about 10 to 15 minutes, open the freezer door and see if you can hear a sizzling noise. If you can, then the problem is the defrost timer which has to be replaced.
If there is no such noise, go to the next step...
DO NOT FORGET TO UNPLUG THE REFRIGERATOR!
6). Remove the back panel in the freezer, unplug at least one wire on the defrost heater (you can locate it using the break down diagram) and check continuity across the defrost heater wires.
If it's open, the defrost heater is bad and has to be replaced.
If it has some resistance, then the problem is the defrost thermostat.
You can check the defrost thermostat continuity only if it's frozen because if it's warm, it should be normally open.
Hope it helped..
Take care..
Hi,
A mechanical defrost timer controls the
defrost cycle of the freezer. In older models, the timer runs
continuously and roughly every six hours, cuts power to the cooling
system and sends power to the defrost heater. In newer models the timer
advances only while the compressor or defrost cycle is running - an
improvement for efficiency. As the timer continues to advance, power to
the heating element is cut and power is restored to the cooling system.
If the timer does not advance, the appliance will be stuck either in
defrost or refrigerate mode, resulting in, respectively, no cooling or
frost build-up. The defrost timer is faulty and need to be replace.
Do you have a heavy frost on the rear panel of the freezer section? If so, you have a defrost system problem. If you will post the complete model number I can help you diagnose which part you need to fix it. In the meantime, you can manually defrost it and it will work for about a week or so until the frost builds back up.
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Thanks you. I was looking at the parts list and I do not see a defrost timer, see something called Bi-Metal Defrost. Model 10656534400 part no. 2196155. Is that the timer?
Thank you. one final question - could the defrost function for this model be all controlled by the motherboard? Or is there always a separate defrost timer?
I have a Kenmore model 56534400. Recently experienced problem with refrigerator & freezer getting warm. Had a repair man come he found frost on the coils behind the freezer panel. He manually defrosted and it is working fine now but I am afraid the problem may re occur. Have also noticed slight frost on the ice bin.
This is very helpful. But which site should I search for the breakdown diagram, fixya.com? Nothing comes up when I do it there. Thank you.
The defrost function for this refrigerator is handled by the units control board. There is no defrost timer.
After three tries I finally got an answer that makes sense. The first two "experts" basically copied and pasted a response from a fix it Web site. Thank you, this is very helpful.
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