I was hoping someone could help weigh in with a technical explanation here.
We have a Whirlpool fridge that is only a few years old, and often notice that food near the back of it (and usually towards the top shelf) is partially frozen. As you get away from the top-center of the fridge this seldom happens, and again, this is an intermittent occurrence (sometimes no food is frozen anywhere in the fridge and everything is fine).
I often go to the fridge and leave the doors open for a few minutes at a time. Usually its to load/unload lots of food to/from it in a short amount of time. My husband says this is the root of the freezing problem we have. His argument is that, since I leave the doors open for a few minutes, the fridge is working harder than it normally should have to in order to keep the food cold, and because of this its over-refrigerating and causing the partial freezing that we're seeing.
However, my understanding (please correct me if I'm wrong) is that there is both a condensor and a thermostat in a modern fridge that should work in unison together: the thermostat tells the condensor when to kick on (such as if the space inside the fridge is too warm) and the condensor is the little unit of magic that cools the air by somehow condensing it.
So, if my understanding is correct, then I would expect the following flow:
- I leave the doors open for a few minutes
- The air inside the fridge gets too warm
- The thermostat tells the condensor to start cooling the air
- At some point in time later (few minutes) I finally close the doors
- At some point in time later (again probably a few minutes) the air is cold again, and the thermostat tells the condensor to stop cooling
So again, if my understanding is all 100% correct, then to me, it sounds like the problem is actually the thermostat, perhaps not telling the condensor to shut off soon enough, and hence allowing it to partially freeze our food at the back of the fridge.
Hence, this problem probably would occur even if you were to very rarely open the fridge doors, and regardless, a correctly-functioning thermostat would take care of this altogether?
Can someone with mechanical/appliance know-how please weigh in here?
Best Answer
You have it correct on how things work. There is 1 piece missing: the evaporator. When you open the door, the thermostat detects the temp increase and starts the compressor. The condenser cools the hot compressed refrigerant. The cool liquid is then metered into the evaporator. As the liquid expands, heat is removed, and the cycle is repeated. If you have food touching the wall where the evaporator is it will freeze. It is not a thermostat problem. It is a problem with things touching the super cooled surface. If there is an air gap between the area that is freezing that air gap will help to cool the box so the compressor will turn off sooner because the air is cooled.
So it is not a thermostat problem as much as an air circulation problem. My refrigerator has the same issue. It is a side by side. The fridge is on the right. The left side of the fridge is where my evaporator is and if anything is pushed tight to the left wall it will freeze because the surface is well below freezing and the temp in the refrigerator box is still warm. Move the stuff away it quits freezing and works properly.
Since I do hvac work I used a thermal imager and photographed the evaporator so my wife would know the zone to keep open and we have not had frozen things in the fridge with half a dozen grandchildren raiding it.