All refrigerators need a constant flow of cold (37 degrees) air to function properly. The cold air is produced in the freezer section
and is then distributed through out the refrigerator, by the evaporator motor fan which is located in the freezer section.
A slightly warmer is then returned to the freezer section to have the heat removed. If the air passages are closed, such as the
return and or, the damper control assembly, which opens and closes to prevent food from freezing in the refrigerator, even
though the evaporator fan is blowing cold air, the refrigerator will not get warm.
Such as the case I had today, where an Amana bottom freezer refrigerator not keeping proper temp. By the way folks,
here is a pop quiz. Which one of the following brands manufactures Amana products:
The answer is The Whirlpool Corporation.
The model number was BR18VC. This puppy was at least 15 years old.
Part number 10442411
66 inches tall
30 inches wide
33 inches deep
When moist air is allowed in the freezer section, frost will build up. this is why it is important to make sure your refrigerator is tightly sealed, allowing the refrigerator to keep proper temp.
There are 3 components in the refrigerator defrost system:
Timer – tracks compressor run time.
Defrost thermostat- senses if evaporator needs defrosting.
Heater -melts accumulating frost of the evaporator.
When the defrost thermostat fails to close, and- allow power to flow though the heater, the defrost cycle will not activate, hence the refrigerator not keeping temp.
The vast majority of refrigerator timers activate after the compressor has ran 8 to 10 hours.
The following is a related video on how to replace the defrost (bimetal) thermostat if your refrigerator section is not keeping proper temp.