47
Section D - Air Circulation
AUTOMATIC DEFROST MODELS
Principals Of Automatic Defrost Operation
All Counter Depth refrigerators operate on the principle that moisture or frost
transfers or migrates to the coldest surfaces (evaporator) in the freezer
compartment. For example, a small amount of water spilled in the freezer
compartment will freeze immediately. However, this ice in time will evaporate and
transfer to the colder surfaces of the freezer evaporator coil.
Air Circulation Patterns
Automatic defrost models have a single evaporator in
the freezer compartment, and have forced air cooling in
the freezer and refrigerator compartments.
The “fin and tube” aluminum type evaporator is located
on the lower back wall of the freezer compartment. A
circulating fan (suction type) pulls air from the freezer
compartment through the grill in the bottom of the
freezer and from the refrigerator compartment through a
duct located in the separating wall in the bottom rear left
hand corner of the cabinet interior. The air is then drawn
up through the fin and tubes of the evaporator surface.
The cold air is forced into a fan cover and discharged
into the top of the freezer and out the air discharge
under the ice maker. See Figure D1. If the food
compartment control is calling for cooling, the automatic
damper in the top of the food compartment will open
and allow cold air to enter the food compartment. If the
food compartment calls for cooling but the fan is not
running, the fan will start is soon as the damper is open
and will continue to run as long as the food
compartment or the freezer compartment call for
cooling.
The air circulating fan operates any time the food
compartment or the freezer compartment call for cooling. During the defrost
period, the compressor and circulating fan do not operate. The power board opens
the electrical circuit to the fan motor and compressor as well as closing the
damper door or keeps the damper door closed during the complete defrost cycle .
Figure D1
To Next Page
Loading...
