KitchenAid Refrigerators • Uploaded on Sep 15, 2013
TEMPERATURE CONTROL
The electronic control checks the resistance of
the thermistors, and compares it to both the
customer temperature settings and the last
thermistor reading taken. This information is
used to determine when to begin a cooling
operation, and if a change is necessary in the
damper setting, or the evaporator fan or compressor
speed.
When a warm refrigerator is first put into a
cooling mode, the air door partially opens, and
the compressor and evaporator fan motors
start to run at maximum rpm. The air door will
gradually move to its fully open position.
As the actual temperature in the refrigerator
nears the selected temperature setting, the
electronic control compares the temperatures
in both compartments. The compartment that
has the greatest need for cooling, will control
the speed of the evaporator fan motor.
Freezer Temperature Control -
Temperature Increasing
When the freezer calls for cooling, the compressor
begins to run at minimum rpm, (see the
chart on page 3-3), and the evaporator fan
begins to run at 2000 rpm. The compressor
and evaporator speeds are continuously updated.
Speed changes are made based on:
• The difference between the actual temperature
and the selected temperature settings.
• The rate of temperature change.
If the temperature increases 4°F above the
selected temperature setting, the evaporator
fan speed begins to gradually increase. The
evaporator fan motor reaches the maximum
speed of 3000 rpm at 5°F above the selected
temperature setting, and the compressor speed
begins to gradually increase. A maximum compressor
speed of 4500 rpm will be reached at
9°F above the selected temperature setting.
Freezer Temperature Control -
Temperature Decreasing
When the freezer temperature begins to decrease,
the process will reverse. The compressor
speed decreases, followed by the evaporator
fan speed.
Refrigerator Temperature Control -
Temperature Increasing
When the refrigerator calls for cooling while
the freezer is satisfied, the air door begins to
open, and the evaporator fan starts to run at
minimum speed. If the temperature continues
to rise, the air door will continue to open. If the
temperature continues to rise after the air door
is fully open, the evaporator fan speed will
gradually increase to a maximum of 3000 rpm.
If the temperature continues to rise, the compressor
starts to run, or if it has already been
running, begins to increase in speed.
Refrigerator Temperature Control -
Temperature Decreasing
As the refrigerator temperature approaches the
selected setting, the control compares the temperatures
in both compartments to determine
which compartment will control the fan speed.
If the freezer is further from the selected temperature
setting, it controls the fan speed, and
the air door begins to close, thus reducing the
airflow to the refrigerator.
If the freezer is satisfied, the air door remains
open, and the fan speed begins to decrease.
When the selected temperature setting is
reached, the air door closes.
Here is the bottom line.... the termperatures are controlled by thermistors in the freezer and refrigerator compartments. Most likely you have a thermistor problem. The freezer thermistor is on the left wall near the back and the refrigerator compartment thermistor is on the back panel left side. They are accessed by removing the single mounting screw and tilting the cover off with the retained thermistor. The thermistor connectors are directly behind the cover. The resistance of the thermistors should be (in Ohms)
8750 at 32 deg
10,400 - 11000 at 25 deg
6800 - 7220 at 40 deg.
If you have no resistance or the resistance readings are way off and / or shorted the thermistor is bad.
If it checks good:
NOTE: If the resistance of the thermistor(s)
was normal, perform the following voltage test.
1. Set the voltmeter to read a maximum
voltage of 10 volts DC.
2. Connect power to the refrigerator and
allow it to enter the "cooling" mode.
3. With the thermistor disconnected and the
refrigerator in the cooling mode, touch the
voltmeter test probes to the thermistor
main harness connector pins. The meter
should indicate approximately 5 volts DC.
If the voltage was not present, check for a
thermistor output at the main control board.
If it fails this test the problem is most likely the control board.
Check them out and let me know what you found out.
If I totally missed the mark here please respond with a good model number so I can go back and start all over.
Thank for choosing FixYa,
Kelly
76 questions posted
Usually answered in minutes!
1,098 Questions
332 Questions
312 Questions
169 Questions
102 Questions