Thermistor Resistance
Resistance
Temperature
-50
250000
200000
150000
100000
50000
0
0
50
100
150
Page 2-5
s
eCTion
2 - T
eChniCal
o
rienTaTion
Temperature
(Degrees F)
Resistance
0
85KOhm
10
62.5KOhm
20
46KOhm
30
34.5KOhm
40
26KOhm
NOTE
All six thermistors can be checked from the control panel by using the service mode. The initial
tests will give you a GO-NO GO check of the thermistor. This will determine if the component
has either shorted or opened. The secondary check will display the temperature that the system
believes the thermistor to be.
If a thermistor is a few degrees off from your findings with a calibrated digital thermometer,
it is not usually a cause for concern. If a thermistor is considerably different than the actual
temperature the system will not provide the proper cooling capacity. This could result in frozen
items in the fresh food compartment or thawing of frozen goods.
If you see a temperature display of –99 for either the fresh food or freezer section it is an
indication of an open thermistor in that compartment. If you see a temperature reading of 99,
it is an indication of a shorted thermistor.
•
•
•
Temperature Monitoring (continued)
The evaporator thermistor monitors the evaporator temperature and is used in the compressor speed
algorithm. A second duty of the evaporator thermistor is termination of the defrost cycle. While there
is a safety thermostat available in case of system failure, the end of defrost is determined by the
thermistor reading.