30
C. Thermistor Check
In the event the cabinet thermistor reading is out of range, the compressor operates on
a fixed time basis of 5-minutes on and 5-minutes off.
In the event the defrost (evaporator) thermistor reading is out of range, defrost initiation
occurs every 6 hours and terminates based on cabinet thermistor temperature.
In the event of both thermistor readings are out of range, the compressor operates on a
fixed time basis of 5-minutes on and 5-minutes off and the defrost cycle initiates every
6 hours and terminates after 45 minutes.
To check thermistor resistance, follow the steps below.
1) Raise the front panel. Move the power switch to the "OFF" position, then unplug the unit.
2) Remove the control box cover.
3) Remove the cabinet and defrost thermistors. See "V.K. Removal and Replacement of
Thermistor."
4) Disconnect the cabinet thermistor (gray (GY) wires) from the RED K3 connector or the
defrost thermistor (orange (O) wires) from the WHITE K3 connector.
5) Immerse the thermistor sensor portion in a glass containing ice and water for 2 or
3 minutes.
6) Check the resistance between the wires at the thermistor connector (cabinet thermistor
gray (G) wires or defrost thermistor orange (O) wires). Normal reading is within 4.7 to
6.2 kΩ. If outside the normal reading, replace the thermistor.
7) Replace the thermistors in their correct position. See "V.K. Removal Replacement of
Thermistor."
8) Reconnect the red and white thermistor connectors to the control board RED K4 and
WHITE K3 thermistor connectors.
9) Replace the control box cover in its correct position.
10) Plug the unit back in. Move the power switch to the "ON" position.
11) Close the front panel.