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3. Controls and Adjustments
a) Default Dip Switch Settings
The dip switch is factory-adjusted to the following positions:
Dip Switch No. 1 2 3 4 5 6 7 8 9 10
KM-501MAH
OFF ON OFF OFF ON ON OFF OFF ON OFF
KM-501MWH OFF OFF OFF OFF ON ON OFF OFF OFF OFF
KM-501MRH
OFF OFF OFF OFF ON ON OFF OFF OFF OFF
Freeze Timer (9 & 10)
Pump-Out Frequency Control (5 & 6)
Pump-Out Timer (3 & 4)
Harvest Timer (1 & 2)
Normally in the OFF position.
b) Harvest Control – Thermistor
A thermistor (semiconductor) is used for a harvest control sensor. The resistance varies
depending on the suction line temperatures. The thermistor detects the temperature of
the evaporator outlet to start the harvest timer. No adjustment is required. If necessary,
check for resistance between thermistor leads, and visually check the thermistor
mounting, located on the suction line next to the evaporator outlet.
Temperature (°F) Temperature (°C)
Resistance (kΩ)
0 -18 14.401
10 -12 10.613
32
0 6.000
50 10 3.871
70 21 2.474
90 32 1.633
Check a thermistor for resistance by using the following procedure:
1) Disconnect the connector K3 on the board.
2) Remove the thermistor. See "V.K. Removal and Replacement of Thermistor."
3) Immerse the thermistor sensor portion in a glass containing ice and water for 2 or 3
minutes.
4) Check for a resistance between thermistor leads. Normal reading is within 3.5 to 7 kΩ.
Replace the thermistor if it exceeds the normal reading.