3. Controls and Adjustments
a) Default Dip Switch Settings
The dip switch is factory-adjusted to the following positions:
Dip Switch No.
KM-650MAH
KM-650MWH
KM-650MRH
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)
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.
1
2
3
OFF OFF OFF OFF ON
OFF OFF OFF OFF ON
OFF OFF OFF OFF ON
Freeze Timer (9 & 10)
Normally in the OFF position.
Pump-Out Frequency Control (5 & 6)
Pump-Out Timer (3 & 4)
Harvest Timer (1 & 2)
0
-18
10
-12
32
0
50
10
70
21
90
32
19
4
5
6
7
8
ON OFF OFF OFF OFF
ON OFF OFF OFF OFF
ON OFF OFF ON OFF
Resistance (kΩ)
14.401
10.613
6.000
3.871
2.474
1.633
9
10