Control Board Replacement; Harvest Control - Thermistor; Bin Control - Hoshizaki KM-1601SWH Service Manual

5. Control Board Replacement

The application switch located between relay X3 & X4 must be set to match the original
board application. Place this switch in the "ALP" position if there is no white wire supplied
to the K1 connector. If there is a white wire, place the switch in the "C" position. If this
switch is placed in the wrong position either the compressor contactor will remain
energized with the control switch in the "OFF" position or the unit will not start.
The dip switches should be adjusted to the factory default settings as outlined in this
manual. Dip switch #8 must remain off.
D. 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.I. 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.
E. Bin Control
When the ambient temperature is below 45°F (7°C), the bin control thermostat
operates to stop the icemaker even if the ice storage bin is empty. When the
thermostat is set in the prohibited range, the icemaker operates continuously
even if the ice storage bin is filled with ice. Setting in the prohibited range might
cause severe damage to the icemaker resulting in failure.
No adjustment is required under normal use, as the bin control is factory-adjusted. Adjust
it, if necessary, so that the icemaker stops automatically within 10 seconds after ice
contacts the bin control thermostat bulb.
0 -18
10 -12
32 0
50 10
70 21
90 32
CAUTION
Resistance (kΩ)
14.401
10.613
6.000
3.871
2.474
1.633