Hoshizaki KM-901MAH, KM-901MWH, KM-901MRH/3 service manual Removal and Replacement of Control Board

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P. Removal and Replacement of Control Board

When replacing a control board follow the precautions below.

CAUTION

1.The control board is fragile; handle very carefully.

2.The control board contains integrated circuits, which are susceptible to failure due to static discharge. It is especially important to touch the metal part of the unit before handling or replacing the control board.

3.Do not touch the electronic devices on the control board or the back of the control board.

4.Do not change wiring and connections. Do not misconnect K3, K4, and K5, because the same connector is used for the thermistor, mechanical bin control, and float switch. K4 is not used on "E" control board models.

5.Always replace the whole control board assembly if it goes bad.

6.Do not short out power supply to test for voltage.

1)Turn off the power supply.

2)Remove the front panel and the control box cover.

3)Disconnect the control board connectors from the control board.

4)Remove the control board.

5)Adjust the dip switches on the new control board to the factory default settings. See "II. C.3.a) Default Dip Switch Settings." CAUTION! Do not adjust S4 dip switch 7 out of the factory default position on this model. This dip switch must be left in the factory default position or this unit will not operate correctly.

6)Install the new control board taking care not to damage it.

7)Connect the control board connectors to the new control board.

8)Replace the control box cover and front panel in their correct positions.

9)Turn on the power supply.

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Contents KM-901MAH KM-901MWH Hoshizaki AMERICA, INC Contents Page Page Indicates important information about the use and care Important Safety InformationSerious injury UnitSpecifications Icemaker 1a. KM-901MAH air-cooled Auxiliary Code T-0, U-01b. KM-901MAH air-cooled Auxiliary Code U-1 and Later 2a. KM-901MWH water-cooled Auxiliary Code T-0, U-0 Water Cooled Condenser2b. KM-901MWH water-cooled Auxiliary Code U-1 and Later 3a. KM-901MRH remote air-cooled Auxiliary Code T-0, U-0 3b. KM-901MRH remote air-cooled Auxiliary Code U-1 and Later 4a. KM-901MRH3 remote air-cooled Auxiliary Code T-0, U-0 4b. KM-901MRH remote air-cooled Auxiliary Code U-1 and Later Condenser Unit Specifications Model URC-9FII. General Information Construction KM-901MAH air-cooledKM-901MWH water-cooled KM-901MRH/3 remote air-cooled Sequence Cycles and Shutdown Sequence of OperationControl Board Auxiliary Code T-0, U-0 Shutdown Control Board Auxiliary Code U-1 and LaterOFF Cycle at Shutdown Mechanical Bin Control Activation Cycle Control Board Sequence Flow ChartSequence Flow Chart Bin FullMinute Harvest Cycle Freeze Cycle Pump-Out Cycle Control Board Auxiliary Code U-1Later Fill CycleControl Board Control Board Layout Control BoardPart Number 2A3792-01 Low Water Safety Harvest Backup Timer and Freeze TimerHigh Temperature Safety Maximum Water Supply Period 6 minutesSequence Step LED Lights and Audible Alarm SafetiesNo. of Beeps Type of Alarm Every 3 sec Energized Time LEDs are On Components Min Max AvgControl Board Auxiliary Code U-1 and Later Harvest Timer S4 dip switch 1 Controls and AdjustmentsDefault Dip Switch Settings S4 Dip Switch S4 Dip Switch NoPump-Out Frequency Control S4 dip switch 5 Pump-Out Timer S4 dip switch 3S4 Dip Switch Setting Time seconds Inlet Control Board S4 Dip Switch Setting Bin Control Bin Control Selector/Harvest Pump Timer S4 dip switchFactory Use S4 dip switch Control Board S4 Dip Switch Setting Pump Motor Time secondsRefill Counter S5 dip switch 2 through 5 G Control Board Freeze Timer S4 dip switch 9Float Switch Control S5 dip switch 1 G Control Board S4 Dip Switch Setting Time MinutesBin Control Float SwitchControl Switch ThermistorWater Pump Switch Discharge Line ModelCooled-AirWater-Cooled Model PressureHigh* Switch Wiring DiagramsKM-901MAH air-cooled and KM-901MWH water-cooled KM-901MRH remote air-cooled PressureSwitchHigh KM-901MRH3 remote air-cooled Switch Cooled-WaterModel Cooled-AirModel High* PressureHigh Pressure Switch SwitchPressure Performance Data 1480 912835 1570KM-901MRH remote air-cooled KM-901MRH3 remote air-cooled IV. Service Diagnosis Diagnostic ProcedurePage OFF Control Board Check Shutdown Thermostatic Bin Control Auxiliary Code T-0, U-0Bin Control Check Control Correct LED Board Lighting SequenceMechanical Bin Control Check Mechanical Bin Control Cleaning Float Switch Check and Cleaning Float Switch CheckFloat Switch Cleaning Thermistor Check Problem Possible Cause Remedy Diagnostic ChartsNo Ice Production Problem Possible Cause Remedy Problem Possible Cause Remedy Evaporator is Frozen Up Problem Possible Cause Remedy Low Ice Production Abnormal Ice Other Service for Refrigerant Lines Removal and Replacement of ComponentsRefrigerant Recovery Brazing Evacuation and Recharge R-404ARemoval and Replacement of Compressor Removal and Replacement of Expansion Valve Page Removal and Replacement of Evaporator Removal and Replacement of Air-Cooled Condenser Removal and Replacement of Water-Cooled Condenser Removal and Replacement of Remote Air-Cooled Condenser Page Adjustment of Water Regulating Valve water-cooled model Removal and Replacement of Thermistor Removal and Replacement of Inlet Water Valve Removal and Replacement of Pump Motor Removal and Replacement of Control Board VI. Cleaning and Maintenance Cleaning and Sanitizing InstructionsCleaning Procedure Sanitizing Procedure Following Cleaning Procedure Maintenance Preparing the Icemaker for Long StorageDrain the water tank