Hoshizaki KM-901MWH, KM-901MAH, KM-901MRH/3 service manual Float Switch Check and Cleaning

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D. Float Switch Check and Cleaning

1. Float Switch Check

To check the float switch, follow the steps below.

1)Turn off the power supply.

2)Remove the front panel and move the control switch to the "OFF" position.

3)Remove the base cover, then disconnect one end of the pump tubing to drain the water tank. See Fig. 2. After the water tank has drained, reconnect the pump tubing.

4)Remove the control box cover.

5)Disconnect the black float switch connector from the control board BLACK K5 connector.

6)Check for continuity across the float switch leads. With the water tank empty, the float switch should be open. If open, continue to step 7. If closed, follow the steps in "IV. D.2. Float Switch Cleaning." After cleaning the float switch, check it again. Replace if necessary.

Disconnect This End of Pump Tubing to Drain Water Tank

7)Reconnect the black float switch connector, then replace the control box cover in its correct position.

Base Cover	Fig. 2

8)Move the control switch to the "ICE" position. Replace the front panel in its correct position, then turn on the power supply. After 1 minute, the 1-minute fill cycle should end and the initial harvest cycle should begin. If the initial harvest cycle begins, the float switch is good and the check is complete. If the initial harvest cycle does not begin, continue to step 9.

9)Turn off the power supply.

10)Remove the front panel.

11)Move the control switch to the "OFF" position.

12)Remove the control box cover.

13)Disconnect the black float switch connector from the control board BLACK K5 connector.

14)Check for continuity across the float switch leads. With the water tank full, the float switch should be closed. If the float switch is closed and the icemaker will not switch from the 1-minute fill cycle to the initial harvest cycle, replace the control board. See "V.P. Removal and Replacement of Control Board."

If the float switch is open, confirm that the water tank is full. If the tank is not full, check the water supply, water filters, and inlet water valve. If the tank is full, follow the steps in "IV.D.2. Float Switch Cleaning." After cleaning the float switch, check it again. Replace if necessary.

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Contents KM-901MAH KM-901MWH Hoshizaki AMERICA, INC Contents Page Page Serious injury Important Safety InformationIndicates important information about the use and care Unit1a. KM-901MAH air-cooled Auxiliary Code T-0, U-0 Specifications Icemaker1b. KM-901MAH air-cooled Auxiliary Code U-1 and Later Water Cooled Condenser 2a. KM-901MWH water-cooled Auxiliary Code T-0, U-02b. 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 Model URC-9F SpecificationsKM-901MAH air-cooled II. General Information ConstructionKM-901MWH water-cooled KM-901MRH/3 remote air-cooled Sequence of Operation Sequence Cycles and ShutdownControl Board Auxiliary Code T-0, U-0 Control Board Auxiliary Code U-1 and Later ShutdownOFF Cycle at Shutdown Mechanical Bin Control Activation Sequence Flow Chart Control Board Sequence Flow ChartCycle Bin FullLater Control Board Auxiliary Code U-1Minute Harvest Cycle Freeze Cycle Pump-Out Cycle Fill CycleControl Board Control Board Control Board LayoutPart Number 2A3792-01 High Temperature Safety Harvest Backup Timer and Freeze TimerLow Water Safety Maximum Water Supply Period 6 minutesNo. of Beeps Type of Alarm Every 3 sec LED Lights and Audible Alarm SafetiesSequence Step Energized Time LEDs are On Components Min Max AvgControl Board Auxiliary Code U-1 and Later Default Dip Switch Settings Controls and AdjustmentsHarvest Timer S4 dip switch 1 S4 Dip Switch S4 Dip Switch NoPump-Out Timer S4 dip switch 3 Pump-Out Frequency Control S4 dip switch 5S4 Dip Switch Setting Time seconds Inlet Factory Use S4 dip switch Bin Control Selector/Harvest Pump Timer S4 dip switchControl Board S4 Dip Switch Setting Bin Control Control Board S4 Dip Switch Setting Pump Motor Time secondsFloat Switch Control S5 dip switch 1 G Control Board Freeze Timer S4 dip switch 9Refill Counter S5 dip switch 2 through 5 G Control Board S4 Dip Switch Setting Time MinutesControl Switch Float SwitchBin Control ThermistorWater Pump Switch Discharge Line Wiring Diagrams ModelCooled-AirWater-Cooled Model PressureHigh* SwitchKM-901MAH air-cooled and KM-901MWH water-cooled PressureSwitch KM-901MRH remote air-cooledHigh KM-901MRH3 remote air-cooled Cooled-AirModel High* Pressure Switch Cooled-WaterModelHigh Pressure Switch SwitchPressure Performance Data 835 9121480 1570KM-901MRH remote air-cooled KM-901MRH3 remote air-cooled Diagnostic Procedure IV. Service DiagnosisPage OFF Shutdown Thermostatic Bin Control Auxiliary Code T-0, U-0 Control Board CheckControl Correct LED Board Lighting Sequence Bin Control CheckMechanical Bin Control Check Mechanical Bin Control Cleaning Float Switch Check Float Switch Check and CleaningFloat Switch Cleaning Thermistor Check Diagnostic Charts Problem Possible Cause RemedyNo Ice Production Problem Possible Cause Remedy Problem Possible Cause Remedy Evaporator is Frozen Up Problem Possible Cause Remedy Low Ice Production Abnormal Ice Other Removal and Replacement of Components Service for Refrigerant LinesRefrigerant Recovery Evacuation and Recharge R-404A BrazingRemoval 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 Cleaning and Sanitizing Instructions VI. Cleaning and MaintenanceCleaning Procedure Sanitizing Procedure Following Cleaning Procedure Preparing the Icemaker for Long Storage MaintenanceDrain the water tank