Hoshizaki KM-901MWH, KM-901MAH, KM-901MRH/3 service manual

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3)1-Minute Fill Cycle – LED 4 is on. WV energizes. After 1 minute, CB checks for a closed F/S. If F/S is closed, the harvest cycle begins. If closed, continue to step 4. If open, WV remains energized through additional 1minute fill cycles until water fills the tank and closes F/S (low water safety). Diagnosis: If WV does not open, check the supply voltage at WV terminals, check continuity on the coil, confirm the screen or external filter is not plugged (no water flow). If unit fails to start harvest, check for open

F/S or bad 1minute timer in CB. See "IV.D. Float Switch Check and Cleaning" and "IV. B. Control Board Check."

4)Initial Harvest Cycle – LEDs 1, 4, and 2 are on. WV remains energized, Comp, FMR,

HGV energize. CB monitors the warming of the evaporator via the thermistor located on the suction line. When the thermistor reaches 48°F (9°C), CB reads a 3.9 kΩ signal from the thermistor and turns harvest termination over to the harvest timer (S4 dip switch 1 & 2). The harvest timer has settings of 60, 90, 120, and 180 seconds. For details, see "II.C.3.b) Harvest Timer (S4 dip switch 1 & 2)." When the harvest timer expires, the harvest cycle is complete. CB checks the position of F/S and proceeds to the next cycle if it is closed or calls for a 1-minute fill cycle if it is open. The minimum total time allowed by CB for a complete harvest cycle is 2 minutes.

"E" CB: WV is energized during harvest for a maximum of 6 minutes or the length of harvest, whichever is shorter.

"G" CB: WV is energized during harvest for a maximum of 6 minutes or the length of harvest minus 0 or 50 seconds (harvest pump timer (S4 dip switch 7)), whichever is shorter. LED 4 goes off when WV deenergizes. LED 3 comes on and PM energizes and runs for the last 0 or 50 seconds of harvest depending on S4 dip switch 7 setting. 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. For details, see "II.C.3.e) Bin Control Selector/Harvest

Pump Timer (S4 Dip Switch 7)."

Diagnosis: Check if Comp is running, HGV and WV still energized. Average harvest cycle at factory setting is 2 to 3 minutes. How long does initial harvest last? 1.5 minutes after initial harvest begins, touch Comp discharge line. Is it hot? If not, check refrigerant pressures and Comp operation. If it is hot, touch the inlet line to the evaporator. Is it hot? If it is hot and the freeze cycle is not starting, check the harvest timer adjustment (S4 dip switch 1 & 2), the thermistor for open circuit, the discharge line temperature, Comp efficiency, and if HGV is fully open. For a thermistor check, see "IV.E. Thermistor Check." If 1-minute fill cycle starts after harvest, check that F/S is clean and operating properly, see "IV.D. Float Switch Check and Cleaning." Make sure PM does not come on last 50 seconds of harvest. For details, see "II.C.3.e) Bin Control Selector/Harvest Pump Timer (S4 Dip Switch 7)."

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Contents KM-901MAH KM-901MWH Hoshizaki AMERICA, INC Contents Page Page Unit Important Safety InformationSerious injury Indicates important information about the use and care1a. 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 Bin Full Control Board Sequence Flow ChartSequence Flow Chart CycleFill Cycle Control Board Auxiliary Code U-1Later Minute Harvest Cycle Freeze Cycle Pump-Out CycleControl Board Control Board Control Board LayoutPart Number 2A3792-01 Maximum Water Supply Period 6 minutes Harvest Backup Timer and Freeze TimerHigh Temperature Safety Low Water SafetyEnergized Time LEDs are On Components Min Max Avg LED Lights and Audible Alarm SafetiesNo. of Beeps Type of Alarm Every 3 sec Sequence StepControl Board Auxiliary Code U-1 and Later S4 Dip Switch S4 Dip Switch No Controls and AdjustmentsDefault Dip Switch Settings Harvest Timer S4 dip switch 1Pump-Out Timer S4 dip switch 3 Pump-Out Frequency Control S4 dip switch 5S4 Dip Switch Setting Time seconds Inlet Control Board S4 Dip Switch Setting Pump Motor Time seconds Bin Control Selector/Harvest Pump Timer S4 dip switchFactory Use S4 dip switch Control Board S4 Dip Switch Setting Bin ControlS4 Dip Switch Setting Time Minutes Freeze Timer S4 dip switch 9Float Switch Control S5 dip switch 1 G Control Board Refill Counter S5 dip switch 2 through 5 G Control BoardThermistor Float SwitchControl Switch Bin ControlWater 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 1570 912835 1480KM-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