Hoshizaki KM-901MWH, KM-901MAH, KM-901MRH/3 Shutdown, Control Board Auxiliary Code U-1 and Later

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(5)Harvest Cycle

Same as the initial harvest cycle. See "II.B.1.a)(2) Initial Harvest Cycle."

Note: Unit continues to cycle until TBC is satisfied or power is turned off. The unit always restarts at the 1-minute fill cycle.

(6)Shutdown

When ice contacts the thermostatic bulb (TBC switch open), TBC shuts down the unit within 10 seconds. TBC is factory set, and generally no adjustment is required. However, adjustment may be needed in some conditions, particularly at higher altitude locations. 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.

Legend: CB–control board; Comp–compressor; FM–fan motor;

FMR–fan motor-remote; F/S–float switch; HGV–hot gas valve; LLV–liquid line valve; PM–pump motor; TBC–thermostatic bin control; WV–inlet water valve

b) "G" Control Board: Auxiliary Code U-1 and Later

The steps in the sequence are as outlined below. When power is supplied, CB red "POWER OK" LED and green "BC CLOSED" LED come on. There is a 5‑second delay before startup. Note that the order of the component LEDs from the outer edge of CB is 1, 4, 3, 2.

(1)1-Minute Fill Cycle

LED 4 is on. WV energizes and the 1-minute fill cycle begins. After 1 minute, CB checks for a closed F/S. If F/S is closed, the harvest cycle begins. If not, WV remains energized through additional 1-minute fill cycles until water fills the tank and closes F/S. This serves as a low water safety to protect PM.

(2)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)." 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. 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)."

LED 4 goes off when WV de‑energizes. 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. When the harvest timer expires, the harvest cycle is complete. CB checks the position of F/S and proceeds to the freeze 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.

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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
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