Off | Hoshizaki KM-901MAH, KM-901MWH, KM-901MRH/3 specification

(3)Freeze Cycle

LED 1 is on. Comp and FMR remain energized, PM, FM, and LLV energize. HGV and WV de-energize. For the first 5 minutes, CB will not accept a signal from F/S. This minimum 5-minute freeze time is short cycle protection for Comp. At the end of 5 minutes, F/S assumes control. As ice builds on the evaporator, the water level in the tank lowers. The freeze cycle continues until F/S opens and terminates the cycle. There is a 15 second delay before CB acknowledges an open F/S.

(4)Pump-Out Cycle

LEDs 1, 3, and 2 are on. LED 4 is on when S4 dip switch 3 & 4 are set to 3 off and 4 on. Comp and FMR remain energized, HGV energizes, WV energizes if S4 dip switch 3 off and 4 on. LLV and FM de‑energize. PM stops for 2 seconds then reverses, taking water from the bottom of the tank and forcing pressure against the check valve seat allowing water to go through the check valve and down the drain. At the same time, water flows through the small tube to power flush F/S. When the pump-out timer expires, the pump-out is complete.

The first pump‑out occurs after the 11th freeze cycle, then every 10th cycle thereafter. The pump-out frequency control is factory set, and generally no adjustment is required. However, where water quality is bad and the icemaker needs a pump-out more often, the pump-out frequency can be adjusted. The pump-out frequency control (S4 dip switch 5 & 6) can be set to have a pump‑out occur every cycle, or every 2, 5, or 10 cycles. Timing of the first pump-out is dependent on S4 dip switch 5 & 6 settings. See the table below. For details, see "II.C.3.d) Pump‑Out Frequency Control (S4 dip switch 5 & 6)."

"G" Control Board Settings

	S4 Dip Switch Setting		Pump-Out	1st Pump-Out
	No. 5	No. 6	Frequency	1st Pump-Out
	No. 5	No. 6	Frequency
	OFF	OFF	Every cycle	After 2nd freeze cycle

	ON	OFF	Every 2 cycles	After 3rd freeze cycle

	OFF	ON	Every 5 cycles	After 6th freeze cycle

	ON	ON	Every 10 cycles	After 11th freeze cycle

(5)Harvest Cycle

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

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

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

Contents

KM-901MAH KM-901MWH Hoshizaki AMERICA, INC Contents Page Page Indicates important information about the use and care Important Safety InformationSerious injury Unit Specifications Icemaker 1a. KM-901MAH air-cooled Auxiliary Code T-0, U-0 1b. KM-901MAH air-cooled Auxiliary Code U-1 and Later 2a. KM-901MWH water-cooled Auxiliary Code T-0, U-0 Water Cooled Condenser 2b. 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-9F II. General Information Construction KM-901MAH air-cooled KM-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 Later OFF Cycle at Shutdown Mechanical Bin Control Activation Cycle Control Board Sequence Flow ChartSequence Flow Chart Bin Full Minute Harvest Cycle Freeze Cycle Pump-Out Cycle Control Board Auxiliary Code U-1Later Fill Cycle Control Board Control Board Layout Control Board Part Number 2A3792-01 Low Water Safety Harvest Backup Timer and Freeze TimerHigh Temperature Safety Maximum Water Supply Period 6 minutes Sequence Step LED Lights and Audible Alarm SafetiesNo. of Beeps Type of Alarm Every 3 sec Energized Time LEDs are On Components Min Max Avg Control 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 No Pump-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 seconds Refill 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 Minutes Bin Control Float SwitchControl Switch Thermistor Water 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* Pressure High Pressure Switch SwitchPressure Performance Data 1480 912835 1570 KM-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-0 Bin Control Check Control Correct LED Board Lighting Sequence Mechanical Bin Control Check Mechanical Bin Control Cleaning Float Switch Check and Cleaning Float Switch Check Float 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-404A Removal 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 Instructions Cleaning Procedure Sanitizing Procedure Following Cleaning Procedure Maintenance Preparing the Icemaker for Long Storage Drain the water tank