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

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

At startup, a 5-second delay occurs while the control board conducts an internal timer check. A beep occurs when the control switch is moved to the "ICE" position. The red LED indicates proper control voltage and remains on unless a control voltage problem occurs. The green LEDs 1 through 4 energize and sequence from initial startup as listed in the table below. Note that the order of the LEDs from the outer edge of the control board is 1, 4, 3, 2. For details, see "II.B. Sequence of Operation."

Sequence Step

 

LED

 

Energized

 

 

 

 

Time LEDs are On

 

 

Components

 

 

Min.

 

Max.

Avg.

 

 

 

 

 

 

 

1-Minute Fill Cycle

4

 

WV

 

 

 

 

 

 

1 minute

Harvest Cycle

 

1, 4, 2

 

Comp, FMR, WV, HGV

 

 

2 minutes

 

20 minutes

 

3 to 5 minutes

Harvest Pump Timer

1, 3, 2

 

Comp, FMR, PM, HGV

 

 

0 seconds

 

50 seconds

harvest pump timer

 

 

 

 

 

 

 

 

 

 

 

setting

Freeze Cycle

1

 

Comp, FM/FMR, PM,

 

 

5 minutes

 

freeze timer

30 to 35 minutes

 

 

 

 

LLV

 

 

 

 

setting

 

Pump-Out Cycle

 

1, 4*, 3, 2 Comp, FMR, WV*, PM,

 

 

10 seconds 20 seconds

*pumpout timer

 

 

 

 

HGV

 

 

 

 

 

 

setting

The built-in safeties shut down the unit and have alarms as listed below.

No. of Beeps

Type of Alarm

Notes

(every 3 sec.)

 

 

1

High Evaporator Temp.

Check for harvest problem (stuck HGV or relay), hot

 

(temperature > 127°F)

water entering unit, stuck HM, or shorted thermistor.

 

(53°C)

 

2

Harvest Backup Timer

Check for open thermistor, HGV not opening, TXV or

 

(harvest > 20 min. for two cycles

LLV leaking by, low charge, inefficient Comp, or WRV

 

in a row)

leaking by.

3

Freeze Timer

Check for F/S stuck closed (up), WV leaking by, HGV

 

(freeze > freeze timer setting for

leaking by, PM not pumping, TXV not feeding properly,

 

two cycles in a row)

LLV not opening, low charge, HM not bypassing, or

 

 

inefficient Comp.

To reset the above safeties, press the "ALARM RESET" button with the power supply on.

6

Low Voltage

Red LED turns off if voltage protection operates.

 

(92Vac±5% or less)

The control voltage safeties automatically reset when

7

High Voltage

voltage is corrected.

 

(147Vac±5% or more)

 

Legend: Comp–compressor; FM–fan motor; FMR–fan motor-remote; F/S–float switch; HGV–hot gas valve; HM–headmaster (C.P.R.); LLV–liquid line valve; PM–pump motor; TXV–thermostatic expansion valve; WRV–water regulating valve; WV–inlet water valve

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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 Cycles and Shutdown Sequence of OperationControl 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 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 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 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 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 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 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