Hoshizaki KM-901MRH/3, KM-901MWH, KM-901MAH Sequence of Operation, Sequence Cycles and Shutdown

Page 20

B. Sequence of Operation

1. Sequence Cycles and Shutdown

a) "E" Control Board: Auxiliary Code T-0, U-0

The steps in the sequence are as outlined below. When power is supplied, CB red "POWER OK" LED comes 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, whichever is shorter.

LED 4 goes off when WV de‑energizes. 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.

(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.

(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 1st freeze cycle, then every 10th cycle thereafter.

The pump-out frequency 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. For details, see "II.C.3.d) Pump‑Out Frequency Control (S4 dip switch 5 & 6)."

20

Page 19 Page 21
Image 20
Page 19 Page 21
Contents KM-901MAH KM-901MWH Hoshizaki AMERICA, INC Contents Page Page Important Safety Information Serious injuryIndicates important information about the use and care UnitSpecifications Icemaker 1a. KM-901MAH air-cooled Auxiliary Code T-0, U-01b. KM-901MAH air-cooled Auxiliary Code U-1 and Later 2a. KM-901MWH water-cooled Auxiliary Code T-0, U-0 Water Cooled Condenser2b. 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-9FII. General Information Construction KM-901MAH air-cooledKM-901MWH water-cooled KM-901MRH/3 remote air-cooled Control Board Auxiliary Code T-0, U-0 Sequence of OperationSequence Cycles and Shutdown Shutdown Control Board Auxiliary Code U-1 and LaterOFF Cycle at Shutdown Mechanical Bin Control Activation Control Board Sequence Flow Chart Sequence Flow ChartCycle Bin FullControl Board Auxiliary Code U-1 LaterMinute Harvest Cycle Freeze Cycle Pump-Out Cycle Fill CycleControl Board Control Board Layout Control BoardPart Number 2A3792-01 Harvest Backup Timer and Freeze Timer High Temperature SafetyLow Water Safety Maximum Water Supply Period 6 minutesLED Lights and Audible Alarm Safeties No. of Beeps Type of Alarm Every 3 secSequence Step Energized Time LEDs are On Components Min Max AvgControl Board Auxiliary Code U-1 and Later Controls and Adjustments Default Dip Switch SettingsHarvest Timer S4 dip switch 1 S4 Dip Switch S4 Dip Switch NoS4 Dip Switch Setting Time seconds Inlet Pump-Out Timer S4 dip switch 3Pump-Out Frequency Control S4 dip switch 5 Bin Control Selector/Harvest Pump Timer S4 dip switch Factory Use S4 dip switchControl Board S4 Dip Switch Setting Bin Control Control Board S4 Dip Switch Setting Pump Motor Time secondsFreeze Timer S4 dip switch 9 Float Switch Control S5 dip switch 1 G Control BoardRefill Counter S5 dip switch 2 through 5 G Control Board S4 Dip Switch Setting Time MinutesFloat Switch Control SwitchBin Control ThermistorWater Pump Switch Discharge Line KM-901MAH air-cooled and KM-901MWH water-cooled Wiring DiagramsModelCooled-AirWater-Cooled Model PressureHigh* Switch High PressureSwitchKM-901MRH remote air-cooled KM-901MRH3 remote air-cooled Switch Cooled-WaterModel Cooled-AirModel High* PressureHigh Pressure Switch SwitchPressure Performance Data 912 8351480 1570KM-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-0Bin Control Check Control Correct LED Board Lighting SequenceMechanical Bin Control Check Mechanical Bin Control Cleaning Float Switch Check and Cleaning Float Switch CheckFloat Switch Cleaning Thermistor Check No Ice Production Diagnostic ChartsProblem Possible Cause Remedy Problem Possible Cause Remedy Problem Possible Cause Remedy Evaporator is Frozen Up Problem Possible Cause Remedy Low Ice Production Abnormal Ice Other Refrigerant Recovery Removal and Replacement of ComponentsService for Refrigerant Lines Brazing Evacuation and Recharge R-404ARemoval 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 InstructionsCleaning Procedure Sanitizing Procedure Following Cleaning Procedure Maintenance Preparing the Icemaker for Long StorageDrain the water tank
Top Page Image Contents