Hoshizaki KM-630MWH, KM-630MRH, KM-630MAH service manual

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2)Defrost Timer

The defrost cycle starts when the Float Switch opens and completes the freeze cycle. But the Defrost Timer does not start counting until the Thermistor senses 48°F at the Evaporator outlet. The period from the end of the freeze cycle up to the point of the Thermistor's sensing varies depending on the ambient and water temperatures.

3)High Temperature Safety - 127 ± 7°F

The temperature of the suction line in the refrigerant circuit is limited by the High Temperature Safety.

During the defrost cycle the Evaporator temperature rises. The Thermistor senses 48°F and starts the Defrost Timer. After the Defrost Timer counts down to zero, the normal freeze cycle begins. If the Evaporator temperature continues to rise, the Thermistor will sense the rise in temperature and at 127 ± 7°F the Thermistor operates the High Temperature Safety.

This High Temperature Safety shuts down the circuit and the icemaker automatically stops.

This High Temperature Safety protects the unit from excessive temperature. The Control Board will Beep every 3 seconds. The white Reset Button on the Control Board must be pressed with power on to reset the Safety.

4)Low Water Safety

If the Pump Motor is operated without water, the mechanical seal can fail. To prevent this type of failure, the Controller Board checks the position of the Float Switch at the end of the initial one minute water fill cycle and at the end of each defrost cycle.

If the Float Switch is in the up position (electrical circuit closed), the Controller Board changes to the ice making cycle. If the Float Switch is in the down position (electrical circuit open), the Controller Board changes to a one minute water fill cycle before starting the ice making cycle. This method allows for a Low Water Safety shut down to protect the Water Pump from mechanical seal failure.

For water-cooled model, if the water is shut off, the unit is protected by the High Pressure Switch.

5)High Voltage Cutout

The maximum allowable supply voltage of this icemaker is limited by the High Voltage Cutout. If miswiring (especially on single phase 3 wire models) causes excessive voltage on the Controller Board, the High Voltage Cutout shuts down the circuit in 3 seconds and the icemaker automatically stops. When the proper supply voltage is resumed, the icemaker automatically starts running again. The Control Board will signal this problem using 7 Beeps every 3 seconds.

6)LED Lights and Audible Alarm Safeties

The red LED indicates proper control voltage and will remain on unless a control voltage problem occurs. At startup a 5 second delay occurs while the board conducts an internal timer check. A short beep occurs when the power switch is turned ON or OFF.

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Contents KM-630MAH KM-630MWH KM-630MRH Hoshizaki AMERICA, INC Contents Maintenance Water TEMP. F Specifications KM-630MAH2a. KM-630MWH Serial #L00001D M20270B 2b. KM-630MWH Serial #M20301E KM-630MRH URC-6F Condenser UnitSpecifications KM-630MAH II. General Information ConstructionKM-630MWH KM-630MRH Controller Board Features of Control Products E Controller BoardController Board SOLID-STATE ControlPage Freeze Cycle Beep every 3 sec. = High Evaporator Temperature 127 FMinute Fill Cycle Harvest CycleControl Products HOS-001A Board Important Water Valve opening is limited to 6 minutes Sequence 1st Cycle2nd Cycle and after with pump drain 2nd Cycle and after with no pump drain For Models with Thermostat Controls and AdjustmentsPage Setting Time Models with Thermostat Checking the Controller Board Models with Mechanical BIN ControlProximity Switch Mechanical BIN ControlExplanation of Operation Troubleshooting Mechanical BIN Control only KM-630MAH KM-630MWH KM-630MRH Wiring Diagrams Page B1 KM-630MRH with auxiliary codes L-0, M-0, M-1 B2 KM-630MRH with auxiliary codes M-2 and after Timing Chart Page 157 Performance DataPressure Drop of Cooling Water Line B1 KM-630MWH Serial #L00001D M20270BB2 KM-630MWH Serial #M20301E 603 Problem Possible Cause Remedy IV. Service Diagnosis 1. no ICE ProductionController Board Problem Possible Cause Remedy Thermistor Evaporator is Frozen UPLOW ICE Production Abnormal ICEOthers Evacuation and Recharge R-404A Removal and Replacement of ComponentsService for Refrigerant Lines Refrigerant RecoveryBrazing Removal and Replacement of Compressor Important Page Removal and Replacement of Expansion Valve Removal and Replacement of DrierRemoval and Replacement of HOT GAS Valve and Line Valve Page Removal and Replacement of Evaporator Important Page Adjustment of Water Regulating Valve WATER-COOLED Model only Page Removal and Replacement of Thermistor Caution Removal and Replacement of FAN Motor Removal and Replacement of Pump Motor Removal and Replacement of Water ValveRemoval and Replacement of Spray Tubes Preparing the Icemaker for Long Storage VI. Cleaning and Maintenance InstructionsPage Cleaning and Sanitizing Procedures Cleaning Procedure Page Sanitizing Procedure Maintenance