Hoshizaki KM-1300MWH, KM-1300MAH, KM-1300MRH service manual

Page 15

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 Evapora- tor 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 Tem- perature 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 Tem- perature 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 Cut-out

The maximum allowable supply voltage of this icemaker is limited by the High Voltage Cut-out.

If miswiring (especially on single phase 3 wire models) causes excessive voltage on the Controller Board, the High Voltage Cut-out 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

15

Image 15
Contents KM-1300MAH KM-1300MWH KM-1300MRH Hoshizaki AMERICA, INC Contents Maintenance KM-1300MAH Air-cooled Specifications2a. KM-1300MWH Water-cooled 2b. KM-1300MWH Water-cooled Serial No. M10156D KM-1300MRH Remote air-cooled Condensing Unit URC-12F Specifications Model URC-12F II. General Information Construction KM-1300MWH Water-cooled KM-1300MRH Remote air-cooled 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 Sequence 1st Cycle 2nd Cycle and after with pump drain 2nd Cycle and after with no pump drain Controls and Adjustments Setting Time Setting Frequency Checking the Controller Board Page III. Technical Information KM-1300MWH Water-cooled KM-1300MRH Remote air-cooled KM-1300MAH Air-cooled and KM-1300MWH Water-cooled Wiring DiagramsCut-out 412 ±21.3 Psig Cut-in 327±21.3 Psig Timing Chart Page Performance Data Serial # L00001F to M10155C KM-1300MWH Water-cooled Serial # M10156D KM-1300MRH Remote air-cooled Problem Possible Cause Remedy IV. Service Diagnosis No ICE ProductionController Board Problem Possible Cause Remedy LOW ICE Production Evaporator is Frozen UPOthers Abnormal ICEService for Refrigerant Lines Refrigerant RecoveryEvacuation and Recharge R-404A Brazing Removal and Replacement of Compressor Important Removal and Replacement of Drier Removal and Replacement of Expansion Valve Removal and Replacement of HOT GAS Valve and Line Valve Removal and Replacement of Evaporator Important Page Page Page Removal and Replacement of Thermistor Important 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. Maintenance and Cleaning InstructionsPage Cleaning Cleaning Procedure Sanitizing Procedure Following Cleaning Procedure Page Maintenance