Hoshizaki KM-470AJ Service Manual
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Hoshizaki KM-470AJ Service Manual

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KM-470AJ
MODULAR CRESCENT CUBER
SERVICE MANUAL
F136-1056（042020)

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  • Page 1 KM-470AJ MODULAR CRESCENT CUBER SERVICE MANUAL F136-1056（042020)

  • Page 2: Table Of Contents

    IMPORTANT This manual should be read carefully before the appliance is serviced. Read the warnings and guidelines contained in this manual carefully as they provide essential information for the continued safe use, service, and maintenance of the appliance. Retain this manual for any further reference that may be necessary. CONTENTS Important Safety Information ....................

  • Page 3: Important Safety Information

    Important Safety Information Throughout this manual, notices appear to bring your attention to situations which could result in death, serious injury, damage to the appliance, or damage to property. WARNING Indicates a hazardous situation which could result in death or serious injury.
  • Page 4 WARNING, continued • Children should be properly supervised around this appliance. • Do not climb, stand, or hang on the appliance or allow children or animals to do so. Serious injury could occur or the appliance could be damaged. • Do not use combustible spray or place volatile or flammable substances near the appliance.

  • Page 5: Construction And Water/Refrigeration Circuit Diagram

    I. Construction and Water/Refrigeration Circuit Diagram A. Construction 1. KM-470AJ Spray Tubes Hot Gas Valve Water Supply Inlet Inlet Water Valve Thermostatic Expansion Valve Cleaning Valve Condenser Control Switch Fan Motor High-Pres- sure Switch Float Switch Drier Control Box Water Pump...

  • Page 6: Water/Refrigeration Circuit Diagram

    B. Water/Refrigeration Circuit Diagram l. KM-470AJ Spray Tubes Condenser Inlet Water Valve Drier Evaporator High-Pressure Water Supply Liquid Line Valve Switch Heat Cleaning Exchanger Thermistor Valve Suction Line Strainer Water Pump Float Switch Hot Gas Water Valve Tank Discharge Line...

  • Page 7: Sequence Of Operation And Service Diagnosis

    II. Sequence of Operation and Service Diagnosis A. Sequence of Operation Flow Chart 1.Operation Flow Chart...
  • Page 8 2.Shutdown Flow Chart Shutdown Flow Chart 3. Ice Level Lowered 1. Bin Full 2. Icemaker Off Shutdown and Restart No ice touching BC bulb. All components Within 10 sec. Icemaker starts at de-energized. after ice contacts "1. 1-Minute Fill Cycle." BC bulb, icemaker shuts down.

  • Page 9: Service Diagnosis

    B.Service Diagnosis WARNING • The appliance should be diagnosed and repaired only by qualified service personnel to reduce the risk of death, electric shock, serious injury, or fire. • Risk of electric shock. Control switch in "OFF" position does not de-energize all loads Use extreme caution and exercise safe electrical practices.
  • Page 10 1. Sequence and Component Diagnosis 3) Power On: Turn on the power supply, then move the control switch to the "ICE" position. A 5-sec. delay occurs. CB red "POWER OK" LED and CB green "BC CLOSED" LED turn on. If CB yellow "BC OPEN" LED is on (indicating a full bin), check CB K4 red jumper.
  • Page 11 4) 1-Min. Fill Cycle – LED 4 is on. WV and X11 relay energize. After 1 min., CB checks for a closed FS. If FS is closed, the harvest cycle begins. If harvest cycle begins (Comp, HGV, and FM energized), continue to step 5a. If FS is open, WV remains energized until FS closes (low water safety protection during initial start up and at the end of each harvest).
  • Page 12 5b) Harvest Pump Timer – LEDs 1, 3, and 2 are on. When the thermistor reaches 9°C, CB reads 3.9 kΩ from the thermistor and turns harvest termination over to the harvest timer (S4 dip switch 1 & 2 and S5 dip switch 4). When WV de-energizes, LED 4 turns off, X11 relay de-energizes and LED 3 turns on.
  • Page 13 a) Freeze Cycle Diagnosis: Confirm Comp, FM, and PM continue. Confirm that FM and LLV energize. Confirm WRV opens. Next, confirm HGV and X10 relay de- energize. During the first 5 min. of freeze, confirm evaporator is cooling. If not, confirm WV de-energized (not leaking by), HGV de-energized (not bypassing), LLV and FM energize, TXV and HM operate correctly, WRV opens, Comp is efficient, and refrigerant charge is correct.
  • Page 14 g) Freeze Termination Diagnosis: After 5 min. in freeze, disconnect CB K5 FS connector. 15 sec. later appliance should switch out of the freeze cycle (15 second delay after FS opens before terminating the freeze cycle). If appliance remains in freeze longer than 15 sec.
  • Page 15 Pump-Out Diagnosis: In the freeze cycle before pump-out (see table above), after 5 min. of freeze disconnect CB black K5 connector (FS connector). Check that PM stops and re-starts. Next, check that PM rotation is correct (water flowing down the drain through CV).

  • Page 16: Control Board Check

    C. Control Board Check Before replacing CB that does not show a visible defect and that you suspect is bad, always conduct the following check procedure. This procedure will help you verify your diagnosis. Alarm Reset: If CB is in alarm (beeping), press the "ALARM RESET" button on CB while CB is beeping.

  • Page 17: Bin Control Check

    D. Bin Control Check BC shuts down the icemaker within 10 sec. when ice contacts the thermostatic bulb, regardless of the cycle at activation. NOTICE When the ambient temperature is below 7°C, BC opens and shuts down the appliance even if the ice storage bin is empty. When BC is set in the prohibited range, the appliance operates continuously even if the ice storage bin is filled with ice.

  • Page 18: Float Switch Check And Cleaning

    E. Float Switch Check and Cleaning FS is used to determine that there is sufficient water in the water tank after the 1-min. fill cycle and after each harvest cycle. FS is also used to determine that the appropriate volume of water has been converted into ice before switching out of the freeze cycle. No adjustment is required.
  • Page 19 6) Wipe down FS housing, shaft, float, and retainer rod with a mixture of 1 part Hoshizaki "Scale Away" and 25 parts warm water. Clean the inside of the rubber boot and hose with cleaning solution.

  • Page 20: Thermistor Check

    F. Thermistor Check To check thermistor resistance, follow the steps below. 1) Turn off the power supply. 2) Remove the front panel. Move the control switch to the "OFF" position. 3) Remove the control box cover. 4) Remove the thermistor from the refrigerant tubing. 5) Immerse the thermistor sensor portion in a glass containing ice and water for 2 or 3 min.

  • Page 21: Diagnostic Tables

    H. Diagnostic Tables 1. No Ice Production No Ice Production - Possible Cause 1. Power Supply a) Off, blown fuse, or tripped breaker. b) Not within specifications. 2. Main Transformer a) Voltage tap switch not set to proper voltage. (208-230/60/1 Models with main b) Coil winding open or shorted.
  • Page 22 No Ice Production - Possible Cause 15. Pump Motor a) Motor winding open. b) Bearing worn out or locked rotor. c) Defective capacitor. d) Mechanical seal worn out. 16. Thermostatic Expansion Valve a) Bulb loose. b) Operating erratically. 17. Liquid Line Valve a) Closed in freeze cycle.
  • Page 23 Freeze-Up - Possible Cause 13. Thermostatic Bin Control a) Defective. See "II.D. Bin Control Check" Freeze Cycle 1. Evaporator a) Scaled up. b) Damaged. 2. Spray Tubes and/or Spray a) Dirty. Guides b) Out of position. 3. Refrigerant Charge a) Low. 4.
  • Page 24 3. Low Ice Production Low Ice Production - Possible Cause Long Harvest Cycle 1. Evaporator a) Scaled up. 2. Spray Tubes and/or Spray a) Dirty. Guides b) Out of position. 3. Refrigerant Charge a) Low. 4. Water Supply a) Low water pressure. b) External water filters clogged.

  • Page 25: Freeze-Up Check List

    I. Freeze-Up Check List Freeze-Up Check List Please Complete When Diagnosing a Freeze-Up, Refrigerant Leak, or Low Charge Make Copies And Use As Needed Model #___________________________ Serial # ______________________Install Date__________Freeze-Up Date___________ List model and manufacture of bin or dispenser__________________________. Date appliance was last cleaned:__________. Appliance of Operation Freeze-Up Defrost Fill...

  • Page 26: Controls And Adjustments

    III. Controls and Adjustments • A Hoshizaki exclusive control board is employed in KM series appliances. • All models are pretested and factory adjusted. • For a control board check procedure, see "II.C. Control Board Check." NOTICE • Fragile, handle very carefully.

  • Page 27: Control Board Layout

    A. Control Board Layout 1. "J" Control Board "J" Control Board • Bin Control Switch Closed LED (green) • "OUTPUT TEST" Button • S4 Dip Switch • "ALARM RESET" Button (on continuously (used to test relays on control board) in thermostatic bin control application) •...

  • Page 28: Led Lights And Audible Alarm Safeties

    B. LED Lights and Audible Alarm Safeties Beep occurs and red "POWER OK" LED turns on when control switch is moved to "ICE" position. Sequence Green LEDs 1 through 4 turn on and sequence from initial startup as listed in the table below.

  • Page 29: Settings And Adjustments

    NOTICE Dip switches are factory set. Failure to maintain factory settings may adversely affect performance and warranty coverage. For more information, contact your Hoshizaki Service Center. 1. Default Dip Switch Settings The dip switches are factory-adjusted to the following positions: S4 Dip Switch No.

  • Page 30: Harvest Timer (S4 Dip Switch 1 & 2)

    However, a setting longer than the factory setting may be advised in cases where the drain provided at harvest needs to be prolonged for extra cleaning. Before changing this setting, contact Hoshizaki Technical Support at 1-800-233-1940 for recommendations. Keep in mind that setting the harvest timer to a longer setting decreases 24-hour production.

  • Page 31: Pump-Out Frequency Control (S4 Dip Switch 5)

    4. Pump-Out Frequency Control (S4 dip switch 5) The pump-out frequency control is factory set to drain the water tank every 10 cycles. 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 can be set to have a pump-out occur every cycle, or every 10 cycles.

  • Page 32: Harvest Pump Time (Harvest Assist) (S4 Dip Switch 7)

    6. Harvest Pump Time (Harvest Assist) (S4 dip switch 7) NOTICE Factory set for proper operation. Do not adjust. Adjustment outside of the factory default setting may result in damage to the appliance. a) Harvest Pump Time (Harvest Assist) Depending on S4 dip switch 7 setting, the pump motor either stays off or is energized during the last seconds of the harvest cycle.

  • Page 33: Freeze Timer (S4 Dip Switch 9 & 10)

    In this case, see "II.H.3. Low Ice Production" for possible solutions. The freeze timer is factory set and no adjustment is required. Before changing this setting, contact Hoshizaki Technical Support at 1-800-233-1940 for recommendations.

  • Page 34: Minimum Harvest Time (S5 Dip Switch 4)

    11. Minimum Harvest Time (S5 dip switch 4) NOTICE Factory set for proper operation. Do not adjust. Adjustment outside the factory default setting may result in damage to the appliance. S5 Dip Switch Setting Minimum Harvest Timer No. 4 120 sec. 70 sec.

  • Page 35: Refrigeration Circuit And Component Service Information

    IV. Refrigeration Circuit and Component Service Information WARNING • This appliance should be diagnosed and repaired only by qualified service personnel to reduce the risk of death, electric shock, serious injury, or fire. • Move the control switch to the "OFF" position and turn off the power supply. Place the disconnect in the "OFF"...
  • Page 36 2. Brazing WARNING • R-404A itself is not flammable at atmospheric pressure and temperatures up to 80°C. • R-404A itself is not explosive or poisonous. However, when exposed to high temperatures (open flames), R-404A can be decomposed to form hydrofluoric acid and carbonyl fluoride both of which are hazardous.
  • Page 37 5) Disconnect the gauge manifold hose from the vacuum pump and attach it to a refrigerant service cylinder. Remember to loosen the connection and purge the air from the hose. For the required refrigerant charge, see the nameplate. Hoshizaki recommends only virgin refrigerant or reclaimed refrigerant which meets ARI Standard 700 (latest edition) be used.

  • Page 38: Component Service Information

    B. Component Service Information NOTICE When replacing a component listed below, see the notes to help ensure proper operation. Component Notes Compressor 1 phase: Install a new start capacitor, run capacitor, and start relay. 3 phase: Install a new magnetic contactor. Thermostatic •...

  • Page 39: Maintenance

    V. Maintenance The maintenance schedule below is a guideline. More frequent maintenance may be required depending on water quality, the appliance's environment, and local sanitation regulations WARNING • Only qualified service technicians should service the appliance. • To reduce the risk of electric shock, do not touch the control switch or service switch with damp hands •...

  • Page 40: Preparing The Appliance For Periods Of Non-Use

    VI. Preparing the Appliance for Periods of Non-Use NOTICE • When storing the appliance for an extended time or in sub-freezing temperatures, follow the instructions below to prevent damage. • To prevent damage to the water pump, do not operate the appliance with the control switch in the "WASH"...
  • Page 41 2. Remove the water from the water tank: 1) Turn off the power supply, then remove the front panel. 2) Move the control switch to the "OFF" position. 3) Drain the water tank. Remove the rubber cap covering the overflow pipe in the water tank.

  • Page 42: Disposal

    VII. Disposal The appliance contains refrigerant and must be disposed of in accordance with applicable national, state, and local codes and regulations. Refrigerant must be recovered by properly certified service personnel.

  • Page 43: Technical Information

    VIII. Technical Information We reserve the right to make changes in specifications and design without prior notice. A. Dimensions/Specifications 1.KM-470AJ...

  • Page 44: Wiring Diagram

    B. Wiring Diagram 1.KM-470AJ...

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