Hoshizaki KM-350MWJ Service Manual
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Hoshizaki KM-350MWJ Service Manual

Modular crescent cuber
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Service Manual
Modular Crescent Cuber
Models
KM-350MAJ, MWJ
KM-520MAJ, MWJ, MRJ
KM-660MAJ, MWJ, MRJ
hoshizakiamerica.com
Number: 73230
Issued: 10-29-2018
Revised: 8-23-2019

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  • Page 1 Service Manual Modular Crescent Cuber Models KM-350MAJ, MWJ KM-520MAJ, MWJ, MRJ KM-660MAJ, MWJ, MRJ Number: 73230 hoshizakiamerica.com Issued: 10-29-2018 Revised: 8-23-2019...
  • Page 2 Hoshizaki provides this manual primarily to assist qualified service technicians in the service of the appliance. Should the reader have any questions or concerns which have not been satisfactorily addressed, please call, send an e-mail message, or write to the Hoshizaki Technical Support Department for assistance. Phone: 1-800-233-1940; (770) 487-2331 Fax: 1-800-843-1056;...

  • Page 3: 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 4 VII. Disposal ......................... 51 VIII. Technical Information ....................52 A. Specification and Performance Data Sheets ............... 52 1. KM-350MAJ ......................52 2. KM-350MWJ ......................53 3. KM-520MAJ ......................54 4. KM-520MWJ ......................55 5. KM-520MRJ with URC-5F ..................56 6. KM-660MAJ ......................57 7.

  • Page 5: 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 6 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 7: Construction And Water/Refrigeration Circuit Diagram

    I. Construction and Water/Refrigeration Circuit Diagram A. Construction 1. Air-Cooled Models (MAJ) Drain Valve Water Supply Inlet Cleaning Valve Spray Tubes Stainer Hot Gas Valve Evaporator Condenser High-Pressure Inlet Water Valve Switch Thermostatic Expansion Valve Fan Motor Liquid Line Valve Float Switch Drier Compressor...

  • Page 8: Water-Cooled Models (Mwj)

    2. Water-Cooled Models (MWJ) Drain Valve Water Supply Inlet Cleaning Valve Spray Tubes Stainer Evaporator Hot Gas Valve Inlet Water Water Regulating Valve Valve Thermostatic High-Pressure Switch Expansion Valve Condenser Drier Float Switch Liquid Line Valve Water Pump Bin Control Sensor Compressor Control Switch Control Box...

  • Page 9: Remote Models (Mrj)

    3. Remote Models (MRJ) Thermostatic Drain Valve Expansion Valve Spray Tubes Water Supply Inlet Cleaning Valve Evaporator Stainer Hot Gas Valve Inlet Water Receiver Tank Valve High-Pressure Switch Drier Float Switch Liquid Line Valve Water Pump Bin Control Crankcase Heater Sensor Compressor Control Switch...

  • Page 10: Water/Refrigeration Circuit Diagram

    B. Water/Refrigeration Circuit Diagram 1. Air-Cooled Models (MAJ)

  • Page 11: Water-Cooled Models (Mwj)

    2. Water-Cooled Models (MWJ)

  • Page 12: Remote Models (Mrj)

    3. Remote Models (MRJ)

  • Page 13: Sequence Of Operation And Service Diagnosis

    II. Sequence of Operation and Service Diagnosis A. Sequence of Operation Flow Chart 1. Operation Flow Chart...

  • Page 14: Shutdown Flow Chart

    2. Shutdown Flow Chart...

  • Page 15: 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 16 1. Sequence and Component Diagnosis 3) Power On: Turn on the power supply, then move the control switch to the "ON" position and the mode switch to the "ICE" position. A 5-sec. delay occurs. CB red "POWER OK" LED turns on. If CB yellow "BC OPEN" LED is on (indicating a full bin), move ice away from BC sensing area.
  • Page 17 5a) Initial Harvest Cycle – LEDs 1, 4, and 2 are on. WV continues. Comp, FMR, and 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 3.9 kΩ from the thermistor and turns harvest termination over to the harvest timer (S4 dip switch 1 &...
  • Page 18 5c) Initial Harvest Cycle Termination Diagnosis: When the thermistor reaches 48°F (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). Check discharge line temperature.
  • Page 19 d) PM Diagnosis: Confirm water is flowing over evaporator from PM and not WV. If PM de-energizes once freeze begins, check for 115VAC at CB K1 #4 (R) to neutral (W). If 115VAC is not present, replace CB. If 115VAC is present and PM is de-energized, check PM capacitor and motor winding continuity.
  • Page 20 7) Pump-Out Cycle – LEDs 1, 3, and 5 are on (10/20 second pump-out). Timing of the first pump-out is determined by S4 dip switch 5. See the table below. Control Board Settings S4 Dip Switch Setting Pump-Out Frequency Control Board No.

  • Page 21: 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 22: Bin Control Check And Adjustment

    The bin control is factory set for use on Hoshizaki America standard ice storage bins. If mounted on a dispenser application or if a change to the ice level in an ice storage bin application is desired, see "II.D.2.
  • Page 23 4) BC controller green "LED 1" LED turns on and CB yellow "BC OPEN/CLOSED" LED is off. a) Bin Empty Diagnosis: If fill cycle does not start, confirm BC controller green "LED 1" LED is on. If not, with BC wire harness connected to CB K4 connector, check for 5VDC at CB K4 pin #3 (W) to CB K4 pin #2 (BK).
  • Page 24 a) Bin Full Diagnosis: Place an object 5" to 7" (127 to 178 mm) away from the BC sensor lens. If shut down cycle does not start, confirm BC controller green "LED 1" LED turns off. If not, check for 4VDC at CB K4 pin #1 (R) to CB K4 pin #2 (BK). If 1VDC is present, confirm object placement.
  • Page 25 • Failure to properly adjust the bin control setting could result in water leakage, ice backup, and icemaker damage. The bin control is factory set to 1 for use on Hoshizaki America standard ice storage bins. See the table below for adjustments to ice level.

  • Page 26: 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 27 6) Wipe down the float switch bracket assembly, stem, and float with a mixture of 1 part Hoshizaki "Scale Away" and 25 parts warm water. Rinse the parts thoroughly with clean water. WARNING! Do not remove the lock nut on the float switch assembly. This is factory sealed and must not be removed.

  • Page 28: 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, then remove the top and right side panels. 3) Remove the thermistor from the refrigerant tubing. 4) Immerse the thermistor sensor portion in a glass containing ice and water for 2 or 3 min.

  • Page 29: Diagnostic Tables

    I. 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. Fuse (Control Box) a) Blown. 3. Control Switch a) In "OFF" or "PUMP" position. b) Defective.
  • Page 30 2. Freeze-Up Defrost and clean the icemaker prior to diagnosing freeze-up. Fill out a freeze-up checklist. See "II.J. Freeze Up Check List," the Hoshizaki America Technician's Pocket Guide, or contact your local distributor for a copy of the freeze-up checklist.
  • Page 31 Freeze-Up - Possible Cause 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. Control Board a) Freeze timer (S4 dip switch 9 & 10) set incorrectly. See "II.C.
  • Page 32 Low Ice Production - Possible Cause Long Freeze Cycle 1. Evaporator a) Scaled up, dirty. 2. Float Switch a) Scaled up, dirty. See "II.E. Float Switch Check b) Float sticking. and Cleaning" c) Defective switch. 3. Inlet Water Valve a) Leaking by. 4.

  • Page 33: Freeze-Up Check List

    J. Freeze-Up Check List Freeze-Up Check List Please Complete When Diagnosing a Freeze-Up, Refrigerant Leak, or Low Charge Technical Support Fax #: 770-487-3360 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:__________.

  • Page 34: 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.D. Control Board Check." NOTICE • Fragile, handle very carefully.

  • Page 35: Control Board Layout

    A. Control Board Layout 1. Control Board Control Board • "ALARM RESET" • "OUTPUT TEST" Button • S4 Dip Switch Button (used to test relays on control board) • K3 (white) Connector • Bin Control Switch (5VDC) BC OPEN/CLOSED Thermistor LED (yellow) (harvest control and high temperature safety)

  • Page 36: Led Lights And Audible Alarm Safeties

    B. LED Lights and Audible Alarm Safeties Beep occurs and red CB "POWER OK" LED turns on when control switch is moved to "ICE" position. Sequence Green LEDs 1 through 5 turn on and sequence from initial startup as listed in the table below.

  • Page 37: 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 38: Harvest Time (S4 Dip Switch 1 & 2)

    2. Harvest Time (S4 dip switch 1 & 2) The harvest timer starts counting when the thermistor reaches 48°F (9°C) at the evaporator outlet and the control board reads 3.9 kΩ from the thermistor. The harvest timer is factory set, and generally no adjustment is required. 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.

  • Page 39: 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 40: Harvest Pump Time (Harvest Assist (S4 Dip Switch 7)

    In this case, see "II.I.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 41: Pump-Out Pump Motor Direction (S5 Dip Switch 1)

    9. Pump-Out Pump Motor Direction (S5 dip switch 1) NOTICE Do not adjust. This must be left in the factory default position or the icemaker will not operate correctly. The pump-out pump motor direction setting determines pump motor rotation during pump-out.

  • Page 42: Anti-Slush (S5 Dip Switch 5)

    12. Anti-Slush (S5 dip switch 5) This dip switch setting provides anti-slush control during the freeze cycle. When the evaporator temperature reaches 36°F (2.2°C) the control board reads a 5.8 kΩ signal from the thermistor and de-energizes the water pump for 10 sec. to melt the ice slush and prevent the ice slush from blocking the water supply tubing, causing irregular freeze patterns.

  • Page 43: 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 44 2. Brazing WARNING • R-404A itself is not flammable at atmospheric pressure and temperatures up to 176°F (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 45 Remember to loosen the connection and purge the air from the hose. For the required refrigerant charge, see the rating label inside the icemaker. Hoshizaki recommends only virgin refrigerant or reclaimed refrigerant which meets ARI Standard 700 (latest edition) be used.

  • Page 46: Component Service Information

    • The thermistor should be at the 12 o'clock position on the tube. • Smoothly fill the recessed area of the thermistor holder with high thermal conductive type sealant. Hoshizaki America part number 4A0683-01 (Silicone Heat Sink Compound 10-8108 manufactured by GC Electronics), KE-4560 RTV (manufactured by ShinEtsu Silicones), or equivalent are recommended.

  • Page 47: Water Regulating Valve Adjustment (Water-Cooled Model)

    C. Water Regulating Valve Adjustment (water-cooled model) The water regulating valve is factory set, and generally no adjustment is required. However, when necessary, adjust the water regulator using the following procedure. 1) Prepare a thermometer to check the condenser drain temperature. Attach a pressure gauge to the high-side line of the system.

  • Page 48: 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 49: 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 50 3. On water-cooled model, remove the water from the water-cooled condenser: 1) Make sure the power supply is off, then remove the front panel and right side panel. 2) Close the condenser water supply line shut-off valve. If connected to a closed loop system, also close the condenser return line shut-off valve.

  • Page 51: 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 52: Technical Information

    VIII. Technical Information We reserve the right to make changes in specifications and design without prior notice. A. Specification and Performance Data Sheets Pressure data is recorded at 5 min. into freezing cycle. The data not in bold should be used for reference only.

  • Page 53: Km-350Mwj

    2. KM-350MWJ Specification Sheet AC SUPPLY VOLTAGE 115/60/1 AMPERAGE 7.5 A ( 5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 15 A MAXIMUM FUSE SIZE 15 A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 780 (4.90)

  • Page 54: Km-520Maj

    3. KM-520MAJ Specification Sheet AC SUPPLY VOLTAGE 115/60/1 AMPERAGE 10.6 A ( 5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 20 A MAXIMUM FUSE SIZE 20 A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 940 (4.68) 840 (3.64) WATER gal./24HR (gal./100 lbs.)

  • Page 55: Km-520Mwj

    4. KM-520MWJ Specification Sheet AC SUPPLY VOLTAGE 115/60/1 AMPERAGE 8.45 A ( 5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 20 A MAXIMUM FUSE SIZE 20 A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 860 (4.65) 880 (4.45) WATER gal./24HR (gal./100 lbs.)

  • Page 56: Km-520Mrj With Urc-5F

    5. KM-520MRJ with URC-5F AC SUPPLY VOLTAGE 115/60/1 AMPERAGE 12.05 A ( 5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 20 A MAXIMUM FUSE SIZE 20 A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 990 (4.80) 920 (4.05) WATER gal./24HR (gal./100 lbs.)

  • Page 57: Km-660Maj

    6. KM-660MAJ Specification Sheet AC SUPPLY VOLTAGE 115/60/1 AMPERAGE 15.2 A ( 5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 20 A MAXIMUM FUSE SIZE 20 A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 1320 (5.12) 1200 (4.34) WATER gal./24HR (gal./100 lbs.)

  • Page 58: Km-660Mwj

    7. KM-660MWJ DATA PENDING...

  • Page 59: Km-660Mrj With Urc-5F

    8. KM-660MRJ with URC-5F Specification Sheet AC SUPPLY VOLTAGE 115/60/1 AMPERAGE 16.1 A ( 5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 20 A MAXIMUM FUSE SIZE 20 A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 1400 (5.60) 1270 (4.72) WATER gal./24HR (gal./100 lbs.)

  • Page 60: Wiring Diagram

    B. Wiring Diagram 1. KM-350M_J, KM-520M_J, KM-660M_J...

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