Hoshizaki KM-255BAH Service Manual
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Hoshizaki KM-255BAH Service Manual

Hoshizaki KM-255BAH Service Manual

Self-contained crescent cuber
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Hoshizaki
Hoshizaki America, Inc.
"A Superior Degree
of Reliability"
www.hoshizaki.com
Self-Contained Crescent Cuber
Models
KM-255BAH
KM-255BWH
SERVICE MANUAL

®
Number: 73146
Issued: 1-2-2007

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Summary of Contents for Hoshizaki KM-255BAH

  • Page 1 Hoshizaki America, Inc. “A Superior Degree of Reliability” www.hoshizaki.com Self-Contained Crescent Cuber Models KM-255BAH KM-255BWH SERVICE MANUAL ® Number: 73146 Issued: 1-2-2007...
  • Page 2 HOSHIZAKI provides this manual primarily to assist qualified service technicians in the service and maintenance of the icemaker. Should the reader have any questions or concerns which have not been satisfactorily addressed, please call, write or send an e-mail message to the HOSHIZAKI Technical Support Department. HOSHIZAKI AMERICA, INC.

  • Page 3: Table Of Contents

    Please review this manual. It should be read carefully before the icemaker is serviced or maintenance operations are performed. Only qualified service technicians should service and maintain the icemaker. This manual should be made available to the technician prior to service or maintenance.
  • Page 4 B. Wiring Diagram ... 3 . KM-55BAH (air-cooled) ... 3 . KM-55BWH (water-cooled) ... 4 C. Performance Data ... 5 . KM-55BAH (air-cooled) ... 5 . KM-55BWH (water-cooled) ... 6 IV. Service Diagnosis ... 7 A. 0-Minute Diagnostic Procedure ... 7 B.

  • Page 5: Specifications

    I. Specifications A. Icemaker 1. KM-255BAH (air-cooled) AC SUPPLY VOLTAGE AMPERAGE MINIMUM CIRCUIT AMPACITY MAXIMUM FUSE SIZE APPROXIMATE ICE PRODUCTION PER 24 HR. lbs./day ( kg/day ) Reference without *marks SHAPE OF ICE ICE PRODUCTION PER CYCLE APPROXIMATE STORAGE CAPACITY ELECTRIC &...

  • Page 6: Km-55Bwh (Water-Cooled)

    2. KM-255BWH (water-cooled) Intentionally Left Blank Note: We reserve the right to make changes in specifications and design without prior notice.

  • Page 7: General Information

    II. General Information A. Construction 1. KM-255BAH (air-cooled) Evaporator Spray Tube Control Box Condenser Fuse Electrical Control Switch Compressor Rear View of Icemaker Harvest Water Valve Freeze Water Valve Wash Valve Drier Water Tank, Bin Control & Pump Motor Bin Control Switch...

  • Page 8: Km-55Bwh (Water-Cooled)

    2. KM-255BWH (water-cooled) Evaporator Spray Tube Control Box Condenser Fuse Electrical Control Switch Compressor Rear View of Icemaker Harvest Water Valve Freeze Water Valve Wash Valve Drier Water Tank, Bin Control & Pump Motor Bin Control Switch (back side of tank) Water Tank Float Switch...

  • Page 9: Sequence Of Operation

    B. Sequence of Operation The steps in the sequence are as outlined below. When power is supplied, the red LED on the control board comes on. A 5 second delay occurs at startup. Note that the order of the green LEDs from the outer edge of the board is , 4, 3, . 1.
  • Page 10 the length of harvest minus 50 seconds, whichever is shorter. PM energizes and runs for the last 50 seconds of harvest. At the end of harvest, the control board checks the position of LF/S and proceeds to the freeze cycle if it is closed or calls for a -minute fill if it is open.
  • Page 12 C. Control Board • A HOSHIZAKI exclusive solid-state control is employed in KM-55BAH and KM-55BWH Self-Contained Crescent Cubers. • All models are pretested and factory-adjusted. . Fragile, handle very carefully. . A control board contains integrated circuits, which are susceptible to failure due to static discharge.

  • Page 13: Control Board Layout

    1. Control Board Layout Control Products "G" Control Board Switch for "C" board and "ALPINE" board (service boards only) Connector K Pins # through #0 #, 9 Magnetic Contactor # Hot Gas Valve (HGV) Water Valve Relay (for harvest water valve operation) #3 Self-Contained Fan Motor (FMS) #4 Pump Motor (icemaking) #5 Pump Motor (harvest)

  • Page 14: Features

    2. Features a) Maximum Water Supply Period – 6 minutes The harvest water valve will be open during harvest for 6 minutes or the length of harvest minus 50 seconds, whichever is shorter. b) Harvest Backup Timer and Freeze Timer The harvest backup timer shuts down the icemaker if, for two cycles in a row, the harvest cycle takes more than 0 minutes to complete.

  • Page 15: F) Led Lights And Audible Alarm Safeties

    f) LED Lights and Audible Alarm Safeties The red LED indicates control voltage (0 to V at K) 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 beep occurs when the control switch is moved to the ICE position.

  • Page 16: Controls And Adjustments

    3. Controls and Adjustments a) Default Dip Switch Settings The dip switches are factory-adjusted to the following positions: Dip Switch No. KM-55BAH OFF ON OFF ON KM-55BWH ON OFF OFF ON S5 Dip Switch (Do Not Adjust) Dip Switch No. KM-55BAH ON OFF ON OFF ON KM-55BWH...

  • Page 17: D) S4 Dip Switch 3, 4, 5, 6, 7, & 8

    No adjustment is required under normal use, as the harvest timer is adjusted to the suitable position. Before changing this setting, call the HOSHIZAKI Technical Support Department at -800-33-940 for recommendations. Keep in mind that setting the harvest timer to a longer setting will decrease 4 hour production.

  • Page 18: G) Bin Control

    g) Bin Control This machine uses a lever-actuated proximity switch (mechanical bin control) to control the ice level in the storage bin. No adjustment is required. (1) Explanation of Operation The bin control is connected to the K4 connector on the control board. When the bin control is calling for ice (proximity switch closed;...

  • Page 19: Control Board Check Procedure

    wire is common) and two separate switches. Check the upper switch by ohming out the black and red wires. When the float is up, the switch should be closed. Check the lower switch by ohming out the black and blue wires in the same manner. If either switch fails, the assembly should be replaced.

  • Page 20: Control Board Replacement

    7. Control Board Replacement ) Unplug the unit from the electrical outlet and disconnect the wiring to the board. ) Install the new board and make the wiring connections. 3) Set the application switch located between relays X3 & X4 to the ALP position. If this switch is placed in the wrong position, the unit will not start.

  • Page 21: Technical Information

    III. Technical Information A. Water Circuit and Refrigeration Circuit 1. KM-255BAH (air-cooled) Harvest Water Water Valve Supply Wash Valve Freeze Water Valve Pump Motor Float Switch Drain Refrigerant Circuit Water Circuit Spray Tube Condenser Evaporator Drier Thermistor Insulation Tube Water Tank...
  • Page 22 2. KM-255BWH (water-cooled) Harvest Water Water Valve Supply Wash Valve Freeze Water Valve Pump Motor Float Switch Drain Refrigerant Circuit Water Circuit Condenser Spray Tube Evaporator Drier Thermistor Insulation Tube Water Tank Expansion Valve Water Regulating Valve Access Valve High Pressure Switch Strainer Suction...

  • Page 23: Wiring Diagram

    B. Wiring Diagram 1. KM-255BAH (air-cooled) * Pressure Switch Cut-out 4± PSIG Cut-in 37± PSIG...
  • Page 24 2. KM-255BWH (water-cooled) Intentionally Left Blank * Pressure Switch Cut-out 384± PSIG Cut-in 84± PSIG...

  • Page 25: Performance Data

    C. Performance Data 1. KM-255BAH (air-cooled) APPROXIMATE ICE PRODUCTION PER 24 HR. lbs./day kg./day APPROXIMATE ELECTRIC CONSUMPTION watts APPROXIMATE WATER CONSUMPTION PER 24 HR. gal./day /day FREEZING CYCLE TIME min. HARVEST CYCLE TIME min. HEAD PRESSURE PSIG kg/cm SUCTION PRESSURE...
  • Page 26 2. KM-255BWH (water-cooled) Intentionally Left Blank Note: . Pressure data is recorded at 5 minutes into freezing cycle. The data not in bold should be used for reference only. . We reserve the right to make changes in specifications and design without prior notice.

  • Page 27: Service Diagnosis

    IV. Service Diagnosis A. 10-Minute Diagnostic Procedure The 0 minute check out procedure is basically a sequence check which can be used at unit start-up or for system diagnosis. Using this check out procedure will allow you to diagnose electrical system and component failures in approximately 0 minutes under normal operating conditions of 70°F or warmer air and 50°F or warmer water temperatures.

  • Page 28: Diagnostic Charts

    of freeze, confirm that the evaporator temperature drops. After 7 minutes in freeze, disconnect the float switch by unplugging the harness from the K5 connector. The unit should switch out of the freeze cycle. Note: At this point, after the initial freeze cycle and every 0th cycle thereafter, LEDs , 3, and  come on, the compressor continues to run, the hot gas valve opens and the fan motor de-energizes.
  • Page 29 Problem Possible Cause [] The icemaker will not start. (continued) f) Transformer g) Wiring to Control Board . Loose connections or h) Thermistor i) Hot Gas Valve j) Water Supply Line k) Water Valves l) Control Board m)Control Switch Remedy 5.
  • Page 30 Problem Possible Cause [] Water continues to a) Float Switch be supplied, and the icemaker will not start. b) Control Board c) Low Water Safety [3] Compressor will a) Magnetic Contactor not start or stops operating. b) Start Capacitor c) Internal Overload Protector Open (check  through 3 to the right and d through f below)
  • Page 31 Problem Possible Cause [5] No water comes from spray tubes. Water pump will not start, or freeze cycle time is e) Control Board too short. (continued) [6] Fan motor will a) Fan Motor not start, or is not operating. b) Control Board [7] All components a) Refrigerant run, but no ice is...

  • Page 32: Evaporator Is Frozen Up

    2. Evaporator is Frozen Up Problem Possible Cause []Freeze cycle time is a) Float Switch too long. b) Water Valves c) Control Board []All ice formed on a) Evaporator evaporator does not b) Water Supply Line fall into bin in harvest cycle.

  • Page 33: Low Ice Production

    Problem Possible Cause [3]Other (continued) g) Water Supply Line h) Water Filter 3. Low Ice Production Problem Possible Cause [] Freeze cycle time is a) See chart .[3] and check dirty air filter or condenser, ambient or water long. temperature, water pressure, condenser water regulating valve (water-cooled model), and refrigerant charge.
  • Page 34 Problem Possible Cause [3] Ice in storage bin a) Drain Line often melts. b) Ice Cube Guides Remedy . Plugged. . Clean. . Out of position. . Place in position. Circulated water falls into bin.

  • Page 35: Removal And Replacement Of Components

    5) Disconnect the vacuum pump, and attach a refrigerant service cylinder to the high- side line. Remember to loosen the connection, and purge the air from the hose. See the nameplate for the required refrigerant charge. Hoshizaki recommends only virgin refrigerant or reclaimed refrigerant which meets ARI Standard No. 700-88 be used.

  • Page 36: Brazing

    8) If necessary, add any remaining charge to the system through the low-side. Use a throttling valve or liquid dispensing device to add the remaining liquid charge through the low-side access port with the unit running. 9) Close the two refrigerant access valves, and disconnect the service manifold hoses. 0) Cap the access valves to prevent a possible leak.

  • Page 37: Removal And Replacement Of Drier

    5) Remove the screws securing the compressor base and the condenser. On water- cooled models, close the water supply line shut-off valve, drain the condenser and then disconnect the water inlet and outlet at the condenser. Carefully slide the refrigeration assembly forward.

  • Page 38: Removal And Replacement Of Expansion Valve

    E. Removal and Replacement of Expansion Valve Sometimes moisture in the refrigeration circuit exceeds the drier capacity and freezes up at the expansion valve. Always install a new drier every time the sealed refrigeration system is opened. Do not replace the drier until after all other repair or replacement has been made.

  • Page 39: Removal And Replacement Of Hot Gas Valve

    F. Removal and Replacement of Hot Gas Valve . Always use a copper tube of the same diameter and length when replacing the hot gas lines; otherwise the performance may be reduced. Always install a new drier every time the sealed refrigeration system is opened.

  • Page 40: Removal And Replacement Of Evaporator

    G. Removal and Replacement of Evaporator Always install a new drier every time the sealed refrigeration system is opened. Do not replace the drier until after all other repairs or replacement have been made. ) Unplug the unit from the electrical outlet. ) Close the water supply line shut-off valve.

  • Page 41: Removal And Replacement Of Water-Cooled Condenser

    8) Place the new condenser in position. 9) Remove the drier (located behind the upper, rear panel), then place the new drier in position. 0) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG. ) Check for leaks using nitrogen gas (40 PSIG) and soap bubbles.

  • Page 42: Adjustment Of Water Regulating Valve - Water-Cooled Model Only

    J. Removal and Replacement of Water Regulating Valve - Water-Cooled Model Only Always install a new drier every time the sealed refrigeration system is opened. Do not replace the drier until after all other repair or replacement has been made. ) Unplug the unit from the electrical outlet.

  • Page 43: Removal And Replacement Of Thermistor

    3) Check that the condenser drain temperature is stable. Top View L. Removal and Replacement of Thermistor . Fragile, handle very carefully. . Always use a recommended sealant (High Thermal Conductive Type), Model KE4560RTV manufactured by SHINETSU SILICONE, Part Code 60Y000-, or Part Code 4A0683-0 equivalent.

  • Page 44: Removal And Replacement Of Fan Motor

    0) Connect the thermistor leads to the K3 connector on the control board. Note: Do not cut the leads of the thermistor while installing it. ) Replace the panels in their correct positions. ) Plug the unit back in. M. Removal and Replacement of Fan Motor Note: When replacing a fan motor with defective winding, it is recommended that a new capacitor be installed.

  • Page 45: Removal And Replacement Of Wash Valve

    O. Removal and Replacement of Wash Valve ) Unplug the unit from the electrical outlet. ) Close the water supply line shut-off valve. 3) Remove the top panel and the insulation panel. 4) Remove the screws securing the valve to the bracket. 5) Disconnect the hoses and the terminals.

  • Page 46: Removal And Replacement Of Spray Tube

    Q. Removal and Replacement of Spray Tube ) Unplug the unit from the electrical outlet. ) Remove the top panel and the insulation panel. 3) Remove the rubber hoses from the spray tube (water supply pipe). 4) Release the clamps, and disconnect the rubber hoses. 5) Remove the spray tube.

  • Page 47: Cleaning And Maintenance Instructions

    1. Cleaning Procedure ) Dilute 5 fl. oz. (48 ml) of recommended cleaner Hoshizaki "Scale Away" or "LIME-A- WAY," (Economics Laboratory, Inc.) with  gallon (3.8 l) of warm water. ) Remove the top panel and the insulation panel.
  • Page 48 It is snapped in place. Remove the drain tube and the frame/pipe from the drain pan. See Fig. 5. 4) Dilute 5 fl. oz. (48 ml) of recommended cleaner Hoshizaki "Scale Away" or "LIME-A-WAY," (Economics Laboratory, Inc.) with  gallon (3.8 l) of warm water.

  • Page 49: Sanitizing Procedure - Following Cleaning Procedure

    2. Sanitizing Procedure - Following Cleaning Procedure ) Dilute approximately 0.5 fl. oz. (5 ml or  tbs) of a 5.5% sodium hypochlorite solution (chlorine bleach) with  gallon (3.8 l) of warm water. Using a chlorine test strip or other method, confirm that you have a concentration of about 00 ppm.

  • Page 50: Preparing The Icemaker For Long Storage

    3. Air Filter (air-cooled model only) The plastic mesh air filter removes dirt and dust from the air, and keeps the condenser from getting clogged. As the filter gets clogged, the icemaker’s performance will be reduced. Check the filter at least twice a month. When it is clogged, use warm water and a neutral cleaner to wash the filter.
  • Page 51 3) Move the control switch to the OFF position. 4) Reconnect the suction hose and harvest water valve hose. 5) Close the potable water supply line drain valve. 6) Remove all ice from the storage bin and clean the bin. 7) Unplug the unit from the electrical outlet.

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Km-255bwh

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