Hoshizaki KM-251BAH Service Manual
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Hoshizaki KM-251BAH Service Manual

Hoshizaki KM-251BAH 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
Model
KM-251BAH
SERVICE MANUAL
1
™
Number: 73140
Issued: 9-15-2006

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Summary of Contents for Hoshizaki KM-251BAH

  • Page 1 Hoshizaki Hoshizaki America, Inc. Self-Contained Crescent Cuber Model KM-251BAH SERVICE MANUAL “A Superior Degree of Reliability” www.hoshizaki.com ™ Number: 73140 Issued: 9-15-2006...
  • 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 IV. Service Diagnosis ......................22 A. 10-Minute Diagnostic Procedure ................22 B. Diagnostic Charts......................23 1. No Ice Production ....................23 2. Evaporator is Frozen Up ..................26 3. Low Ice Production ....................27 4. Abnormal Ice ......................27 5. Other........................28 V.

  • Page 5: Specifications

    I. Specifications A. Icemaker 1. KM-251BAH (air-cooled) AC SUPPLY VOLTAGE 115/60/1 AMPERAGE 9 A ( 5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY MAXIMUM FUSE SIZE APPROXIMATE ICE PRODUCTION Ambient WATER TEMP. (°F) PER 24 HR. Temp.(°F) lbs./day ( kg/day )

  • Page 6: General Information

    II. General Information A. Construction 1. KM-251BAH (air-cooled) Rear View of Icemaker Harvest Water Valve Expansion Freeze Valve Water Valve Wash Valve Evaporator Drier Spray Tube Water Tank, Bin Control & Pump Motor Bin Control Bin Control Switch Detector (back side of tank)

  • Page 7: Sequence Of Operation

    UF/S closes again, FWV closes 3 seconds later. This continues until the tank has refilled the number of times determined by the refill counter (S5 dip switch is factory set - do not adjust). The KM-251BAH refills 9 times. After the final refill, the freeze continues until LF/S opens and terminates the freeze cycle.
  • Page 8 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 1-minute fill if it is open.

  • Page 10: Control Board

    C. Control Board • A HOSHIZAKI exclusive solid-state control is employed in the KM-251BAH Self- Contained Crescent Cuber. • All models are pretested and factory-adjusted. CAUTION 1. Fragile, handle very carefully. 2. A control board contains integrated circuits, which are susceptible to failure due to static discharge.

  • Page 11: Control Board Layout

    1. Control Board Layout Control Products "G" Control Board Connector K2 Transformer Relay LEDs (4) (indicate which relays are energized as listed below) Switch for "C" board LED 1 (green) and "ALPINE" board Compressor (Comp) (service boards only) LED 4 (green) Connector K1 Freeze Water Valve Pins #1 through #10...

  • Page 12: 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 20 minutes to complete.

  • Page 13: F) Led Lights And Audible Alarm Safeties

    f) LED Lights and Audible Alarm Safeties The red LED indicates control voltage (10 to 12V at K2) 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 14: Controls And Adjustments

    3. Controls and Adjustments a) Default Dip Switch Settings The dip switches are factory-adjusted to the following positions: S4 Dip Switch Dip Switch No. KM-251BAH OFF ON OFF ON ON ON OFF OFF OFF S5 Dip Switch (Do Not Adjust) Dip Switch No.

  • Page 15: C) Harvest Timer (S4 Dip Switch 1 & 2)

    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 1-800-233-1940 for recommendations. Keep in mind that setting the harvest timer to a longer setting will decrease 24 hour production.

  • Page 16: 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 17: 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 18: Control Board Replacement

    7. Control Board Replacement 1) Turn off the power supply and disconnect the wiring to the board. 2) 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 19: Technical Information

    III. Technical Information A. Water Circuit and Refrigeration Circuit 1. KM-251BAH (air-cooled) Harvest Water Water Valve Spray Tube Access Valve Condenser Supply Wash Valve High Pressure Switch Evaporator Freeze Drier Water Valve Thermistor Insulation Tube Strainer Hot Gas Valve Pump...

  • Page 20: Wiring Diagram

    B. Wiring Diagram 1. KM-251BAH (air-cooled) * Pressure Switch Cut-out 412± PSIG Cut-in 327±21 PSIG...

  • Page 21: Performance Data

    C. Performance Data 1. KM-251BAH (air-cooled) APPROXIMATE ICE WATER TEMP. (ºF/ºC) AMBIENT TEMP. PRODUCTION PER 24 HR. (ºF/ºC) 50/10 70/21 90/32 70/21 80/27 90/32 lbs./day kg./day 100/38 APPROXIMATE ELECTRIC 70/21 CONSUMPTION 80/27 90/32 100/38 watts APPROXIMATE WATER 70/21 0.35 0.31 0.28...

  • Page 22: Service Diagnosis

    IV. Service Diagnosis A. 10-Minute Diagnostic Procedure The 10 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 10 minutes under normal operating conditions of 70°F or warmer air and 50°F or warmer water temperatures.

  • Page 23: Diagnostic Charts

    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 10th cycle thereafter, LEDs 1, 3, and 2 come on, the compressor continues to run, the hot gas valve opens and the fan motor de-energizes.
  • Page 24 Problem Possible Cause Remedy 5. Fan not operating. 5. See chart 1.[6] 6. Refrigerant line or 6. Clean and replace drier. components plugged. f) Transformer 1. Coil winding opened 1. Replace. or shorted. g) Wiring to Control Board 1. Loose connections or 1.
  • Page 25 Problem Possible Cause Remedy c) Internal Overload 1. Loose terminal. 1. Tighten or replace. Protector Open (check 1 through 3 to the right 2. Voltage. 2. Check and correct. and d through f below) 3. Dirty condenser. 3. Clean. d) Starter 1.

  • Page 26: Evaporator Is Frozen Up

    Problem Possible Cause Remedy b) Control Board 1. Defective. 1. See "II.C.6. Control Board Check Procedure." [7] All components a) Refrigerant 1. Undercharged. 1. Check for leaks and run, but no ice is recharge. produced. 2. Air or moisture 2. Replace drier and trapped.

  • Page 27: Low Ice Production

    Problem Possible Cause Remedy c) Refrigerant 1. Undercharged. 1. Check for leaks and recharge. d) Expansion Valve 1. Bulb out of position or 1. Place in position. loose attachment. 2. Defective. 2. Replace. e) Hot Gas Valve 1. Coil winding opened. 1.

  • Page 28: Other

    5. Other Problem Possible Cause Remedy [1] Icemaker will not stop a) Bin Control 1. See "II.C.4. Bin Control Troubleshooting." when bin is filled with ice. [2] Abnormal noise. a) Pump Motor 1. Bearings worn out. 1. Replace b) Fan Motor 1.

  • Page 29: 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 30: 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. 10) Cap the access valves to prevent a possible leak.

  • Page 31: Removal And Replacement Of Drier

    5) Remove the screws securing the compressor base and the condenser. Carefully slide the refrigeration assembly forward. 6) Remove the terminal cover on the compressor, and disconnect the compressor wiring. 7) Remove the discharge and suction pipes. 8) Remove the hold-down bolts, washers and rubber grommets. 9) Remove the compressor.

  • Page 32: Removal And Replacement Of Expansion Valve

    E. Removal and Replacement of Expansion Valve IMPORTANT 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 33: Removal And Replacement Of Hot Gas Valve

    F. Removal and Replacement of Hot Gas Valve IMPORTANT 1. 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 34: Removal And Replacement Of Evaporator

    G. Removal and Replacement of Evaporator IMPORTANT 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. 1) Turn off the power supply. 2) Close the water supply line shut-off valve.

  • Page 35: Removal And Replacement Of Thermistor

    8) Place the new condenser in position. 9) Remove the drier (located behind the upper, rear panel), then place the new drier in position. 10) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG. 11) Check for leaks using nitrogen gas (140 PSIG) and soap bubbles.

  • Page 36: Removal And Replacement Of Fan Motor

    8) Attach the new thermistor to the suction pipe very carefully to prevent damage to the leads. Secure it using the thermistor holder and recommended foam insulation. 9) Secure the insulation using plastic cable ties. 10) Connect the thermistor leads to the K3 connector on the control board. Note: Do not cut the leads of the thermistor while installing it.

  • Page 37: Removal And Replacement Of Wash Valve

    7) Install the new water valve, and replace the removed parts in the reverse order of which they were removed. Make sure the washers are in place in the fitting nuts. 8) Open the water supply line shut-off valve. 9) Turn on the power supply. 10) Check for leaks.

  • Page 38: Removal And Replacement Of Spray Tube

    8) Install the new pump, then replace the removed parts in the reverse order of which they were removed. 9) Turn on the power supply and check for leaks. 10) Replace the panels in their correct positions. N. Removal and Replacement of Spray Tube 1) Turn off the power supply.

  • Page 39: Cleaning And Maintenance Instructions

    1. Cleaning Procedure 1) Dilute 5 fl. oz. (148 ml) of recommended cleaner Hoshizaki "Scale Away" or "LIME-A- WAY," (Economics Laboratory, Inc.) with 1 gallon (3.8 l) of warm water. 2) Remove the top panel and the insulation panel.
  • Page 40 It is snapped in place. Remove the drain tube and the frame/pipe from the drain pan. See Fig. 5. Bracket (R) 24) Dilute 5 fl. oz. (148 ml) of recommended cleaner Hoshizaki "Scale Away" or "LIME-A-WAY," (Economics Laboratory, Drain Pan Inc.) with 1 gallon (3.8 l) of warm water.

  • Page 41: Sanitizing Procedure - Following Cleaning Procedure

    2. Sanitizing Procedure - Following Cleaning Procedure 1) Dilute approximately 0.5 fl. oz. (15 ml or 1 tbs) of a 5.25% sodium hypochlorite solution (chlorine bleach) with 1 gallon (3.8 l) of warm water. Using a chlorine test strip or other method, confirm that you have a concentration of about 200 ppm.

  • Page 42: 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 43 14) Reconnect the suction hose and harvest water valve hose. 15) Close the potable water supply line drain valve. 16) Remove all ice from the storage bin and clean the bin. 17) Turn off the power supply at the breaker box. 18) Place the panels back in their correct positions.

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