Hoshizaki KMS-750MLH Service Manual
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Hoshizaki KMS-750MLH Service Manual

Hoshizaki KMS-750MLH Service Manual

Modular crescent cuber serenity series
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Hoshizaki
Hoshizaki America, Inc.
"A Superior Degree
of Reliability"
www.hoshizaki.com
Modular Crescent Cuber
Serenity Series
Model
KMS-750MLH
Including
Condensing Unit Model SRK-7H
SERVICE MANUAL
™
Number: 73152
Issued: 8-13-2007

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Summary of Contents for Hoshizaki KMS-750MLH

  • Page 1 Hoshizaki America, Inc. “A Superior Degree of Reliability” www.hoshizaki.com Modular Crescent Cuber Serenity Series Model KMS-750MLH Including Condensing Unit Model SRK-7H SERVICE MANUAL ™ Number: 73152 Issued: 8-13-2007...
  • Page 2 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 for assistance. HOSHIZAKI AMERICA, INC.

  • Page 3: Table Of Contents

    This manual should be made available to the technician prior to service or maintenance. I. Specifications ... 5 A. Icemaker ... 5 1. KMS-750MLH – SRK-7H ... 5 B. Condensing Unit ... 6 1. SRK-7H ... 6 II. General Information ... 7 A.
  • Page 4 III. Technical Information ... 4 A. Water Circuit and Refrigeration Circuit ... 4 B. Wiring Diagrams ... 5 1. KMS-750MLH – SRK-7H ... 5 C. Performance Data ... 6 1. KMS-750MLH – SRK-7H ... 6 IV. Service Diagnosis ... 7 A.

  • Page 5: Specifications

    1636 ( 5.1 ) 109 ( 15.6 ) 245 ( 31.8 ) KMS-750MLH : 30" x 24" x 28" ( 762 x 610 x 711 mm ) SRK-7H : 50" x 17" x 28" ( 1270 x 432 x 711 mm ) KMS-750MLH : Stainless steel;...

  • Page 6: Condensing Unit

    B. Condensing Unit 1. SRK-7H AC SUPPLY VOLTAGE AMPERAGE MINIMUM CIRCUIT AMPACITY MAXIMUM FUSE SIZE EXTERIOR DIMENSIONS ( WxDxH ) DIMENSIONS INCLUDING LEGS ( WxDxH ) EXTERIOR FINISH WEIGHT CONNECTIONS - ELECTRIC - REFRIGERANT COMPRESSOR CONDENSER COMPRESSOR PROTECTION FAN MOTOR PROTECTION REFRIGERANT CIRCUIT PROTECTION REFRIGERANT CONTROL REFRIGERANT CHARGE...

  • Page 7: General Information

    II. General Information A. Construction 1. Icemaker Bin Control Switch Control Switch Fill Water Valve Service Switch Spray Tubes Hot Gas Valve Float Switch Drain Water Valve Liquid Line Valve Service Valve (High Side) Drier Wash Valve Thermistor Service Valve (Low Side) Harvest Water Valve Control Box...

  • Page 8: Condensing Unit

    2. Condensing Unit Liquid Line Valve Headmaster (C.P. Regulator) Access Valve Junction Box Receiver Tank Accumulator Hot Gas Valve Compressor Thermostat (Discharge Pipe) Shut-off Valve (Low Side) Condenser Fan Motor and Fan Blade Shut-off Valve (High Side)

  • Page 9: Sequence Of Operation

    LF/S opens and terminates ice production, provided the 5 minute freeze timer has expired. Note: Because the KMS-750MLH does not require a refill, the UF/S is not used. 4. Pump-Out Cycle LEDs 1, 4, 3, and  are on. With dip switches 5 and 6 in the factory default postion, the 1st pump out occurs after the 11th freeze cycle and every 10th cycle thereafter.

  • Page 10: Normal Harvest Cycle

    5. Normal Harvest Cycle LEDs 1, 4 and  are on. Comp, FMR and HGVs remain energized. HWV and X1 relay energize, PM stops. As the evaporator warms, the thermistor reaches 48°F (9°C). The control board then receives the thermistor's 3.9 kΩ signal and starts the harvest timer. When the harvest timer completes its count down, the harvest cycle is complete.

  • Page 12: Control Board

    C. Control Board • A HOSHIZAKI exclusive solid-state control is employed in the KMS-750MLH Modular Crescent Cuber. • All models are pretested and factory-adjusted. 1. 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 Alarm Reset Button Bin Control Switch Closed LED (green) Bin Control Switch Open LED (yellow) Part Number Alarm Buzzer LED  (green) Hot Gas Valves (HGV) Power LED (red) (lights when power is supplied to the board) LED 3 (green)

  • 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 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. The green LEDs 1 through 4 energize and sequence from initial startup as listed in the table below.

  • Page 16: Controls And Adjustments

    The harvest timer starts counting when the thermistor reads 48°F (9°C) at the evaporator outlet. 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 1-800-33-1940 for recommendations. Keep in mind that setting the harvest timer to a longer setting will decrease 4 hour production.

  • Page 17: C) Pump-Out Timer (S4 Dip Switch 3 & 4)

    c) Pump-Out Timer (S4 dip switch 3 & 4) Leave in the factory default position; otherwise, the harvest water valve will not open during pump out. During cycles when a pump out is called for, the pump motor drains the water tank for the time determined by the pump-out timer.

  • Page 18: F) Freeze Timer (S4 Dip Switch 9 & 10)

    f) Freeze Timer (S4 dip switch 9 & 10) Adjust to proper specification, or the unit may not operate correctly. The freeze timer setting determines the maximum allowed freeze time to prevent possible freeze-up issues. Upon termination of freeze timer, the control board initiates the harvest cycle.

  • Page 19: Control Board Replacement

    5. Control Board Replacement The application switch located between relay X3 & X4 must be set to match the original board application. Place this switch in the ALP position. The dip switches should be adjusted to the factory default settings as outlined in this manual. S4 dip switch #8 must remain in the "OFF"...

  • Page 20: Float Switch

    The float has  switches within the float switch. The lower switch (black and blue wires) is used for low water safety protection and termination of the freeze cycle. The upper switch (black and red wires) is not used on the KMS-750MLH. 2. Cleaning Depending on local water conditions, scale may build up on the float, float switch shaft and inside the housing.
  • Page 21 Black - Common Blue - Lower Switch Red - Upper Switch Mechanical Lock Housing Upper Switch (Not used on the KMS-750MLH) Lower Switch Retainer Clip Float Fig. 1 Float Switch...

  • Page 22: Bin Control

    F. 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 red K4 connector on the control board. When the bin control is calling for ice (proximity switch closed;...

  • Page 23: Switches

    G. Switches Two control switches are used to control operation in KMS Series Modular Crescent Cubers. These switches are referred to as the "control switch" and the "service switch" and are located on the control box. 1. Control Switch The control switch has three positions: "OFF" for power off; "ICE" for icemaking, and "SERVICE"...

  • Page 24: Technical Information

    III. Technical Information A. Water Circuit and Refrigeration Circuit...

  • Page 25: Wiring Diagrams

    B. Wiring Diagrams 1. KMS-750MLH – SRK-7H...

  • Page 26: Performance Data

    C. Performance Data 1. KMS-750MLH – SRK-7H APPROXIMATE ICE AMBIENT TEMP. 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...

  • Page 27: 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 (1°C) or warmer air and 50°F (10°C) or warmer water temperatures.
  • Page 28 5) Freeze Cycle – LED 1 is on. The compressor, fan motors and pump motor remain energized. The liquid line valves energize and the hot gas valves de-energize (also de-energizing the X1 relay). The unit is held in freeze by a 5 minute short cycle protection timer.

  • Page 29: Diagnostic Charts

    B. Diagnostic Charts 1. No Ice Production Problem Possible Cause [1] The icemaker will not a) Power Supply to start. Condensing Unit b) High Pressure Control 1. Tripped or bad c) Thermostat (Condens- ing Unit High Tempera- ture Safety) d) Wire Harness Terminal Block: Condensing Unit and Icemaker e) Fuse (Icemaker fused...
  • Page 30 Problem Possible Cause [1] The icemaker will not m) Control Board start. (continuted) n) Control Board in Alarm 1. Audible alarm. [] Water continues to a) Float Switch be supplied, and the icemaker will not start. b) Control Board [3] Compressor will a) Control Switch not start or stops operating.
  • Page 31 Problem Possible Cause [5] No water comes from a) Water Supply Line spray tubes. Water pump will not start, or freeze cycle time is b) Fill or Harvest Water too short. Valve c) Water System d) Pump Motor e) Control Board [6] Fan motor will a) Fan Motor not start, or is not...

  • Page 32: Evaporator Is Frozen Up

    2. Evaporator is Frozen Up Problem Possible Cause [1]Freeze cycle time is a) Float Switch too long. b) Fill or Harvest Water Valve 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

    3. Low Ice Production Problem Possible Cause [1] Freeze cycle time is a) See chart 1.[3]. Also check dirty condenser coil, ambient temperature and long. refrigerant charge. b) See chart .[1] and check float switch, water valves and control board. [] Harvest cycle time is a) See chart .[] and check evaporator, water supply line, harvest water valve, long.

  • Page 34: Removal And Replacement Of Components

    V. Removal and Replacement of Components 1.Ensure all components, fasteners and thumbscrews are securely in place after the equipment is serviced. . The Polyol Ester (POE) oils used in R-404A units can absorb moisture quickly. Therefore it is important to prevent moisture from entering the system when replacing or servicing parts.

  • Page 35: Evacuation And Recharge [R-404A]

    Remember to loosen the connection and purge the air from the hose. For the required refrigerant charge, see the charge label inside the front panel on the icemaker or on the nameplate on the condensing unit. Hoshizaki recommends only virgin refrigerant or reclaimed refrigerant which meets ARI Standard No. 700-88 be used.

  • Page 36: Condensing Unit

    B. Condensing Unit 1. Removal and Replacement of Compressor 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. Install the new drier with the arrow on the drier in the direction of the refrigerant flow.

  • Page 37: Removal And Replacement Of Condenser

    2. Removal and Replacement of Condenser 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. Install the new drier with the arrow on the drier in the direction of the refrigerant flow.

  • Page 38: Removal And Replacement Of Headmaster (Condensing Pressure Regulator - C

    5) Disconnect the valve body. Remove the strainer and check valve. 6) Place the new valve and strainer in position. 7) Remove the drier, then place the new drier in position (located in the icemaker). Install the new drier with the arrow on the drier in the direction of the refrigerant flow. 8) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.

  • Page 39: Removal And Replacement Of Fan Motor

    8) Braze all fittings with nitrogen gas flowing at a pressure of 3 to 4 PSIG. Always protect the headmaster body by using a damp cloth to prevent it from overheating. Do not braze with the headmaster body exceeding 50°F (11°C). 9) Check for leaks using nitrogen gas (140 PSIG) and soap bubbles.

  • Page 40: Removal And Replacement Of Expansion Valve

    4) Remove the spray tubes and the insulation at the "U" shaped notch where the refrigeration tubing passes through the molded chassis. 5) Disconnect the evaporator tubing. 6) Remove the pop rivets securing the evaporator, then lift out the evaporator. 7) Install the new evaporator.

  • Page 41: Removal And Replacement Of Hot Gas Valve And Liquid Line Valve

    7) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG. 1. Do not heat the wall of the machine. Place a steel barrier for protection. . Always protect the valve body by using a damp cloth to prevent the valve from overheating.

  • Page 42: Removal And Replacement Of Pump Motor

    Always protect the valve body by using a damp cloth to prevent the valve from overheating. Do not braze with the valve body exceeding 50°F (11°C). 9) Check for leaks using nitrogen gas (140 PSIG) and soap bubbles. 10) Evacuate the system, and charge it with refrigerant. See the nameplate on the condensing unit for the required refrigerant charge.

  • Page 43: Removal And Replacement Of Thermistor

    7) Remove the bracket and water valve from the unit. 8) Install the new water valve and replace the removed parts in the reverse order of which they were removed. 9) Close the water supply line drain valve. 10) Open the water supply line shut-off valve. 11) Turn on the power supply and check for leaks.

  • Page 44: Cleaning And Maintenance Instructions

    1. Cleaning Procedure 1) Dilute  fl. oz. (650 ml) of the recommended cleaner Hoshizaki "Scale Away" or "LIME-A-WAY" (Economics Laboratory, Inc.) with 4 gal. (15 l) of warm water. ) Remove all ice from the evaporator and the dispenser or storage bin unit.
  • Page 45 9) Remove the insulation panel by removing the thumbscrews, then pour the cleaning solution into the water tank. 10) Move the service switch to the "WASH" position. 11) Replace the insulation panel and the front panel in their correct positions. 1) Turn on the power supply and start the washing process.

  • Page 46: Sanitizing Procedure - Following Cleaning Procedure

    2. Sanitizing Procedure - Following Cleaning Procedure 1) Dilute a 5.5% sodium hypochlorite solution (chlorine bleach) with water. (Add  fl. oz. (60 ml) of sanitizer to 4 gal. (15 l) of water). ) Remove the insulation panel, if it is in its normal position. 3) Pour the sanitizing solution into the water tank.

  • Page 47: Preparing The Icemaker For Long Storage

    C. Preparing the Icemaker for Long Storage When the icemaker is not used for two or three days under normal conditions, it is sufficient to only move the control switch to the "OFF" position. When storing the icemaker for extended time or in sub-freezing temperatures, turn the water off and drain out all water from the water lines and remove the ice from the dispenser or storage bin.
  • Page 48 16) Disconnect the float switch vent hose from the drain hose tee. Move the service switch to the "DRAIN" position and the control switch to the "SERVICE" position. 17) From the tee on the drain hose, blow the drain water valve out using compressed air or carbon dioxide.

This manual is also suitable for:

Srk-7hSerenity series

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