Hoshizaki Hoshizaki America, Inc. Cubelet Icemaker/Dispenser Models DCM-751BAH(-OS) DCM-751BWH(-OS) “A Superior Degree of Reliability” SERVICE MANUAL www.hoshizaki.
WARNING Only qualified service technicians should install and service the appliance. To obtain the name and phone number of your local Hoshizaki Certified Service Representative, visit www.hoshizaki.com. No service should be undertaken until the technician has thoroughly read this Service Manual. Failure to service and maintain the appliance in accordance with this manual will adversely affect safety, performance, component life, and warranty coverage and may result in costly water damage.
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.................................................................................................. 5 I.
B. Important Notes for Component Replacement............................................................. 42 C. Icemaking Unit............................................................................................................. 44 1. Upper Bearing Wear Check ................................................................................... 44 2. Removal and Replacement of Extruding Head....................................................... 45 3. Removal and Replacement of Auger....................
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. NOTICE Indicates a situation which could result in damage to the appliance or property. IMPORTANT Indicates important information about the use and care of the appliance.
WARNING, continued • Children should be properly supervised around the 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. They might catch fire. • Keep the area around the appliance clean. Dirt, dust, or insects in the appliance could cause harm to individuals or damage to the appliance.
I. Construction and Water/Refrigeration Circuit Diagrams A. Construction Spout B Storage Bin 1.
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B. Water/Refrigeration Circuit Diagrams 1.
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Maximum 90 seconds 1. Fill Cycle 5 sec. 5 minutes To bypass, press the "SERVICE" button after GM starts. 2. Ice Purge Cycle 12 (S1 dip switch 4) 3. 1-in-12 Drain Cycle & Restart (optional) 2. Bin Control Shutdown & Restart WV energized FT starts (90 sec.) 6 to 10 sec. 2. Ice Purge Cycle Comp de-energized FM de-energized GM energized GMPR energized Ice level lowered 3. Icemaker Restart UFS open LFS open FT starts (90 sec.
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. Use extreme caution and exercise safe electrical practices. • Moving parts (e.g., fan blade) can crush and cut. Keep hands clear. • CHOKING HAZARD: Ensure all components, fasteners, and thumbscrews are securely in place after the appliance is serviced.
7) Startup–"POWER OK" LED is on: Move the power switch to the "ON" position, then move the control switch to the "ICE" position. CB "POWER OK" LED is on. "POWER OK" LED Diagnosis: Check that CB "POWER" LED is on. If not, check for proper power supply voltage (115VAC) input to CT. If 115VAC is not present, check the breaker, power switch, and safety switch. Next, check that the power protect relay is de‑energized and contacts between terminals #6 (BR) and #2 (BK) are closed.
9) Ice Purge Cycle–"GM" LED is on. UFS closes (WV de-energizes) and "WTRIN" LED turns off. 5‑sec. GM delay timer and 30-min. FZT start. 5-sec. GM delay timer terminates. GM and GMPR energize. 5‑min. IPT starts. GM runs for 5 min. to clear any ice from the evaporator. Diagnosis: If "GM" LED is off, check that UFS closed. If UFS is closed and "GM" LED does not turn on, replace CB. If "GM" LED is on and GM is off, confirm 115VAC at CB K1 connector pin #2 (BR) to neutral (W).
12) Drain Cycle–"FLUSH" (drain) LED is on. IMPORTANT! Drain valve will not energize unless the safety switch is engaged. The appliance is factory set to drain the evaporator and reservoir once every hour for 2 seconds. A manual drain is provided when cleaning the appliance by moving the control switch from the "ICE" position to the "DRAIN" position. A 1-in-12 drain cycle is also available. For further details, see "III.C. 3. Drain Frequency Control (S1 dip switch 4).
13) Shutdown–Bin fills and ice engages BC actuator paddle. 6 to 10-sec. shutdown sequence begins. Diagnosis: Check that BC actuator paddle is activated and not sticking. Check BC proximity switch continuity to confirm BC proximity switch is open. If BC actuator is engaged and BC proximity switch is closed, replace BC proximity switch. If BC proximity switch is open and Comp, FM, and GM do not de‑energize, replace CB. See "II.C. Control Board Check.
C. Control Board Check Before replacing a 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. Before proceeding, check for proper voltage per appliance nameplate. Check that the 24VAC 1A fuse and 115VAC 3A GM fuse are good. • Check the S1 dip switch settings to assure that they are in the factory default position. For factory default settings, see "III.C.1. Default Dip Switch Settings.
2) 5VDC Output Checks: There are seven 5VDC circuits on the appliance, "DRAIN" position through control switch, high-pressure switch (HPS), gear motor protect relay (GMPR), bin control (BC), float switch (FS), ice dispense switch, and water dispense switch. • 5VDC CB K9 Connector: See Fig. 1.
c. Gear Motor Protect Relay (GMPR) CB K9 connector pins #5 (W/O) and #6 (W/O): When GMPR is de‑energized, GMPR terminals #3 and #5 are open and 5VDC is present between CB K9 connector pin #5 (W/O) and CB red K4 connector pin closest to CB black K3 connector. If 5VDC is not present, replace CB. When GMPR is energized, GMPR terminals #3 and #5 are closed and 5VDC is present between CB K9 connector pin #5 (W/O) and pin #6 (W/O) to CB red K4 connector pin closest to CB black K3 connector.
• 5VDC CB K7 Connector: See Figs. 3, 4, 5, and 6. • Water Dispense Switch/Water Dispense Sensor f. Push Button Model–"WTRDP" LED is on: Before engaging the water dispense switch, check for the correct VDC from the locations given in the "Disengaged" column in the table below. If the VDC is different than in the table, replace CB. If the VDC is correct, engage the water dispense switch. "WTRDP" LED turns on. If not, confirm that the water dispense signal VDC matches the "Engaged" column in the table below.
g. Opti-Serve Model–"WTRDP" LED is on: Before engaging the water dispense Opti‑Serve sensor, check for the correct VDC from the locations given in the "Disengaged" column in the table below. If the VDC is different than in the table, replace CB. If the VDC is correct, engage the Opti‑Serve sensor. "WTRDP" LED turns on. If not, confirm that the water dispense signal VDC matches the "Engaged" column in the table below. If not, replace the Opti-Serve sensor.
• Ice Dispense Switch/Ice Dispense Sensor: h. Push Button Model–"ICE" and "AM" LEDs are on: Before engaging the ice dispense switch, check for the correct VDC from the locations given in the "Disengaged" column in the table below. If the VDC is different than in the table, replace CB. If the VDC is correct, engage the ice dispense switch. "ICE" LED turns on. If not, confirm position of dispense mode switch and that the portion and continuous VDC matches the "Engaged" column in the table below.
i. Opti-Serve Model–"ICE" and "AM" LEDs are on: Before engaging the ice dispense Opti-Serve sensor, check for the correct VDC from the locations given in the "Disengaged" column in the table below. If the VDC is different than in the table, replace CB. If the VDC reading is correct, engage the Opti-Serve sensor. "ICE" LED turns on. If not, confirm position of dispense mode switch and that the portion and continuous VDC matches the "Engaged" column in the table below.
3) Fill Cycle–"WTRIN" LED is on: "WTRIN" LED turns on only when the reservoir water level is low enough to open LFS. Diagnosis: Confirm LFS is open. If "WTRIN" LED is off and LFS is open and the control switch is in the "ICE" position (open), replace CB. If "WTRIN" LED is on and water is not filling the reservoir, check for 24VAC at CB K2 connector between pin #8 (W/BR) and a neutral (LBU).
D. Bin Control Check When the actuator paddle is not engaged, BC is closed and the appliance produces ice. S1 dip switch 7 must be in the "OFF" position. When ice fills the chute and engages the actuator paddle, BC opens and CB shuts down the appliance within 10 seconds. NOTICE! Do not place S1 dip switch 7 in the "ON" position. For details, see "III.C.1. Default Dip Switch Settings." 1) Remove the front and top panels. 2) Remove the storage bin cover.
E. Float Switch Check and Cleaning 1. Float Switch Check 1) Remove the front panel and move the control switch to the "DRAIN" position. 2) Press and hold the safety switch to start draining the appliance. IMPORTANT! Appliance will not start unless the safety switch is engaged. 3) Allow the water to drain from the reservoir, then release the safety switch. Move the control switch to the "ICE" position. 4) Remove the FS molex plug from the control box and check continuity across FS wires.
Red (R) (upper float switch) Black (BK) (common) Dark Blue (DBU) (lower float switch) Magnet (towards top) Upper Float (blue) Spring Retainer Clip Magnet (towards top) Lower Float (white) Plastic Retainer Clip Fig. 7 Float Switch Assembly Reservoir Cover Reservoir Fig.
F. Diagnostic Tables Before consulting the diagnostic tables, check for correct installation, proper voltage per appliance nameplate, and adequate water pressure (10 to 113 PSIG). Check control board using the steps in "II.C. Control Board Check." 1. No Ice Production No Ice Production - Possible Cause Startup 1. Power Supply a) Off, blown fuse, or tripped breaker. b) Loose connection. c) Not within specifications. 2. Power Switch a) "OFF" position. b) Defective. 3.
No Ice Production - Possible Cause Freeze Cycle 1. Control Board a) Defective. 2. Start Relay a) Defective. 3. Start Capacitor or Run Capacitor a) Defective. 4. Compressor a) External protector. b) Motor winding. c) Mechanical failure. 5. High-Pressure Switch Activates a) Dirty condenser. b) Ambient temperature too warm. c) Fan motor not operating. d) Refrigerant overcharged. e) Defective. f) Refrigerant lines or components restricted. 6. Fan Motor a) Capacitor defective. b) Motor winding.
2. Ice/Water Dispensing Ice Dispense-Push Button 1. Power Supply a) Off, blown fuse, or tripped breaker. 2. Control Board a) Ice dispense switch circuit open or no power (5VDC) from control board. b) No power (115VAC) to ice dispense solenoid, ice dispense motor, or agitating motor. 3. Ice Dispense Switch a) Defective. 4. Dispense Mode Switch a) Defective. 5. Ice Dispense Motor a) Motor windings. 6. Ice Dispense Solenoid a) Defective or loose connection. 7. Shutter Assembly a) Defective. 8.
III. Controls and Adjustments • A Hoshizaki exclusive control board is employed in the DCM-751 series. • All models are pretested and factory set. • For a control board check procedure, see "II.C. Control Board Check." NOTICE • Fragile, handle very carefully. • The control board contains integrated circuits, which are susceptible to failure due to static discharge. It is especially important to touch the metal part of the appliance when handling or replacing the control board.
A. Control Board Layout 1.
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B. LED Lights and Audible Alarm Safeties The "POWER" LED indicates proper control voltage and will remain on unless a control voltage problem occurs. For further details, see "II. Sequence of Operation and Service Diagnosis." Sequence Step Fill Cycle LED WTRIN Icemaking Sequence Energized Components Min. WV - Max. On until UFS closes. Alarm sounds after 90 sec. 5 min. *On until UFS closes. Alarm sounds after 90 sec. Ice Purge Cycle GM GM, FM 5 min.
C. 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 Hoshizaki Technical Support at 1-800-233-1940. 1. Default Dip Switch Settings The S1 dip switch settings are factory-set to the following positions: Dip Switch No.
4. Continuous Dispensing Timer (S1 dip switch 5 & 6) The dispense mode switch must be in the "CONTINUOUS" position for this setting to apply. The factory setting allows ice to be dispensed continuously on push button models and for a maximum of 60 sec. on Opti-Serve models. S1 Dip Switch Setting Dispense Time No. 5 No. 6 OFF OFF No Limit ON OFF 20 Seconds OFF ON 60 Seconds ON ON No Limit 5.
D. Power Switch, Control Switch, and Dispense Mode Switch The power switch, control switch, and dispense mode switch are used to control the operation of the appliance. 1. Power Switch WARNING! The power switch does not turn off all power supply to the unit. 115VAC power supply is present on control board K1 connector pin #2 (BR) and control board X1 relay (BR) when the power switch is in the "OFF" position. Fig. 10 2. Control Switch The control switch has 3 positions, "ICE," "OFF," and "DRAIN." See Fig.
3. Dispense Mode Switch The dispense mode switch has 2 positions, "CONTINUOUS" and "PORTION." See Fig. 12. a) CONTINUOUS When the dispense mode switch is in the "CONTINUOUS" position, ice dispenses as follows: Push Button: Ice dispenses continuously with button engaged. OS: Ice dispenses for a maximum of 60 seconds per activation. b) PORTION CONTROL When the dispense mode switch is in the "PORTION" position, ice dispenses for the ICE amount of time determined by the ice dispense time setting.
IV. Removal and Replacement of Components 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. • Move the control switch and the power switch to the "OFF" position and turn off the power supply before servicing. Lockout/Tagout to prevent the power supply from being turned back on inadvertently.
1. Refrigerant Recovery The appliance is provided with refrigerant access valves. Using proper refrigerant practices, recover the refrigerant from the access valves and store it in an approved container. Do not discharge the refrigerant into the atmosphere. 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.
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. See the nameplate inside the appliance for the required refrigerant charge. Hoshizaki recommends only virgin refrigerant or reclaimed refrigerant which meets ARI Standard 700 (latest edition) be used. 6) A liquid charge is required for charging an R-404A system (to prevent fractionation).
Evaporator Assembly Spout A Evaporator Assembly Spout B Power Switch Cutter Extruding Head and Upper Bearing Auger 4A1038-014 CONTROL ICE OFF DISPENSE MODE PORTION DRAIN Safety Switch Evaporator Heater CONTINUOUS Washer Allen Head Cap Screw (with seal) Not reusable Evaporator Allen Head Cap Screw with Washer Mechanical Seal "O" Ring Housing and Lower Bearing Hex Head Bolt with Washer Spline Coupling Fig.
C. Icemaking Unit 1. Upper Bearing Wear Check To ensure that the bearing inside the extruding head does not exceed the wear tolerance of .02", follow the instructions below. See Fig. 15. 1) Move the control switch to the "OFF" position, then turn off the power supply. Remove the front and top panels, then move the power switch to the "OFF" position. 2) Remove the storage bin cover. Remove spout B, then remove spout A and the cutter. See Fig. 14. .
2. Removal and Replacement of Extruding Head 1) Move the control switch to the "DRAIN" position and drain all of the water from the evaporator. 2) After the water has stopped draining, move the control switch to the "OFF" position, then turn off the power supply. Remove the front and top panels, then move the power switch to the "OFF" position. 3) Remove the storage bin cover. Remove spout B, then remove spout A and the cutter. See Fig. 14. 4) Remove the apron panel, then remove the left side panel.
4. Removal and Replacement of Evaporator NOTICE • 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. • When brazing, protect the drier by using a wet cloth to prevent the drier from overheating. Do not allow the drier to exceed 250°F (121°C).
16) Evacuate the system, and charge it with refrigerant. See the nameplate for the required refrigerant charge. 17) Install the new auger assembly with the upper part of the mechanical seal attached. Secure the auger assembly using new allen head cap screws. 18) Replace the evaporator bracket and reconnect the water hoses. 19) Replace spout A, spout B, and the storage bin cover in their correct positions. 20) Move the power switch to the "ON" position, then replace the panels in their correct positions.
13) Install the lower part of the mechanical seal on the lower housing. 14) Lower the evaporator down and secure it to the lower housing. 15) Install the auger assembly with the upper part of the mechanical seal attached. Secure the auger assembly using new allen head cap screws. 16) Replace the evaporator bracket in its correct position. 17) Replace spout A, spout B, and the front cover of the storage bin in their correct positions.
D. Dispense Components 1. Dispense Auger and Agitator 1) Move the control switch to the "OFF" position, then turn off the power supply. Remove the front and top panels, then move the power switch to the "OFF" position. 2) Remove the storage bin cover. 3) Remove the thumbscrews from the vertical plane, then loosen the thumbscrews from the horizontal plane of the motor bracket. Slide the motor back. Note: Hold the dispense auger/agitator to prevent it from dropping when sliding back the motor. See Fig. 16.
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. • Move the control switch and power switch to the "OFF" positions, then turn off the power supply before servicing. Lockout/Tagout to prevent the power supply from being turned back on inadvertently.
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. When the appliance 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 appliance for extended time or in sub-freezing temperatures, follow the instructions below. 1.
2. On water-cooled model only, remove the water from the water-cooled condenser: 1) Make sure the control switch and the power switch are in the "OFF" position and that the power supply is off. Remove the top, apron, and left side panels. 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. 3) Open the condenser water supply line drain valve.
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.
VIII. Technical Information A. Specification Sheets 1. DCM-751BAH AC SUPPLY VOLTAGE COMPRESSOR GEAR MOTOR FAN MOTOR AGITATING MOTOR DISPENSING MOTOR OTHER MAXIMUM FUSE SIZE MAX. HACR BREAKER (USA ONLY) MAX. CIRC. BREAKER (CANADA ONLY) MINIMUM CIRCUIT AMPACITY APPROXIMATE ICE PRODUCTION PER 24 HR. lbs./day (kg/day) Reference without *marks SHAPE OF ICE ICE HARDNESS FACTOR APPROXIMATE STORAGE CAPACITY ELECTRIC & WATER CONSUMPTION ELECTRIC W (kWH/100 lbs.) POTABLE WATER gal./24HR (gal./100 lbs.
2. DCM-751BAH-OS AC SUPPLY VOLTAGE COMPRESSOR GEAR MOTOR FAN MOTOR AGITATING MOTOR DISPENSING MOTOR OTHER MAXIMUM FUSE SIZE MAX. HACR BREAKER (USA ONLY) MAX. CIRC. BREAKER (CANADA ONLY) MINIMUM CIRCUIT AMPACITY APPROXIMATE ICE PRODUCTION PER 24 HR. lbs./day (kg/day) Reference without *marks SHAPE OF ICE ICE HARDNESS FACTOR APPROXIMATE STORAGE CAPACITY ELECTRIC & WATER CONSUMPTION ELECTRIC W (kWH/100 lbs.) POTABLE WATER gal./24HR (gal./100 lbs.
3. DCM-751BWH AC SUPPLY VOLTAGE COMPRESSOR GEAR MOTOR AGITATING MOTOR DISPENSING MOTOR OTHER MAXIMUM FUSE SIZE MAX. HACR BREAKER (USA ONLY) MAX. CIRC. BREAKER (CANADA ONLY) MINIMUM CIRCUIT AMPACITY APPROXIMATE ICE PRODUCTION PER 24 HR. lb./day (kg/day) Reference without *marks SHAPE OF ICE ICE HARDNESS FACTOR APPROXIMATE STORAGE CAPACITY ELECTRIC & WATER CONSUMPTION ELECTRIC W (kWH/100 lb.) POTABLE WATER WATER-COOLED CONDENSER gal./24HR (gal./100 lb.
4. DCM-751BWH-OS AC SUPPLY VOLTAGE COMPRESSOR GEAR MOTOR AGITATING MOTOR DISPENSING MOTOR OTHER MAXIMUM FUSE SIZE MAX. HACR BREAKER (USA ONLY) MAX. CIRC. BREAKER (CANADA ONLY) MINIMUM CIRCUIT AMPACITY APPROXIMATE ICE PRODUCTION PER 24 HR. lb./day (kg/day) Reference without *marks SHAPE OF ICE ICE HARDNESS FACTOR APPROXIMATE STORAGE CAPACITY ELECTRIC & WATER CONSUMPTION ELECTRIC W (kWH/100 lb.) POTABLE WATER WATER-COOLED CONDENSER gal./24HR (gal./100 lb.
B. Performance Data 1. DCM-751BAH(-OS) APPROXIMATE Ambient ICE PRODUCTION Temp. (°F) PER 24 HR. Water Temp. (°F) 50 70 90 70 801 363 757 343 725 329 80 695 315 666 302 639 290 90 612 278 583 265 562 255 lb.
2. DCM-751BWH(-OS) APPROXIMATE Ambient ICE PRODUCTION Temp. (°F) PER 24 HR. Water Temp. (°F) 50 70 90 70 800 363 779 353 758 344 80 738 335 719 326 700 317 90 681 309 685 311 646 293 lb./day kg/day 100 629 285 612 278 563 255 APPROXIMATE ELECTRIC 70 1274 -- 1275 -- 1276 -- CONSUMPTION 80 1277 -- 1278 -- 1279 -- 90 1280 -- 1281 -- 1284 -- watts 100 1286 -- 1289 -- 1291 -- APPROXIMATE WATER 70 474 1.79 513 1.94 686 2.
C. Wiring Diagrams 1.
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