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Hoshizaki KMD-450MAH, Service Manual

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Hoshizaki KMD-450MAH Service Manual Download Page 15

15

C. Control Board

• A Hoshizaki exclusive solid-state control board is employed in KMD-450MAH and 

KMD-450MWH Modular Crescent Cubers.

• All models are pretested and factory set.
• For a control board check procedure, see "IV.B. Control Board Check."

CAUTION

1. The control board is fragile; handle very carefully.
2. 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 unit before handling or replacing the control board.

3. Do not touch the electronic devices on the control board or the back of the 

control board.

4. Do not change wiring and connections.
5. Always replace the whole control board assembly if it goes bad.
6. Do not short out power supply to test for voltage.

Summary of Contents for KMD-450MAH

Page 1: ...Hoshizaki A Superior Degree of Reliability www hoshizaki com Models KMD 450MAH KMD 450MWH Modular Crescent Cuber Hoshizaki America Inc SERVICE MANUAL Number 73161 Issued 9 3 2009...

Page 2: ...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...

Page 3: ...Lights and Audible Alarm Safeties 18 3 Controls and Adjustments 19 a Default Dip Switch Settings 19 b Harvest Timer S1 dip switch 1 2 20 c Pump Out Timer S1 dip switch 3 4 20 d Pump Out Frequency Cont...

Page 4: ...Bin Control Check and Cleaning 37 1 Bin Control Check 37 2 Bin Control Cleaning 37 D Float Switch Check and Cleaning 38 1 Float Switch Check 38 2 Float Switch Cleaning 39 E Thermistor Check 41 F Diag...

Page 5: ...of Fan Motor air cooled and remote air cooled models 61 L Removal and Replacement of Water Valves 61 M Removal and Replacement of Pump Motor 62 N Removal and Replacement of Control Board 62 VI Cleani...

Page 6: ...ock serious injury or fire follow basic precautions including the following Electrical connection must be hard wired and must meet national state and local electrical code requirements Failure to meet...

Page 7: ...eel Galvanized Steel Rear WEIGHT Net 130 lbs 59 kg Shipping 170 lbs 77 kg CONNECTIONS ELECTRIC Permanent Connection WATER SUPPLY Inlet 1 2 FPT DRAIN Outlet 3 4 FPT 5 8 OD Tube CUBE CONTROL SYSTEM Floa...

Page 8: ...d Steel Rear WEIGHT Net 130 lbs 59 kg Shipping 170 lbs 77 kg CONNECTIONS ELECTRIC Permanent Connection WATER SUPPLY Inlet 1 2 FPT Cond Inlet 1 2 FPT DRAIN Outlet 3 4 FPT Cond Outlet 3 8 FPT 5 8 OD Tub...

Page 9: ...Tube Water Supply Inlet Junction Box Condenser Control Box Drier Hot Gas Valve Compressor Float Switch Pump Motor Bin Control Control Switch Expansion Valve Inlet Water Valve Wash Valve Condenser Fan...

Page 10: ...unction Box Condenser Control Box Drier Hot Gas Valve Compressor Float Switch Pump Motor Bin Control Control Switch Expansion Valve Inlet Water Valve Wash Valve Water Regulator Drain Valve Water Tank...

Page 11: ...0 seconds of harvest When the harvest timer expires the harvest cycle is complete CB checks the position of F S and proceeds to the freeze cycle if it is closed or calls for a 1 minute fill cycle if i...

Page 12: ...e first pump out occurs after the 1st freeze cycle then every 10th cycle thereafter The pump out frequency is factory set and generally no adjustment is required However if the icemaker needs a pump o...

Page 13: ...left in the factory default position or this unit will not operate correctly The water tank drains for a maximum of 5 minutes or until F S opens DV and PM if applicable then de energize When BC close...

Page 14: ...hot gas valve LLV liquid line valve PM pump motor WV inlet water valve Components Energized when the Control Switch is in the SERVICE Position When in the SERVICE position the control switch supplies...

Page 15: ...le very carefully 2 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 unit before handli...

Page 16: ...s are energized as listed below LED 5 X1 Relay Compressor Comp Fan Motor Remote FMR LED 4 X6 Relay Drain Valve DV LED 8 X4 Relay Inlet Water Valve WV WV1 on units with 2 inlet water valves K7 Connecto...

Page 17: ...seconds The ALARM RESET button on the control board must be pressed with power on to reset the safety d Low Water Safety The control board checks the position of the float switch at the end of the ini...

Page 18: ...or setting The built in safeties shut down the unit and have alarms as listed below No of Beeps every 3 sec Type of Alarm Notes 1 High Evaporator Temp temperature 127 F 53 C Check for harvest problem...

Page 19: ...ng positions S1 Dip Switch Dip Switch No 1 2 3 4 5 6 7 8 9 10 KMD 450MAH OFF OFF ON ON ON ON ON ON OFF ON KMD 450MWH OFF OFF ON ON ON ON ON ON OFF OFF S2 Dip Switch Do Not Adjust Dip Switch No 1 2 3 4...

Page 20: ...1 dip switch 3 4 S1 Dip Switch Setting Time seconds No 1 No 2 OFF OFF 60 ON OFF 90 OFF ON 120 ON ON 180 c Pump Out Timer S1 dip switch 3 4 When a pump out is called for the pump motor de energizes aft...

Page 21: ...Every cycle ON OFF Every 2 cycles OFF ON Every 5 cycles ON ON Every 10 cycles e Harvest Pump Timer S1 dip switch 7 8 CAUTION Factory set for proper operation Do not adjust Adjustment outside of the fa...

Page 22: ...0 ON OFF 50 OFF OFF 60 OFF ON 70 ON ON 100 g Pump Out Drain Selector S2 dip switch 1 CAUTION Factory set for proper operation Do not adjust Adjustment outside of the factory default setting may result...

Page 23: ...must be left in the factory default position or the unit will not operate correctly Factory set The refill counter determines the number of refills during the freeze cycle The KMD 450MAH and KMD 450MW...

Page 24: ...thermistor temperature drops to 36 F 2 C 5 5 k or more After this time the unit will not shut down until the next harvest cycle is complete For a bin control check procedure see IV C 1 Bin Control Ch...

Page 25: ...power is supplied to the pump motor in all three positions 2 When the control switch is in the OFF position or in the ICE position the service switch has no power and can be left in any position a DR...

Page 26: ...Supply Wash Valve Spray Tubes Condenser High Pressure Switch Strainer Hot Gas Valve Discharge Line Access Valve Suction Line Expansion Valve Refrigeration Circuit Water Circuit Water Tank Evaporator...

Page 27: ...r Hot Gas Valve Discharge Line Access Valve Expansion Valve Refrigeration Circuit Water Circuit Drain Water Tank Evaporator Drier Thermistor Insulation Tube Float Switch Pump Motor Drain Valve Heat Ex...

Page 28: ...and a compressor terminal block are included in the control box to allow easier access for a multimeter For details see III B 2 Multimeter Access Points High Pressure Switch Air Cooled Model Water Co...

Page 29: ...ctor terminals correspond to components as outlined in Fig 2 b Compressor Terminal Block A compressor terminal block is included in the control box to allow easier access for a multimeter The terminal...

Page 30: ...21 80 27 90 32 min 100 38 70 21 80 27 90 32 min 100 38 70 21 245 17 2 264 18 6 288 20 2 80 27 260 18 2 289 20 3 311 21 9 90 32 264 18 6 310 21 8 333 23 4 PSIG kg cm 2 G 100 38 268 18 8 315 22 2 355 2...

Page 31: ...2 273 19 2 281 19 8 90 32 273 19 2 272 19 1 279 19 6 PSIG kg cm 2 G 100 38 277 19 4 274 19 2 286 20 1 70 21 55 3 9 56 3 9 57 4 0 80 27 55 3 9 56 4 0 57 4 0 90 32 56 3 9 57 4 0 58 4 1 PSIG kg cm2 G 10...

Page 32: ...ts and the settings are flexible For factory default settings see II C 3 a Default Dip Switch Settings As you go through the procedure check to assure the components energize and de energize correctly...

Page 33: ...mp operation If it is hot touch the inlet line to the evaporator Is it hot If it is hot and PM does not run per the harvest timer setting and or the freeze cycle does not start check the harvest timer...

Page 34: ...in freeze with F S removed check the thermistor for loose attachment or out of spec For a thermistor check see IV E Thermistor Check If the unit remains in freeze with F S removed and the thermistor...

Page 35: ...k PM circuit and capacitor and PM terminal on the diagnostic connector violet wire for voltage For diagnostic connector details see III B 2 Diagnostic Connector If DV does not open check the supply vo...

Page 36: ...nnector to a white neutral wire for 115V For location of the control switch wire see III B 2 Diagnostic Connector Always choose a white neutral wire to establish a good neutral connection when checkin...

Page 37: ...Bin Control Cleaning If the bin control switch still reads closed replace the bin control 7 Reconnect the wire connector to the control board K1 nine pin connector then move the control switch to the...

Page 38: ...aning Wire Connector To Control Board K1 nine pin connector Harness Connector Bin Control Switch Connector Actuator Paddle Switch Mount Fig 5 1 Float Switch Check To check the float switch follow the...

Page 39: ...of the control box is secure and that the water tank is full If the tank is not full check the water supply water filters and inlet water valve If the tank is full follow the steps in IV D 2 Float Swi...

Page 40: ...the retainer rod excessively when removing it See Fig 8 11 Wipe down the float switch housing shaft float and retainer rod with a mixture of 1 part Hoshizaki Scale Away and 25 parts warm water Rinse t...

Page 41: ...istor holder and the suction pipe 9 Wipe off any moisture on the suction pipe 10 Smoothly apply recommended sealant KE4560RTV Part Code 60Y000 11 or 4A0683 01 to the thermistor holder concave 11 Attac...

Page 42: ...2 Bad contacts 2 Check for continuity and replace f High Pressure Control 1 Bad contacts 1 Check for continuity and replace 2 Dirty air filter or condenser 2 Clean 3 Ambient or condenser water temper...

Page 43: ...nded pressure b Float Switch 1 Connector disconnected 1 Reconnect 2 Float does not move freely or switch defective 2 Clean or replace See IV D Float Switch Check and Cleaning c Control Board 1 Defecti...

Page 44: ...trol Board Check d Water System 1 Water leaks 1 Check connections for water leaks and repair 7 Fan motor will not start or is not operating except water cooled model a Fan Motor 1 Motor winding open 1...

Page 45: ...c Evaporator 1 Scaled up 1 Clean 2 Damaged 2 Replace d Spray Tubes 1 Dirty 1 Clean 2 Out of position 2 Place in position e Pump Motor 1 RPM too slow 1 See chart 1 5 f Thermistor 1 Disconnected loose o...

Page 46: ...Coil winding open 1 Replace 2 Plunger does not move 2 Replace 3 Wiring to hot gas valve 3 Check for loose or open connection Reconnect or replace i Expansion Valve 1 Open 1 Check and replace 2 Bulb l...

Page 47: ...lace e Spray Tubes 1 Dirty 1 Clean 2 Out of position 2 Place in position f Pump Motor 1 RPM too slow 1 See chart 1 5 g Condenser except water cooled model 1 Air filter or condenser clogged 1 Clean h R...

Page 48: ...d 1 Clean or replace e Evaporator 1 Scaled up 1 Clean 2 Damaged 2 Replace f Hot Gas Valve 1 Does not open or opens partially 1 Check and replace g Expansion Valve 1 Wide open in harvest 1 Check and re...

Page 49: ...fective 3 See IV C Bin Control Check and Cleaning 2 Abnormal noise a Pump Motor 1 Bearings worn out 1 Replace b Fan Motor except water cooled model 1 Bearings worn out 1 Replace 2 Fan blade deformed 2...

Page 50: ...or soap bubbles to check for leaks Add a trace of refrigerant to the system if using an electronic leak detector and then raise the pressure using nitrogen gas 140 PSIG DO NOT use R 404A as a mixture...

Page 51: ...UTION 1 Always install a new drier every time the sealed refrigeration system is opened 2 Do not replace the drier until after all other repair or replacement has been made Install the new drier with...

Page 52: ...AUTION 1 Always install a new drier every time the sealed refrigeration system is opened 2 Do not replace the drier until after all other repair or replacement has been made Install the new drier with...

Page 53: ...eration circuit may exceed drier capacity and freeze up at the expansion valve CAUTION 1 Always install a new drier every time the sealed refrigeration system is opened 2 Do not replace the drier unti...

Page 54: ...the new drier with the arrow on the drier in the direction of the refrigerant flow 5 When brazing protect the valve body and drier by using wet cloths to prevent the valve body and drier from overheat...

Page 55: ...st corrosion Use sandpaper to remove the coating from the brazing connections before unbrazing 6 Remove the screws securing the evaporator brackets then lift out the evaporator 7 Remove the pop rivets...

Page 56: ...ion 9 Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG 10 Use an electronic leak detector or soap bubbles to check for leaks Add a trace of refrigerant to the sy...

Page 57: ...and outlet piping and the refrigeration inlet and outlet piping at the condenser 9 Remove the old condenser and install the new condenser 10 Remove the drier then place the new drier in position 11 Br...

Page 58: ...p on the spring retainer underneath the spring While holding the valve open blow out the condenser using the compressed air or carbon dioxide supply until water stops coming out 7 Recover the refriger...

Page 59: ...a thermometer to check the condenser drain temperature Attach a pressure gauge to the high side line of the system 2 Five minutes after a freeze cycle starts confirm that the thermometer reads 104 F t...

Page 60: ...cable ties foam insulation thermistor holder and thermistor See Fig 12 6 Scrape away the old sealant on the thermistor holder and the suction pipe 7 Wipe off any moisture on the suction pipe 8 Smooth...

Page 61: ...cover in its correct position remote air cooled model 9 Turn on the power supply L Removal and Replacement of Water Valves 1 Turn off the power supply 2 If replacing the inlet water valve close the i...

Page 62: ...eck for leaks 9 Replace the front panel in its correct position Fig 13 Thumbscrew Pump Motor Connector Drain Valve Drain Hose Discharge Hose N Removal and Replacement of Control Board 1 Turn off the p...

Page 63: ...contact with skin or eyes 4 To prevent damage to the water pump do not leave the control switch in the SERVICE position for extended periods of time when the water tank is empty 1 Cleaning Procedure...

Page 64: ...excessively when removing it h Wipe down the float switch housing shaft float and retainer rod with cleaning solution Rinse the parts thoroughly with clean water i Reassemble the float switch Replace...

Page 65: ...l 32 Repeat steps 18 through 31 three more times to rinse thoroughly Note If you do not sanitize the icemaker go to step 14 in 2 Sanitizing Procedure 2 Sanitizing Procedure Following Cleaning Procedur...

Page 66: ...off oil or dirt buildup 2 Dispenser Unit Storage Bin and Scoop Wash your hands before removing ice Use the plastic scoop provided bin accessory The dispenser unit storage bin is for ice use only Do n...

Page 67: ...er water supply line drain valve 6 Move the control switch to the ICE position 7 Replace the front panel in its correct position then turn on the power supply 8 Blow the icemaker water supply line out...

Page 68: ...to the condenser water supply line drain valve 5 Open the water regulating valve by using a screwdriver to pry up on the spring retainer underneath the spring While holding the valve open blow out the...

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