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47

9. ADJUSTMENT OF WATER REGULATING VALVE - WATER-COOLED

MODEL ONLY

The Water Regulating Valve (also called “WATER REGULATOR”) is factory-adjusted.
No adjustment is required under normal use. Adjust the Water Regulator, if necessary,
using the following procedures.

1) Attach a pressure gauge to the high-side line of the system. Or prepare a
thermometer to check for the condenser drain temperature.

2) Rotate the adjustment screw by using a flat blade screwdriver, so that the pressure
gauge shows the temperature specified in the table, 5 minutes after a freeze cycle
or icemaking process starts. When the pressure exceeds 270 PSIG, or the
condenser drain temperature exceeds the temperature range, rotate the adjustment
screw counterclockwise. See Fig. 1.

3) Check that the pressure or the condenser drain temperature holds a stable setting.

Fig. 1

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Summary of Contents for KM-280MAH

Page 1: ...HOSHIZAKI MODULAR CRESCENT CUBER MODEL KM 280MAH KM 280MWH SERVICE MANUAL NO 73117 ISSUED AUG 15 2004 REVISED ...

Page 2: ...3 1940 Technical Service 770 487 2331 Fax 770 487 3360 NOTE To expedite assistance all correspondence communication MUST include the following information Model Number Serial Number Complete and detailed explanation of the problem 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 c...

Page 3: ...d Serial M20315D 7 II GENERALINFORMATION 8 1 CONSTRUCTION 8 a KM 280MAH Air cooled 8 b KM 280MWH Water cooled 9 2 CONTROLLER BOARD 10 a SOLID STATECONTROL 10 b CONTROLLER BOARD 10 c SEQUENCE 14 d CONTROLS AND ADJUSTMENTS 17 e CHECKING CONTROLLER BOARD 21 3 MECHANICAL BIN CONTROL 22 a PROXIMITYSWITCH 22 b EXPLANATION OF OPERATION 22 c TROUBLESHOOTING 23 III TECHNICALINFORMATION 24 1 WATERCIRCUITAND...

Page 4: ...D REPLACEMENT OF HOT GAS VALVE AND LINE VALVE 43 7 REMOVAL AND REPLACEMENT OF EVAPORATOR 45 8 REMOVAL AND REPLACEMENT OF WATER REGULATING VALVE WATER COOLED MODEL ONLY 46 9 ADJUSTMENT OF WATER REGULATING VALVE WATER COOLED MODEL ONLY 47 10 REMOVAL AND REPLACEMENT OF THERMISTOR 48 11 REMOVAL AND REPLACEMENT OF FAN MOTOR 49 12 REMOVAL AND REPLACEMENT OF WATER VALVE 50 13 REMOVAL AND REPLACEMENT OF P...

Page 5: ...5 I SPECIFICATIONS 1 KM 280MAH Air cooled Note We reserve the right to make changes in specifications and design without prior notice ...

Page 6: ...6 2a KM 280MWH Water cooled Serial L00001E M10134C Note We reserve the right to make changes in specifications and design without prior notice ...

Page 7: ...7 2b KM 280MWH Water cooled Serial M20315D Note We reserve the right to make changes in specifications and design without prior notice ...

Page 8: ...Tubes Water Supply Inlet Control Switch Condenser Hot Gas Valve Expansion Valve Fan Motor Condenser Compressor Drier Float Switch Control Box Water Pump Bin Control Thermostat except models with Mechanical Bin Control Mechanical Bin Control except models with Thermostat ...

Page 9: ... Supply Inlet Control Switch Water Regulator Expansion Valve Hot Gas Valve Compressor Float Switch Drier Water Pump Control Box Bin Control Thermostat except models with Mechanical Bin Control Mechanical Bin Control except models with Thermostat ...

Page 10: ...he board or the back of the board to prevent damage to the board 4 Do not change wiring and connections Do not misconnect K3 K4 and K5 because the same connector is used for the Thermistor white Float Switch black and Mechanical Bin Control red For machines with thermostat there is no connection on K4 5 Always replace the whole board assembly when it goes bad 6 Do not short out power supply to tes...

Page 11: ... prevent this type of failure the Controller Board checks the position of the Float Switch at the end of the initial one minute water fill cycle and at the end of each defrost cycle If the Float Switch is in the up position electrical circuit closed the Controller Board changes to the ice making cycle If the Float Switch is in the down position electrical circuit open the Controller Board changes ...

Page 12: ...nergizes Check for F S stuck closed up WV leaking by HGV leaking by TXV not feeding properly low charge or inefficient compressor To manually reset the above safeties depress white alarm reset button with the power supplyON 6 beeps every 3 sec Low Voltage Voltage is 92 Vac or less 7 beeps every 3 sec High Voltage Control voltage 147 Vac 5 The red LED will de energize if voltage protection operates...

Page 13: ... white wire supplied to the K1 connector If there is a white wire place the switch in the C position If this switch is placed in the wrong position either the compressor contactor will remain ener gized with the control switch OFF or the unit will not start The dip switches should be adjusted per the adjustment chart published in the Tech Specs book Number 8 must remain in the OFF position ...

Page 14: ...t 5 minutes in freeze cycle Ready to complete freeze cycle when Float Switch circuit opens 4 Defrost Timer stops counting Defrost cycle is completed and freeze cycle starts IMPORTANT Board never accepts freeze completion signal within the first 5 minutes in freeze cycle IMPORTANT 1 Board never accepts defrost completion signal within the first 2 minutes in defrost cycle 2 Defrost cycle time is lim...

Page 15: ...ANT Water Valve opening is limited to 6 minutes 5 After the first 5 minutes in freeze cycle Ready to complete freeze cycle when Float Switch circuit opens 4 Defrost Timer stops counting Defrost cycle is completed and freeze cycle starts IMPORTANT Board never accepts freeze completion signal within the first 5 minutes in freeze cycle IMPORTANT 1 Board never accepts defrost completion signal within ...

Page 16: ... minutes 4 After the first 5 minutes in freeze cycle Ready to complete freeze cycle when Float Switch circuit opens 3 Defrost Timer stops counting Defrost cycle is completed and freeze cycle starts IMPORTANT Board never accepts freeze completion signal within the first 5 minutes in freeze cycle IMPORTANT 1 Board never accepts defrost completion signal within the first 2 minutes in defrost cycle 2 ...

Page 17: ...so determines the time to restrain completion of a defrost cycle i e the minimum defrost time Switch Nos 5 and 6 Used for adjustment of the Drain Counter The Pump Motor drains the Water Tank at the frequency determined by the Drain Counter Switch No 7 Used only on models with mechanical bin control Dip Switch should be set ON Models with bin thermostat Switch No 7 should be set in the OFF position...

Page 18: ...90 1 633 Check a thermistor for resistance by using the following procedures i Disconnect the connector K3 on the board ii Remove the Thermistor See V 10 REMOVAL AND REPLACEMENT OF THERMISTOR iii Immerse the Thermistor sensor portion in a glass containing ice and water for 2 or 3 minutes iv Check for a resistance between Thermistor leads Normal reading is within 3 5 to 7 kΩ Replace the Thermistor ...

Page 19: ...ain the Water Tank every 10 cycles and no adjustment is required However where water quality is bad and the icemaker needs a pump drain more often the Drain Counter can be adjusted as shown in the table below 2 Defrost Timer No adjustment is required under normal use as the Defrost Timer is adjusted to the suitable position However if necessary when all the ice formed on the Evaporator does not fa...

Page 20: ...lly within 10 seconds after ice contacts the Bin Control Thermostat Bulb SETTING FREQUENCY Dip Switch Dip Switch No 5 No 6 OFF OFF everycycle ON OFF every2cycles OFF ON every5cycles ON ON every10cycles 5 Freeze Timer CAUTION Adjust to proper specification or the unit may not operate correctly Two new dip switches numbered 9 and 10 have been added to the improved E board to better prevent possible ...

Page 21: ...t a 1 5 kΩ 3 5 kΩ resistor to the Connector K3 pins 1 and 2 and energize the unit After the 1 minute 5 second water supply cycle and the 2 minute 10 second defrost cycle the unit should start the freeze cycle ii After the above step i disconnect the Float Switch leads from the Controller Board within the first 5 minutes of the freeze cycle The unit should go into the defrost cycle after the first ...

Page 22: ...ontrol board to shut down the unit iii When the bin control is in the normal position bin is not full a 7 9 KΩ reading is sent to the control board to continue operation 2 During operation the controller board will only shut down the machine if a 15 8 KΩ signal is received from the bin control during the first 5 minutes of the freeze cycle i If ice pushes the lever to the right after the first fiv...

Page 23: ...related issues are resolved ii Dip switch No 7 should be in the on position If the switch is in the off position the controller board will not receive input from the bin control iii Move the lever to the far right a If the machine does not shut off check the resistance values of the resistor wire harness You should read approximately 15 8 KΩ between the black terminal and the red terminal that con...

Page 24: ...24 III TECHNICAL INFORMATION 1 WATER CIRCUIT AND REFRIGERANT CIRCUIT a KM 280MAH ...

Page 25: ...25 b KM 280MWH ...

Page 26: ...AMS a KM 280MAH with auxiliary codes L 0 M 0 and M 1 and KM 280MWH with auxiliary codes L 0 M 0 and M 1 Note Pressure Switch MAH MWH Cut out 412 PSIG Cut in 327 21 PSIG 21 0 Cut out 384 PSIG Cut in 284 21 PSIG 21 0 MWH ...

Page 27: ...27 KM 280MAH with auxiliary codes M 2 and after and KM 280MWH with auxiliary codes M 2 and after ...

Page 28: ...28 3 TIMING CHART ...

Page 29: ...29 ...

Page 30: ...ATA a KM 280MAH Note Pressure data is recorded at 5 minutes into freeze 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 31: ...l L00001E M10134C Note Pressure data is recorded at 5 minutes into freeze 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 32: ...re data is recorded at 5 minutes into freeze cycle The data not with should be used for reference only We reserve the right to make changes in specifications and design without prior notice c KM 280MWH Serial M20315D ...

Page 33: ... Check for continuity and Control replace f Transformer 1 Thermal fuse blown out 1 Replace or coil winding opened g Wiring to 1 Loose connections or 1 Check for continuity and Controller Board open replace h Thermistor 1 Leads short circuit or 1 See II 2 d CONTROLS open and High AND ADJUSTMENTS 1 Temperature Safety Defrost Control operates i Hot Gas Solenoid 1 Continues to open in 1 Check for powe...

Page 34: ...t 1 6 water cooled model 6 Refrigerant line or 6 Clean and replace Drier components plugged c Water Regulator 1 Set too high 1 Adjust lower d Overload Protector 1 Bad contacts 1 Check for continuity and replace 2 Voltage too low 2 Increase voltage 3 Refrigerant overcharged or 3 Recharge undercharged 4 Line Valve continues to 4 Check Line Valve s close in freeze cycle and operation in freeze cycle ...

Page 35: ...Controller Board 1 Defective 1 See II 2 e CHECKING CONTROLLER BOARD 6 Fan Motor will a Fan Motor 1 Motor winding opened 1 Replace not start or is 2 Bearing worn out 2 Replace not operating 3 Wiring to Fan Motor 3 Check for loose connection or open and replace 4 Defective Capacitor 4 Replace 5 Fan blade bound 5 Check and replace b Controller Board 1 Defective 1 See II 2 e CHECKING CONTROLLER BOARD ...

Page 36: ...ation in harvest cycle harvest cycle and replace f Thermistor 1 Out of position or loose 1 See V 10 REMOVAL attachment AND REPLACEMENT OF THERMISTOR g Controller Board 1 Defrost Timer is set too 1 Adjust longer referring short to II 2 d CONTROLS AND ADJUSTMENT 2 Defrost Timer 2 Defective 2 See II 2 e CHECKING CONTROLLER BOARD 3 Others a Spray Tubes 1 Clogged 1 Clean 2 Out of position 2 Place in po...

Page 37: ...ls into bin b See chart 1 5 and check water supply line Water Solenoid Valve water system Pump Motor or Controller Board c Drain Valve 1 Dirty 1 Clean 2 Cloudy or a See chart 2 1 and 3 and check Float Switch Water Solenoid Valve irregular cube Controller Board Spray Tubes water system refrigerant charge or Expansion Valve b Spray Guide 1 Dirty 1 Clean c Water Quality 1 High hardness or contains 1 ...

Page 38: ...gerant Access Valves one on the low side and one on the high side line 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 b EVACUATION AND RECHARGE R 404A 1 Attach Charging Hoses a Service Manifold and a Vacuum Pump to the system Be sure to connect charging hoses to both High a...

Page 39: ...ant Access Valves and disconnect the Hoses and Service Mani fold 10 Cap the Access Valves to prevent a possible leak 2 BRAZING DANGER 1 Refrigerant R 404A itself is not flammable at atmospheric pressure and temperatures up to 176 F 2 Refrigerant R 404A itself is not explosive or poisonous However when exposed to high temperatures open flames R 404A can be decomposed to form hydrofluoric acid and c...

Page 40: ...power supply 2 Remove the panels 3 Recover the refrigerant and store it in an approved container 4 Remove the Terminal Cover on the Compressor and disconnect the Compressor Wiring 5 Remove the Discharge and Suction Pipes using brazing equipment 6 Remove the Hold down Bolts Washers and Rubber Grommets 7 Slide and remove the Compressor Unpack the new Compressor package Install the new Compressor 8 A...

Page 41: ...dels see the Nameplate for the required refrigerant charge For remote air cooled models see the Charge Label in the machine compartment 16 Connect the Terminals and replace the Terminal Cover in its correct position 17 Replace the panels in their correct positions 18 Turn on the power supply ...

Page 42: ...ks using nitrogen gas 140 PSIG and soap bubbles 7 Evacuate the system and charge it with refrigerant For air cooled and water cooled models see the Nameplate for the required refrigerant charge For remote air cooled models see the Charge Label in the machine compartment 8 Replace the panels in their correct positions 9 Turn on the power supply 5 REMOVAL AND REPLACEMENT OF EXPANSION VALVE IMPORTANT...

Page 43: ...aks using nitrogen gas 140 PSIG and soap bubbles 9 Evacuate the system and charge it with refrigerant For air cooled and water cooled models see the Nameplate for the required refrigerant charge For remote air cooled models see the Charge Label in the machine compartment 10 Attach the Bulb to the suction line in position Be sure to secure it with clamps and to insulate it 11 Place the new set of E...

Page 44: ... to prevent the valve from overheating Do not braze with the valve body exceeding 250 F 7 Install the new Drier 8 Check for leaks using nitrogen gas 140 PSIG and soap bubbles 9 Evacuate the system and charge it with refrigerant For air cooled and water cooled models see the Nameplate for the required refrigerant charge For remote air cooled models see the Charge Label in the machine compartment 10...

Page 45: ...sis 5 Remove the Insulation Tube and disconnect the Evaporator Inlet Tubing at the Tee next to the Expansion Valve 6 Lift up the Evaporator and disconnect the Evaporator Outlet Tubing 7 Install the new Evaporator 8 Install the new Drier 9 Check for leaks using nitrogen gas 140 PSIG and soap bubbles 10 Evacuate the system and charge it with refrigerant For air cooled and water cooled models see the...

Page 46: ...r 5 Disconnect the Capillary Tube at the Condenser outlet using brazing equipment 6 Disconnect the Flare connections of the valve 7 Remove the screws and the valve from the Bracket 8 Install the new valve and braze the Capillary Tube 9 Install the new Drier 10 Check for leaks using nitrogen gas 140 PSIG and soap bubbles 11 Evacuate the system and charge it with refrigerant See the Nameplate for th...

Page 47: ...stem Or prepare a thermometer to check for the condenser drain temperature 2 Rotate the adjustment screw by using a flat blade screwdriver so that the pressure gauge shows the temperature specified in the table 5 minutes after a freeze cycle or icemaking process starts When the pressure exceeds 270 PSIG or the condenser drain temperature exceeds the temperature range rotate the adjustment screw co...

Page 48: ...ol Box Cover 4 Disconnect the Thermistor leads from the K3 Connector on the Controller Board 5 Remove the Plastic Cable Ties Foam Insulation Thermistor Holder and Thermistor See Fig 2 6 Scrape away the old sealant on the Thermistor Holder and the Suction Pipe 7 Wipe off moisture or condensation on the Suction Pipe 8 Smoothly apply recommended sealant KE4560RTV Part Code 60Y000 11 or 4A0683 01 to t...

Page 49: ...ller Board Note Do not cut the leads of the Thermistor while installing it 12 Replace the Control Box Cover and the panels in their correct positions 13 Turn on the power supply 11 REMOVAL AND REPLACEMENT OF FAN MOTOR Note When replacing a Fan Motor with defective winding it is recommended that a new capacitor be installed 1 Turn off the power supply 2 Remove the panels 3 Remove the Junction Box C...

Page 50: ...e Shut off Valve 3 Remove the Front Panel 4 Remove the Valve Outlet Tubing by releasing the Clamp 5 Remove the Bracket from the unit 6 Remove the Fitting Nut and Water Valve 7 Disconnect the Terminals from the Water Valve 8 Install the new Water Valve and replace the removed parts in the reverse order of which they were removed 9 Open the Water Supply Line Shut off Valve 10 Turn on the power suppl...

Page 51: ...nd replace the removed parts in the reverse order of which they were removed 13 Turn on the power supply and check for leaks 14 Replace the Base Cover in its correct position 15 Replace the Front Panel in its correct position 14 REMOVAL AND REPLACEMENT OF SPRAY TUBES 1 Turn off the power supply 2 Remove the Front Panel and the Insulation Panel 3 Remove the Rubber Hoses from the Spray Tubes Water S...

Page 52: ...aker until the proper ambient temperature is resumed When the icemaker is not used for two or three days it is sufficient to only move the Control Switch to the OFF position unless the icemaker will be at sub freezing tem peratures 1 On water cooled model only first remove the water from the water cooled condenser 1 Remove the Front Panel 2 Move the Control Switch on the Control Box to the OFF pos...

Page 53: ...he ICE position 8 Blow the potable water line out using compressed air or carbon dioxide 3 Drain the Potable Water Tank 1 Turn off the power supply 2 Move the Control Switch to the OFF position 3 Drain the Water Tank by removing the base cover and one end of the pump tubing See Fig 4 4 Replace the removed parts in their correct positions 5 Remove all ice from the Storage Bin and clean the Storage ...

Page 54: ... 3 Always wear liquid proof gloves for safe handling of the cleaning and sanitizing solution This will prevent irritation in case the solution comes into contact with skin IMPORTANT 1 The Cleaning Valve is used to allow solution flow to the inside of the Evaporator during the cleaning and sanitizing operation It should be closed for all icemaking operation The Compressor will not operate unless th...

Page 55: ...Tank by removing one end of the Pump Tubing See Fig 4 7 Replace the removed parts in their correct positions 8 Pour the cleaning solution into the Water Tank 9 Fully open the Cleaning Valve on the left side wall of the machine compartment 10 Move the Control Switch on the Control Box to the WASH position 11 Replace the Insulation Panel and the Front Panel in their correct positions 12 Turn on the ...

Page 56: ...25 Turn on the power supply to rise off the cleaning solution 26 Turn off the power supply after 5 minutes 27 Remove the Front Panel and Insulation Panel 28 Drain the Water Tank by removing one end of the Pump Tubing See Fig 4 29 Replace the removed parts in their correct positions Note Do not replace the InsulationPanel when you proceed to b SANITIZING PROCEDURE 28 Repeat the above steps 17 throu...

Page 57: ... 5 Turn on the power supply and start the sanitizing process 6 Turn off the power supply after 15 minutes 7 Remove the Front Panel and if necessary the Insulation Panel 8 Drain the Water Tank See the above step 5 in a CLEANING PROCEDURE 9 Replace the removed parts and the Insulation Panel in their correct position 10 Repeat the above steps 17 through 29 in a CLEANING PROCEDURE two times to rinse t...

Page 58: ...up 2 Storage Bin and Scoop Wash your hands before removing ice Use the plastic scoop provided The Storage Bin is for ice use only Do not store anything else in the bin Keep the scoop clean Clean it by using a neutral cleaner and rinse thoroughly Clean the bin liner by using a neutral cleaner Rinse thoroughly after cleaning 3 Condenser Except water cooled model Check the Condenser once a year and c...

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