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Hoshizaki Serenity Series KMS-822MLH, Service Manual, Page: 33 / 47

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Hoshizaki Serenity Series KMS-822MLH Service Manual Download Page 33

33

E. Thermistor Check

To check thermistor resistance, follow the steps below.

1) Turn off the power supply.
2) Remove the front panel, then move the control switch to the "OFF" position.
3) Remove the right side panel, then remove the control box cover.
4) Remove the thermistor.
5) Immerse the thermistor sensor portion in a glass containing ice and water for 2 or 

3 minutes.

6) Disconnect the white thermistor connector from CB WHITE K3 connector and check the 

resistance between thermistor leads. Normal reading is within 4.7 to 6.2 kΩ. If outside 
the normal reading, replace the thermistor. See "V.B. Important Notes for Component 
Replacement." If inside the normal reading, continue to the next step.

7) Replace the thermistor in its correct position. See "V.B. Important Notes for Component 

Replacement."

8) Reconnect the white thermistor connector to CB WHITE K3 connector.
9) Replace the control box cover in its correct position, then turn on the power supply.

10) Move the control switch to the "ICE" position.
11) Once the harvest cycle starts, begin timing the harvest cycle.
12) The harvest timer and harvest cycle should terminate within 2 to 5 minutes. If the 

harvest cycle does not terminate within 2 to 5 minutes, the harvest timer is bad and 
CB should be replaced.

Legend: 

CB

–control board

Summary of Contents for Serenity Series KMS-822MLH

Page 1: ... Superior Degree of Reliability www hoshizaki com Model KMS 822MLH Including Condensing Unit Model SRK 10H Modular Crescent Cuber Serenity Series Hoshizaki America Inc SERVICE MANUAL Number 73182 Issued 2 18 2011 ...

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 Department for assistance HOSHIZAKI AMERICA INC 618 Highway 74 South Peachtree City GA 30269 Attn Hoshizaki Technical Support Department Phone 1 800 233 1940 Technical Support 770 487 2331 Fax 1 800...

Page 3: ...4 dip switch 3 4 18 d Pump Out Frequency Control S4 dip switch 5 6 18 e Harvest Pump Timer S4 dip switch 7 19 f Factory Use S4 dip switch 8 19 g Freeze Timer S4 dip switch 9 10 19 h Float Switch Control S5 dip switch 1 20 i Refill Counter S5 dip switch 2 through 5 20 D Control Switch 20 III Technical Information 21 A Water Circuit and Refrigeration Circuit 21 B Wiring Diagram 22 C Performance Data...

Page 4: ...nostic Charts 34 1 No Ice Production 34 2 Freeze Up 35 3 Low Ice Production 37 V Replacement of Components 38 A Service for Refrigerant Lines 38 1 Refrigerant Recovery 38 2 Brazing 39 3 Evacuation and Recharge R 404A 39 B Important Notes for Component Replacement 41 VI Cleaning and Maintenance 42 A Cleaning and Sanitizing Instructions 42 1 Cleaning Procedure 43 2 Sanitizing Procedure Following Cle...

Page 5: ...ualified service personnel to reduce the risk of electric shock injury or fire Move the control switch to the OFF position and turn off the power supply to the SRK condensing unit before any servicing to the KMS or SRK is undertaken Place the KMS disconnect if applicable in the off position Lockout Tagout to prevent the power supply from being turned back on inadvertently Do not make any alteratio...

Page 6: ...uipment The remote condensing unit requires an independent power supply of proper capacity See the nameplate for electrical specifications Failure to use a properly sized breaker or fuse can result in a tripped breaker blown fuses or damage to existing wiring This could lead to heat generation or fire THE REMOTE CONDENSING UNIT MUST BE GROUNDED Failure to properly ground the remote condensing unit...

Page 7: ... OD Tube REFRIGERATION Liquid Line 1 2 Copper Tube Field Connection Suction Line 5 8 Copper Tube Field Connection CUBE CONTROL SYSTEM Float Switch HARVEST CONTROL SYSTEM Hot Gas and Water Thermistor and Timer ICE MAKING WATER CONTROL Timer Controlled Overflow Pipe Float Switch COOLING WATER CONTROL N A BIN CONTROL SYSTEM Mechanical Bin Control COMPRESSOR In SRK CONDENSING UNIT Air Cooled Remote Co...

Page 8: ... Connection REFRIGERATION Liquid Line 1 2 Copper Tube Field Connection Suction Line 5 8 Copper Tube Field Connection COMPRESSOR Hermetic Model CS10K6E PFV 279 CONDENSER Air Cooled Fin and Tube Type COMPRESSOR PROTECTION Auto Reset Overload Protector Internal FAN MOTOR PROTECTION Thermal Protection REFRIGERATION CIRCUIT PROTECTION Auto Reset High Pressure Switch Discharge Line Thermostat REFRIGERAN...

Page 9: ...er Hot Gas Valve HGV Float Switch Pump Motor Bin Control Control Switch Expansion Valves TXV Inlet Water Valve Cleaning Valve Drain Valve Spray Guide High Side Service Valve Low Side Service Valve Liquid Line Valve LLV Evaporator Bin Control Extension Bracket Bin Control Cover Insulation Fuse KMS ...

Page 10: ...master CPR Control Box Hot Gas Valve HGV Condenser Fan Motors FMR High Side Service Valve Low Side Service Valve Compressor Condenser Liquid Line Valve LLV Receiver Accumulator Discharge Thermostat High Pressure Switch Fuse SRK ...

Page 11: ...ee II C 3 b Harvest Timer S4 dip switch 1 2 WV is energized during harvest for a maximum of 6 minutes or the length of harvest minus 50 seconds Harvest Pump Timer S4 dip switch 7 whichever is shorter 50 seconds before the harvest timer terminates LED 4 and WV de energize LED 3 comes on DVR energizes energizing PM for the last 50 seconds of harvest For details see II C 3 e Harvest Pump Timer S4 dip...

Page 12: ...g Pump Out Frequency 1st Pump Out No 5 No 6 OFF OFF Every cycle After 2nd freeze cycle ON OFF Every 2 cycles After 3rd freeze cycle OFF ON Every 5 cycles After 6th freeze cycle ON ON Every 10 cycles After 11th freeze cycle e Harvest Cycle Same as the initial harvest cycle See II B 1 b Initial Harvest Cycle Note Unit continues to cycle until BC is satisfied or power is turned off The unit always re...

Page 13: ...FMRs fan motors remote F S float switch HGVs hot gas valves KMS and SRK LLVs liquid line valves KMS and SRK PM pump motor WV inlet water valve 1 Bin Full Shutdown Delay Fill Cycle 15 sec after activation Harvest Cycle At the end of the harvest cycle or up to 15 sec into the freeze cycle if activated at the end of the harvest cycle Freeze Cycle 15 sec after activation if activated at least 15 sec b...

Page 14: ...ue 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 Do not misconnect K3 K4 and K5 because the same connector is used for the thermistor bin control and float switch 5 Always replace the w...

Page 15: ... 4 Pump Motor icemaking 5 Drain Valve Relay DVR pump motor during harvest pump timer and pump motor and drain valve during pump out 6 Inlet Water Valve WV 7 10 Component Power Supply 8 Open Bin Control Switch Open LED yellow S4 Dip Switch Bin Control Switch Closed LED green Alarm Buzzer Power LED red lights when power is supplied to the control board LED 2 X2 Relay Hot Gas Valves HGVs LED 3 X3 Rel...

Page 16: ...ies 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 stuck HGV hot water entering unit stuck HM or shorted thermistor 2 Harvest Backup Timer harvest 20 min for two cycles in a row Check for open thermistor HGV not opening TXV or LLVs leaking by low charge or inefficient Comp 3 Free...

Page 17: ...adjust Factory Use 8 b Harvest Timer S4 dip switch 1 2 The harvest timer starts when the thermistor reads 48 F 9 C at the evaporator outlet and the control board reads the thermistor s 3 9 kΩ signal The harvest timer is factory set and generally no adjustment is required However a setting longer than the factory setting may be advised in cases where harvest needs to be prolonged for extra cleaning...

Page 18: ...r with the inlet water valve during the pump out cycle Therefore S4 dip switch 3 4 must be set to 3 off and 4 on See III B Wiring Diagram S4 Dip Switch Setting Time seconds Inlet Water Valve No 3 No 4 T1 T2 OFF OFF 10 150 closed ON OFF 10 180 closed OFF ON 10 120 open ON ON 20 180 closed T1 Time to drain the water tank T2 Harvest timer at pump out d Pump Out Frequency Control S4 dip switch 5 6 The...

Page 19: ...use it shares power with the inlet water valve which de energizes the last 50 seconds of harvest See III B Wiring Diagram S4 Dip Switch Setting Pump Motor Time seconds No 7 ON 50 OFF 0 f Factory Use S4 dip switch 8 Factory set for proper operation Do not adjust This must be left in the factory default position g Freeze Timer S4 dip switch 9 10 CAUTION Adjust to proper specification or the unit may...

Page 20: ...ting Single or Double Float Switch Application No 1 OFF Single On Double i Refill Counter S5 dip switch 2 through 5 CAUTION Factory set Do not adjust Otherwise the unit will not operate correctly S5 dip switch 2 through 5 allows for refills during the freeze cycle The KMS 822MLH does not refill D Control Switch The control switch has three positions OFF for power off ICE for icemaking and WASH to ...

Page 21: ...lves Strainer SRK 10H Fans Condenser Headmaster C P R Check Valve Hot Gas Valve Strainer High Pressure Switch Discharge Thermostat Discharge Line Compressor Receiver Accumulator Suction Line Hot Gas Valve Strainer Check Valves Expansion Valve Float Switch Drain Valve Drain Pump Motor Water Tank Evaporator Thermistor Low Side Service Valves Liquid Line Liquid Line Valve Suction Line ...

Page 22: ... B Wiring Diagram 1 KMS 822MLH with SRK 10H Thermostat Cut out 266 F 9 F 130 C 5 C Cut in 239 F 9 F 115 C 5 C Transformer Output 10 5V at 115V High Pressure Switch Cut out 426 22 PSIG Cut in 341 22 PSIG 0 ...

Page 23: ... 1 90 32 192 13 5 223 15 7 243 17 1 PSIG kg cm 2 G 100 38 196 13 8 228 16 0 262 18 4 70 21 36 2 5 37 2 6 43 3 0 80 27 37 2 6 39 2 8 47 3 3 90 32 37 2 6 41 2 9 48 3 4 PSIG kg cm 2 G 100 38 40 2 8 43 3 0 54 3 8 16 200 BTU h AT 90ºF 32ºC WT 70ºF 21ºC 1 900 BTU h AT 90ºF 32ºC WT 70ºF 21ºC CONDENSER VOLUME 226 CU IN SRK 10H Note Pressure data is recorded at 5 minutes into freezing cycle The data not in...

Page 24: ...k to assure the components energize and de energize correctly If not those components and controls are suspect 1 Turn off the power supply then access the control box Clear any ice from BC 2 Turn on the power supply then move the control switch to the ICE position A 5 second delay occurs The red POWER OK LED and green BC CLOSED LED on CB come on If the yellow BC OPEN LED is on check BC See IV C 1 ...

Page 25: ...ory default position Check CB K1 connector Pin 5 DBu wire and DVR solenoid for 115VAC If 1 minute fill cycle starts after harvest see IV D Float Switch Check and Cleaning If the thermistor reading is in proper range and CB fails to terminate the harvest cycle and initiate the freeze cycle CB is bad and must be replaced 5 Freeze Cycle LED 1 is on Comp FMRs and PM remain energized LLVs energize HGVs...

Page 26: ...y 5 cycles After 6th freeze cycle ON ON Every 10 cycles After 11th freeze cycle Diagnosis Confirm CB S4 dip switch 3 4 settings are in the factory default positions 3 off and 4 on Check that Comp continues Confirm WV and HGVs energize and LLVs de energize Next check that DVR PM and DV energize If DVR does not energize LED 3 on check CB 5 pin DBu wire on CB K1 ten pin connector for 115VAC If no vol...

Page 27: ...voltage and the red LED is off CB is bad and should be replaced If the secondary circuit does not have proper voltage check CT primary circuit Check for 115VAC at CB K1 ten pin connector 10 pin BR wire to a white neutral wire for 115VAC Always choose a white neutral wire to establish a good neutral connection when checking voltages For additional checks see IV F 1 No Ice Production 3 The OUTPUT TE...

Page 28: ...nnector from CB RED K4 connector 5 If BC is accessible from the dispenser unit storage bin continue to step 7 If BC is not accessible from the dispenser unit storage bin follow the instructions below to remove BC a Loosen the screws securing the control box then lift the control box off and hang it from the base See Fig 1 b Remove the insulation Remove the thumbscrews securing the bin control asse...

Page 29: ...replace BC and control box in their correct positions 15 Replace the control box cover 16 Replace the panels in their correct positions 17 Turn on the power supply to start the automatic icemaking process Legend BC bin control CB control board Fig 1 Bin Control Proximity Switch Closed calling for ice Bin Control Cable Bin Control Proximity Switch Open bin full unit off or shutting down Bin Control...

Page 30: ... Fig 1 b Remove the insulation Remove the thumbscrews securing the bin control assembly Remove the bin control assembly 6 Remove BC from the extension bracket See Fig 3 7 Wipe down BC assembly with a mixture of 1 part Hoshizaki Scale Away and 25 parts warm water Rinse the parts thoroughly with clean water 8 Reassemble BC assembly and replace it in its correct position Note If the magnet was remove...

Page 31: ...control box cover 7 Disconnect the black float switch connector from the control board BLACK K5 connector 8 Check for continuity across F S leads With the water tank empty F S should be open If open continue to step 9 If closed follow the steps in IV D 2 Float Switch Cleaning After cleaning the float switch check it again Replace if necessary 9 Reconnect the black F S connector to CB BLACK K5 conn...

Page 32: ...eplace the water shield overflow pipe overflow cap cube guide A cube guide B and insulation panel in their correct positions Be careful not to cross thread the overflow pipe 6 Disconnect the vent tube and the flush tube from the top of the float switch then remove the float switch assembly from the mounting bracket and remove the rubber boot from the bottom of the float switch assembly See Fig 5 7...

Page 33: ...ide the normal reading replace the thermistor See V B Important Notes for Component Replacement If inside the normal reading continue to the next step 7 Replace the thermistor in its correct position See V B Important Notes for Component Replacement 8 Reconnect the white thermistor connector to CB WHITE K3 connector 9 Replace the control box cover in its correct position then turn on the power sup...

Page 34: ...ure Switch SRK a Dirty condenser b Condensing unit fan not operating c Headmaster C P R open d Refrigerant overcharged e Bad contacts f Refrigerant lines or components plugged 5 Thermostat SRK a Ambient temperature too warm b Compressor or compressor components faulty c Defective d Hot gas valve open e Dirty condenser f Condensing unit fan not operating 6 Wire Harness a Disconnected or loose conne...

Page 35: ...20 Liquid Line Valves KMS SRK a Closed in freeze cycle b Open in harvest cycle 21 Condensing Unit Fan Motor a Motor winding open b Bearing worn out or locked rotor c Defective capacitor 22 Headmaster C P R a Defective 23 Drain Valve Relay a Bad contacts closed Pump motor runs constantly b Defective coil 24 Drain Valve a Dirty leaking by b Defective coil 25 Water System a Water leaks causing short ...

Page 36: ...ted or defective 11 Expansion Valve TXV a Defective 12 Hot Gas Valves KMS SRK a Closed 13 Liquid Line Valves KMS SRK a Open 14 Drain Valve Relay a Bad contacts Open coil Not allowing pump motor operation during last 50 seconds of harvest Freeze Cycle 1 Evaporator a Scaled up b Damaged 2 Spray Tubes and or Spray Guides a Dirty b Out of position 3 Refrigerant charge a Low 4 Control Board See IV B Co...

Page 37: ...creen or orifice clogged 9 Compressor a Inefficient or off 10 Liquid Line Valves KMS SRK a Erratic or open in harvest 11 Expansion Valve TXV a Defective 12 Headmaster C P R a Defective Long Freeze Cycle 1 Evaporator a Scaled up dirty 2 Float Switch See IV D Float Switch Check and Cleaning a Scaled up dirty b Float sticking c Defective switch 3 Inlet Water Valve a Leaking by 4 Hot Gas Valves KMS SR...

Page 38: ...ronic leak detector 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 with pressurized air for leak testing CAUTION 1 Do not leave the system open for longer than 15 minutes when replacing or servicing parts The Polyol Ester POE oils used in R 404A u...

Page 39: ...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 the arrow on the drier in the direction of the refrigerant flow 3 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 2 Use an electronic le...

Page 40: ...ace the service cylinder on the scales if the service cylinder is not equipped with a dip tube invert the service cylinder then place it on the scales Open the high side valve on the gauge manifold 7 Allow the system to charge with liquid until the proper charge weight is met 8 If necessary add any remaining charge to the system through the low side CAUTION To prevent compressor damage use a throt...

Page 41: ...se copper tube of the same diameter and length when replacing valve lines Fan Motor Install a new capacitor Pump Motor Install a new capacitor Thermistor Attach the new thermistor to the suction line in the same location as the previous thermistor The thermistor should be at the 12 o clock position on the tube Smoothly fill the recessed area of the thermistor holder with high thermal conductive ty...

Page 42: ...have fallen into the dispenser unit storage bin 3 The dispenser unit storage bin is for ice use only Do not store anything else in the dispenser unit storage bin A Cleaning and Sanitizing Instructions Hoshizaki recommends cleaning and sanitizing this unit at least once a year More frequent cleaning and sanitizing however may be required in some existing water conditions WARNING 1 To prevent injury...

Page 43: ...e guide B then remove cube guide A See Fig 6 Remove the overflow cap overflow pipe and water shield 5 Remove the drain plug Allow the water tank to drain then replace the drain plug in its correct position Be careful not to cross thread it 6 Replace the water shield overflow pipe overflow cap cube guide A and cube guide B in their correct positions Be careful not to cross thread the overflow pipe ...

Page 44: ...ning valve is completely closed 19 Replace the front panel in its correct position 20 Turn on the power supply to fill the water tank with water 21 Turn off the power supply after 3 minutes 22 Remove the front panel and fully open the cleaning valve 23 Move the control switch to the WASH position 24 Replace the front panel in its correct position 25 Turn on the power supply to rinse off the cleani...

Page 45: ...panel 8 Remove the insulation panel Remove cube guide B then remove cube guide A Remove the overflow cap overflow pipe and water shield 9 Remove the drain plug Allow the water tank to drain then replace the drain plug in its correct position 10 Replace the water shield overflow pipe overflow cap cube guide A cube guide B and insulation panel in their correct positions 11 Repeat steps 17 through 30...

Page 46: ... for Long Storage CAUTION 1 When storing the icemaker for an extended time or in sub freezing temperatures follow the instructions below to prevent damage 2 To prevent damage to the water pump seal do not operate the icemaker with the control switch in the WASH position when the water tank is empty When the icemaker is not used for two or three days it is sufficient to only move the control switch...

Page 47: ...ug Allow the water tank to drain then replace the drain plug in its correct position Be careful not to cross thread it 5 Replace the water shield overflow pipe overflow cap cube guide A cube guide B and insulation panel in their correct positions Be careful not to cross thread the overflow pipe 6 Remove all ice from the dispenser unit storage bin Clean the dispenser unit storage bin using a neutra...

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