Hoshizaki KM-280MAH, KM-280MWH Service Manual

NO. 73117 ISSUED: AUG. 15, 2004

REVISED:

HOSHIZAKI

MODULAR CRESCENT CUBER

MODEL

KM-280MAH KM-280MWH

SERVICE MANUAL

IMPORTANT

Only qualified service technicians should attempt to service or maintain this icemaker. No service or maintenance should be undertaken until the technician has thoroughly read this Service Manual.

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 concerns which have not been satisfactorily addressed, please call or write to the HOSHIZAKI Technical Support Depar tment for assistance.

HOSHIZAKI AMERICA, INC. 618 Highway 74 South Peachtree City, GA 30269

Attn: HOSHIZAKI Technical Support Department

Phone: 1-800-233-1940 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

• Please review this manual. It should be read carefully before the icemaker is serviced or maintenance operations performed. Only qualified service technicians should service and maintain the icemaker. This manual should be made available to the technician prior to service or maintenance.

CONTENTS

PAGE

I. SPECIFICATIONS ...................................................................................................... 5

1. KM-280MAH (Air-cooled) ..................................................................................... 5

2a. KM-280MWH (Water-cooled) Serial #L00001E - M10134C ............................... 6

2b. KM-280MWH (Water-cooled) Serial #M20315D ................................................ 7

II. GENERAL INFORMATION ........................................................................................ 8

1. CONSTRUCTION ................................................................................................. 8

[a] KM-280MAH (Air-cooled) ............................................................................... 8

[b] KM-280MWH (Water-cooled) ......................................................................... 9

2. CONTROLLER BOARD ..................................................................................... 10

[a] SOLID-STATE CONTROL ........................................................................... 10

[b] CONTROLLER BOARD ............................................................................... 10

[c] SEQUENCE ................................................................................................ 14

[d] CONTROLS AND ADJUSTMENTS ............................................................. 17

[e] CHECKING CONTROLLER BOARD ........................................................... 21

3. MECHANICAL BIN CONTROL........................................................................... 22

[a]

PROXIMITY SWITCH ................................................................................... 22

[b] EXPLANATION OF OPERATION................................................................ 22

[c]

TROUBLESHOOTING ................................................................................. 23

III. TECHNICAL INFORMATION .................................................................................. 24

1. WATER CIRCUIT AND REFRIGERANT CIRCUIT .............................................. 24

[a] KM-280MAH ................................................................................................ 24

[b] KM-280MWH ............................................................................................... 25

2. WIRING DIAGRAMS .......................................................................................... 26

[a] KM-280MAH and KM-280MWH ................................................................... 26

3. TIMING CHART .................................................................................................. 28

4. PERFORMANCE DATA .................................................................................... 30

[a] KM-280MAH ................................................................................................ 30

[b] KM-280MWH Serial #L00001E - M10134C ................................................. 31

[c]

KM-280MWH Serial #M20315D .................................................................. 32

IV. SERVICE DIAGNOSIS ...........................................................................................33

1. NO ICE PRODUCTION.........................................................................................33

2. EVAPORATOR IS FROZEN UP ..........................................................................36

3. LOW ICE PRODUCTION......................................................................................37

4. ABNORMAL ICE ..................................................................................................37

5. OTHERS ..............................................................................................................37

V. REMOVAL AND REPLACEMENT OF COMPONENTS............................................38

1. SERVICE FOR REFRIGERANT LINES ..............................................................38

[a] REFRIGERANT RECOVERY........................................................................38

[b] EVACUATION AND RECHARGE [R-404A]...................................................38

2. BRAZING.............................................................................................................39

3. REMOVAL AND REPLACEMENT OF COMPRESSOR .......................................40

4. REMOVAL AND REPLACEMENT OF DRIER .....................................................42

5. REMOVAL AND REPLACEMENT OF EXPANSION VALVE ...............................42

6. REMOVAL AND 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 ........................................4 8

11. REMOVAL AND REPLACEMENT OF FAN MOTOR...........................................4 9

12. REMOVAL AND REPLACEMENT OF WATER VALVE........................................50

13. REMOVAL AND REPLACEMENT OF PUMP MOTOR ......................................... 50

14. REMOVAL AND REPLACEMENT OF SPRAY TUBES ........................................51

VI. CLEANING AND MAINTENANCE INSTRUCTIONS...............................................52

1. PREPARING THE ICEMAKER FOR LONG STORAGE......................................52

2. CLEANING...........................................................................................................54

[a] CLEANING PROCEDURE .............................................................................55

[b] SANITIZING PROCEDURE ...........................................................................5 7

3. MAINTENANCE....................................................................................................58

I. SPECIFICATIONS

1. KM-280MAH (Air-cooled)

Note: We reserve the right to make changes in specifications and design without prior notice.

2a. KM-280MWH (Water-cooled) Serial #L00001E- M10134C

Note: We reserve the right to make changes in specifications and design without prior notice.

2b. KM-280MWH (Water-cooled) Serial #M20315D -

Note: We reserve the right to make changes in specifications and design without prior notice.

II. GENERAL INFORMATION

1. CONSTRUCTION

[a] KM-280MAH (Air-cooled)

Spray Tubes Water Supply Inlet

Control Switch

Bin Control Thermostat (except models with Mechanical Bin Control)

Expansion Valve Fan Motor

Compressor Float Switch

Water Pump

Mechanical Bin Control (except models with Thermostat)

Condenser Hot Gas Valve

Condenser Drier Control Box

[b] KM-280MWH (Water-cooled)

Spray Tubes Water Supply Inlet

Control Switch

Bin Control Thermostat (except models with Mechanical Bin Control)

Water Regulator

Expansion Valve Hot Gas Valve

Compressor Float Switch Drier

Water Pump Control Box

Mechanical Bin Control (except models with Thermostat)

2. CONTROLLER BOARD

[a] SOLID-STATE CONTROL

1) A HOSHIZAKI exclusive solid-state control is employed in Modular Crescent Cubers.

2) A Printed Circuit Board (hereafter called “Controller Board”) includes a stable and high quality control system.

3) All models are pretested and factory-adjusted.

[b] CONTROLLER BOARD

CAUTION

1. Fragile, handle very carefully.

2. A controller 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 when handling or replacing the board.

3. Do not touch the electronic devices on the 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 test for voltage.

PART NUMBER TYPE

2A1410-01 HOS-001A (Control Products)

Features of Control Products “E” Controller Board

1) Maximum Water Supply Period - 6 minutes Water Solenoid Valve opening, in the Defrost (Harvest) Cycle, is limited by the defrost

timer. The Water Valve cannot remain open longer than the maximum period. The Water Valve can close in less than six minutes if the defrost cycle is completed.

2) Defrost Timer The defrost cycle starts when the Float Switch opens and completes the freeze cycle. But

the Defrost Timer does not start counting until the Thermistor senses 48°F at the Evaporator outlet. The period from the end of the freeze cycle up to the point of the Thermistor's sensing varies depending on the ambient and water temperatures.

3) High Temperature Safety - 127 ± 7°F The temperature of the suction line in the refrigerant circuit is limited by the High

Temperature Safety. During the defrost cycle the Evaporator temperature rises. The Thermistor senses 48°F and starts the Defrost Timer. After the Defrost Timer counts down to zero, the normal freeze cycle begins. If the Evaporator temperature continues to rise, the Thermistor will sense the rise in temperature and at 127 ± 7°F the Thermistor operates the High Temperature Safety. This High Temperature Safety shuts down the circuit and the icemaker automatically stops. This High Temperature Safety protects the unit from excessive temperature. The Control Board will Beep every 3 seconds. The white Reset Button on the Control Board must be pressed with power on to reset the Safety.

4) Low Water Safety If the Pump Motor is operated without water, the mechanical seal can fail. To 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 to a one minute water fill cycle before starting the ice making cycle. This method allows for a Low Water Safety shut down to protect the Water Pump from mechanical seal failure. For water-cooled model, if the water is shut off, the unit is protected by the High Pressure Switch.

5) High Voltage Cutout The maximum allowable supply voltage of this icemaker is limited by the High Voltage Cutout.

If miswiring (especially on single phase 3 wire models) causes excessive voltage on the Controller Board, the High Voltage Cutout shuts down the circuit in 3 seconds and the icemaker automatically stops. When the proper supply voltage is resumed, the icemaker automatically starts running again. The Control Board will signal this problem using 7 Beeps every 3 seconds.

6) LED Lights and Audible Alarm Safeties The red LED indicates proper 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 short beep occurs when the power switch is turned ON or OFF.

The green LED’s 1-4 represent the corresponding relays and energize and sequence 5 seconds from initial start-up as follows:

Sequence Step LED’s on Length: Min. Max. Avg.

1 Minute Fill Cycle LED4 60 sec. Harvest Cycle LED1, 4, & 2 2 min. 20 min. 3-5 min. Freeze Cycle LED1 5 mi n. 6 0 min. 30-35 min. Reverse Pump Out LED1, 3, & 2 10 sec. 20 sec. Factory set.

{LED 1 – Comp; LED 2 - HGV/CFM; LED 3 – PM; LED 4 - WV} The built in safeties shut down the unit and have alarms as follows:

1 beep every 3 sec. = High Evaporator Temperature >127 ° F. Check for defrost problem (stuck HGV or relay), hot water entering unit, stuck

headmaster, or shorted thermistor. 2 beeps every 3 sec. = Defrost Back Up Timer. Defrost >20 minutes.

Orange LED marked 20 MIN energizes. Check for open thermistor, HGV not opening, TXV leaking by, low charge, or inefficient compressor.

3 beeps every 3 sec. = Freeze Back Up Timer. Freeze > 60 minutes. Yellow LED marked 60 MIN energizes. Check for F/S stuck closed (up), WV leaking by, HGV leaking by, TXV not feeding properly, low charge, or inefficient compressor.

4 beeps every 3 sec. = Short Circuit between the K4 connection on

Machines with mechanical bin control ONLY

the control board and the bin control relay. Check connections and replace wire harness if necessary.

5 beeps every 3 sec. = Open Circuit between the K4 connection on the control board and the bin control relay. Check connections and replace wire harness if necessary.

To manually reset the above safeties, depress white alarm reset button with the power supply ON.

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. The voltage safety automatically resets when voltage is corrected.

The Output Test switch “S3” provides a relay sequence test. With power OFF, place S3 ON and switch power to ICE. The correct lighting sequence should be none, 2, 3, 4, 1, & 4, normal sequence every 5 seconds. S3 should remain in the “OFF” position for normal operation.

The application switch located between relay X3 & X4 must be set to match the original board application. Place this switch in the ALP position if there is no 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 energized 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.

(Control Products HOS-001A Board)

[c] SEQUENCE

1st Cycle

1. Unit energized and Control Switch to “ICE” position. Water supply cycle starts.

2. After 1 minute, Defrost cycle starts.

3. Thermistor reads 48° F. Defrost Timer starts counting.

5. After the first 5 minutes in freeze cycle. Ready to complete freeze cycle when Float Switch circuit opens.

IMPORTANT

Board never accepts freeze completion signal within the first 5 minutes in freeze cycle.

IMPORTANT

Water Valve opening is limited to 6 minutes.

4. Defrost Timer stops counting. Defrost cycle is completed and freeze cycle starts.

IMPORTANT

1. Board never accepts defrost completion signal within the first 2 minutes in defrost cycle.

2. Defrost cycle time is limited to 20 minutes even if Defrost Timer does not stop counting.

2nd Cycle and after with pump drain

IMPORTANT

Freeze cycle time is limited to 60 minutes even if Float Switch does not open.

1. Float Switch opens and signals to complete freeze cycle. Drain timer starts counting.

2. Drain timer stops counting. Pump drain is completed

3. Thermistor reads 48° F. Defrost Timer starts counting.

IMPORTANT

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.

IMPORTANT

Board never accepts freeze completion signal within the first 5 minutes in freeze cycle.

4. Defrost Timer stops counting. Defrost cycle is completed and freeze cycle starts.

IMPORTANT

1. Board never accepts defrost completion signal within the first 2 minutes in defrost cycle.

2. Defrost cycle time is limited to 20 minutes even if Defrost Timer does not stop counting.

2nd Cycle and after with no pump drain

IMPORTANT

Freeze cycle time is limited to 60 minutes even if Float Switch does not open.

1. Float Switch opens and signals to complete freeze cycle.

2. Thermistor reads 48° F. Defrost Timer starts counting.

IMPORTANT

Water Valve opening is limited to 6 minutes.

4. After the first 5 minutes in freeze cycle. Ready to complete freeze cycle when Float Switch circuit opens.

IMPORTANT

Board never accepts freeze completion signal within the first 5 minutes in freeze cycle.

3. Defrost Timer stops counting. Defrost cycle is completed and freeze cycle starts.

IMPORTANT

1. Board never accepts defrost completion signal within the first 2 minutes in defrost cycle.

2. Defrost cycle time is limited to 20 minutes even if Defrost Timer does not stop counting.

[d] CONTROLS AND ADJUSTMENTS

The Dip Switch is factory-adjusted to the following positions:

FOR MODELS WITH MECHANICAL BIN CONTROL:

DIP SWITCH NO. 1 2 3 4 5 6 7 8 9 10

KM-280MAH ON OFF OFF ON ON ON ON OFF OFF OFF KM-280MWH OFF OFF OFF ON ON ON ON OFF OFF ON

FOR MODELS WITH THERMOSTAT :

DIP SWITCH NO. 1 2 3 4 5 6 7 8 9 10

KM-280MAH ON OFF OFF ON ON ON OFF OFF OFF OFF KM-280MWH OFF OFF OFF ON ON ON OFF OFF OFF ON

Switch Nos. 1 and 2:

Used for adjustment of the Defrost Timer. The Defrost Timer starts counting when the Thermistor reads a certain temperature

at the Evaporator outlet. Switch Nos. 3 and 4:

Used for adjustment of the Drain Timer.

When a freeze cycle is completed, the Pump Motor stops, and the icemaker resumes operation in 2 seconds. Then the Pump Motor drains the Water Tank for the time determined by the Drain Timer. The Drain Timer also 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.) Switch No. 8:

Used only for checking the Controller Board. Usually set in OFF position.

Switch Nos. 9 and 10: Used for adjustment of Freeze Timer.

The Freeze Timer determines maximum freeze cycle time. Upon termination of Freeze Timer, machine initiates the harvest cycle. After 2 consecutive timer terminations, machine will shut down, possibly indicating a problem.

1) Defrost Control A thermistor (Semiconductor) is used for a defrost control sensor. The resistance

varies depending on the Suction Line temperatures. The Thermistor detects the temperature of the Evaporator outlet to start the Defrost Timer. No adjustment is required. If necessary, check for resistance between Thermistor leads, and visually check the Thermistor mounting, located on the Suction Line next to the Evaporator outlet.

Temperature (°F) Resistance (kΩ)

0 14.401 10 10.613 32 6.000 50 3.871 70 2.474

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 if it exceeds the normal reading.

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