Hoshizaki American, Inc. KMD-410MAH Service Manual

NO. F043-809

ISSUED: JUN. 18, 2010

REVISED:

HOSHIZAKI

MODULAR CRESCENT CUBER

MODEL

KMD-410MAH

KMD-410MWH

SERVICE MANUAL

CONTENTS PAGE

I. SPECIFICATIONS --------------------------------------------------------------------------------------- 1

1. SPECIFICATIONS ---------------------------------------------------------------------------------- 1 [a] KMD-410MAH (air-cooled) --------------------------------------------------------------------- 1 [b] KMD-410MWH (water-cooled) ---------------------------------------------------------------- 2

II. GENERAL INFORMATION -------------------------------------------------------------------------- 3

1. CONSTRUCTION ----------------------------------------------------------------------------------- 3 [a] KMD-410MAH ------------------------------------------------------------------------------------- 3 [b] KMD-410MWH ------------------------------------------------------------------------------------ 4

2. SEQUENCE OF OPERATION ------------------------------------------------------------------- 5 [a] ONE MINUTE FILL CYCLE ------------------------------------------------------------------- 5 [b] INITIAL HARVEST CYCLE -------------------------------------------------------------------- 5 [c] FREEZE CYCLE --------------------------------------------------------------------------------- 5 [d] DRAIN CYCLE ------------------------------------------------------------------------------------ 5 [e] NORMAL HARVEST CYCLE ----------------------------------------------------------------- 6

3. CONTROL BOARD ---------------------------------------------------------------------------------- 8 [a] CONTROL BOARD LAYOUT ----------------------------------------------------------------- 9 [b] FEATURES ---------------------------------------------------------------------------------------- 10 [c] CONTROLS AND ADJUSTMENTS ---------------------------------------------------------- 12 [d] CONTROL BOARD CHECK PROCEDURE ----------------------------------------------- 15 [e] CONTROL BOARD REPLACEMENT ------------------------------------------------------- 15

4. HARVEST CONTROL – THERMISTOR -------------------------------------------------------- 15

5. FLOAT SWITCH -------------------------------------------------------------------------------------- 16 [a] EXPLANATION OF OPERATION ------------------------------------------------------------ 16 [b] CLEANING ----------------------------------------------------------------------------------------- 16 [c] FLOAT SWITCH CHECK PROCEDURE --------------------------------------------------- 16

6. BIN CONTROL ---------------------------------------------------------------------------------------- 17

[a] EXPLANATION OF OPERATION ------------------------------------------------------------ 17 [b] BIN CONTROL CHECK PROCEDURE ----------------------------------------------------- 17

7. SWITCHES --------------------------------------------------------------------------------------------- 18 [a] CONTROL SWITCH ----------------------------------------------------------------------------- 18 [b] SERVICE SWITCH ------------------------------------------------------------------------------ 18

III. TECHNICAL INFORMATION ----------------------------------------------------------------------- 19

1. WATER CIRCUIT AND REFRIGERANT CIRCUIT ------------------------------------------- 19

2. WIRING DIAGRAM ----------------------------------------------------------------------------------- 20

3. TIMING CHART --------------------------------------------------------------------------------------- 21

4. PERFORMANCE DATA ----------------------------------------------------------------------------- 22 [a] KMD-410MAH ------------------------------------------------------------------------------------- 22 [b] KMD-410MWH ------------------------------------------------------------------------------------ 23

IV. SERVICE DIAGNOSIS ------------------------------------------------------------------------------- 24

1. 10-MINUTE DIAGNOSTIC PROCEDURE ------------------------------------------------------ 24

2. DIAGNOSTIC CHARTS ----------------------------------------------------------------------------- 26 [a] NO ICE PRODUCTION ------------------------------------------------------------------------- 26 [b] EVAPORATOR IS FROZEN UP -------------------------------------------------------------- 29 [c] LOW ICE PRODUCTION ----------------------------------------------------------------------- 30 [d] ABNORMAL ICE ---------------------------------------------------------------------------------- 30 [e] OTHER ---------------------------------------------------------------------------------------------- 31

V. REMOVAL AND REPLACEMENT ----------------------------------------------------------------- 32

1. SERVICE FOR REFRIGERANT LINES --------------------------------------------------------- 32 [a] SERVICE INFORMATION ---------------------------------------------------------------------- 32 [b] REFRIGERANT RECOVERY ----------------------------------------------------------------- 33 [c] EVACUATION AND RECHARGE ------------------------------------------------------------ 33

2. BRAZING ------------------------------------------------------------------------------------------------ 34

3. COMPRESSOR ---------------------------------------------------------------------------------------- 34

4. DRIER ---------------------------------------------------------------------------------------------------- 35

5. HOT GAS VALVE ------------------------------------------------------------------------------------- 36

6. EXPANSION VALVE --------------------------------------------------------------------------------- 37

7. EVAPORATOR ---------------------------------------------------------------------------------------- 38

8. WATER REGULATING VALVE – WATER-COOLED MODEL ONLY-------------------- 39

9. ADJUSTMENT OF WATER REGULATING VALVE – WATER-COOLED

MODEL ONLY ------------------------------------------------------------------------------------------ 40

10. FAN MOTOR ------------------------------------------------------------------------------------------- 40

11. PUMP MOTOR ---------------------------------------------------------------------------------------- 41

12. WATER VALVE ---------------------------------------------------------------------------------------- 42

13. DRAIN VALVE, CLEANING VALVE -------------------------------------------------------------- 42

14. WATER TANK ----------------------------------------------------------------------------------------- 43

15. FLOAT SWITCH --------------------------------------------------------------------------------------- 44

16. BIN CONTROL SWITCH ---------------------------------------------------------------------------- 45

17. THERMISTOR ----------------------------------------------------------------------------------------- 46

18. CONTROL BOX --------------------------------------------------------------------------------------- 47 [a] CONTROL & SERVICE SWITCH------------------------------------------------------------- 48 [b] FUSE ------------------------------------------------------------------------------------------------- 48 [c] FUSE HOLDER ----------------------------------------------------------------------------------- 48 [d] CONTROL BOARD ------------------------------------------------------------------------------ 49 [e] MAGNETIC CONTACTOR --------------------------------------------------------------------- 49 [f] CONTROL BOARD TRANSFORMER ------------------------------------------------------- 49 [g] STARTER ------------------------------------------------------------------------------------------- 49 [h] RUN CAPACITOR -------------------------------------------------------------------------------- 49 [i] START CAPACITOR ----------------------------------------------------------------------------- 49 [j] CAPACITOR FOR PUMP MOTOR ----------------------------------------------------------- 50

19. SPRAY TUBE, WATER SUPPLY TUBE, SPRAY GUIDE ---------------------------------- 50

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

1. CLEANING ---------------------------------------------------------------------------------------------- 52 [a] CLEANING PROCEDURE --------------------------------------------------------------------- 52 [b] SANITIZING PROCEDURE -------------------------------------------------------------------- 55

2. MAINTENANCE --------------------------------------------------------------------------------------- 55

[a] STAINLESS STEEL EXTERIOR---------------------------------------------------------------56 [b] STORAGE BIN AND SCOOP ----------------------------------------------------------------- 56 [c] AIR FILTER (AIR-COOLED MODEL ONLY) ---------------------------------------------- 56 [d] CONDENSER (AIR-COOLED MODEL ONLY) ------------------------------------------- 56

3. PREPARING THE ICEMAKER FOR LONG STORAGE ------------------------------------ 56

iii

I. SPECIFICATIONS

1. SPECIFICATIONS

[a] KMD-410MAH (air-cooled)

AC SUPPLY VOLTAGE 115/60/1 㩷 AMPERAGE 8.0 A (5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 15 A MAXIMUM FUSE SIZE 15 A APPROXIMATE ICE PRODUCTION Ambient WATER TEMP. (°F) PER 24 HR. Temp.(°F) 50 70 90 lbs./day (kg/day) 70 *415 (188) 388 (176) 354 (160) Reference without *marks 80 395 (179) 353 (160) 320 (145) 90 388 (176) *324 (147) 289 (131) 100 382 (173) 316 (143) 257 (117) SHAPE OF ICE Crescent Cube ICE PRODUCTION PER CYCLE 8.5 lbs. (3.9 kg) 416 pcs. APPROXIMATE STORAGE CAPACITY N/A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 780(5.8) 710(4.1) WATER gal./24HR (gal./100 lbs.) 73(22.6) 148(35.7) EXTERIOR DIMENSIONS (WxDxH) 22-1/4" x 24-1/8" x 24" (565 x 613 x 610 mm) EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear) WEIGHT Net 126 lbs. (57 kg), Shipping 161 lbs. (73 kg) CONNECTIONS - ELECTRIC Permanent - Connection

- WATER SUPPLY Inlet 1/2" FPT

- DRAIN Outlet 3/4" FPT CUBE CONTROL SYSTEM Float Switch HARVESTING CONTROL SYSTEM Hot Gas and Water, Thermistor and Timer ICE MAKING WATER CONTROL Timer Controlled, Overflow Pipe COOLING WATER CONTROL N/A BIN CONTROL SYSTEM Mechanical Level Switch with Delay COMPRESSOR Hermetic, Model NT6217GKV CONDENSER Air-Cooled, Fin and tube type EVAPORATOR Vertical type, Stainless Steel and Copper REFRIGERANT CONTROL Thermostatic Expansion Valve REFRIGERANT CHARGE R-404A, 1 lb. 2.3 oz. (520g) DESIGN PRESSURE High 467PSIG, Low 206PSIG P.C. BOARD CIRCUIT PROTECTION High Voltage Cut-out (Internal) COMPRESSOR PROTECTION Auto-reset Overload Protector (Internal) REFRIGERANT CIRCUIT PROTECTION Auto-reset High Pressure Control Switch LOW WATER PROTECTION Float Switch ACCESSORIES - SUPPLIED N/A

- REQUIRED Ice Dispenser or Ice Storage Bin OPERATING CONDITIONS VOLTAGE RANGE 104 - 127 V AMBIENT TEMP. 45 -100° F WATER SUPPLY TEMP. 45 - 90° F

WATER SUPPLY PRESSURE 10 - 113PSIG

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

[b] KMD-410MWH (water-cooled)

AC SUPPLY VOLTAGE 115/60/1 㩷 AMPERAGE 6.5 A (5 Min. Freeze AT 104°F / WT 80°F) MINIMUM CIRCUIT AMPACITY 15 A MAXIMUM FUSE SIZE 15 A APPROXIMATE ICE PRODUCTION Ambient WATER TEMP. (°F) PER 24 HR. Temp.(°F) 50 70 90 lbs./day (kg/day) 70 *440 (200) 423 (192) 392 (178) Reference without *marks 80 427 (194) 401 (182) 364 (165) 90 423 (192) *382 (173) 347 (157) 100 414 (188) 373 (169) 315 (143) SHAPE OF ICE Crescent Cube ICE PRODUCTION PER CYCLE 8.2 lbs. (3.7 kg) 416 pcs. APPROXIMATE STORAGE CAPACITY N/A ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F ELECTRIC W (kWH/100 lbs.) 680(4.3) 670(3.7) WATER gal./24HR (gal./100 lbs.) 89(23.2) 120(27.2) WATER COOLED CONDENSER 552(145) 267(61) gal./24HR (gal./100 lbs.) 㩷㩷 EXTERIOR DIMENSIONS (WxDxH) 22-1/4" x 24-1/8" x 24" (565 x 613 x 610 mm) EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear) WEIGHT Net 128 lbs. (58 kg), Shipping 163 lbs. (74 kg) CONNECTIONS - ELECTRIC Permanent - Connection

- WATER SUPPLY Inlet 1/2" FPT Cond. Inlet 1/2" FPT

- DRAIN Outlet 3/4" FPT Cond. Outlet 1/2" FPT CUBE CONTROL SYSTEM Float Switch HARVESTING CONTROL SYSTEM Hot Gas and Water, Thermistor and Timer ICE MAKING WATER CONTROL Timer Controlled, Overflow Pipe COOLING WATER CONTROL N/A BIN CONTROL SYSTEM Mechanical Level Switch with Delay COMPRESSOR Hermetic, Model NT6217GKV CONDENSER Water-Cooled, Tube in tube type EVAPORATOR Vertical type, Stainless Steel and Copper REFRIGERANT CONTROL Thermostatic Expansion Valve REFRIGERANT CHARGE R-404A, 14.1 oz. (400g) DESIGN PRESSURE High 427PSIG, Low 206PSIG P.C. BOARD CIRCUIT PROTECTION High Voltage Cut-out (Internal) COMPRESSOR PROTECTION Auto-reset Overload Protector (Internal) REFRIGERANT CIRCUIT PROTECTION Auto-reset High Pressure Control Switch LOW WATER PROTECTION Float Switch ACCESSORIES - SUPPLIED N/A

- REQUIRED Ice Dispenser or Ice Storage Bin OPERATING CONDITIONS VOLTAGE RANGE 104 - 127 V AMBIENT TEMP. 45 -100° F WATER SUPPLY TEMP. 45 - 90° F

WATER SUPPLY PRESSURE 10 - 113 PSIG

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

II. GENERAL INFORMATION

1. CONSTRUCTION

[a] KMD-410MAH

Cleaning

Valve

Access Valve (High Side)

Thermistor

Access Valve (Low Side)

Cube Guide

Water Tank

Spray Tube

Pump Motor

Water Supply Tube

Spray Guide

Float Switch

Drain Valve

Water Supply Inlet

Hot Gas Valve

Condenser

Expansion Valve

Fan Motor

Compressor

Control Box

Harvest Water Valve

Fill Water Valve

Control Switch

Service Switch

Fuse Holder (Fuse)

Drier

Bin Control Switch

[b] KMD-410MWH

Cleaning Valve

Access Valve (High Side)

Thermistor

Access Valve (Low Side)

Cube Guide

Water Tank

Spray Tube

Pump Motor

Spray Guide

Float Switch

Water Supply Tube

Drain Valve

Water Supply Inlet

Hot Gas Valve

Water Regulator

Expansion Valve

Condenser

Compressor

Drier

Control Box

Harvest Water Valve

Fill Water Valve

Control Switch

Service Switch

Fuse Holder (Fuse)

Bin Control Switch

2. SEQUENCE OF OPERATION

The steps in the sequence are as outlined below. When power is supplied, a 5 second delay occurs at startup. Note that the order of the LEDs from the outer edge of the board is 5, 6, 8, 9, 4, 7.

[a] ONE MINUTE FILL CYCLE

LED 8 is on. HWV opens and the fill period begins. After 1 minute, the board checks for a closed LF/S. If LF/S is closed, the harvest cycle begins. If not, HWV will remain energized through additional 1 minute cycles until water enters the sump and LF/S closes. This serves as a low water safety to protect the water pump.

[b] INITIAL HARVEST CYCLE

LEDs 5, 6, and 8 are on. HWV remains open, Comp energizes, HGV opens, and harvest begins. As the evaporator warms, the thermistor located on the suction line checks for a 9°C temperature. When 9°C is reached, a 3.9 k signal turns the harvest over to the adjustable harvest timer which is factory set for normal conditions. The timer has settings of 60, 90, 120, and 180 seconds (S1 dip switch 1 & 2). When the harvest timer completes its count down, the harvest cycle is complete and the freeze cycle starts. The minimum total time allowed by the board for a complete harvest cycle is 2 minutes. HWV is open during harvest for a maximum of 6 minutes or the length of harvest minus 0, 10, 30, or 50 seconds (adjustable by S1 dip switch 7 & 8), whichever is shorter. LED 8 goes off when HWV closes. PM energizes and runs for the last 0, 10, 30, or 50 seconds of harvest depending on S1 dip switch 7 & 8 setting. LED 7 comes on when PM energizes. At the end of harvest, the control board checks the position of LF/S and proceeds to the freeze cycle if it is closed or calls for a 1-minute fill if it is open.

[c] FREEZE CYCLE

LEDs 5 & 7 are on. Comp continues to run, PM and FMS energize, HGV closes and the freeze cycle starts. For the first 5 minutes after the thermistor temperature reaches 2°C, the control board will not accept a signal from LF/S and UF/S. This minimum freeze period acts as a short cycle protection. At the end of this period, LF/S and UF/S assumes control. As ice builds on the evaporator the water level in the sump lowers and LF/S opens, FWV opens (LED 9 is on when FWV is open). The refill will last until UF/S closes or for 60 seconds, whichever is shorter. After UF/S closes, FWV closes 3 seconds later. KMD-410 refills 1 time. After the refill, the freeze continues until LF/S opens again and terminates ice production.

[d] DRAIN CYCLE

LEDs 4, 5, 6, and 7 are on. Comp continues to run, HGV opens, FMS de-energizes. PM stops for 2 seconds, DV energizes, then restarts to take water from the sump and force it through DV and down the drain. When the drain timer stops counting, the drain is complete. The drain timer is 10 or 20 seconds (S1 dip switch 3 & 4). Drain cycle always occurs on the 2nd harvest after startup. Then, depending on the control board setting, drain cycle occurs every cycle, or every 2nd, 5th, or 10th cycles (S1 dip switch 5 & 6).

[e] NORMAL HARVEST CYCLE

LEDs 5, 6, and 8 are on. Comp continues to run, HGV remains open and HWV opens. As the evaporator warms, the thermistor reaches 9ºC. The control board then receives the thermistor’s 3.9k signal and starts the harvest timer. HWV is open during harvest for a maximum of 6 minutes or the length harvest minus 0, 10, 30, or 50 seconds (adjustable by S1 dip switch 7 & 8), whichever is shorter. LED 8 goes off when HWV closes. PM energizes and runs for the last 0, 10, 30, or 50 seconds of harvest depending on S1 dip switch 7 & 8 setting. LED 7 comes on when PM energizes. At the end of harvest, the control board checks for the position of LF/S and proceeds to the freeze cycle if it is closed or calls for a 1-minute fill if it is open. The unit continues to cycle through [c], [d], and [e] sequence until the bin control is activated and shuts the unit down. When the bin control is activated, the “POWER OK” LED flashes.

Note: To prevent incomplete batches of ice from foaming on the evaporator, the control

board will only shut down the machine within the first 5 minutes of the freeze cycle after the thermistor temperature reaches 2 ºC. If ice pushes the bin control actuator in (open) after this minimum freeze period, the control board will allow the machine to complete the freeze cycle and the following harvest cycle before shutting down the machine.

Legend: Comp–compressor; DV–drain valve; FMS–self-contained fan motor; FWV–fill

water valve; HGV–hot gas valve; HWV–harvest water valve; LF/S–lower float switch contacts; UF/S–upper float switch contacts; PM–pump motor

cycle (S1 dip

4. Drain Cycle

Factory set for every

Switch 5 & 6)

Pump motor stops

for 2 sec. and then

runs for 10/20 sec.

(S1 dip switch 3 & 4)

PM de-energizes 0/2 sec.,

energizes for 10/20

sec.

COMP continues

DV energized/

HGV energized

FMS de-energized

xMinimum freeze time: 5 minutes

xMaximum freeze time: freeze time setting

xLower float switch used to initiate water

Tank refill (1 refill for KMD-410)

xUpper float switch used to terminate

water tank refill (1 minute maximum fill

time)

COMP continues

PM continues

FWV energized/

de-energized

for refill only

FMS energized

HGV de-energized

0, 0,30,

or 50 sec

xMaximum harvest water valve time: 6 minutes

(HWV time is 6 minutes of the length of harvest

minus 0, 10, 30, or 50 sec. (S1 dip switch

7 & 8), whichever is shorter. PM energizes

and runs for the last 0, 10, 30, or 50 sec. of

harvest.)

xMaximum harvest time: 20 minutes

COMP energized

HGV energized

HWV continues

FWV de-energized

DV de-energized

KMD-410MAH, 410MWH

HWV energized

5 second delay

“H” board will have

Legend:

COMP - compressor

DV – drain valve

FMS – self-contained fan motor

FWV – fill water valve

HGV – hot gas valve

HWV – harvest water valve

LF/S – lower float switch contacts

PM – pump motor

UF/S – upper float switch contacts

3. CONTROL BOARD

* A HOSHIZAKI exclusive solid-state control is employed in KMD-410MAH and

KMD-410MWH Crescent Cubers.

* All models are pretested and factory-adjusted.

1. Fragile, handle very carefully.

2. A 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 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.

5. Always replace the whole board assembly if it goes bad.

6. Do not short out power supply to test for voltage.ᴾ

[a] CONTROL BOARD LAYOUT

#4 Harvest Water Valve #5 Freeze Water Valve

#1, 2, 3 Float Switch

[b] FEATURES

a) Maximum Water Supply Period - 6 minutes

The harvest water valve will be open during harvest for 6 minutes or the length of harvest minus 0, 10, 30, or 50 seconds (adjustable by S dip switch 7 & 8), whichever is shorter.

b) Harvest Backup Timer and Freeze Timer

The harvest backup timer shuts down the icemaker if, for two cycles in a row, the harvest cycle takes more than 20 minutes to complete. The control board will signal this problem using 2 beeps every 3 seconds. The freeze timer shuts down the icemaker if, for two cycles in a row, the freeze cycle takes longer than the time specified to complete. The control board will signal this problem using 3 beeps every 3 seconds. The time is factory set using S1 dip switch 9 & 10. The alarm reset button on the control board must be pressed with power on to reset either of these safeties.

c) High Temperature Safety

The temperature of the suction line in the refrigeration circuit is limited by the high temperature safety. This protects the unit from excessively high temperatures. If the evaporator temperature rises above 53°C ± 4°C, the thermistor operates the safety. This shuts down the circuit and the icemaker automatically stops. The control board will signal this problem using 1 beep every 3 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 lower float switch at the end of the initial one minute water fill cycle and at the end of each harvest cycle. If the lower float switch is in the up position (electrical circuit closed), the control board changes to the next cycle. If the lower float switch is in the down position (electrical circuit open), the control board changes to additional one minute water fill cycles until water enters the sump and the float switch closes. When the float switch closes, the control board changes to the next cycle. The unit will not start without adequate water in the sump. This serves as a low water safety to protect the water pump. For water-cooled model, if the condenser water supply is shut off, the unit is protected by the high-pressure switch.

e) High Voltage and Low Voltage Cut-outs

The maximum and minimum allowable supply voltages of this icemaker are limited by the high voltage and low voltage cut-outs. If miswiring (especially on single 3 phase wire models) causes excessive voltage ( 294 Vac ± 5% or more) on the control board, the high voltage cut-out shuts down the circuit in 3 seconds and the icemaker automatically stops. The control board will signal this problem using 7 beeps every 3 seconds. The icemaker also automatically stops in cases of insufficient voltage (184Vac ± 5% or less). The control board will signal this problem using 6 beeps every 3 seconds. When the proper supply voltage is resumed, the icemaker automatically starts running again.

f) LED Lights and Audible Alarm Safeties

The control board includes LED indicator lights, audible alarm safeties, and an output test feature. The "POWER OK" LED indicates control voltage and will remain on unless a control voltage problem occurs. The “POWER OK” LED flashes continuously when the bin is full and DV energizes for a maximum of 5 minutes to drain the water tank. At startup, a 5 second delay occurs to stabilize the circuit. LEDs 4 through 8 energize and sequence from initial startup as listed in the table below. Note that the order of the LEDs from the outer edge of the board is 5, 6, 8, 9, 4, 7. For more information, see "2. SEQUENCE OF OPERATION".

5, 7 (and 9 at refill)

HWV

HWV, HGV, Comp

Comp, PM, FMS (FWV at refill)

DV- drain valve; FMS-self-contained fan motor;

WRV-water regulating valve;

[c] CONTROLS AND ADJUSTMENTS

a) Default Dip Switch Settings

The dip switch is factory-adjusted to the following positions:

KMD-410MAH KMD-410MWH

Do not adjust the S2 dip switch. These must be left in the factory default position, or the unit will not operate properly.

b) Harvest Timer (S1 dip switch 1 & 2)

Used for adjustment of the harvest timer. The harvest timer starts counting when the thermistor reads a certain temperature at the evaporator outlet.

c) Drain Timer (S1 dip switch 3 & 4)

Once every ten freeze cycles, the drain valve opens to drain the water tank for the time determined by the drain timer. These switches also determine the time to delay completion of a defrost cycle, i.e. the minimum defrost time. Do not change this setting, or the unit will not operate properly or produce high quality ice.

T1: Time to drain the water tank T2: Harvest timer at drain

Drain cycle always occurs on the 2nd harvest after startup. Then, depending on the drain frequency control setting (dip switch 5 & 6), drain cycle occurs every cycle, or every 2nd, 5th, or 10th cycle.

d) Drain Frequency Control (S1 dip switch 5 & 6)

The water tank drains at the frequency set by the drain frequency control. The drain frequency control is factory-adjusted to drain the water tank every 10 cycles, and no adjustment is required. However, where water quality is bad and the icemaker needs a drain more often, the drain frequency can be adjusted as shown in the table below.

e) Water Saver Timer (S1 dip switch 7 & 8)

The water saver timer allows the water valve to close and the pump motor to circulate water in the tank during the final part of harvest. The water valve is open during harvest for a maximum of 6 minutes or the length of harvest minus 0, 10, 30, or 50 seconds (determined by the water saver timer setting), whichever is shorter. When the water valve closes, the pump motor energizes and runs for the time determined by the water saver timer setting. The water saver timer is factory-adjusted, and no adjustment is required.

f) Freeze Timer (S1 dip switch 9 & 10)

The freeze timer setting determines the maximum allowed freeze time to prevent possible freeze-up issues. Upon termination of freeze timer, machine initiates the harvest cycle. After 2 consecutive timer terminations, machine will shut down, possibly indicating a problem. The freeze timer is factory adjusted, and no adjustment is required.

Time(50/60Hz)

(minutes)

60/60 60/50

100/70

120/100

g) Pump-Out Pump Motor Delay (S2 dip switch 1)

The pump-out pump motor delay determines whether or not the pump motor de-energizes for 2 seconds before restarting at the beginning of a drain cycle. The pump-out pump motor delay is factory adjusted and no adjustment is required.

h) Refill Counter (S2 dip switch 2, 3, & 4)

Do not adjust. These must be left in the factory default position or the unit will not operate properly. The KMD-410MAH and KMD-410MWH refill 1 time.

i) Factory Use (S2 dip switch 5)

Must remain off.

j) Anti-Slush Control (S2 dip switch 6)

The anti-slush control helps prevent slushing during the freeze cycle on small icemakers. It is deactivated on the KMD-410 series. When activated, the thermistor located on the suction line checks for a 34 ºF (1 ºC) temperature as the evaporator cools. When 34 ºF (1 ºC) is reached, a 5.9 k signal causes the control board to de-energize the pump motor for 10 seconds. Do not adjust. This must be left in the factory default position or the unit will not operate properly.

[d] CONTROL BOARD CHECK PROCEDURE

Before replacing a control board 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.

1) Check the dip switch settings to assure that S1 dip switch 3, 4, 7, 8, 9, & 10 and S2 dip switch 1 through 6 are in the factory default position. S1 dip switch 1, 2, 5, & 6 are cleaning adjustments and the settings are flexible.

2) Move the control switch to the "ICE" position and check for proper control voltage. If the

"POWER OK" LED is on, the control voltage is good. If the "POWER OK" LED is off, check the control transformer circuit. If no voltage is present, check the power supply circuit.

3) The output test button provides a relay sequence test. Make sure the control switch is in the "ICE" position, then press the "OUTPUT TEST" button. The correct lighting sequence should be 5, 6, 7, 8, 9, 4. Some components (e.g., the compressor) will cycle during the test. Each LED flashes three times in 5 seconds. LED 5 continues to flash while LED 6 flashes. Following the output test sequence, the icemaker will resume normal operation beginning with the 1 minute fill cycle.

[e] CONTROL BOARD REPLACEMENT

The dip switches should be adjusted to the factory default settings as outlined in this manual. S2 dip switch 5 must remain off.

4. HARVEST CONTROL – THERMISTOR

A thermistor (semiconductor) is used as a harvest control sensor and anti-slush sensor. The resistance varies depending on the suction line temperatures. The thermistor detects the temperature of the evaporator outlet to start the harvest timer or momentarily stop the pump motor during the freeze cycle. 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.

Check a thermistor for resistance by using the following procedure:

1) Disconnect the thermistor (orange wires) at the 2-pin connector on the control box. See Fig. 1.

2) Remove the thermistor. See "V. 17. THERMISTOR."

3) Immerse the thermistor sensor portion in a glass containing ice and water for 2 or 3 minutes.

4) Check for a resistance between thermistor leads.

Thermistor Connector (orange wires)

Bin Control Wires (black)

Float Switch Connector (red wires)

Normal reading is within 3.5 to 7 k. Replace the thermistor if it exceeds the normal reading.

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