Hoshizaki KMD-210AB-HC User manual

F138-1074 (072020)
SERVICE MANUAL
MODULAR CRESCENT CUBER KMD-210AB-HC

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CONTENTS PAGE
I. SPECIFICATIONS --------------------------------------------------------------------------------------- 1
1. DIMENSIONS/SPECIFICATIONS --------------------------------------------------------------- 1
II. GENERAL INFORMATION --------------------------------------------------------------------------- 2
1. CONSTRUCTION ------------------------------------------------------------------------------------ 2
2. SEQUENCE OF OPERATION -------------------------------------------------------------------- 3
[a] ONE MINUTE FILL CYCLE -------------------------------------------------------------------- 3
[b] INITIAL HARVEST CYCLE --------------------------------------------------------------------- 3
[c] FREEZE CYCLE ---------------------------------------------------------------------------------- 3
[d] DRAIN CYCLE ------------------------------------------------------------------------------------ 3
[e] NORMAL HARVEST CYCLE ------------------------------------------------------------------ 4
3. CONTROL BOARD ---------------------------------------------------------------------------------- 6
[a] CONTROL BOARD LAYOUT ------------------------------------------------------------------ 7
[b] FEATURES ---------------------------------------------------------------------------------------- 8
[c] CONTROLS AND ADJUSTMENTS --------------------------------------------------------- 10
[d] CONTROL BOARD CHECK PROCEDURE ---------------------------------------------- 14
[e] CONTROL BOARD REPLACEMENT ------------------------------------------------------ 14
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
KMD-210AB-HC ------------------------------------------------------------------------------------- 21
IV. SERVICE DIAGNOSIS ------------------------------------------------------------------------------ 22
1. 10-MINUTE DIAGNOSTIC PROCEDURE ----------------------------------------------------- 22
2. DIAGNOSTIC CHARTS ----------------------------------------------------------------------------- 24
[a] NO ICE PRODUCTION ------------------------------------------------------------------------ 24
[b] EVAPORATOR IS FROZEN UP ------------------------------------------------------------- 26
[c] LOW ICE PRODUCTION ---------------------------------------------------------------------- 27
[d] ABNORMAL ICE --------------------------------------------------------------------------------- 28
[e] OTHER --------------------------------------------------------------------------------------------- 28
V. REMOVAL AND REPLACEMENT----------------------------------------------------------------- 29
1. SERVICE FOR REFRIGERANT LINES -------------------------------------------------------- 29
[a] SERVICE INFORMATION --------------------------------------------------------------------- 29
[b] REFRIGERANT RECOVERY ----------------------------------------------------------------- 30
[c] REFRIGERANT REMOVAL ------------------------------------------------------------------- 30
[d] EVACUATION AND RECHARGE ----------------------------------------------------------- 30
2. WELDING REPAIR FOR R290 REFRIGERATION CIRCUIT ----------------------------- 31
3. COMPRESSOR --------------------------------------------------------------------------------------- 32

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4. DRIER --------------------------------------------------------------------------------------------------- 33
5. HOT GAS VALVE ------------------------------------------------------------------------------------ 34
6. EXPANSION VALVE -------------------------------------------------------------------------------- 35
7. EVAPORATOR ---------------------------------------------------------------------------------------- 36
8. WATER REGULATING VALVE – WATER-COOLED MODEL ONLY ------------------- 37
9. ADJUSTMENT OF WATER REGULATING VALVE – WATER-COOLED
MODEL ONLY ----------------------------------------------------------------------------------------- 38
10. FAN MOTOR ------------------------------------------------------------------------------------------ 38
11. PUMP MOTOR ---------------------------------------------------------------------------------------- 39
12. WATER VALVE --------------------------------------------------------------------------------------- 40
13. DRAIN VALVE ---------------------------------------------------------------------------------------- 40
14. WATER TANK ----------------------------------------------------------------------------------------- 41
15. FLOAT SWITCH -------------------------------------------------------------------------------------- 42
16. BIN CONTROL SWITCH --------------------------------------------------------------------------- 43
17. THERMISTOR ---------------------------------------------------------------------------------------- 44
18. CONTROL BOX -------------------------------------------------------------------------------------- 46
[a] CONTROL & SERVICE SWITCH ------------------------------------------------------------ 48
[b] FUSE ------------------------------------------------------------------------------------------------ 48
[c] FUSE HOLDER ----------------------------------------------------------------------------------- 48
[d] CONTROL BOARD ------------------------------------------------------------------------------ 48
[e] MAGNETIC CONTACTOR -------------------------------------------------------------------- 48
[f] CONTROL BOARD TRANSFORMER ------------------------------------------------------- 48
[g] STARTER ------------------------------------------------------------------------------------------ 49
[h] RUN CAPACITOR ------------------------------------------------------------------------------- 49
[i] START CAPACITOR ----------------------------------------------------------------------------- 49
[j] CAPACITOR FOR PUMP MOTOR ----------------------------------------------------------- 49
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 -------------------------------------------------------------------------------------- 56
[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

1
I. SPECIFICATIONS
1. DIMENSIONS/SPECIFICATIONS

2
II. GENERAL INFORMATION
1. CONSTRUCTION
Spray Guide
Spray Tube
Drain Valve
Water Supply Inlet
Water Tank
Cube Guide
Pump Motor
Float Switch
Condenser
Fan Motor
Hot Gas Valve
Compressor
Control Box
Expansion Valve
Harvest Water Valve
Fill Water Valve
Control Switch
Service Switch
Fuse Holder (Fuse)
Bin Control Switch
Drier
Thermistor
Water Supply Tube

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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 kΩ 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). When the refill counter is activated, 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-210AB-HC refills 1 time. After the refill, the freeze continues until LF/S
opens again and terminates ice production.
Note: The refill counter is deactivated before shipping.
[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).

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[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 9°C. The control board then receives the
thermistor’s 3.9kΩ signal and starts the harvest timer. 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 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°C. 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

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KMD-210AB-HC
“H” board will have
5 second delay
·Maximum 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.) ·Maximum harvest time: 20 minutes
·Minimum freeze time: 5 minutes ·Maximum freeze time: freeze time setting ·Lower float switch used to initiate water tank refill ·Upper float switch used to terminate water tank refill (1 minute maximum fill time)
Factory set for every 10th cycle (S1 dip
Switch 5 & 6) Pump motor stops for 2 sec. and then runs for 10/20 sec. (S1 dip switch 3 & 4)
0, 0,30, or 50 sec
HWV energized
COMP energized HGV energized HWV continues FWV de-energized DV de-energized
COMP continues
PM continues FWV energized/ de-energized for refill only FMS energized HGV de-energized
PM de-energizes 0/2 sec., energizes for 10/20 sec. COMP continues DV energized/ HGV energized FMS de-energized
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
4. Drain Cycle
5 minutes after the thermistor temperature reaches 2°C
Note: The refill counter is deactivated before shipping.

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3. CONTROL BOARD
* A HOSHIZAKI exclusive solid-state control is employed in KMD-210AB-HC Crescent
Cuber.
* All models are pretested and factory-adjusted.
CAUTION
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.

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[a] CONTROL BOARD LAYOUT
#4 Harvest Water Valve
#5 Freeze Water Valve
#1, 2, 3 Float Switch
P01771-02
Control Board
Model KMD-210AB-HC
Part Number P01771-02
Type HKM2006V003

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[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 S1 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.
Note: The refill counter is deactivated before shipping.
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.

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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".
Sequence Step LED Energized
Components
Time LEDs are On
Min. Max. Avg.
1 Minute Fill Cycle 8 HWV 60 sec
Harvest Cycle 5, 6, 8 WV, HGV,
Comp 2 min. 20 min. 3 to 5 min.
Last 0, 10, 30, or 50 seconds (adjustable by dip switch) of harvest, WV de-energizes and PM
energizes (LEDs 5, 6, and 7 are on)
Freeze Cycle 5, 7 (and
9 at refill)
Comp, PM, FMS
(FWV at refill) 5 min. freeze timer
setting 25 to 30 min.
Drain 5, 6, 4, 7 Comp, HGV,
DV, PM 10 sec. 20 sec. factory default setting
Note: The refill counter is deactivated before shipping.
The built in safeties shut down the unit and have alarms as listed below.
No. of Beeps
(every 3 sec.)Type of AlarmNotes
1High Evaporator Temp.
(temperature > 127°F (53°C))
Check for harvest problem (stuck HGV or relay), 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
leaking by, low charge, inefficient Comp, or WRV
leaking by.
3
Freeze Timer
(freeze > specified setting for
two cycles in a row)
Timer is factory set using S1 dip
switch 9 & 10
Check for a float switch stuck closed (up), WV
leaking by, HGV leaking by, PM not pumping, TXV
not feeding properly, low charge, or inefficient
Comp.
To reset the above safeties, press the “ALARM RESET” button with the power supply on.
6Low Voltage
(184Vac ± 5% or less)
“POWER OK” LED will turn off if voltage protection
operates.
The control voltage safeties automatically reset
when voltage is corrected.
7High Voltage
(294Vac ± 5% or more)
Legend: Comp–compressor; DV–drain valve; FMS–self-contained fan motor; FVW–fill
water valve; HGV–hot gas valve; HM–headmaster; HWV–harvest water valve;
WRV–water regulating valve; PM–pump motor; TXV–thermostatic expansion valve

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[c] CONTROLS AND ADJUSTMENTS
a) Default Dip Switch Settings
The dip switch is factory-adjusted to the following positions:
S1 Dip Switch No. 1 2 3 4 5 6 7 8 9 10
KMD-210AB-HC OFF OFF OFF OFF ON ON ON ON OFF OFF
S2 Dip Switch
* Functions of S2 dip switch nos. 2
through 6 depend on program version.
S2 Dip Switch No. 1 2 3 4 5 6
KMD-210AB-HC ON OFF OFF OFF ON OFF
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.
Dip Switch Setting Time (seconds)
No. 1 No. 2
OFF OFF 60
ON OFF 90
OFF ON 120
ON ON 180

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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 harvest cycle, i.e. the minimum harvest time.
Do not change this setting, or the unit will not operate properly or produce high quality ice.
Dip Switch Setting Time (seconds)
No. 3 No. 4 T1 T2
OFF OFF 10 120
ON OFF 10 180
OFF ON 20 120
ON ON 20 180
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.
Dip Switch Setting Frequency
No. 5 No. 6
OFF OFF Every cycle
ON OFF Every 2 cycles
OFF ON Every 5 cycles
ON ON Every 10 cycles
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.
Dip Switch Setting Time (seconds)
No. 7 No. 8
OFF OFF 0
ON OFF 10
OFF ON 30
ON ON 50

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f) Freeze Timer (S1 dip switch 9 & 10)
CAUTION
Adjust to proper specification, or the unit may not operate correctly.
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.
Dip Switch Setting Time (50/60Hz)
(minutes)
No. 9 No. 10
OFF OFF 60/60
ON OFF 80/50
OFF ON 100/70
ON ON 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.
S2 Dip Switch Setting Delay (seconds)
No. 1
OFF 0
ON 2
h) Harvest Promotion Control (S2 dip switch 2)
Do not adjust. This must be left in the factory default position or the unit will not operate
properly.
It is deactivated on the KMD-210AB-HC.
When activated, this control promotes harvest of ice on the evaporator that is hard to
remove. If the harvest cycle exceeds 6 minutes, the pump motor starts to operate for a
maximum of 3 minutes.
S2 Dip Switch Setting Harvest Promotion
Control
No. 2
OFF Activated
ON Deactivated

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i) Refill Counter (S2 dip switch 3)
Do not adjust. This must be left in the factory default position or the unit will not operate
properly. The refill counter is deactivated before shipping.
j) Harvest Completion Detection Control (S2 dip switch 4)
Do not adjust. This must be left in the factory default position or the unit will not operate
properly.
It is deactivated on the KMD-210AB-HC.
When activated, this control determines whether ice remains on the evaporator at the end of
a harvest cycle and at the beginning of a freeze cycle. If ice drops and activates the bin
control switch in the last 10 seconds of a harvest cycle, the control determines that ice still
remains on the evaporator and extends the harvest cycle for 30 seconds. If the bin control
switch is activated at the beginning of a freeze cycle, the control determines that ice still
remains on the evaporator and starts a harvest cycle after the minimum freeze cycle time
has passed.
S2 Dip Switch Setting Harvest Completion
Detection Control
No. 4
OFF Deactivated
ON Activated
k) Overfreeze Detection Control (S2 dip switch 5)
Do not adjust. This must be left in the factory default position or the unit will not operate
properly.
It is deactivated on the KMD-210AB-HC.
When activated, the thermistor detects the temperature of the evaporator outlet to find
overfreeze in a harvest cycle and at the beginning of a freeze cycle. If the difference
between the maximum temperature after the water saver timer starts counting and the
temperature at the end of a harvest cycle is 4K or more and if the temperature at the end of
a harvest cycle is 48°F (9°C) or less, the harvest cycle is extended for 30 seconds. If the
difference between the temperature at the beginning of a freeze cycle and the minimum
temperature after 30 seconds in the freeze cycle is 2.5K or more and less than 3.5K, the
next harvest cycle is extended for 30 seconds. If the above conditions occur in succession,
the number of occurrence times 30 seconds will be added to the harvest cycle time. If the
above temperature difference is 3.5K or more, the freeze cycle ends after the minimum
freeze cycle time and a harvest cycle starts. If the evaporator outlet temperature is more
than 3.5°C but not more than 5°C at the end of harvest cycle, the harvest cycle is extended
for 50 seconds before moving on to the freeze cycle. If the evaporator outlet temperature is
3.5°C or less, another harvest cycle starts. The harvest cycle does not repeat more than
three times. The freeze cycle starts even if the evaporator outlet temperature is 3.5°C or less
at the end of the third harvest cycle.
S2 Dip Switch Setting Overfreeze Detection
Control
No. 5
OFF Deactivated
ON Activated

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l) Anti-Slush Control (S2 dip switch 6)
Do not adjust. This must be left in the factory default position or the unit will not operate
properly.
When activated (Ver. 1.1), the thermistor located on the suction line checks for a 41°F (5°C)
temperature as the evaporator cools. When 41°F (5°C) is reached, a 4.8 kΩ signal causes
the control board to de-energize the pump motor for 10 seconds.
When activated (Ver. 2.0), the thermistor located on the suction line checks for a 50°F
(10°C) temperature as the evaporator cools. When 50°F (10°C) is reached, a 3.9 kΩ signal
causes the control board to de-energize the pump motor for 10 seconds and energize it for
50 seconds repeatedly. When 34°F (1°C) is reached, a 5.9 kΩ signal causes the control
board to de-energize the pump motor for 10 seconds, energize it for 50 seconds,
de-energize it again for 10 seconds, then energize it continuously.
S2 Dip Switch Setting Anti-Slush Control
No. 6
OFF Activated
ON Activated
[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) To perform a relay sequence test, move the control switch to the “ICE” position while
pressing 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 test. Each LED comes on
for 5 seconds. LED 5 is on while LED 6 is on. 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.

15
4. HARVEST CONTROL – THERMISTOR
A thermistor (semiconductor) is used as a harvest control sensor, anti-slush sensor, and
overfreeze sensor.
The resistance varies depending on the suction line temperatures. The thermistor detects
the temperature of the evaporator outlet to start the harvest timer, to momentarily stop the
pump motor during the freeze cycle, or to extend the harvest cycle time. 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) Temperature (°C) Resistance (kΩ)
0 -18 14.401
10 -12 10.613
32 0 6.000
50 10 3.871
70 21 2.474
90 32 1.633
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. below.
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. Normal reading is within 3.5 to 7 kΩ.
Replace the thermistor if it exceeds the normal reading.
Thermistor Connector
(orange wires)
Bin Control Wires
(black)
Float Switch Connector
(red wires)

16
5. FLOAT SWITCH
[a] EXPLANATION OF OPERATION
The float operates 2 switches within the float switch. The lower switch (black and blue wires)
is used for low water safety protection, initiating the freeze cycle refill and terminating the
freeze cycle. The upper switch (black and red wires) is used to terminate the freeze cycle
refill only. Refill will last until the upper float switch closes or the 1 minute countdown timer
ends, whichever comes first.
Note: The refill counter is deactivated before shipping.
[b] CLEANING
Depending on local water conditions, scale may build up on the float, float switch shaft and
inside the housing. Scale on the float or shaft can cause the float to stick causing erratic
operation. The float switch should be cleaned and checked before replacing.
First, disconnect the float switch connector from the control box and remove the water tank
and pump motor bracket together from the icemaker. Twist the mechanical lock inside of the
pump motor bracket and remove the float switch. See "V. 15. FLOAT SWITCH." Remove
the retainer clip from the shaft and slide the float off the shaft. Soak the switch assembly in
ice machine cleaner. Wipe down the shaft, float, housing with cleaning solution. See "VI.
CLEANING AND MAINTENANCE INSTRUCTIONS."
[c] FLOAT SWITCH CHECK PROCEDURE
Before replacing a float switch that you suspect is bad, make sure the float switch has been
cleaned. This procedure will help you verify your diagnosis. The float switch has three wires.
The black wire is common. The blue wire is for the lower float switch contact and the red
wire is for the upper float switch contact.
1) Disconnect the black float switch connector from the control box.
2) Drain the reservoir water.
3) Turn the control switch to "ICE".
4) As water fills the reservoir, the float switch contacts should close. Check continuity of the
lower float switch contacts using the black and blue wires and the upper float switch
contacts using the black and red wires. With the float positioned all the way up, both float
switch contacts should be closed. If either float switch contact fails, the assembly should
be replaced.
5) Turn the control switch to "OFF".
6) Drain the reservoir water.
7) As water drains, the float switch contacts should open. Check continuity of the upper float
switch contacts using the black and red wires and the lower float switch contacts using
the black and blue wires. With the float positioned all the way down, both float switch
contacts should be open. If either float switch contact fails, the assembly should be
replaced.
8) Reconnect the black connector to the control box when finished.

17
6. BIN CONTROL
This machine uses a lever-actuated proximity switch (mechanical bin control) to control the
ice level in the storage bin. No adjustment is required.
[a] EXPLANATION OF OPERATION
The bin control is connected to the K1 connector (pins 4 & 5) on the control board.
When the bin control is calling for ice (proximity switch closed; "POWER OK" LED on), the
control board continues icemaking operations. When the bin control is activated in the bin
full position (proximity switch open; "POWER OK" LED flashing), the control board drains
and shuts down the unit. However, to prevent incomplete batches of ice from forming on the
evaporator, the control board will only shut down the machine during the freeze cycle before
the five minute timer expires. The five minute timer starts counting down when the
thermistor temperature reaches 2°C. If, during the freeze cycle, ice pushes in the lever after
the five minute timer expires, the control board will allow the machine to complete the freeze
cycle and the following harvest cycle before shutting down the machine.
[b] BIN CONTROL CHECK PROCEDURE
1) Clear any ice away from the bin control.
2) Make sure the control switch is in the "ICE" position.
3) Check that the "POWER OK" LED on the control board is on.
4) Activate the bin control actuator (press the actuator in). Check that the "POWER OK" LED
flashes.
5) Disconnect the bin control at the 2-pin connector attached to the black wires coming from
the K1 connector (pins 4 & 5) on the control board.
6) Check for continuity across the bin control leads. When calling for ice, the bin control
proximity switch should be closed. If open, replace the bin control. Activate the bin control
actuator (press the actuator in), check for continuity across the bin control leads. The bin
control proximity switch should be open. If closed, replace the bin control.
7) Reconnect the 2-pin connector. Allow the machine to cycle into the freeze cycle. In the
first 5 minutes of the freeze cycle, activate the bin control actuator (press the actuator in).
The "POWER OK" LED should flash and the machine should turn off. If not, replace the
control board.