Hoshizaki KMD901MWH Service Manual

Hoshizaki America, Inc.

Hoshizaki

Modular Crescent Cuber

Models
KMD-901MAH

“A Superior Degree

of Reliability”

www.hoshizaki.com

KMD-901MWH
KMD-901MRH

SERVICE MANUAL

™

Number: 73154
Issued: 3-28-2008

IMPORTANT

Only qualied service technicians should attempt to install, service, or maintain
this icemaker. No service or maintenance should be undertaken until the
technician has thoroughly read this Service Manual. Failure to service and
maintain the equipment in accordance with this manual may adversely affect
safety, performance, and warranty coverage.

HOSHIZAKI provides this manual primarily to assist qualied 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, 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: [phone] Technical Service
[phone]
Fax: [phone]
[phone]
E-mail: [e-mail]

Web Site: www.hoshizaki.com

NOTE: To expedite assistance, all correspondence/communication MUST include the

following information:

  •ModelNumber

  •SerialNumber

  •Completeanddetailedexplanationoftheproblem.

2

IMPORTANT

This manual should be read carefully before the icemaker is serviced or
maintenance operations are performed. Only qualied service technicians
should install, service, and maintain the icemaker. Read the warnings
contained in this booklet carefully as they give important information regarding
safety. Please retain this booklet for any further reference that may be
necessary.

CONTENTS

I. Specications ...................................................................................................................... 5

A. Icemaker ....................................................................................................................... 5

1. KMD-901MAH (air-cooled) ....................................................................................... 5

2. KMD-901MWH (water-cooled) ................................................................................. 6

3. KMD-901MRH (remote air-cooled) .......................................................................... 7

B. Condenser Unit ............................................................................................................. 8

1. URC-9F .................................................................................................................... 8

II. General Information ......................................................................................................... 10

A. Construction ................................................................................................................ 10

1. KMD-901MAH (air-cooled) ..................................................................................... 10

2. KMD-901MWH (water-cooled) ................................................................................11

3. KMD-901MRH (remote air-cooled) ........................................................................ 12

B. Sequence of Operation ............................................................................................... 13

1. One Minute Fill Cycle ............................................................................................. 13

2. Initial Harvest Cycle .............................................................................................. 13

3. Freeze Cycle ......................................................................................................... 13

4. Pump-Out Cycle ................................................................................................... 13

5. Normal Harvest Cycle ........................................................................................... 14

C. Control Board .............................................................................................................. 16

1. Control Board Layout ............................................................................................. 17

2. Features ................................................................................................................. 18

a) Maximum Water Supply Period – 6 minutes ....................................................... 18

b) Harvest Backup Timer and Freeze Timer ........................................................... 18

c) High Temperature Safety .................................................................................... 18

d) Low Water Safety ............................................................................................... 18

e) High Voltage and Low Voltage Cut-outs ............................................................. 18

f) LED Lights and Audible Alarm Safeties ............................................................... 19

3. Controls and Adjustments ...................................................................................... 20

a) Default Dip Switch Settings ................................................................................ 20

b) Harvest Timer (S4 dip switch 1 & 2) ................................................................... 20

c) Pump-Out Timer (S4 dip switch 3 & 4)................................................................ 21

d) Pump-Out Frequency Control (S4 dip switch 5 & 6) ........................................... 21

e) S4 Dip Switch 7 & 8 ........................................................................................... 22

f) Freeze Timer (S4 dip switch 9 & 10) .................................................................... 22

g) Float Switch Control (S5 dip switch 1 through 5) ................................................ 22

4. Control Board Check Procedure ............................................................................ 22

5. Control Board Replacement ................................................................................ 23

D. Harvest Control – Thermistor ...................................................................................... 23

3

E. Bin Control .................................................................................................................. 24

1. Explanation of Operation ........................................................................................ 24

2. Bin Control Check Procedure ................................................................................ 24

III. Technical Information ...................................................................................................... 25

A. Water Circuit and Refrigeration Circuit ........................................................................ 25

1. KMD-901MAH (air-cooled) ..................................................................................... 25

2. KMD-901MWH (water-cooled) ............................................................................... 26

3. KMD-901MRH (remote air-cooled) ........................................................................ 27

B. Wiring Diagrams .......................................................................................................... 28

1. KMD-901MAH and KMD-901MWH ........................................................................ 28

2. KMD-901MRH ....................................................................................................... 29

C. Performance Data ....................................................................................................... 30

1. KMD-901MAH (air-cooled) ..................................................................................... 30

2. KMD-901MWH (water-cooled) ............................................................................... 31

3. KMD-901MRH (remote air-cooled) ........................................................................ 32

IV. Service Diagnosis ........................................................................................................... 33

A. 10-Minute Diagnostic Procedure ................................................................................ 33

B. Diagnostic Charts ........................................................................................................ 34

1. No Ice Production ................................................................................................... 34

2. Evaporator is Frozen Up ........................................................................................ 38

3. Low Ice Production ................................................................................................ 39

4. Abnormal Ice ......................................................................................................... 39

5. Other ...................................................................................................................... 40

V. Removal and Replacement of Components .................................................................... 41

A. Service for Refrigerant Lines ....................................................................................... 41

1. Refrigerant Recovery ............................................................................................. 41

2. Brazing .................................................................................................................. 41

3. Evacuation and Recharge (R-404A) ...................................................................... 42

B. Removal and Replacement of Compressor ................................................................. 43

C. Removal and Replacement of Expansion Valve .......................................................... 44

D. Removal and Replacement of Hot Gas Valve or Line Valve ....................................... 45

E. Removal and Replacement of Evaporator ................................................................... 46

F. Removal and Replacement of Water Regulating Valve - Water-Cooled Model Only .... 46

G. Adjustment of Water Regulating Valve - Water-Cooled Model Only ............................ 47

H. Removal and Replacement of Headmaster (Condensing Pressure Regulator - C.P.R.)

- Remote Air-Cooled Model Only ............................................................................... 48

I. Removal and Replacement of Thermistor .................................................................... 49

J. Removal and Replacement of Fan Motor ..................................................................... 50

K. Removal and Replacement of Inlet Water Valve or Drain Valve .................................. 50

L. Removal and Replacement of Pump Motor ................................................................. 51

M. Removal and Replacement of Bin Control .................................................................. 52

VI. Cleaning and Maintenance ............................................................................................. 53

A. Cleaning and Sanitizing Instructions ........................................................................... 53

1. Cleaning Procedure ................................................................................................ 54

2. Sanitizing Procedure - Following Cleaning Procedure ........................................... 55

B. Maintenance ................................................................................................................ 56

C. Preparing the Icemaker for Long Storage ................................................................... 57

4

I. Specications

A. Icemaker

1. KMD-901MAH (air-cooled)

AC SUPPLY VOLTAGE 208-230/60/1 (3 wire with netrual for 115V)
AMPERAGE 10.8 A ( 5 Min. Freeze AT 104°F / WT 80°F)
MINIMUM CIRCUIT AMPACITY 20 A
MAXIMUM FUSE SIZE 20 A
APPROXIMATE ICE PRODUCTION Ambient WATER TEMP. (°F)
PER 24 HR. Temp.(°F) 50 70 90
lbs./day ( kg/day ) 70 *890 (404) 864 (392) 803 (364)
Reference without *marks 80 870 (395) 830 (376) 754 (342)

90 864 (392) *801 (363) 730 (331)

100 843 (382) 784 (356) 665 (302)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 11.6 lbs. (5.3 kg) 624pcs.
APPROXIMATE STORAGE CAPACITY N/A
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 1940(5.8) 1810(4.9)
WATER gal./24HR (gal./100 lbs.) 160(20.0) 372(41.8)
EXTERIOR DIMENSIONS (WxDxH) 42" x 24-5/8" x 28" (1067 x 625 x 713 mm)
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
WEIGHT Net 240 lbs. (109 kg), Shipping 278 lbs. (126 kg)
CONNECTIONS - ELECTRIC Permanent - Connection

- WATER SUPPLY Inlet 1/2" FPT

- DRAIN Outlet 3/4" FPT

5/8" OD Tube
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 Lever Switch and Timer
COMPRESSOR Hermetic, Model CS12K6E-PFV-237
CONDENSER Air-Cooled , Fin and tube type
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve
REFRIGERANT CHARGE R404A, 4 lb. 3 oz. (1900g)
DESIGN PRESSURE High 467PSIG, Low 230PSIG
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 187 - 253 V

AMBIENT TEMP. 45 -100° F
WATER SUPPLY TEMP. 45 - 90° F

WATER SUPPLY PRESSURE 10 - 113 PSIG

Note: We reserve the right to make changes in specications and design without prior

notice.

5

2. KMD-901MWH (water-cooled)

AC SUPPLY VOLTAGE 208-230/60/1 (3 wire with netrual for 115V)
AMPERAGE 7.8A ( 5 Min. Freeze AT 104°F / WT 80°F)
MINIMUM CIRCUIT AMPACITY 20 A
MAXIMUM FUSE SIZE 20 A
APPROXIMATE ICE PRODUCTION Ambient WATER TEMP. (°F)
PER 24 HR. Temp.(°F) 50 70 90
lbs./day ( kg/day ) 70 *876 (397) 874 (397) 831 (377)
Reference without *marks 80 875 (397) 872 (396) 805 (365)

90 874 (397) *870 (395) 812 (368)

100 852 (386) 856 (388) 759 (344)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 12.3 lbs. (5.6 kg) 624pcs.
APPROXIMATE STORAGE CAPACITY N/A
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 1520(4.2) 1480(4.1)
WATER gal./24HR (gal./100 lbs.) 213(24.5) 351(40.1)
WATER COOLED CONDENSER 1088(125) 593(68)

gal./24HR (gal./100 lbs.)
EXTERIOR DIMENSIONS (WxDxH) 30" x 24-5/8" x 28" (762 x 625 x 713 mm)
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
WEIGHT Net 219 lbs. (99 kg), Shipping 251 lbs. (114 kg)
CONNECTIONS - ELECTRIC Permanent - Connection

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

- DRAIN Outlet 3/4" FPT Cond. Outlet 3/8" FPT

5/8" OD Tube
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 Pressure Regulator
BIN CONTROL SYSTEM Mechanical Lever Switch and Timer
COMPRESSOR Hermetic, Model CS10K6E-PFV-237
CONDENSER Water-cooled, Tube in tube type
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve
REFRIGERANT CHARGE R404A, 2 lb. 3.3 oz. (1000g)
DESIGN PRESSURE High 427PSIG, Low 230PSIG
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 187 - 253 V

AMBIENT TEMP. 45 -100° F
WATER SUPPLY TEMP. 45 - 90° F
WATER SUPPLY PRESSURE 10 - 113 PSIG

Note: We reserve the right to make changes in specications and design without prior

notice.

6

3. KMD-901MRH (remote air-cooled)

AC SUPPLY VOLTAGE 208-230/60/1 (3 wire with netrual for 115V)
AMPERAGE 10.0A ( 5 Min. Freeze AT 104°F / WT 80°F)
MINIMUM CIRCUIT AMPACITY 20 A
MAXIMUM FUSE SIZE 20 A
APPROXIMATE ICE PRODUCTION Ambient WATER TEMP. (°F)
PER 24 HR. Temp.(°F) 50 70 90
lbs./day ( kg/day ) 70 *848 (385) 827 (375) 768 (348)
Reference without *marks 80 832 (377) 798 (362) 723 (328)

90 827 (375) *775 (352) 705 (320)

100 805 (365) 759 (344) 641 (291)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 12 lbs. (5.4 kg) 624pcs.
APPROXIMATE STORAGE CAPACITY N/A
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 1710(5.3) 1600(4.5)
WATER gal./24HR (gal./100 lbs.) 155(20.0) 383(45.2)
EXTERIOR DIMENSIONS (WxDxH) 30" x 24-5/8" x 28" (762 x 625 x 713 mm)
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
WEIGHT Net 226 lbs. (103 kg), Shipping 258 lbs. (117 kg)
CONNECTIONS - ELECTRIC Permanent - Connection

- WATER SUPPLY Inlet 1/2" FPT

- DRAIN Outlet 3/4" FPT

5/8" OD Tube
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 Lever Switch and Timer
COMPRESSOR Hermetic, Model CS10K6E-PFV-279
CONDENSER Air-Cooled Remote, Condenser Unit URC-9F
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve

Condensing Pressure Regulator on URC-9F

REFRIGERANT CHARGE R404A, 9 lbs. 14.7 oz. (4500g)

(Icemaker 5 lbs. 15.9 oz. Cond. Unit 3 lbs. 14.8 oz.)
DESIGN PRESSURE High 467PSIG, Low 230PSIG
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, Remote Condenser Unit
OPERATING CONDITIONS VOLTAGE RANGE 187 - 253 V

AMBIENT TEMP. 45 -100° F

WATER SUPPLY TEMP. 45 - 90° F

WATER SUPPLY PRESSURE 10 - 113 PSIG

Note: We reserve the right to make changes in specications and design without prior

notice.

7

B. Condenser Unit

1. URC-9F

Unit: mm [inches]

8

AC SUPPLY VOLTAGE 115/60/1 (Connection to Icemaker)

FAN MOTOR 115 V Total 1.3FLA 65W

EXTERIOR DIMENSIONS (WxDxH) 32-3/16" x 15-11/16" x 21-15/16" (817 x 398 x 558 mm)

DIMENSIONS INCLUDING LEGS (WxDxH) 34-5/16" x 18-1/8" x 36-15/16" (871 x 460 x 938 mm)

EXTERIOR FINISH Galvanized Steel

WEIGHT Net 81 lbs. ( 37 kg ) Shipping 92 lbs. ( 42 kg )

CONNECTIONS - ELECTRIC Permanent - Connection

- REFRIGERANT Discharge Line 1-1/16"-12 UNF Fitting (#10 AEROQUIP)

Liquid Line 5/8"-18 UNF Fitting (#6 AEROQUIP)

CONDENSER Air-cooled, Fin and tube type

FAN MOTOR PROTECTION Thermal Protection

REFRIGERANT CONTROL Condensing Pressure Regulator

REFRIGERANT CHARGE R-404A 3 lbs. 14.8 oz. (1780g)

DESIGN PRESSURE High 467 PSIG

OPERATING CONDITIONS VOLTAGE RANGE 104 ~ 127 V

AMBIENT TEMP. -20 ~ 122 °F

ACCESSORIES -SUPPLIED Leg 2 pcs

Hex. Head Bolt w/Washer 8 x 16 8 pcs

Hex. Nut 8 8 pcs

Note: We reserve the right to make changes in specications and design without prior

notice.

9

II. General Information

A. Construction

1. KMD-901MAH (air-cooled)

Spray
Tubes

Inlet Water Valve

Water Supply Inlet

Hot Gas Valve

Junction Box

Condenser

Float Switch

Drain Valve

Water Pump

Expansion Valves

Bin Control

Control Box

Condenser
Fan Motor

Drier

Line Valve

Compressor

10

2. KMD-901MWH (water-cooled)

Spray
Tubes

Inlet Water Valve

Water Supply Inlet

Hot Gas Valve

Junction Box

Condenser

Control Box

Water
Regulator

Float Switch

Drain Valve

Water Pump

Drier

Line Valve

Expansion Valves

Compressor

Bin Control

11

3. KMD-901MRH (remote air-cooled)

Spray
Tubes

Inlet Water Valve

Water Supply Inlet

Hot Gas Valve

Junction Box

Control Box

Receiver
Tank

Float Switch

Drain Valve

Water Pump

Expansion Valves

Bin Control

Drier

Line Valve

Compressor

12

B. Sequence of Operation

The steps in the sequence are as outlined below. When power is supplied, the red
"POWER OK" LED and the green "BC CLOSED" LED on the control board come on (If
the yellow "BC OPEN" LED is on, the unit will not start. In this case clear ice away from
the bin control actuator). A 5-second delay occurs at startup. Note that the order of the
green sequence LEDs from the outer edge of the board is 1, 4, 3, 2.

1. One Minute Fill Cycle

LED 4 is on. WV opens and the ll period begins. After 1 minute, the board checks for
a closed F/S. If F/S is closed, the harvest cycle begins. If not, WV will remain energized
through additional 1 minute cycles until water enters the sump and F/S closes. This
serves as a low water safety to protect the water pump.

2. Initial Harvest Cycle

LEDs 1, 4, and 2 are on. WV remains open, Comp, FMR, HGV energize. The control
board monitors the warming of the evaporator via the thermistor located on the suction
line. When the thermistor reaches 48°F (9°C), the control board reads a 3.9 kΩ signal
from the thermistor and turns harvest termination over to the adjustable harvest timer
which is factory set for normal conditions. The timer has settings of 60, 90, 120, and
180 seconds (S4 dip switch 1 & 2). For details, see "II.C.3.b) Harvest Timer." When the
harvest timer completes its countdown, 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. WV is open during harvest for a maximum of 6 minutes or the length of
harvest minus 50 seconds, whichever is shorter. LED 4 goes off when WV closes.
PM energizes and runs for the last 50 seconds of harvest. LED 3 comes on when
PM energizes. At the end of harvest, the control board checks the position of F/S and
proceeds to the freeze cycle if it is closed or calls for a 1-minute ll if it is open.

3. Freeze Cycle

LED 1 is on. Comp, FMR, and PM continue to run, FMS energizes, LLV opens, HGV
closes and the freeze cycle starts. For the rst 5 minutes the control board will not
accept a signal from F/S. This 5 minute minimum freeze acts as a short cycle protection.
At the end of 5 minutes, F/S assumes control. As ice builds on the evaporator the water
level in the sump lowers. The freeze continues until F/S opens and terminates ice
production.

4. Pump-Out Cycle

LEDs 1, 4, 3, and 2 are on. With S4 dip switch 5 and 6 in the factory default position, the
1st pump out occurs after the 11th freeze cycle and every 10th cycle thereafter. Comp
and FMR continue to run, DV and WV open, HGV opens, LLV closes, and FMS de­energizes. PM stops for 2 seconds. SR energizes, restarting PM and taking water from
the sump and forcing it to go through DV and down the drain. At the same time, water
ows through the vent tube to power ush the F/S. After 10 seconds, the pump out is
complete. The pump-out 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 pump out more often, the pump-out frequency can be adjusted.
The pump-out frequency control can be set to have a pump out occur every cycle,
or every 2, 5, or 10 cycles (S4 dip switch 5 & 6). For details, see "II.C.3.d) Pump-Out
Frequency Control."

13

5. Normal Harvest Cycle

LEDs 1, 4, and 2 are on. Comp, FMR, and HGV remain energized and WV opens. PM
stops. As the evaporator warms, the thermistor reaches 48°F (9°C). The control board
then receives the thermistor's 3.9 kΩ signal and starts the harvest timer. When the
harvest timer completes its countdown, the harvest cycle is complete. The minimum total
time allowed by the board for a complete harvest cycle is 2 minutes. WV is energized
during harvest for a maximum of 6 minutes or the length of harvest minus 50 seconds,
whichever is shorter. LED 4 goes off when WV closes. PM energizes and runs for the
last 50 seconds of harvest. LED 3 comes on when PM energizes. At the end of harvest,
the control board checks the position of F/S and proceeds to the freeze cycle if it is
closed or calls for a 1-minute ll if it is open.
The unit continues to cycle through freeze and harvest cycles until the bin control
activates (opens) and shuts the unit down.

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

board will only shut down the machine within the rst 5 minutes of the freeze
cycle. If ice pushes the bin control actuator in (open) after the rst ve minutes of
the freeze cycle, 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; FMR–remote fan motor; FMS–self-contained
fan motor; F/S–oat switch; HGV–hot gas valve; LLV–Liquid Line Valve;
PM–pump motor; SR–service relay; WV–inlet water valve

14

Cycle

4. Pump-Out

•Minimumfreezetime:5minutes

•Maximumfreezetime:freezetimersetting

F/S in

control

5 minute timer

in control

F/S closed

PM stops for 2 sec.,

SR energizes, starting

Freeze cycle

operation turned

Comp continues

FMR continues

PM, DV & WV for

10 sec. each 1, 2, 5, or

10 cycles.

Comp continues

FMR continues

over to F/S

HGV de-energized

WV de-energized

PM energized

FMS energized

LLV energized

HGV energized

FMS de-energized

LLV de-energized

2. Harvest Cycle 3. Freeze Cycle

•Maximuminletwatervalvetime:6minutes

1. One Minute

(WV time is 6 minutes or the length of harvest

Fill Cycle

minus 50 sec., whichever is shorter. PM

energizes and runs for the last 50 sec. of

harvest.)

•Maximumharvesttime:20minutes

1 to 3 minute timer

in control

Thermistor in

control

50 sec.

F/S closed

F/S Check

PM energized

WV de-energized

Thermistor temp

reaches 48°F (9°C)

Comp energized

HGV energized

FMR energized

WV continues

F/S open

F/S Check

WV Energized

F/S open

(3.9 kΩ or less)

Harvest timer starts

LLV de-energized

If F/S is open, compressor stops and cycle returns to 1 minute ll

Components Energized when the Control Switch is in the "WASH" Position

The "WASH" position on the control switch is used when cleaning and sanitizing the unit. When in the

"WASH" position, power is supplied to the pump motor. With the cleaning valve closed, the cleaner and

sanitizer ow over the outside of the evaporator plate assembly. With the cleaning valve open, the cleaner

and sanitizer ow over both the outside and the inside of the evaporator plate assembly.

Note: Close the cleaning valve after cleaning and sanitizing are complete, otherwise the unit will not re-start

when the control switch is placed in the "ICE" position.

KMD-901MAH, KMD-901MWH, and KMD-901MRH Sequence Flow Chart and Component Operation

Cycle Steps

"G" board will have

Initial startup always

5 second delay

begins here

Legend:

Comp–compressor

DV–drain valve

FMR–remote fan motor

FMS–self-contained fan motor

F/S–oat switch

HGV–hot gas valve

LLV–liquid line valve

PM–pump motor

SR–service relay

WV–inlet water valve

15

C. Control Board

•AHOSHIZAKIexclusivesolid-statecontrolisemployedinKMD-901MAH,

KMD-901MWH, and KMD-901MRH Modular Crescent Cubers.

•Allmodelsarepretestedandfactory-adjusted.

CAUTION

1. Fragile, handle very carefully.

2. The 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 before 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, mechanical bin
control, and oat switch.

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

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

16

1. Control Board Layout

Control Products "G" Control Board

"ALARM RESET" Button

Bin Control Switch
Closed LED (green)

Bin Control Switch
Open LED (yellow)

Part Number

Alarm Buzzer

LED 2 (green)
Hot Gas Valve (HGV)
Self-Contained Fan
Motor (FMS) (FMS off
when LED on)

Power LED (red)
(lights when power
is supplied to the
board)

LED 3 (green)
Pump Motor (PM)
(PM on, but LED off,
at freeze cycle)

LED 4 (green)
Inlet Water Valve
(WV)

S4 Dip
Switch

"OUTPUT TEST" Button
(used to test relays on board)

Connector K3
Harvest Control
(thermistor)

Connector K4
Mechanical Bin
Control

S5 Dip Switch
(factory set ­do not adjust)
Connector K5
Float Switch

Label
(board revision level
indicated on label
on side of relay)

Connector K1

Pins #1 through #10
#1, 9 Magnetic Contactor
#2 Hot Gas Valve (HGV)
#3 Liquid Line Valve (LLV)
#4 Pump Motor (icemaking)
#5 Pump Motor (harvest,
pump out)
#6 Inlet Water Valve (WV)
#7, 10 Supply Voltage
#8 Open

LED 1 (green)
Compressor (Comp)

Switch for "C" board
and "ALPINE" board
(service boards only)

Connector K2
Transformer

Control Board

Part Number 2A3792-01 (factory); 2A3792-02 (service)

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2. Features

a) Maximum Water Supply Period – 6 minutes

The inlet water valve will be open during harvest for 6 minutes or the length of harvest
minus 50 seconds, 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 specied to complete. The control board will signal this
problem using 3 beeps every 3 seconds. The time is factory set using S4 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 127 ± 7°F (53 ± 4°C), the control board reads a
.804 kΩ signal from the thermistor and 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 oat switch at the end of the initial one
minute water ll cycle and at the end of each harvest cycle. If the oat switch is in the up
position (electrical circuit closed), the control board changes to the ice making cycle. If
the oat switch is in the down position (electrical circuit open), the control board changes
to additional one minute water ll cycles until water enters the sump and the oat switch
closes. When the oat switch closes, the control board changes to the ice making 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 water 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 phase 3 wire models) causes excessive voltage
(147Vac ±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 (92Vac ±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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