Hoshizaki KM-1601MRH/3 User manual

Hoshizaki
“A Superior Degree
of Reliability”
www.hoshizaki.com
Models
KM-1601MRH/3
Modular Crescent Cuber
Hoshizaki America, Inc.
Number: 73129
Issued: 6-16-2006
Revised: 3-28-2011
SERVICE MANUAL

2
IMPORTANT
Only qualied service technicians should install, service, and maintain the
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, component life, 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 Support
[phone]
Fax: [phone]
[phone]
E-mail: [email protected]
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.

3
CONTENTS
Important Safety Information ................................................................................................. 5
I. Specications...................................................................................................................... 6
A. Icemaker ....................................................................................................................... 6
1. KM-1601MRH with URC-21F ................................................................................... 6
2. KM-1601MRH with URC-22F .................................................................................. 7
3. KM-1601MRH3 with URC-21F ................................................................................ 8
4. KM-1601MRH3 with URC-22F ................................................................................ 9
B. Condenser Unit ........................................................................................................... 10
II. General Information ..........................................................................................................11
A. Construction.................................................................................................................11
1. KM-1601MRH, KM-1601MRH3 ...............................................................................11
2. URC-21F, URC-22F............................................................................................... 12
B. Sequence of Operation ............................................................................................... 13
1. Sequence Cycles and Shutdown ........................................................................... 13
a) One Minute Fill Cycle ....................................................................................... 13
b) Initial Harvest Cycle ........................................................................................ 13
c) Freeze Cycle ................................................................................................... 13
d) Pump-Out Cycle .............................................................................................. 13
e) Normal Harvest Cycle ..................................................................................... 14
2. Sequence Flow Chart............................................................................................ 15
C. Control Board .............................................................................................................. 16
1. Control Board Layout ............................................................................................. 17
2. LED Lights and Audible Alarm Safeties ................................................................. 18
3. Controls and Adjustments...................................................................................... 19
a) Default Dip Switch Settings.............................................................................. 19
b) Harvest Timer (dip switch 1 & 2)...................................................................... 19
c) Pump-Out Timer (dip switch 3 & 4) .................................................................. 20
d) Pump-Out Frequency Control (dip switch 5 & 6) .............................................. 20
e) Factory Use (S4 dip switch 7 & 8).................................................................... 20
f) Freeze Timer (dip switch 9 & 10)....................................................................... 21
D. Control Switch ............................................................................................................. 21
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.

4
III. Technical Information ...................................................................................................... 22
A. Water Circuit and Refrigeration Circuit ........................................................................ 22
B. Wiring Diagrams.......................................................................................................... 23
1. KM-1601MRH......................................................................................................... 23
2. KM-1601MRH3 ...................................................................................................... 24
C. Performance Data ....................................................................................................... 25
1. KM-1601MRH with URC-21F ................................................................................. 25
2. KM-1601MRH with URC-22F................................................................................. 26
3. KM-1601MRH3 with URC-21F............................................................................... 27
4. KM-1601MRH3 with URC-22F............................................................................... 28
IV. Service Diagnosis ........................................................................................................... 29
A. Diagnostic Procedure ................................................................................................. 29
B. Control Board Check ................................................................................................... 31
C. Bin Control Check ....................................................................................................... 32
D. Float Switch Check and Cleaning ............................................................................... 33
1. Float Switch Check ................................................................................................ 33
2. Float Switch Cleaning............................................................................................ 34
E. Thermistor Check........................................................................................................ 35
F. Diagnostic Charts ........................................................................................................ 36
1. No Ice Production................................................................................................... 36
2. Evaporator is Frozen Up ........................................................................................ 39
3. Low Ice Production ................................................................................................ 40
4. Abnormal Ice ......................................................................................................... 41
5. Other...................................................................................................................... 41
V. Replacement of Components .......................................................................................... 42
A. Service for Refrigerant Lines....................................................................................... 42
1. Refrigerant Recovery ............................................................................................. 42
2. Brazing .................................................................................................................. 43
3. Evacuation and Recharge (R-404A)...................................................................... 43
B. Important Notes for Component Replacement............................................................ 45
VI. Cleaning and Maintenance Instructions ......................................................................... 46
A. Cleaning and Sanitizing Procedures ........................................................................... 46
1. Cleaning Procedure................................................................................................ 47
2. Sanitizing Procedure - Following Cleaning Procedure ........................................... 48
B. Maintenance................................................................................................................ 49
C. Preparing the Icemaker for Long Storage ................................................................... 49

5
Important Safety Information
Throughout this manual, notices appear to bring your attention to situations which could
result in death, serious injury, or damage to the unit.
WARNING Indicates a hazardous situation which could result in death or
serious injury.
CAUTION Indicates a situation which could result in damage to the unit.
IMPORTANT Indicates important information about the use and care of the
unit.
WARNING
This icemaker should be destined only to the use for which it has been
expressly conceived. Any other use should be considered improper and
therefore dangerous. The manufacturer cannot be held responsible for injury or
damage resulting from improper, incorrect, and unreasonable use.
To reduce the risk of death, electric shock, serious injury, or re, follow
basic precautions including the following:
•Onlyqualiedservicetechniciansshouldinstall,service,andmaintainthe
icemaker.
•Electricalconnectionmustbehard-wiredandmustmeetnational,state,and
local electrical code requirements. Failure to meet these code requirements
could result in death, electric shock, serious injury, re, or severe damage to
equipment.
•Thisunitrequiresanindependentpowersupply.Seethenameplatefor
proper voltage and breaker/fuse size. Failure to use a proper breaker or fuse
can result in a tripped breaker, blown fuse, or damage to existing wiring. This
could lead to heat generation or re.
•THE ICEMAKER MUST BE GROUNDED. Failure to properly ground the
icemaker could result in death or serious injury.
•Movethecontrolswitchtothe"OFF"positionandturnoffthepowersupply
before servicing. Lockout/Tagout to prevent the power supply from being
turned back on inadvertently.
•Donotmakeanyalterationstotheunit.Alterationscouldresultinelectric
shock, injury, re, or damage to the unit.
Additional Warning for Remote Air-Cooled Model
•THE REMOTE CONDENSER UNIT MUST BE GROUNDED. The power
supply and ground wire to the remote condenser unit are supplied from the
icemaker. Failure to properly ground the remote condenser unit could result
in death or serious injury.

6
I. Specications
A. Icemaker
1. KM-1601MRH with URC-21F
AC SUPPLY VOLTAGE 208-230/60/1 (3 wire with neutral for 115V)
AMPERAGE 11.6 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 *1508 (684) 1483 (673) 1399 (634)
Reference without *marks 80 1489 (675) 1450 (658) 1338 (607)
90 1483 (673) *1422 (645) 1320 (599)
100 1449 (657) 1398 (634) 1227 (557)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 29.8 lbs. (13.5 kg) 1440 pcs.
APPROXIMATE STORAGE CAPACITY N/A
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 2670(4.5) 2450(3.9)
WATER gal./24HR (gal./100 lbs.) 263(18.5) 483(32.0)
EXTERIOR DIMENSIONS (WxDxH) 30" x 27.4" x 41.7" (762 x 695 x 1059 mm)
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
WEIGHT Net 259 lbs. (117 kg), Shipping 316 lbs. (143 kg)
CONNECTIONS - ELECTRIC Permanent - Connection
- WATER SUPPLY Inlet 1/2" FPT
- DRAIN Outlet 3/4" FPT
3/8" 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 Thermostat
COMPRESSOR Hermetic, Model CS18K6E-PFV
CONDENSER Air-Cooled Remote, Condenser Unit URC-21F
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve
Condensing Pressure Regulator on URC-21F
REFRIGERANT CHARGE R-404A, 24 lb. 4.0 oz. (11,000g)
(Icemaker 14 lbs. 8.8 oz. Cond. Unit 9 lb. 11.2 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
2. KM-1601MRH with URC-22F
Note: We reserve the right to make changes in specications and design without prior
notice.
AC SUPPLY VOLTAGE 208-230/60/1 (3 wire with neutral for 115V)
AMPERAGE 11.6 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 *1493 (677) 1471 (667) 1410 (640)
Reference without *marks 80 1476 (670) 1441 (654) 1364 (619)
90 1471 (667) *1417 (643) 1346 (610)
100 1449 (657) 1400 (635) 1280 (581)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 27.9 lbs. (12.7 kg) 1440 pcs.
APPROXIMATE STORAGE CAPACITY N/A
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 2740(4.64) 2590(4.17)
WATER gal./24HR (gal./100 lbs.) 264(18.6) 521(34.9)
CEC/CEE TIER LEVEL 2
ENERGY STAR YES
EXTERIOR DIMENSIONS (WxDxH) 30" x 27.4" x 41.7" (762 x 695 x 1059 mm)
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
WEIGHT Net 259 lbs. (117 kg), Shipping 316 lbs. (143 kg)
CONNECTIONS - ELECTRIC Permanent - Connection
- WATER SUPPLY Inlet 1/2" FPT
- DRAIN Outlet 3/4" FPT
3/8" 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 Thermostat
COMPRESSOR Hermetic, Model CS18K6E-PFV
CONDENSER Air-Cooled Remote, Condenser Unit URC-22F
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve
Condensing Pressure Regulator on URC-22F
REFRIGERANT CHARGE (w/URC-22F) R-404A, 22 lb. 4.3 oz. (10,100g)
(Icemaker 14 lbs. 8.8 oz. Cond. Unit 9 lb. 11.2 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
ENG.F-011.1.0205

8
3. KM-1601MRH3 with URC-21F
AC SUPPLY VOLTAGE 208-230/60/3
AMPERAGE 8.4 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 *1471 (667) 1448 (657) 1354 (614)
Reference without *marks 80 1453 (659) 1417 (643) 1290 (585)
90 1448 (657) *1392 (631) 1277 (579)
100 1408 (639) 1365 (619) 1171 (531)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 28.0 lbs. (12.7 kg) 1440 pcs.
APPROXIMATE STORAGE CAPACITY N/A
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 2640(4.6) 2410(3.9)
WATER gal./24HR (gal./100 lbs.) 267(19.2) 491(33.4)
EXTERIOR DIMENSIONS (WxDxH) 30" x 27.4" x 41.7" (762 x 695 x 1059 mm)
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
WEIGHT Net 259 lbs. (117 kg), Shipping 316 lbs. (143 kg)
CONNECTIONS - ELECTRIC Permanent - Connection
- WATER SUPPLY Inlet 1/2" FPT
- DRAIN Outlet 3/4" FPT
3/8" 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 Thermostat
COMPRESSOR Hermetic, Model CS18K6E-TF5
CONDENSER Air-Cooled Remote, Condenser Unit URC-21F
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve
Condensing Pressure Regulator on URC-21F
REFRIGERANT CHARGE R-404A, 24 lb. 4.0 oz. (11,000g)
(Icemaker 14 lbs. 8.8 oz. Cond. Unit 9 lb. 11.2 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.

9
4. KM-1601MRH3 with URC-22F
Note: We reserve the right to make changes in specications and design without prior
notice.
AC SUPPLY VOLTAGE 208-230/60/3
AMPERAGE 8.4 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 *1486 (674) 1458 (661) 1366 (620)
Reference without *marks 80 1465 (664) 1422 (645) 1300 (590)
90 1458 (661) *1391 (631) 1280 (581)
100 1422 (645) 1365 (619) 1178 (534)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 28.3 lbs. (12.8 kg) 1440 pcs.
APPROXIMATE STORAGE CAPACITY N/A
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 2640(4.55) 2460(3.97)
WATER gal./24HR (gal./100 lbs.) 267(19.2) 498(33.5)
CEC/CEE TIER LEVEL 2
ENERGY STAR YES
EXTERIOR DIMENSIONS (WxDxH) 30" x 27.4" x 41.7" (762 x 695 x 1059 mm)
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
WEIGHT Net 259 lbs. (117 kg), Shipping 316 lbs. (143 kg)
CONNECTIONS - ELECTRIC Permanent - Connection
- WATER SUPPLY Inlet 1/2" FPT
- DRAIN Outlet 3/4" FPT
3/8" 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 Thermostat
COMPRESSOR Hermetic, Model CS18K6E-TF5
CONDENSER Air-Cooled Remote, Condenser Unit URC-22F
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve
Condensing Pressure Regulator on URC-22F
REFRIGERANT CHARGE R-404A, 22 lb. 4.3 oz. (10,100g)
(Icemaker 14 lbs. 8.8 oz. Cond. Unit 7 lb. 11.5 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
ENG.F-011.1.0205

10
B. Condenser Unit
1. URC-21F, URC-22F
Note: We reserve the right to make changes in specications and design without prior
notice.
AC SUPPLY VOLTAGE 115/60/1 (Connection to Icemaker)
FAN MOTOR 115 V Total 2.6FLA 130W
EXTERIOR DIMENSIONS (WxDxH) 46-3/8" x 15-11/16" x 25-15/16" (1178 x 398 x 659 mm)
DIMENSIONS INCLUDING LEGS (WxDxH) 48-7/16" x 18-1/8" x 40-7/8" (1230 x 460 x 1039 mm)
EXTERIOR FINISH Galvanized Steel
WEIGHT URC-21F Net 158 lbs. (72 kg ) Shipping 169 lbs. ( 77 kg )
URC-22F Net 134 lbs. (61 kg ) Shipping 145 lbs. ( 66 kg )
CONNECTIONS - ELECTRIC Permanent - Connection
- REFRIGERANT Discharge Line 1-1/16"-12 UNF Fitting (#10 PARKER)
Liquid Line 5/8"-18 UNF Fitting (#6 PARKER)
CONDENSER Air-cooled, Fin and tube type
FAN MOTOR PROTECTION Thermal Protection
REFRIGERANT CONTROL Condensing Pressure Regulator
REFRIGERANT CHARGE URC-21F R-404A 9 lb. 11 oz. (4400g)
URC-22F R-404A 7 lb. 11.5 oz. (3500g)
DESIGN PRESSURE High 467 PSIG 32.2 Bar
OPERATING CONDITIONS VOLTAGE RANGE 104 ~ 127 VAC
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

11
II. General Information
A. Construction
1. KM-1601MRH, KM-1601MRH3
Spray Tube Inlet Water Valve
Water Supply Inlet
Hot Gas Valve
Junction Box
Check Valve
Expansion Valve
Line Valve
Receiver
Capacitor Box
(KM-1601MRH)
Transformer Box
(KM-1601MRH3)
Drier
Compressor
Cleaning Valve
Control Box
Control Switch
Bin Control
Thermostat
Float Switch
Water Pump
Evaporator

12
2. URC-21F, URC-22F
Junction Box
Headmaster
(C.P.R.)
Condenser Fan Motors
Liquid Line
Connection
Fan Blade
Condenser
Discharge Line
Connection
Fan Blade

13
B. Sequence of Operation
1. Sequence Cycles and Shutdown
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 control
board is 1, 4, 3, 2.
a) One Minute Fill Cycle
LED 4 is on. WV opens and the ll period begins. After 1 minute, the control 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.
b) Initial Harvest Cycle
LEDs 1, 4, and 2 are on. WV remains open, Comp and FMR energize, HGV opens,
and harvest begins. As the evaporator warms, the thermistor located on the suction
line checks for a 48°F (9°C) temperature. When 48°F (9°C) is reached, a 3.9 kΩsignal
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 (dip switch 1 & 2). The
water valve is open during harvest for a maximum of 6 minutes or the length of harvest,
whichever is shorter. 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 control
board for a complete harvest cycle is 2 minutes.
c) Freeze Cycle
LED 1 is on. Comp and FMR continue to run, PM and FMS energize, LLV opens, HGV
and WV close 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.
d) Pump-Out Cycle
LEDs 1, 3, and 2 are on. Comp and FMR continue to run, HGV opens, LLV closes, and
FMS deenergizes. PM stops for 2 seconds and reverses, taking water from the bottom of
the sump and forcing pressure against the check valve seat allowing water to go through
the check valve and down the drain. At the same time water ows through the small
tube to power ush the F/S. When the pump-out timer stops counting, the pump out is
complete.
Pump out always occurs on the 2nd harvest after startup. Then, depending on the control
board setting, pump out occurs every cycle, or every 2nd, 5th or 10th cycle (dip switch
5 & 6).

14
e) Normal Harvest Cycle
LEDs 1, 4, and 2 are on. Comp and FMR continue to run, HGV remains open and WV
opens. As the evaporator warms, the thermistor reaches 48°F (9°C). The control board
then receives the thermistor's 3.9 kΩsignal and starts the harvest timer. The water valve
is open during harvest for a maximum of 6 minutes or the length of harvest, whichever is
shorter. When the harvest timer completes its count down, the harvest cycle is complete
and the next freeze cycle starts. The unit continues to cycle through 3, 4 and 5 sequence
until the bin control senses ice and shuts the unit down.
Legend: Comp–compressor; FMR–remote fan motor; FMS–self-contained fan motor;
F/S–oat switch; HGV–hot gas valve; LLV–Liquid Line Valve; PM–pump motor;
WV–inlet water valve

15
1. One Minute
Fill Cycle
2. Harvest Cycle 3. Freeze Cycle
4. Pump-Out
Cycle
Cycle Steps
WV Energized
F/S open
F/S closed
Comp energized HGV energized FMR energized WV continues
Thermistor temp reaches 48°F (9°C) (3.9 kΩor less) Harvest timer starts
F/S open
Comp continues FMR continues HGV de-energized WV de-energized PM energized FMS energized
F/S closed
Freeze cycle operation turned over to F/S
Pump motor stops for 2 sec. and then reverses for 10/20 sec. each 1, 2, 5, or 10 cycles. Comp continues FMR continues HGV energized FMS de-energized
F/S Check
F/S Check
•Maximuminletwatervalvetime:6minutes •Maximumharvesttime:20minutes
Thermistor in control
1 to 3 minute timer in control
•Minimumfreezetime:5minutes •Maximumfreezetime:freezetimersetting
5 minute timer in control
F/S in control
Initial startup always begins here
"E"controlboardwill have 5 second delay
If F/S is open, compressor stops and cycle returns to 1 minute ll
Legend: Comp - compressor; FMS - self-contained fan motor; HGV - hot gas valve; WV - inlet water valve FMR - remote fan motor; F/S - oat switch; PM - pump motor
"E" Control Board Sequence Flow Chart
KM-1601MRH/URC-21F, URC-22F
KM-1601MRH3/URC-21F, URC-22F
2. Sequence Flow Chart

16
C. Control Board
•A Hoshizaki exclusive solid-state control is employed in KM-1601MRH and
KM-1601MRH3 Modular Crescent Cubers.
•All models are pretested and factory-adjusted.
CAUTION
1. The control board is 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 when handling or replacing the control board.
3. Do not touch the electronic devices on the control board or the back of the
control board.
4. Do not change wiring and connections. Do not misconnect K3, K4 and K5,
because the same connector is used for the thermistor and oat switch. K4 is
not connected.
5. Always replace the whole control board assembly if it goes bad.
6. Do not short out power supply to test for voltage.

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Control Board
Part Number 2A1410-01 (factory); 2A1410-02 (service)
"E" Control Board
1. Control Board Layout
Output Test Switch
(used to test relays on control
board)
Connector K3
Harvest Control
(thermistor)
Connector K4
Open
(not connected)
Microprocessor
(control board
revision level
indicated by last 2
digits on label)
Connector K5
Float Switch
Part Number
Connector K1
Pins #1 through #10
#1, 9 Magnetic Contactor
#2 Hot Gas Valve
#3 Line Valve
Self-Contained Fan Motor (FMS)
#4 Pump Motor (icemaking)
#5 Pump Motor (drain)
#6 Water Valve
#7, 10 Power (line, bin control)
#8 Open
Switchfor"C"and
"ALPINE"controlboard
(service control boards only)
Alarm Reset Switch
Backup Freeze
Timer LED
Dip Switch
Backup Harvest
Timer LED
Alarm Buzzer
Power LED
(lights when
power is supplied
to the control
board)
Relay LEDs (4)
(indicate which
relays are energized
as listed below)
LED 2
Hot Gas Valve (HGV)
Self-Contained Fan
Motor (FMS) (FMS
off when LED on)
LED 3
Pump Motor (PM)
(on at pump out only)
LED 4
Water Valve (WV)
LED 1
Compressor (Comp)
Remote Fan Motor
(FMR)
Transformer
Connector

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2. LED Lights and Audible Alarm Safeties
The red LED indicates proper control voltage and will remain on unless a control voltage
problem occurs. At startup a 5 second delay occurs while the control board conducts an
internal timer check. A short beep occurs when the power switch is turned OFF.
The green LEDs 1 through 4 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 control board is 1,
4,3,2.Formoreinformation,see"II.B.SequenceofOperation."
Sequence Step LED Energized
Components
Time LEDs are On
Min. Max. Avg.
1 Minute Fill Cycle 4 WV 60 seconds
Harvest Cycle 1, 4, and 2 WV, HGV,
Comp, FMR
2 minutes 20 minutes 3 to 5 minutes
Freeze Cycle 1 Comp, PM,
FMR/FMS,
LLV
5 minutes freeze timer
setting
30 to 35 minutes
Reverse Pump Out 1, 3, and 2 Comp, HGV,
PM, FMR
10 seconds 20 seconds factory setting
The built in safeties shut down the unit and have alarms as follows:
No. of Beeps
(every 3 sec.) Type of Alarm Notes
1High Evaporator Temp.
(temperature > 127°F)
(53°C)
Check for harvest problem (stuck HGV or
relay), hot water entering unit, stuck HM,
or shorted thermistor.
2Harvest Backup Timer
(harvest > 20 min. for two
cycles in a row)
Orange LED marked H TIMER lights up.
Check for open thermistor, HGV not
opening, TXV leaking by, low charge, or
inefficient compressor.
3Freeze Timer
(freeze > specied setting
for two cycles in a row)
Timer is factory set using
dip switches 9 & 10
Yellow LED marked F TIMER lights up.
Check for F/S stuck closed (up), WV
leaking by, HGV leaking by, TXV not
feeding properly, low charge, HM not
bypassing, or inefficient compressor.
To manually reset the above safeties, press the alarm reset button with the power
supply on.
6Low Voltage
(92Vac ±5% or less)
Red LED will turn off if voltage protection
operates.
The control voltage safeties automatically
reset when voltage is corrected.
7High Voltage
(147Vac ±5% or more)
Legend: Comp–compressor; FMR–remote fan motor; FMS–self-contained fan motor;
F/S–oat switch; HGV–hot gas valve; HM–headmaster (C.P.R.); LLV–Liquid
Line Valve; PM–pump motor; TXV–thermostatic expansion valve; WV–inlet
water valve

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3. Controls and Adjustments
CAUTION
Dip switches are factory set. Failure to maintain factory settings may adversely
affect performance and warranty coverage. For more information, contact
Hoshizaki Technical Support at 1-800-233-1940.
a) Default Dip Switch Settings
The dip switch is factory-adjusted to the following positions:
Dip Switch No. 1 2 3 4 5 6 7 8 9 10
KM-1601MRH/3 OFF OFF ON OFF ON ON OFF OFF OFF ON
Freeze Timer (9 & 10)
Pump-Out Frequency Control (5 & 6)
Pump-Out Timer (3 & 4)
Harvest Timer (1 & 2)
Normally in the OFF position.
b) Harvest Timer (dip switch 1 & 2)
The harvest timer starts counting when the thermistor reads 48°F (9°C) at the evaporator
outlet and sends a 3.9 kΩsignal to the control board.
No adjustment is required under normal use, as the harvest timer is adjusted to the
suitable position. However, a setting longer than the factory setting may be advised in
cases where the ush provided at harvest needs to be prolonged for extra cleaning.
Before changing this setting, call the Hoshizaki Technical Support Department at
1-800-233-1940 for recommendations. Keep in mind that setting the harvest timer to a
longer setting will decrease 24 hour production.
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) Pump-Out Timer (dip switch 3 & 4)
When a freeze cycle is completed, the pump motor stops, and the icemaker resumes
operation in 2 seconds. Then, during cycles when a pump out is called for, the pump
motor drains the water tank for the time determined by the pump-out timer. The pump-out
timer also acts in place of the harvest timer during cycles with a pump out.
The pump-out timer is factory-adjusted, and no adjustment is required.
Dip Switch Setting Time (seconds)
No. 3 No. 4 T1 T2
OFF OFF 10 150
ON OFF 10 180
OFF ON 10 120
ON ON 20 180
T1: Time to drain the water tank
T2: Harvest timer at pump out
Pump out always occurs on the 2nd harvest after startup. Then, depending on the
pump-out frequency control setting (dip switch 5 & 6), pump out occurs every cycle, or
every 2nd, 5th or 10th cycle.
d) Pump-Out Frequency Control (dip switch 5 & 6)
The pump motor drains the water tank at the frequency set by the pump-out frequency
control.
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 drain more often, the pump-out 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) Factory Use (S4 dip switch 7 & 8)
Factory set for proper operation. Do not adjust. This must be left in the factory default
position.