Hoshizaki DKM-500BAH User Manual

Hoshizaki America, Inc.

Hoshizaki

Crescent Cube Icemaker / Dispenser

Model
DKM-500BAH

“A Superior Degree

of Reliability”

www.hoshizaki.com

Service Manual

™

Number: 73138
Issued: 9-20-200

6

IMPORTANT

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

HOSHIZAKI provides this manual primarily to assist qualified service technicians in the
service and maintenance of the unit.

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

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

CONTENTS

I. Specifications ...................................................................................................................... 5

II. General Information ........................................................................................................... 6

A. Construction .................................................................................................................. 6

B. Sequence of Operation ................................................................................................. 7

1. One Minute Fill Cycle .............................................................................................. 7

2. Initial Harvest Cycle ................................................................................................ 7

3. Freeze Cycle ........................................................................................................... 7

4. Pump-Out Cycle ..................................................................................................... 7

5. Normal Harvest Cycle ............................................................................................ 7

C. Control Board ................................................................................................................ 9

1. Control Board Layout ............................................................................................. 10

2. Features ................................................................................................................ 11

a) Maximum Water Supply Period – 6 minutes ...................................................... 11

b) Harvest Backup Timer and Freeze Timer .......................................................... 11

c) High Temperature Safety ................................................................................... 11

d) Low Water Safety .............................................................................................. 11

e) High Voltage and Low Voltage Cut-outs ............................................................ 11

f) LED Lights and Audible Alarm Safeties .............................................................. 12

3. Controls and Adjustments ..................................................................................... 13

a) Default Dip Switch Settings ............................................................................... 13

b) Harvest Control – Thermistor ............................................................................ 13

c) Harvest Timer (dip switch 1 & 2) ........................................................................ 14

d) Pump-Out Timer (dip switch 3 & 4) ................................................................... 14

e) Pump-Out Frequency Control (dip switch 5 & 6) ............................................... 15

f) Freeze Timer (dip switch 9 & 10) ........................................................................ 15

g) Bin Control ........................................................................................................ 15

4. Bin Control Troubleshooting ................................................................................... 16

a) Machine Will Not Start ....................................................................................... 16

b) Machine Will Not Shut Off ................................................................................. 16

5. Control Board Check Procedure ............................................................................ 16

6. Control Board Replacement .................................................................................. 17

D. Switches ...................................................................................................................... 17

1. Control Switch ....................................................................................................... 17

2. Service Switch ....................................................................................................... 17

a) DRAIN ............................................................................................................... 17

b) CIRCULATE ...................................................................................................... 18

c) WASH ................................................................................................................ 18

3

III. Technical Information ...................................................................................................... 19

A. Water Circuit and Refrigeration Circuit ........................................................................ 19

B. Wiring Diagram ............................................................................................................ 20

C. Timing Chart ............................................................................................................... 21

D. Performance Data ....................................................................................................... 23

IV. Service Diagnosis ........................................................................................................... 24

A. 10-Minute Diagnostic Procedure ................................................................................ 24

B. Diagnostic Charts ........................................................................................................ 25

1. Ice Making ............................................................................................................. 25

a) No Ice Production .............................................................................................. 25

b) Evaporator is Frozen Up .................................................................................... 28

c) Low Ice Production ............................................................................................ 29

d) Abnormal Ice ..................................................................................................... 29

e) Other ................................................................................................................. 30

2. Dispensing ............................................................................................................. 30

V. Removal and Replacement of Components .................................................................... 32

A. Service for Refrigerant Lines ...................................................................................... 32

1. Refrigerant Recovery ............................................................................................. 32

2. Evacuation and Recharge (R-404A) ...................................................................... 32

B. Brazing ........................................................................................................................ 33

C. Removal and Replacement of Compressor ................................................................ 33

D. Removal and Replacement of Drier ............................................................................ 34

E. Removal and Replacement of Expansion Valve .......................................................... 35

F. Removal and Replacement of Hot Gas Valve .............................................................. 35

G. Removal and Replacement of Evaporator .................................................................. 36

H. Removal and Replacement of Condenser .................................................................. 37

I. Removal and Replacement of Thermistor .................................................................... 38

J. Removal and Replacement of Fan Motor .................................................................... 38

K. Removal and Replacement of Inlet Water Valve ......................................................... 39

L. Removal and Replacement of Pump Motor ................................................................. 39

M. Removal and Replacement of Spray Tubes ................................................................ 40

N. Removal and Replacement of Gear Motor ................................................................ 40

O. Removal and Replacement of Dispense Switch ......................................................... 41

P. Removal and Replacement of Solenoid ...................................................................... 41

VI. Cleaning and Maintenance Instructions ......................................................................... 42

A. Cleaning Instructions .................................................................................................. 42

1. Cleaning Procedure – Icemaker ............................................................................ 42

2. Sanitizing Procedure – Icemaker ........................................................................... 43

3. Cleaning Procedure – Bin ...................................................................................... 44

4. Sanitizing Procedure – Bin .................................................................................... 44

B. Maintenance Instructions ............................................................................................ 45

1. Exterior Panels ...................................................................................................... 45

2. Air Filters ............................................................................................................... 45

3. Condenser ............................................................................................................. 45

C. Preparing the Icemaker for Long Storage ................................................................... 45

4

AC SUPPLY VOLTAGE 115/60/1
AMPERAGE 13.3 A ( 5 Min. Freeze AT 104°F / WT 80°F)
MINIMUM CIRCUIT AMPACITY 15 A
MAXIMUM FUSE SIZE 15 A
APPROXIMATE ICE PRODUCTION Ambient WATER TEMP. (°F)
PER 24 HR. Temp.(°F) 50 70 90
lbs./day ( kg/day ) 70 *466 (211) 448 (203) 420 (191)
Reference without *marks 80 453 (205) 425 (193) 395 (179)

90 448 (203) *406 (184) 376 (170)

100 390 (177) 399 (181) *348 (158)
SHAPE OF ICE Crescent Cube
ICE PRODUCTION PER CYCLE 7.2 lbs. (3.2 kg) 360 pcs.
APPROXIMATE STORAGE CAPACITY 200 lbs (91 Kg)
APPROXIMATE ICE DISPENSING SPEED 13 lbs/min (6 kg/min)
ELECTRIC & WATER CONSUMPTION 90/70°F 70/50°F
ELECTRIC W (kWH/100 lbs.) 1150 (6.8) 1049 (5.4)
WATER gal./24HR (gal./100 lbs.) 66 (16.3) 110 (23.6)
EXTERIOR DIMENSIONS (WxDxH) 30" x 28" x 77" With 6" Flanged Legs
EXTERIOR FINISH Stainless Steel, Galvanized Steel (Rear)
INTERIOR FINISH Polyethylene 1 pc. Mol

d

INSULATION Polyurethane Foam
WEIGHT Net 385 lbs. ( 175 kg ), Shipping 410 lbs. (186 kg)
CONNECTIONS - ELECTRIC Cord Connection

- WATER SUPPLY Inlet 1/2" FPT

- DRAIN Outlet 3/4" FPT x 2
CUBE CONTROL SYSTEM Float Switch
HARVESTING CONTROL SYSTEM Hot Gas and Water, Thermistor and Timer
ICE MAKING WATER CONTROL Timer Controlled. Overflow
COOLING WATER CONTROL N/A
BIN CONTROL SYSTEM Proximity Switch with Delay
COMPRESSOR Hermetic, Model RS55C2E-CAA-219
CONDENSER Air-cooled, Fin and tube type
EVAPORATOR Vertical type, Stainless Steel and Copper
REFRIGERANT CONTROL Thermostatic Expansion Valve
REFRIGERANT CHARGE R-404A, 2lbs (907g)
DESIGN PRESSURE High 467 PSIG, Low 170 PSIG
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

OPERATING CONDITIONS VOLTAGE RANGE 104 - 127 V

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

I. Specifications

A. DKM-500BAH

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

notice.

5

II. General Information

A. Construction

1. DKM-500BAH

Bin Cover

Inlet Water Valve

Expansion
Valve

Water Pump

Float Switch

Mechanical Bin
Control

Circulating Valve

Hot Gas Valve

Spray Tubes

Drain Valve

Water Supply
Inlet

Ice Cube Guide

Bin

Front Panel

Dispense Switch

Condenser

Dispense Switch
Connector

Condenser
Fan Motor

Drain Pan

Control
Switches

Agitator

Shutter

Chain

Solenoid
Assembly

Spout
Extension

Gear Motor
Assembly

Drier

Compressor

Strainer

Control Box

6

B. 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 1, 4, 3, 2.

1. One Minute Fill Cycle

LED 4 is on. WV opens and the fill period begins. After 1 minute, the board checks for a
closed F/S. If F/S is closed, the harvest cycle begins. If not, the unit will not start without
adequate water in the sump. This serves as a low water safety to protect the water pump.
WV will remain energized through additional 1 minute cycles until water enters the sump
and F/S closes.

2. Initial Harvest Cycle

LEDs 1, 4, and 2 are on. WV remains open, Comp energizes, 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 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 (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.

3. Freeze Cycle

LED 1 is on. Comp continues to run, PM and FMS energize, HGV and WV close and
the freeze cycle starts. For the first 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, 3, and 2 are on. Comp continues to run, HGV opens, and FMS de-energizes.
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. 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).

5. Normal Harvest Cycle

LEDs 1, 4, and 2 are on. Comp continues 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 kΩ signal 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.

Note: The unit continues to cycle through 3, 4 and 5 sequence until the bin control is

activated (within first 5 minutes of freeze) and shuts the unit down.

Legend:
switch; HGV–hot gas valve; PM–pump motor; SR–Service Relay; WV–inlet water
valve

Comp–compressor; DV–Drain Valve; FMS–self-contained fan motor; F/S–float

7

Cycle

4. Pump-Out

PM stops for 2 sec., SR

energizes, starting PM &

Comp continues

DV for 10/20 sec. each 1,

2, 5, or 10 cycles.

HGV energized

FMS de-energized

3. Freeze Cycle

2. Harvest Cycle

• Minimum freeze time: 5 minutes

• Maximum freeze time: freeze timer setting

• Bin control can only shut down unit within

F/S in

control

5 minute timer

in control

first 5 minutes of freeze cycle

1 to 3 minute timer

in control

F/S closed

F/S Check

F/S

Freeze cycle

operation turned

over to

Comp continues

HGV de-energized

WV de-energized

PM energized

Thermistor temp

reaches 48°F (9°C)

(3.9 kΩ or less)

Harvest timer starts

FMS energized

F/S open

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

control

Thermistor in

• Maximum inlet water valve time: 6 minutes

• Maximum harvest time: 20 minutes

DKM-500BAH Sequence Flow Chart and Component Operation

Fill Cycle

1. One Minute

F/S closed

F/S Check

Comp energized

WV Energized

HGV energized

WV continues

F/S open

Cycle Steps

"E" board will have

Initial startup always

5 second delay

begins here

8

Comp–compressor; DV–drain valve; FMS–self-contained fan motor; F/S–float switch;

Legend:

HGV–hot gas valve; PM–pump motor; SR–service relay; WV–inlet water valve

C. Control Board

• A HOSHIZAKI exclusive solid-state control is employed in the DKM-500BAH Crescent
Cube Icemaker / Dispenser.

• All units 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. Do not misconnect K3, K4 and K5,
because the same connector is used for the thermistor, float switch and
mechanical bin control.

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

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

9

1. Control Board Layout

Control Products "E" Control Board

Alarm Reset Switch

Backup Freeze
Timer LED

Backup Harvest
Timer LED

Alarm Buzzer

Dip Switch

Output Test Switch
(used to test relays on board)

Connector K3
Harvest Control
(thermistor)

Connector K4
Mechanical Bin
Control

Power LED
(lights when
power is supplied
to the 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)

Transformer
Connector

Microprocessor
(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 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" board
and "ALPINE" board
(service boards only)

Control Board

Part Number 2A1410-01 (factory); 2A1410-02 (service)

Type HOS-001A (Control Products - 10 Pin)

10

2. Features

a) Maximum Water Supply Period – 6 minutes

Inlet water valve opening, in the harvest cycle, is limited by the harvest timer. The water
valve cannot remain open longer than the maximum period. The water valve can close in
less than six minutes if the harvest cycle is completed.

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 dip switches 9 &

10.
The 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 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 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 float switch at the end of the initial one
minute water fill cycle and at the end of each harvest cycle.
If the float switch is in the up position (electrical circuit closed), the control board changes
to the ice making cycle. If the 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 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.

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.

11

f) LED Lights and Audible Alarm Safeties

The red LED indicates proper control voltage and will remain on unless a control voltage
problem occurs. At startup a 5 second delay occurs while the board conducts an internal
timer check. A short beep occurs when the power switch is turned 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 board is 1, 4, 3, 2.
For more information, see "II.B. Sequence of Operation."

Sequence Step LED

1 Minute Fill Cycle
Harvest Cycle

Freeze Cycle

Pump Out 1, 3, and 2 Comp, HGV,

The built in safeties shut down the unit and have alarms as follows:

No. of Beeps

(every 3 sec.)

1 High Evaporator Temp.

2 Harvest Backup Timer

4 WV 60 seconds
1, 4, and 2 WV, HGV,

1 Comp, PM,

Type of Alarm

(temperature > 127°F)
(53°C)

(harvest > 20 min. for two
cycles in a row)

Energized

Components

Comp

FMS

PM, SR, DV

Min. Max. Avg.

2 minutes 20 minutes 3 to 5 minutes

5 minutes freeze timer

10 seconds 20 seconds factory setting

Check for harvest problem (stuck HGV or
relay), hot water entering unit, or shorted
thermistor.

Orange LED marked H TIMER lights up.
Check for open thermistor, HGV not
opening, TXV leaking by, low charge, or
inefficient compressor.

Time LEDs are On

setting

Notes

30 to 35 minutes

3 Freeze Timer

(freeze > specified setting
for two cycles in a row)
Timer is factory set using
dip switches 9 & 10

4 Short Circuit

(between the K4 connec­tion on the control board
and the bin control)

5 Open Circuit

(between the K4 connec­tion on the control board
and the bin control)

To manually reset the above safeties, press the alarm reset button with the power
supply on.

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, or inefficient
compressor.

Resistor wire harness shorted. Check
and replace wire harness if necessary.

Resistor wire harness circuit open or
control board open. Check and replace
component if necessary.

12

No. of Beeps

(every 3 sec.)

Type of Alarm

Notes

Legend:

6 Low Voltage

(92Vac ±5% or less)

7 High Voltage

(147Vac ±5% or more)

Comp–compressor; DV–Drain Valve; FMS–self-contained fan motor; F/S–float

Red LED will turn off if voltage protection
operates.
The control voltage safeties automatically
reset when voltage is corrected.

switch; HGV–hot gas valve; PM–pump motor; SR–Service Relay; TXV–
thermostatic expansion valve; WV–inlet water valve

3. Controls and Adjustments

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

DKM-500BAH ON OFF OFF OFF ON ON ON OFF OFF ON

Freeze Timer (9 & 10)

Normally in the OFF position.

Mechanical Bin Control

Pump-Out Frequency Control (5 & 6)

Pump-Out Timer (3 & 4)

Harvest Timer (1 & 2)

b) Harvest Control – Thermistor

A thermistor (semiconductor) is used for a harvest control sensor. The resistance varies
depending on the suction line temperatures. The thermistor detects the temperature of
the evaporator outlet to start the harvest timer. No adjustment is required. If necessary,
check for resistance between thermistor leads, and visually check the thermistor
mounting, located on the suction line next to the evaporator outlet.

Temperature (°F) 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

13

Check a thermistor for resistance by using the following procedure:

1) Disconnect the connector K3 on the board.

2) Remove the thermistor. See "V.H. Removal and Replacement of Thermistor."

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

4) Verify the temperature of the glass, then check for resistance between thermistor leads.
See the table above for temperature and resistance values. Normal reading is within

3.5 to 7 kΩ. Replace the thermistor if it exceeds the normal reading.

c) Harvest Timer (dip switch 1 & 2)

The harvest timer starts counting when the thermistor reads 48°F (9°C) at the
evaporator outlet.
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 flush 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

No. 1 No. 2

(seconds)

OFF OFF 60

ON OFF 90

OFF ON 120

ON ON 180

d) 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 pump­out 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

No. 3 No. 4

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

Time (seconds)

T1

T2

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

14