Hoshizaki DKM-500BAJ, DKM-500BWJ User Manual

Service Manual

Crescent Cube Icemaker / Dispenser

Models
DKM-500BAJ
DKM-500BWJ

hoshizakiamerica.com

Number: 73212
Issued: 6-16-2017

WARNING

Only qualied service technicians should install and service the appliance. To
obtain the name and phone number of your local Hoshizaki Certied Service
Representative, visit www.hoshizaki.com. No service should be undertaken until
the technician has thoroughly read this Service Manual. Failure to service and
maintain the appliance in accordance with this manual will adversely affect safety,
performance, component life, and warranty coverage. Proper installation is the
responsibility of the installer. Product failure or property damage due to improper
installation is not covered under warranty.

Hoshizaki provides this manual primarily to assist qualied service technicians in the
service of the appliance.

Should the reader have any questions or concerns which have not been satisfactorily
addressed, please call, send an e-mail message, or write to the Hoshizaki Technical
Support Department for assistance.

Phone: [phone]
Fax: [phone]

E-mail: [e-mail]

618 Highway 74 South
Peachtree City, GA 30269
Attn: Hoshizaki Technical Support Department

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 appliance is serviced. Read
the warnings and guidelines contained in this manual carefully as they provide
essential information for the continued safe use, service, and maintenance of the
appliance. Retain this manual for any further reference that may be necessary.

CONTENTS

Important Safety Information ................................................................................................. 5

I. Construction and Water/Refrigeration Circuit Diagram ....................................................... 7

A. Construction .................................................................................................................. 7

1. Air-Cooled Models (BAJ) .......................................................................................... 7

2. Water-Cooled Models (BWJ) ................................................................................... 8

B. Water/Refrigeration Circuit Diagram .............................................................................. 9

1. Air-Cooled Models (BAJ) .......................................................................................... 9

2. Water-Cooled Models (BWJ) ................................................................................. 10

II. Sequence of Operation and Service Diagnosis ................................................................11

A. Sequence of Operation Flow Chart .............................................................................. 11

B. Service Diagnosis ....................................................................................................... 12

C. Control Board Check ................................................................................................... 19

D. Bin Control Check ....................................................................................................... 20

E. Switches ...................................................................................................................... 22

1. Control Switch ........................................................................................................ 22

2. Service Switch ....................................................................................................... 22

F. Float Switch Check and Cleaning ................................................................................ 23

1. Float Switch Check ................................................................................................ 23

2. Float Switch Cleaning ............................................................................................ 24

G. Thermistor Check ........................................................................................................ 25

H. Diagnostic Tables ........................................................................................................ 26

III. Controls and Adjustments ............................................................................................... 30

A. Control Board Layout .................................................................................................. 31

B. LED Lights and Audible Alarm Safeties ....................................................................... 32

C. Settings and Adjustments ............................................................................................ 33

1. Default Dip Switch Settings .................................................................................... 33

2. Harvest Timer (S4 dip switch 1 & 2) ...................................................................... 33

3. Pump-Out Timer (S4 dip switch 3 & 4) .................................................................. 34

4. Pump-Out Frequency Control (S4 dip switch 5) ..................................................... 34

5. Harvest Pump Time (S4 dip switch 6) .................................................................... 35

6. Harvest Pump Timer Operation (S4 dip switch 7) .................................................. 35

7. Factory Use (S4 dip switch 8)................................................................................. 36

8. Freeze Timer (S4 dip switch 9 & 10) ...................................................................... 36

9. Float Switch Selector (S5 dip switch 1) ................................................................. 36

10. Rell Counter (S5 dip switch 2 and 3) .................................................................. 36

11. Minimum Harvest Time (S5 dip switch 4) ............................................................. 37

12. Anti-Slush (S5 dip switch 5) ................................................................................. 37

3

IV. Refrigeration Circuit and Component Service Information.............................................. 38

A. Refrigeration Circuit Service Information .................................................................... 38

B. Component Service Information .................................................................................. 41

C. Water Regulating Valve Adjustment (water-cooled model) .......................................... 41

V. Maintenance .................................................................................................................... 42

VI. Preparing the Appliance for Periods of Non-Use ............................................................ 43

VII. Disposal ......................................................................................................................... 45

VIII. Technical Information .................................................................................................... 46

A. Specication and Performance Data Sheets ............................................................... 46

1. DKM-500BAJ ......................................................................................................... 46

2. DKM-500BWJ ........................................................................................................ 47

B. Wiring Diagram ........................................................................................................... 48

4

Important Safety Information

Throughout this manual, notices appear to bring your attention to situations which could
result in death, serious injury, damage to the appliance, or damage to property.

WARNING Indicates a hazardous situation which could result in death or

serious injury.

NOTICE Indicates a situation which could result in damage to the

appliance or property.

IMPORTANT Indicates important information about the use and care of the

appliance.

WARNING

The appliance 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. Failure to service and maintain the
appliance in accordance with this manual will adversely affect safety, performance,
component life, and warranty coverage and may result in costly water damage.

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 and service this appliance.

• The appliance must be installed in accordance with applicable national, state, and
local codes and regulations.

• The appliance requires an independent power supply of proper capacity. See the
nameplate for electrical specications. Failure to use an independent power supply
of proper capacity can result in a tripped breaker, blown fuse, damage to existing
wiring, or component failure. This could lead to heat generation or re.

• THE APPLIANCE MUST BE GROUNDED: The appliance is equipped with a
NEMA5-20 three-prong grounding plug to reduce the risk of potential shock
hazards. It must be plugged into a properly grounded, independent 3-prong wall
outlet. If the outlet is a 2-prong outlet, it is your personal responsibility to have
a qualied electrician replace it with a properly grounded, independent 3-prong
wall outlet. Do not remove the ground prong from the power cord and do not use
an adapter plug. Failure to properly ground the appliance could result in death or
serious injury.

• Do not use an extension cord.

• To reduce the risk of electric shock, do not touch the control switch, service switch,
or plug with damp hands. Make sure the control switch is in the "OFF" position
before plugging in or unplugging the appliance.

• Do not use an appliance with a damaged power cord. The power cord should not
be altered, jerked, bundled, weighed down, pinched, or tangled. Such actions could
result in electric shock or re. To unplug the appliance, be sure to pull the plug, not
the cord, and do not jerk the cord.

5

WARNING, continued

• Do not make any alterations to the appliance. Alterations could result in electric
shock, injury, re, or damage to the appliance.

• The appliance is not intended for use by persons (including children) with reduced
physical, sensory, or mental capabilities, or lack of experience and knowledge,
unless they have been given supervision or instruction concerning use of the
appliance by a person responsible for their safety.

• Children should be properly supervised around the appliance.

• Do not climb, stand, or hang on the appliance or allow children or animals to do so.
Serious injury could occur or the appliance could be damaged.

• Do not use combustible spray or place volatile or ammable substances near the
appliance. They might catch re.

• Keep the area around the appliance clean. Dirt, dust, or insects in the appliance
could cause harm to individuals or damage to the appliance.

NOTICE

• Follow the water supply, drain connection, and maintenance instructions carefully to
reduce the risk of costly water damage.

• In areas where water damage is a concern, install in a contained area with a oor
drain.

• Install the appliance in a location that stays above freezing. Normal operating
ambient temperature must be within 45°F to 100°F (7°C to 38°C). If the normal
operating ambient temperature is above 90°F (32°C), the compressor insulation
cover must be removed.

• Do not leave the appliance on during extended periods of non-use, extended
absences, or in sub-freezing temperatures. To properly prepare the appliance for
these occasions, follow the instructions in "IV. Preparing the Appliance for Periods
of Non-Use."

• Do not place objects on top of the appliance.

• The storage bin is for ice use only. Do not store anything else in the storage bin.

6

I. Construction and Water/Refrigeration Circuit Diagram

A. Construction

1. Air-Cooled Models (BAJ)

Mechanical Bin
Control

Inlet Water Valve

Expansion Valve

Water Pump

Float Switch

Bin Cover

Wash Valve

Hot Gas Valve

Spray Tubes

Drain Valve

Water Supply
Inlet

Ice Cube Guide

Bin

Agitator

Shutter

Chain

Dispense Switch

Front Panel

Condenser

Dispense Switch
Connector

Condenser
Fan Motor

Drain Pan

Solenoid
Assembly

Spout
Extension

Gear Motor
Assembly

Drier

Compressor

Strainer

Control
Switches

Control Box

7

2. Water-Cooled Models (BWJ)

Bin Cover

Mechanical Bin
Control

Wash Valve

Hot Gas Valve

Spray Tubes

Inlet Water Valve

Expansion Valve

Dispense Switch

Water Pump

Float Switch

Drain Valve

Strainer

Water Supply
Inlet

Ice Cube Guide

Bin

Agitator

Shutter

Chain

Solenoid
Assembly

Spout
Extension

Condenser

Line Valve

Front Panel

Drier

Dispense Switch
Connector

Drain Pan

8

Control
Switches

Gear Motor
Assembly

Water
Regulator

Compressor

Control Box

B. Water/Refrigeration Circuit Diagram

1. Air-Cooled Models (BAJ)

9

2. Water-Cooled Models (BWJ)

10

II. Sequence of Operation and Service Diagnosis

A. Sequence of Operation Flow Chart

10th cycle

2 sec., then reverses

for 10/20 sec.

4. Pump-Out Cycle

• Pump motor stops for

(S4 dip switch 3 & 4)

FS opens or

freeze timer

FS in control

terminates

• Factory set for every

Comp continues

FMR continues

HGV energized

PM de-energizes for 2 sec.,

Anti-Slush

Thermistor temperature

reaches 36°F (2.2°C)

then energizes for 10/20 sec.

FM de-energized

(5.8 kΩ).

PM de-energized for

10 sec.

LLV de-energized

3. Ice Level Lowered

Icemaker starts at

"1. 1-Minute Fill Cycle."

To 1 above

MBC closed

(MBC actuator paddle disengaged)

Green "BC CLOSED" LED on

Yellow "BC OPEN" LED off

3. Freeze Cycle

2. Harvest Cycle

• Minimum freeze time: 5 min.

• Maximum freeze time: freeze timer

• Maximum inlet water valve time: 6 min. or the length of

harvest minus 50 sec. (S4 dip switch 7), whichever is shorter.

setting (S4 dip switch 9 & 10)

• Maximum harvest time: 20 min.

5-min. minimum

freeze timer in

Harvest Pump

1 to 3-min. harvest timer in

control (S4 dip switch 1 & 2)

Thermistor in

control

control

Timer

FS closed

50 sec.

FS closed

All components

de-energized.

2. Icemaker Off

Comp continues

FMR continues

FM energized

LLV energized

PM energized

HGV de-energized

Yellow "BC OPEN" LED continues. All

FS check

FS open

PM energized

WV de-energized

Thermistor temperature reaches

48°F (9°C) (3.9 kΩ or less). Harvest

timer starts (1 to 3 min.).

Comp energized

FM energized

HGV energized

WV energized

components de-energized.

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 icemaker. 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 icemaker will not restart when the control switch is

placed in the "ICE" position.

freeze cycle if activated at the end of the harvest cycle.

• Fill Cycle–15 sec. after activation.

"J" Control Board With Harvest Pump Timer Operation Sequence Flow Chart

FS open

1. 1-Minute

Cycle

Fill Cycle

Steps

FS check

WV energized

Startup

Shutdown Delay:

1. Bin Full

If FS is open, Comp stops and cycle returns to 1-min. ll.

Shutdown

and Restart

the 5-min. short cycle protection timer terminates.

• Harvest Cycle–At the end of the harvest cycle, or up to 15 sec. into the

• Freeze Cycle–15 sec. after activation if activated at least 15 sec. before

Otherwise, at the end of the next harvest cycle.

MBC open (MBC actuator paddle engaged)

Green "BC CLOSED" LED off

Yellow "BC OPEN" LED on

Legend:

Comp–compressor

FM–fan motor

FS–oat switch

HGV–hot gas valve

LLV–liquid line valve

MBC–mechanical bin control

PM–pump motor

MBC Operation

WV–inlet water valve

11

B. Service Diagnosis

WARNING

• The appliance should be diagnosed and repaired only by qualied service
personnel to reduce the risk of death, electric shock, serious injury, or re.

• Risk of electric shock. Control switch in "OFF" position does not de-energize all
loads Use extreme caution and exercise safe electrical practices.

• Moving parts (e.g., fan blade) can crush and cut. Keep hands clear.

• Before servicing the appliance, move the control switch to the "OFF" position and
turn off the power supply.

• CHOKING HAZARD: Ensure all components, fasteners, and thumbscrews are
securely in place after the appliance is serviced. Make sure that none have fallen
into the dispenser unit/ice storage bin.

• Make sure all food zones in the appliance and dispenser unit/ice storage bin are
clean after service.

The diagnostic procedure is a sequence check that allows you to diagnose the electrical
system and components. Before proceeding, check for correct installation, proper
voltage per nameplate, and adequate water supply. Check CB using the steps in "II.C.
Control Board Check." Check dip switch settings to assure that S4 dip switch 3, 4, 7, 8,
9, 10 and S5 dip switch 1 through 5 are in the factory default position. S4 dip switch 1, 2,
5, 6 are cleaning adjustments and the settings are exible. For factory default settings,
see "III.C.1. Default Dip Switch Settings."

Note: • When checking high voltage (115VAC), always choose a white (W) neutral wire to

establish a good neutral connection.

• When checking voltage from the CB K1 connector (10 pin connector), pull
CBK1connector out slightly to allow room for multimeter test leads contact.

Conrm that the location meets installation requirements:

• The appliance is not intended for outdoor use. Normal operating ambient
temperature should be within 45°F to 100°F (7°C to 38°C).

• Allow 6" (15 cm) clearance at rear, sides, and top for proper air circulation and
ease of maintenance and/or service should they be required.

• The appliance should not be located in a corrosive environment.

1) Turn off the power supply, then access the control box. Move the control switch to the
"OFF" position. Clear any ice from BC.

2) Check that the 115VAC 10A fuse is good.

12

1. Diagnosis

3) Power On: Turn on the power supply, then move the control switch to the "ICE" position.
A 5-sec. delay occurs. CB red "POWER OK" LED and green "BC CLOSED" LED turn
on. If yellow "BC OPEN" LED is on (indicating a full bin), check MBC. Move ice away
from MBC actuator paddle. If yellow "BC OPEN" LED stays on, see"II.D. Mechanical
Bin Control Check."

Note: • CB red "POWER OK" LED remains on unless the 10.5VAC power supply is

interrupted (K2 connector).

• Check CB using the steps in "II.C. Control Board Check."

• Conrm CB green "BC CLOSED" LED is on. If CB yellow "BC OPEN" LED is on,
remove ice from BC. If no ice is around BC and yellow "BC OPEN" LED is on,
see "II.D. Mechanical Bin Control Check."

a) Power On Diagnosis: If CB red "POWER OK" LED is off, conrm 10A fuse is good.

Check for 115VAC at control switch #2 (BK) to neutral (W) then at control switch
#3(P) to neutral (W). If 115VAC is present on #2 (BK) and not on #3(P), replace
control switch. If 115VAC is present on control switch #3 (P), check for 115VAC at
HPS pink (P) wire to neutral (W) then HPS black (BK) wire to neutral (W). If115VAC
is present at HPS pink (P) wire and not at HPS black (BK) wire, HPS is open.
See HPS Diagnosis below. If 115VAC is present at HPS black (BK) wire, check
for 10.5VAC at CB K2#1 red (R) wire to CB K2 #2 red (R) wire. If 10.5VAC is not
present, check CT continuity. If open, replace CT.

b) HPS Diagnosis: Let refrigeration circuit pressures equalize. If HPS does not

reset and pressures are equalized, replace HPS. Check that the condenser coil
is not clogged or restricted and the FM is operating correctly. If pressures are not
equalized, reclaim refrigerant and diagnose refrigeration circuit restriction. Check
that there are no restrictions in the refrigeration circuit.
Harvest Cycle: HGV, strainer, or check valve.
Freeze Cycle: FM, TXV, WRV, HM, LLV, strainer, check valve, drier, and damaged
line set or tting.

4) 1-Min. Fill Cycle – LED 4 is on. WV and X11 relay energize. Water begins to ll
the water tank. After 1 min., CB checks for a closed FS. If FS is closed, the harvest
cycle begins (X10, X12, Comp, and HGV energize). Continue to step 5a. If FS is open,
WV remains energized through additional 1-min. ll cycles until water enters the water
tank and FS closes (low water safety protection during initial start up and at the end of
each harvest).
Diagnosis: Check that water enters the water tank. If not, check that the water supply
line shut-off valve is open and screens or external lters are clear. Check for 115VAC
at CB K1 #6(O) to neutral (W). If 115VAC is not present, replace CB. If 115VAC is
present, and WV does not energize, check for 115VAC at WV. If 115VAC is present,
check coil continuity. Ifopen, replace WV. If the water tank lls, but the appliance fails to
start harvest (Comp energized), check for open FS. See "II.E. Float Switch Check and
Cleaning." If FS is closed and CB fails to start the harvest cycle after 1 min., replace
CB.

13

5a) Initial Harvest Cycle – LEDs 1, 4, and 2 are on. WV and X11 relay continue. Comp,

HGV, X12, and X10 relays energize. CBmonitors the warming of the evaporator via
the thermistor located on the suction line. When the thermistor reaches 48°F (9°C), CB
reads 3.9 kΩ from the thermistor and turns harvest termination over to the harvest timer
(S4 dip switch 1 & 2). The harvest timer has settings of 60, 90, 120, and 180 sec. The
pump-out timer (S4 dip switch 3 & 4) acts in place of the harvest timer during cycles
with a pump-out (S4 dip switch 5). WV and X11 relay are energized during harvest for a
maximum of 6 min. or the length of harvest minus 50sec., whichever is shorter. 50sec.
before harvest terminates, PM energizes. See step 5b below.

a) Comp Diagnosis: Check that evaporator is warming. Ifnot, conrm that Comp

energizes. If not, check for 115VAC at CB K1 #1 or #9 (V) to neutral (W). If 115VAC is
not present, check for 115VAC at CB K1 #7 or #10 (BK) to neutral (W). If115VAC is
present at #7 or #10 (BK) and not at #1 or #9 (V), replace CB. If 115VAC is present,
check for 115VAC at CR solenoid. If 115VAC is present, conrm contacts are closed.
If not, replace CR. If CR contacts are closed, check Comp start and run capacitors,
Comp start relay, and Comp motor winding.

b) HGV Diagnosis: If Comp is energized and evaporator is not warming, check that

HGV energizes and opens. Check for 115VAC at CB K1 #2 (P) to neutral (W).
If115VAC is not present, replace CB. If 115VAC is present, check for 115VAC at HGV
coil and check HGV coil continuity. Replace as needed.

c) LLV Diagnosis: Conrm that LLV is de-energized and closed (not bypassing).

If energized, replace CB. If de-energized and bypassing, replace LLV.

d) WRV Diagnosis: Conrm WRV is not leaking by.

5b) Harvest Pump Time – LEDs 1, 3, and 2 are on. When the thermistor reaches 48°F

(9°C), CB reads 3.9 kΩ from the thermistor and turns harvest termination over to
the harvest timer (S4 dip switch 1 & 2). 50 sec. before the harvest timer terminates,
LED3turns on and PM energizes. Comp, HGV, X10, and X12 relays continue.
LED4turns off, WV and X11 relay de-energize.

a) Thermistor Diagnosis: Place a thermometer on the suction line next to the

thermistor. Has it warmed to 48°F (9°C) or warmer? Conrm thermistor status.
See"II.F. Thermistor Check."

b) Contorl Board Diagnosis: If the thermistor reading is in proper range, dip switch7is

on and WV continues, check for 115VAC at CB K1 #6(O) to neutral (W). If115VAC is
present, and LED 4 is off, replace CB. If LED 3is on and PM is not energized, check
for 115VAC at CB K1 #5(DBU) to neutral (W). If115VAC is not present, replace CB.

c) Relay Diagnosis: If 115VAC is present and PM is not energized, check for 115VAC

at X12relay terminal #8 (P) to terminal #7neutral (W). If115VAC is present, check
for 115VAC at X12 relay terminal #6 (DBU) to neutral (W) and terminal #4 (Y) to
neutral(W). If 115VAC is present on terminal #6(DBU) and not on terminal #4(Y),
replace X12 relay.

d) Pump Motor Diagnosis: If 115VAC is present on X12 terminal #4(Y) to neutral (W)

and PM is not energized, check PM capacitor and motor winding continuity.

14

5c) Initial Harvest Cycle Termination Diagnosis: When the harvest timer (S4 dip switch

1 & 2) terminates, harvest cycle terminates. If 1-min. ll cycle starts after harvest timer
terminates, check that FS is clean and operating properly, see "II.E. Float Switch Check
and Cleaning." If FS is closed, CB proceeds to the next cycle. Ifnot, replace CB.
Note: The minimum total time allowed by CB for a complete harvest cycle is 2 min.

Maximum harvest time allowed is 20 min.

IMPORTANT! S4 dip switch 7 must remain on. Otherwise, PM will not energize
during the last 50 sec. of harvest.

6) Freeze Cycle – LED 1 is on. Comp and PM continue. FM and LLV (if applicable)
energize. HGV, X10, and X12 relays de-energize. Appliance is held in freeze by a
5-min. short cycle protection timer. After 5-min. timer terminates and FS opens, freeze
cycle terminates. When the thermistor reaches 36°F (2.2°C), CB reads 5.8 kΩ from the
thermistor and de-energizes the PM for 10 sec. (anti-slush). After 10 sec. CB energizes
PM and freeze cycle continues.
Note: PM power supply switches from CBK1 #5(DBU) in harvest to K1 #4 (R) in freeze.

a) Freeze Cycle Diagnosis: Conrm Comp and PM continue. Conrm that FM and

LLV (if applicable) energize. Conrm WRV (if applicable) opens. Next, conrm HGV,
X10, and X12 relays de-energize. During the rst 5 min. of freeze, conrm evaporator
is cooling. If not, conrm WV de-energized (not leaking by), HGV de-energized (not
bypassing), LLV (if applicable) and FM energize, TXV operating correctly, WRV
(ifapplicable) opens, Comp is efficient, and refrigerant charge is correct. See "VIII.A.
Specication and Performance Data Sheet."
When the thermistor reaches 36°F (2.2°C), CB reads 5.8 kΩ from the thermistor and
de-energizes the PM for 10 sec. then, energizes PM for the duration of the freeze
cycle.

b) Comp Diagnosis: If Comp de-energizes once freeze begins, check that appliance

has not shut off on HPS ("POWER OK" LED off). If so, check "3)b) HPS Diagnosis."
If "POWER OK" LED is on, check for 115VAC at CB K1 #1 (V) or #9 (V) to
neutral(W). If 115VAC is not present and LED 1 is on, replace CB. If 115VAC is
present, check for 115VAC at CR coil. If 115VAC is present, check CR coil and
contact continuity. Replace as needed. If CR is okay, check Comp start relay and
start and run capacitors. Next, check Comp motor winding continuity. If Comp is
energized but evaporator is not cooling, check for an inefficient Comp. See "VIII.B.
Performance Data Sheets."

c) WV and HGV Diagnosis: If WV is energized, check for 115VAC at CB K1 #6 (O) to

neutral (W). If 115VAC is present after PM energizes in harvest cycle, replace CB.
If 115VAC is not present, replace WV (bypassing). If HGV did not de-energize at
the end of harvest, check for 115VAC at CB K1 #2 (P) to neutral (W). If 115VAC is
present 50 sec. after PM energizes, replace CB. If 115VAC is not present, replace
HGV (bypassing).

15