Only qualied service technicians should install and service the icemaker. To
obtain the name and phone number of your local Hoshizaki Certied 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 icemaker in accordance with this manual will adversely affect safety,
performance, component life, and warranty coverage and may result in costly water
damage. 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 qualied 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, send an e-mail message, or write to the Hoshizaki Technical Support
Department for assistance.
HOSHIZAKI AMERICA, INC.
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.
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IMPORTANT
This manual should be read carefully before the icemaker is serviced. Read
the warnings and guidelines contained in this booklet carefully as they provide
essential information for the continued safe use, service, and maintenance of the
icemaker. Retain this booklet for any further reference that may be necessary.
CONTENTS
Important Safety Information ................................................................................................. 5
I. Construction and Water Refrigeration Circuit Diagrams ..................................................... 7
A. Construction .................................................................................................................. 7
B. Water/Refrigeration Circuit Diagrams ............................................................................ 8
II. Sequence of Operation and Service Diagnosis ................................................................. 9
A. Sequence of Operation Flow Chart ............................................................................... 9
B. Service Diagnosis ....................................................................................................... 10
C. Control Board Check ................................................................................................... 14
D. Bin Control Check ....................................................................................................... 23
E. Float Switch Check and Cleaning ............................................................................... 24
F. Diagnostic Tables ......................................................................................................... 26
III. Controls and Adjustments ............................................................................................... 29
A. Control Board Layout .................................................................................................. 30
B. LED Lights and Audible Alarm Safeties ....................................................................... 32
C. Settings and Adjustments ............................................................................................ 33
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.
NOTICEIndicates a situation which could result in damage to the
appliance or property.
IMPORTANTIndicates 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 qualied service technicians should install and service the 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 specications. 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
NEMA5-15 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
qualied 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 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.
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WARNING, continued
• Do not make any alterations to the appliance. Alterations could result in electric
shock, injury, re, or damage to the appliance.
• Do not place ngers or any other objects into the ice discharge opening.
• 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.
• Young children should be properly supervised around the appliance.
• Do not climb, stand, or hang on the appliance or appliance door 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).
• 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 "VI. 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.
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I. Construction and Water Refrigeration Circuit Diagrams
A. Construction
DCM-270BAH
DCM-270BAH-OS
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B. Water/Refrigeration Circuit Diagrams
DCM-270BAH(-OS)
Inlet Water Valve
Water
Supply
Reservoir
Overow
Water Level
Float
Switch
Evaporator
Bin
Bin Drain
Hose
Thermostatic
Expansion Valve
Evaporator Water
Supply Hose
Drier
Fan
Air-Cooled Condenser
Gear Motor
High-Pressure Switch
To Drain
Drain Valve
To Drain
Dispense Water Valve
Refrigeration Circuit
Water Circuit
Compressor
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II. Sequence of Operation and Service Diagnosis
A. Sequence of Operation Flow Chart
1-beep alarm continues
WV energized
GM de-energized
When UFS closes,
alarm resets and
2. Ice Purge Cycle
Low Water Safety
90 sec. FT exceeded
starts.
1-beep alarm sounds
90 sec. PT starts
PT
90 seconds
terminates
exceeded
FT
1-beep alarm sounds
PT starts
UFS open
WV energized
Comp de-energized
FM de-energized
GM energized
Legend:
BC-bin control
Comp-compressor
DC-drain cycle
DT-drain timer
DV-drain valve
FM-fan motor
FT-ll timer (low water safety)
GM-gear motor
LFS-lower oat switch
PT-purge timer
UFS-upper oat switch
WV-inlet water valve
3. Freeze Cycle
DCM-270B_H(-OS)
1-in-1 drain cycle. DV energizes for 2 seconds every hour
"F-A" Control Board Sequence Flow Chart
4. 1-in-12 Drain Cycle - Although the factory default 1-in-1 drain cycle
is recommended, a 1-in-12 drain cycle is available. For 1-in-12 drain
cycle sequence, see "3. 1-in-12 Drain Cycle & Restart (optional)."
2. Ice Purge Cycle
To bypass, press the
Rell
(S1 Dip Switch 4).
Does not affect operation.
"SERVICE" button after
GM starts.
Maximum
90 seconds
5 minutes 5 sec.
LFS closed
UFS closed
UFS open
LFS open
Comp energized
FM energized
GM energized
FT terminates
WV de-energized
Comp energized
FM energized
FT starts (90 sec.)
WV energized
Comp energized
FM energized
GM energized
GM energized
GM energized
3. Icemaker Restart
2. Icemaker Off
1. Bin Full
to "2. Ice Purge Cycle" above
Ice level lowered
6 to 10 sec.
BC closed
(BC large balance plate disengaged)
All Components de-energized
to "1. Fill Cycle" above
4. Icemaker Restart
10-min. DT terminates
DV de-energized
1-in-12 DT reset
3. 10-Minute Drain
DV energized
GM de-energized
5 minutes
2. Ice Purge Cycle
Comp de-energized
FM de-energized
GM energized
LFS closed
UFS closed
FT terminates
WV de-energized
BC open
(BC large balance
Maximum
Power Switch "ON"
Control Switch in "ICE"
1. Startup
90 seconds
WV energized
FT starts (90 sec.)
"POWER OK" LED on
If Fill > 90 sec. FT
1-beep alarm sounds
WV energized
When UFS closes
alarm resets and
2. Ice Purge Cycle starts.
2. Bin Control
1. Fill Cycle
plate engaged)
Shutdown & Restart
1. DT Initiates DC
(S1 dip switch 4)
&Restart(optional)
3. 1-in-12 Drain Cycle
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B. Service Diagnosis
WARNING
• The appliance should be diagnosed and repaired only by qualied service
personnel to reduce the risk of death, electric shock, serious injury, or re.
• Risk of electric shock. Use extreme caution and exercise safe electrical practices.
• Moving parts (e.g., fan blade) can crush and cut. Keep hands clear.
• 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 storage bin.
• Make sure all food zones in the appliance are clean after service. For cleaning
procedures, see the instruction manual or the maintenance label.
1. Ice Production Check
To check ice production, remove the front, top, and left side panels. Place a container
under the spout and dispense all ice from the icemaker. Note: The ice dispense switch
times out after 20 sec. Re-engage every 20 sec. until bin is empty. Move the control
switch and power switch to the "OFF" position. Remove the bin top cover. Pour warm
water over the remaining ice. After the ice is removed/melted, place the bin top cover
in its original position. Do not secure at this time. Remove the control box cover, then
move the control switch to the "ICE" position and the power switch to the "ON" position.
Once the gear motor starts, press the "SERVICE" button on the control board (located
in the control box). WARNING! Risk of electric shock. Care should be taken not to
touch live terminals. Lift the bin top cover and monitor the evaporator extruding head.
WARNING! Keep hands, hair, and loose clothing clear of the agitator rotating
inside of the storage bin. Once ice begins to ll the bin, start a 10 min. timer. After
10min., move the power switch to the "OFF" position. Place an empty container under
the spout and dispense all ice from the icemaker. Note: The ice dispense switch times
out after 20 sec. Re-engage every 20sec. until bin is empty. Move the power switch to
the "OFF" position. Weigh the ice to establish the batch weight (minus the weight of the
container). Multiply the batch weight by 144for the total production in 24 hr. Replace the
control box cover and bin top cover in their original positions and secure. Replace all
panels in their original positions and secure. Move the power switch to the "ON" position
to start the automatic icemaking process.
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2. Diagnostic Procedure
The diagnostic procedure is a sequence check that allows you to diagnose the electrical
system and components. Before proceeding, check for correct installation, adequate
water pressure (10 to 113 PSIG), and proper voltage per unit nameplate.
Note: • When checking high voltage (115VAC), always choose a neutral (W) wire to
establish a good neutral connection.
• When checking low voltage (24VAC), always choose a neutral (LBU) wire.
• When checking control board DC voltage (5VDC), always place the red positive
test lead from the multimeter to CB K5 pin closest to CB K4 connector.
See "II.C. Control Board Check."
• To speed up the diagnostic process, the 5-min. ice purge cycle may be bypassed
by pressing the "SERVICE" button on the control board after the gear motor
starts. WARNING! Risk of electric shock. Care should be taken not to touch
live terminals.
1) Move the power switch to the "OFF" position, then disconnect the power cord from the
electrical outlet. Remove the front, top, and left side panels. Remove the control box
cover.
2) Reconnect the power cord into the electrical outlet, then move the power switch to the
"ON" position.
3) Move the control switch to the "DRAIN" position. CB "POWER OK" LED and "FLUSH"
(drain) LED turns on.
Diagnosis "POWER OK" LED: Check that CB "POWER OK" LED is on. If not, check
for 115VAC at control transformer brown (BR) wire to neutral (W). If 115VAC is not
present, check the power switch, power cord connection, and breaker. If 115VAC is
present, check control transformer continuity. Replace as needed. Next, check for
24VAC at control transformer red (R) wire to neutral (LBU). If 24VAC is not present,
check control transformer continuity. Replace as needed. If 24VAC is present, check
24VAC 1A fuse. If fuse is good, check for 24VAC at CB K8 #1 (W/R) to CB K8 #2 (LBU).
If 24VAC is present and "POWER OK" LED is off, replace CB.
Diagnosis DV: If DV does not energize, check for 24VAC at CB K2 #10 (W/DBU) to
neutral (LBU). If24VAC is not present, check control switch continuity. If open while in
the "DRAIN" position, replace control switch. If closed, check for 0VDC at control board
K9 #1 (W/BK) to K9 #2 (W/BK). If5VDC is present and control switch is closed, replace
CB. If 24VAC is present, check for restricted DV and DV solenoid continuity. Clean or
replace as needed.
3) After all of the water has drained, move control switch to the "ICE" position.
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4) Fill Cycle – "WTRIN" LED is on. WV energizes. The 90-sec. low water safety timer
begins. LFS closes. Nothing occurs at this time. The reservoir continues to ll until
UFS closes, terminating the 90-sec. low water safety timer, starting the 30-min. freeze
timer, and de-energizing WV. Diagnosis: Check that "WTRIN" LED turns on and water
lls the reservoir. If not, check for water supply line shut-off valve closed, restricted
water lters, and restricted WV screen. Next, check for 24VAC at CB K2 #8 (W/BR)
to neutral(LBU). If 24VAC is not present, replace CB. If 24VAC is present, turn off the
power switch, disconnect the WV wires and check WV solenoid continuity. If open,
replace WV. Reconnect WV wires, move the power switch to the "ON" position, then
check that DV is not leaking by. Check that WV shuts off when UFS closes.
Note: Low Water Safety– If UFS remains open 90 sec. after WV energizes, a 1-beep
alarm sounds. This alarm resets automatically once UFS closes.
5) Ice Purge Cycle – "GM" LED is on. 5-sec. GM delay timer and 30-min. freeze timer
start. WV de-energizes and "WTRIN" LED turns off. Once the 5-sec. GM delay timer
terminates, GM and CDR energize. CDR cannot energize unless GM circuit is complete
(fuse, internal protector, and windings). Once CDR energizes, CB K9 #5 W/O and
CB K9 #6 W/O 5VDC circuit closes and 5-min. ice purge timer starts. See "II.C.3)c.
Compressor Delay Relay (5-min. Ice Purge Timer Circuit)." If CDR de-energizes, CB
K9#5 W/O and CB K9 #6 W/O circuit opens and an 8-beep alarm occurs. See "III.B.
LED Lights and Alarm Safeties." Note: To bypass ice purge cycle and go straight to
freeze cycle, press "SERVICE" button on CB during 5-sec. GM delay time.
Diagnosis CB: Check that UFS closed, WV LED turned off and WVde-energized.
IfUFS is closed, "WV" LED is off, and "GM" LED is off, replace CB. If "GM" LED is
on and GM is off, conrm 115VAC at CB K1 #2 (BR) to neutral(W). If115VAC is not
present, check for loose connection from power switch. If 115VAC is present, check for
115VAC at CB K1 #3 (BK) to neutral (W). If115VAC is not present, replace CB.
Diagnosis GM: If115VAC is present at CB K1 #2 (BR) to neutral(W), check GM fuse,
GM capacitor, GM windings, and GM coupling between auger and GM.
Diagnosis CDR: See "II.C.3)c. Compressor Delay Relay (5-min. Ice Purge Timer
Circuit)." Once 5-min. ice purge timer terminates, freeze cycle begins.
6) Freeze Cycle – "COMP" LED is on. 5-min. ice purge timer terminates or "SERVICE"
button pressed. "COMP" LED turns on. "GM" LED remains on. Comp and FM energize.
GM and CDR continue. Ice production begins 4 to 6 minutes after Comp energizes
depending on ambient and water conditions. Diagnosis Comp: Check that "COMP"
LED is on and that Comp energizes. If "COMP" LED is off, conrm 5-min. ice purge
timer has terminated. Check for 0VDC across CB K9 #3 (W/O) and CB K9 #5 (W/O).
If 5VDC is present, CDR contacts are open. Check for 115VAC at CDR #7 (O) to CDR
#8 (W). If115VAC is present, check CDR continuity between CDR #3 (W/O) and
CDR #5 (W/O). If open, replace CDR. If closed and"COMP" LED remains off, replace
CB. If"COMP" LED is on and Comp is off, check for 115VAC at each CB X1 brown
(BR) wire to neutral(W). If 115VAC is present on one and not the other, replace CB.
If115VAC is present on both, check Comp windings, start relay, and capacitors.
Note: If CDR de-energizes, CB K9 #5 W/O and CB K9 #6 W/O circuit opens, Comp
de-energizes and an 8-beep alarm occurs. See "III.B. LED Lights and Alarm Safeties."
Diagnosis FM: If FM does not energize, check FM capacitor, windings, and bearings.
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7) Rell Cycle/Low Water Safety – As ice is produced, the water level in the reservoir
drops. UFS opens. Nothing occurs at this time. When LFS opens, WV energizes,
90-sec. low water safety timer (ll timer) starts. Comp, GM, CDR, and FM continue.
When UFS closes, WV de-energizes, 90-sec. low water safety timer (ll timer)
terminates and 30-min. freeze timer resets. If UFS remains open 90 sec. after WV
energizes (ll timer exceeded), a 90-sec. shutdown cycle starts. Comp and FM
de-energize and CB signals a 1-beep alarm every 5 sec. 90-sec. ice purge timer
starts. GM and CDR continue to clear ice from the evaporator. 90-sec. purge timer
terminates, GM and CDR de-energize. WV and 1-beep alarm continue until UFS closes.
Diagnosis– Check that "WTRIN" LED is on. If not, check LFS. See "II.E. Float Switch
Check and Cleaning." If LFS is open and "WTRIN" LED is off, replace CB. If "WTRIN"
LED is on, check that the reservoir lls. If not, check the water supply line, restricted
water lters, WV solenoid, restricted WV screen. If WV is energized and rell exceeds
90-sec. low water safety timer (ll timer), check DV leaking by or open UFS.
See "II.E.Float Switch Check and Cleaning."
Note: Each time UFS closes, 30-min. freeze timer starts. The 30-min. freeze timer resets
when UFS closes again. If UFS does not close again within 30 min., CB shuts
down the unit and sounds a 5-beep alarm every 5 sec. See "II.B. LED Lights and
Alarm Safeties."
10) Shutdown – Bin lls with ice activating BC microswitch. Within 10 sec. control
board shutsdown unit. Diagnosis: Check that BC large balance plate is activated
and not sticking. Check BC microswitch continuity. When BC large balance plate is
down (icemaking), BC microswitch is closed. When BC large balance plate is up BC
microswitch is open. If not, replace BC microswitch. If BC microswitch is open and
Comp, FM, and GM do not de-energize, replace CB. See "II.C. Control Board Check
Procedure."
Before replacing a CB that does not show a visible defect and that you suspect is bad,
always conduct the following check procedure. This procedure will help you verify your
diagnosis. Before proceeding, check for proper voltage per appliance nameplate. Check
that the 24VAC 1A fuse and 115VAC 3A GM breaker are good.
• Check the S1 dip switch settings to assure that they are in the factory default position.
For factory default settings, see "III.C.1. Default Dip Switch Settings." S1 dip switch
7determines bin control application. WARNING! Do not adjust S1 dip switch 7 out
of the factory default position. This dip switch must be left in the factory default
position or the appliance will not operate correctly.
• When checking for 115VAC high-voltage (primary), always choose a 115VAC
neutral(W) to establish a good neutral connection.
• When checking for 24VAC low-voltage (secondary), always choose a 24VAC
neutral(LBU) to establish a good neutral connection. If the appliance is in alarm, see
"III.B. LED Lights and Audible Alarm Safeties."
• When checking for 5VDC, use CBred K4 connector pin closest to CB black
K3connector for DC ground (GND).
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1) Startup-"POWER OK" LED on: Move control switch to "ICE" position, then move
power switch to "ON" position. "POWER OK" LED turns on. "POWER" LED remains
on unless power supply is interrupted. NOTICE!Appliance will not start unless the safety switch is engaged. Diagnosis: Checkthat "POWER OK" LED is on. If not,
check for proper 115VAC supply voltage to CT (main breaker or fuse and power switch).
Next, check for proper 24VAC output from CT. Next, check that 1A fuse is good. Check
for 24VAC from CB K8connector pin #1 (W/R) to CB K8 connector pin #2(LBU).
If24VAC is present and "POWER OK" LED is off, replace CB.
2) 5VDC Output Checks: There are seven 5VDC circuits on the appliance.
a) 3 circuits at CB K9 connector: Control switch "DRAIN" position, high-pressure switch
(HPS), and compressor delay relay (CDR).
b) 2 circuits at CB K8 connector: Bincontrol (BC) and oat switch (FS upper and
lower).
c) 2 circuits at CB K7 connector: Ice dispense (push button, and OS sensor), and water
dispense (push button and OS sensor).
2a) 5VDC CB K9 Connector: See Fig. 1.
5VDC CB K9 Connector
ComponentPin # (Wire Color)
Control Switch "DRAIN" Position#1 (W/BK) and #2 (W/BK)
• "ICE" Position: When the control switch is in the "ICE" position, CB K9 connector
pin#1and pin #2are open. 5VDC is present between CB K9 connector
pin #1(W/BK) and pin #2 (W/BK). If not, conrm 5VDC between pin#1 (W/BK) and
CBred K4 connector, pin closest to CBblack K3connector. If 5VDC is not present,
replace CB.
• "DRAIN" Position: When control switch is in the "DRAIN" position, CB K9 connector
pin #1 (W/BK) and pin#2(W/BK) are closed. 5VDC is present between both CB
K9connector pin #1(W/BK) and pin#2 (W/BK) to CBred K4connector, pin closest
to CB black K3 connector. If 5VDC is not present, replace CB.
b) High-Pressure Switch (HPS)
CB K9 connector pins #3 (Y) and #4 (Y): When HPS is closed, 5VDC is present
between both CB K9 connector pins #3(Y) and pin #4 (Y) to CB red K4 connector
pin closest to CB black K3 connector. If5VDC is not present on pin #3 (Y) or pin
#4(Y), replace CB. If 5VDC is present on CBK9connector pin #3 (Y) and not on CB
K9connector pin #4 (Y), HPS is most likely open. CB sounds a 3-beep alarm. Check
HPS continuity. If HPS is open and CB is not in alarm, replace CB.
c) Compressor Delay Relay (CDR)
CB K9 connector pins #5 (W/O) and #6(W/O): When CDR is de-energized (GM off),
CDRterminals #3 and #5 are open and 5VDC is present between CBK9connector
pin #5 (W/O) and CBK9connector pin #6(W/O). If5VDC is not present, check CDR
continuity between terminals #3 and #5. If open, replaceCB. When CDR is energized,
CDR terminals #3 and #5close and 0VDC is present between CB K9 connector pin
#5 (W/O) and pin #6(W/O). 5VDC is present between CB K9 connector pin #5 (W/O)
to CB red K4 connector pin closest to CB black K3connector and CB K9 connector
pin #6 (W/O) to CB red K4 connector pin closest to CB black K3connector. If GM is
energized and CDR terminals #3& #5 are open, an 8-beep alarm occurs. See "III.B.
LED Lights and Audible Alarm Safeties." If CDR terminals #3 and #5 are closed
and 0VDC is present between CB K9 connector pin #5 (W/O) and pin #6(W/O),
5-min. Comp delay timer starts. IfComp does not energize after 5-min. delay timer
terminates, replace CB.
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2b) 5VDC CB K8 Connector: See Fig. 2.
5VDC CB K8 Connector
ComponentPin # (Wire Color)
Bin Control (BC)#3 (GY) and #4 (GY)
Float Switch (FS) Common #5 (BK) Common
Upper Float Switch (UFS)#6 (R)
Lower Float Switch (LFS)#7 (BU)
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
Lower Float Switch (LFS) (BU)
Red Positive
Test Lead
Upper Float Switch (UFS) (R)
2b) 5VDC CB K8 Connector Continued:
Multimeter
5VDC
Black Negative
Test Lead
Control Board K8 Connector
Bin Control (GY)
Float Switch (FS) Common (BK)
Fig. 2
a) Bin Control (BC)
CB K8 connector pins #3 (GY) and #4 (GY): When BC is closed (icemaking),
5VDC is present between CB K8 connector pin #3(GY) and pin#4(GY) to CB red
K4 connector pin closest to CB black K3 connector. If5VDC is not present on either
pin, replace CB. If 5VDC is present on pin#3(GY) and not on pin #4 (GY), BC is
open. See "II.D. Bin Control Check."
b) Float Switch (FS): Upper (UFS) and Lower (LFS):
CB K8 connector pins #5 common (BK), #6 UFS (R), and #7LFS (BU): 5VDC is
present between CB K8 connector pin #5common (BK) and CB red K4connector pin
closest to CB black K3connector at all times. If 5VDC is not present, replace CB. For
further oat switch diagnostics, see "II.E. Float Switch Check and Cleaning."
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2c) 5VDC CB K7 Connector: See Figs. 3, 4, 5, and 6.
a) Water Dispense
1. Push Button Model
CB K7 connector pins #3 (W/BK) and #8 (P): "WTRDP" LED is on: Before engaging
the water dispense switch, check for the correct VDC from the locations given in
the "Disengaged" column in the table below. If the VDC is different than in the table,
replace CB. If the VDC is correct, engage the water dispense switch. "WTRDP" LED
turns on. If not, conrm that the water dispense signal VDC matches the "Engaged"
column in the table below. If not, check the water dispense switch continuity when
engaged (closed). If the water dispense switch is open when engaged, replace the
water dispense switch. If the VDC matches the "Engaged" column below and the
"WTRDP" LED does not turn on, replace CB.
5VDC CB K7 Connector
ComponentPin # (Wire Color) To CB VDC GroundDisengaged Engaged
5VDC Power Supply#3 (W/BK)
Water Dispense Signal#8 (P)0VDC5VDC
Multimeter
Red K4 pin closest
To
to black K3
5VDC5VDC
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
Red Positive
Test Lead
Water Dispense (P)
(switch signal)
5VDC
Black Negative
Test Lead
Control Board K7 Connector
Water Dispense (W/BK)
(5VDC power supply)
Fig. 3
18
Page 19
2. Opti-Serve Model
CB K8 connector pins #7 (R), #8 (P), and #9(BK): Before engaging the water
dispense OS sensor, check for the correct VDC from the locations given in the
"Disengaged" column in the table below. If the VDC is different than in the table,
replace CB. If the VDC is correct, engage the OS sensor. "WTRDP" LED turns on.
If not, conrm that the water dispense signal VDC matches the "Engaged" column
in the table below. If not, replace the OS sensor. If the VDC matches the "Engaged"
column below and the "WTRDP" LED does not turn on, replace CB.
VDC Sensor Ground#7 (R)
Water Dispense Signal#8 (P)0VDC5VDC
5VDC Power Supply #9 (BK)5VDC5VDC
Multimeter
Red K4 pin closest
To
to black K3
0VDC0VDC
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
Red Positive
Test Lead
Water Dispense (BK)
(5VDC power)
5VDC
Water Dispense (P)
(switch signal)
Fig. 4
Black Negative
Test Lead
Water Dispense (R)
(VDC GND)
Control Board K7 Connector
19
Page 20
b) Ice Dispense
1. Push Button Model
CB K7 connector pins #2 (Y) and #3 (W/BK): "ICE" and "AM" LEDs are on: Before
engaging the ice dispense switch, check for the correct VDC from the locations given
in the "Disengaged" column in the table below. If the VDC is different than in the
table, replace CB. If the VDC is correct, engage the ice dispense switch. "ICE" LED
turns on. If not, check the ice dispense switch continuity when engaged (closed).
If the ice dispense switch is open when engaged, replace. If the VDC matches the
"Engaged" column below and the "ICE" LED does not turn on, replace CB.
5VDC CB K7 Connector
ComponentPin # (Wire Color) To CB VDC GroundDisengaged Engaged
5VDC Power Supply#3 (W/BK)
Ice Dispense Signal#2 (Y)0VDC5VDC
Red K4 pin closest
To
to black K3
Multimeter
5VDC5VDC
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
5VDC
Red Positive
Test Lead
Black Negative
Test Lead
Control Board K7 Connector
Ice Dispense (Y)
(ice dispense signal)
Ice Dispense (W/BK)
(5VDC power supply)
Fig. 5
20
Page 21
2. Opti-Serve Model
CB K8 connector pins #1 (W/R), #2 (Y), and #3(W/BK): Before engaging the ice
dispense OS sensor, check for the correct VDC from the locations given in the
"Disengaged" column in the table below. If the VDC is different than in the table,
replace CB. If the VDC reading is correct, engage the OS sensor. "ICE" LED turns
on. If not, conrm that the ice dispense signal VDC matches the "Engaged" column
in the table below. If not, replace the OS sensor. Ifthe VDC matches the "Engaged"
column below and the "ICE" LED does not turn on, replace CB.
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
Red Positive
Test Lead
Ice Dispense (W/BK)
(5VDC power supply)
5VDC
Black Negative
Test Lead
Control Board K7 Connector
Ice Dispense (W/R)
(VDC ground)
Ice Dispense (Y)
(ice dispense signal)
Fig. 6
21
Page 22
3) Fill Cycle–"WTRIN" LED is on: "WTRIN" LED turns on only when the reservoir water
level is low enough to open LFS. Diagnosis: Conrm LFS is open. If "WTRIN" LED
is off and LFS is open and the control switch is in the "ICE" position (open), replace
CB. If "WTRIN" LED is on and water is not lling the reservoir, check for 24VAC at
CBK2connector between pin #8 (O) and neutral (LBU). If the "WTRIN" LED is on
and 24VAC is not present between CB K2 connector pin # 8 (O) and neutral (LBU),
conrm 24VAC at CB K2 connector between pin #7 (W/R) and neutral (LBU). If 24VAC
is present between CB K2 connector pin #7 (W/R) and neutral (LBU) and not between
CBK2connector pin #8 (O) and neutral (LBU), replace CB.
4) Ice Purge Cycle–"GM" LED is on: "GM" LED turns on once UFS closes (reservoir
full). If UFS is closed and "GM" LED is off, replace CB. If "GM" LED is on but GM does
not start, check for 115VAC from CB K1 connector pin #3 (BK) to neutral (W).
If 115VAC is not present, conrm 115VAC from CB K1 connector pin #2 (BR) to neutral
(W). If 115VAC is present on CB K1 connector pin #2 (BR) but not on CB K1 connector
pin #3 (BK), replace CB. Once GM energizes, CDR energizes and 5 min. PT starts.
5) Freeze Cycle–"GM" and "COMP" LED are on: 5-min. PT terminates or press the
"SERVICE" button on CB after the "GM" LED turns on to bypass ice purge cycle.
WARNING! Risk of electric shock. Care should be taken not to touch live
terminals. After 5-min. PT terminates, "COMP" LED turns on. If not, conrm CDR
conacts are closed. See step "2a)3. Compressor delay relay" above. If CDR contacts
are closed, replace CB. If"COMP" LED turns on and Comp does not start, check for
115VAC from the CB X1 relay (BR) and (R) to neutral (W). If 115VAC is present on CB
X1 relay (BR) and not on CB X1 relay (R), replace CB.
Legend: AM–agitating motor (gear motor this model); BC–bin control; CB–control board;
When BC (microswitch) is not engaged, BC circuit (CB K8 #3 (GY) and CB K8 #4 (GY))
is closed and the appliance produces ice.
S1 dip switch 7 must be in the "OFF" position and S1 dip switch 8 must be in the "ON"
position. When ice lls the bin and engages BC large balance plate, BC opens and CB
shutsdown the appliance within 10 seconds. NOTICE! Do not place S1 dip switch 7 in
the "ON" position or S1 dip switch 8 in the "OFF" position. For details, see "III.C.1.
Default Dip Switch Settings."
1) Move the power switch to the "OFF" position.
2) Remove the front, top, and left side panels.
3) Move the control switch to the "OFF" position.
4) Remove the thumbscrews securing the storage bin cover. WARNING! Keep hands,
hair, and loose clothing clear of the agitator rotating inside of the storage bin.
5) Disconnect BC connector from the back of the control box.
6) Check for continuity across BC microswitch. If BC large balance plate is not engaged
and BC microswitch is open, replace BC microswitch.
7) Press and hold BC large balance plate. While BC large balance plate is engaged, check
for continuity across BC microswitch. If BC large balance plate is engaged and BC
microswitch is open, replace BC microswitch.
8) Disengage BC large balance plate.
9) Reconnect BC connector. Remove the control box cover.
10) Move the move the control switch to the "ICE" position, then move the power switch to
the "ON" position.
11) Make sure the "GM" LED is on. There is a delay of at least 5 seconds before the "GM"
LED turns on after power-up. After the "GM" LED turns on, press the "SERVICE" button
on CB to bypass the 5-min. ice purge timer. WARNING! Risk of electric shock. Care should be taken not to touch live terminals. "COMP" LED turns on.
12) When Comp starts, press and hold BC large balance plate.
13) Comp and GM should de-energize within 10seconds. Diagnosis: If not, and BC
microswitch is found open and the appliance continues to run, replace CB.
14) Move the power switch to the "OFF" position. Leave the control switch in the "ICE"
position.
15) Replace the storage bin cover and secure.
16) Replace the control box cover, left side, top, and front panels in their correct positions.
17) Move the power switch to the "ON" position to start the automatic icemaking process.
Legend: BC–bin control; CB–control board; Comp–compressor; GM–gear motor
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Page 24
E. Float Switch Check and Cleaning
1. Float Switch Check
1) Remove the front, top, and left side panels, then move the control switch to the "DRAIN"
position.
2) After the water has drained from the reservoir, remove the FS molex plug from the
control box and check continuity across FS wires. Common (BK) to UFS (R) and
common (BK) to LFS (BU). See Fig. 7. With the reservoir empty, oat switches are open.
If open, continue to step 3. If closed, follow the steps in "II.E.2. Float Switch Cleaning."
After cleaning, check them again. Replace if necessary.
3) Replace the FS molex plug on the control box.
4) Move the control switch to the "ICE" position.
5) The reservoir lls. Once UFS closes GM starts.
6) Move the control switch to the "OFF" position.
7) Remove the FS molex plug from the control box and check continuity across FS wires.
Common (BK) to UFS (R) and common (BK) to LFS (BU). With the reservoir full, oat
switches are closed. If open, follow the steps in "II.E.2. Float Switch Cleaning." After
cleaning, check them again. Replace if necessary.
8) Move the control switch to the "ICE" position.
9) Replace the left side, top, and front panels in their correct positions.
2. Float Switch Cleaning
Depending on water conditions, scale may build up on FS. Scale on the switch can cause
the oats to stick. In this case, FS should be cleaned and checked.
1) Remove the front, top, and left side panels, then move the control switch to the "DRAIN"
position.
2) After the water has drained from the reservoir, move the control switch to the "OFF"
position and the power switch to the "OFF" position.
3) Remove FS assembly from the reservoir cover. See Fig. 8.
4) Wipe down FS assembly with a mixture of 1 part Hoshizaki Scale Away and 25 parts
warm water. Rinse the FS assembly thoroughly with clean water.
5) While not necessary, the oats can be removed from the shaft during cleaning. If you
remove them, note that the blue oat is on top. The oats must be installed with the
magnets inside them towards the top of the switch. See Fig. 8. Installing the oats
upside down will affect the timing of FS operation.
6) Rinse FS assembly thoroughly with clean water and replace in its correct position.
7) Move the control switch to the "ICE" position.
7) Replace the left side, top, and front panels in their correct positions.
8) Move the power switch to the "ON" position to start the automatic icemaking process.
Legend: Comp–compressor; FS–oat switch; GM–gear motor
24
Page 25
Red (R)
(upper oat switch)
Blue (BU)
(lower oat switch)
Black (BK)
(common)
Magnet (towards top)
Upper Float (blue)
Magnet (towards top)
Lower Float (white)
Float Switch Assembly
Spring Retainer Clip
Plastic Retainer Clip
Fig. 7
Reservoir Cover
Reservoir
Fig. 8
25
Page 26
F. Diagnostic Tables
Before consulting the diagnostic tables, check for correct installation, proper voltage per
appliance nameplate, and adequate water pressure (10 to 113 PSIG). Check control
board using the steps in "II.C. Control Board Check."
1. No Ice Production
No Ice Production - Possible Cause
Startup
1. Power Supplya) Off, blown fuse, or tripped breaker.
b) Loose connection.
c) Not within specications.
2. Power Switcha) "OFF" position.
b) Defective.
3. Control Transformer a) Coil winding open or shorted.
4. 1A 24VAC Fuse (Control Box)a) Blown.
5. Control Switcha) In "DRAIN" position.
b) Bad contacts.
6. Control Board
See "II.C. Control Board Check"
7. Bin Controla) Tripped with bin lled with ice.
8. High-Pressure Switcha) Control board in 3 or 4-beep alarm. See "III.B. LED Lights and
1. Control Boarda) No power to inlet water valve (24VAC).
2. Inlet Water Valvea) Screen or orice clogged.
3. Water Supplya) Water supply off or improper water pressure.
4. Float Switcha) Float does not move freely.
5. Drain Valvea) Sticking.
1. Control Boarda) No power to gear motor.
2. Gear Motora) 3A breaker tripped.
3. Couplinga) Defective.
4. Compressor Delay Relaya) Defective.
a) In alarm. See "III.B. LED Lights and Audible Alarm Safeties."
b) Defective.
b) Microswitch defective.
c) Large balance plate does not move freely.
Audible Alarm Safeties."
Fill Cycle
b) No power to oat switch (5VDC) or not reading oat switch
condition.
b) Coil winding.
b) External water lters clogged.
b) Defective.
Ice Purge Cycle
b) Internal protector open.
c) Motor winding.
d) Mechanical failure.
26
Page 27
No Ice Production - Possible Cause
Freeze Cycle
1. Control Boarda) No power to compressor delay relay circuit (5VDC) or not
reading circuit.
2. Control Boarda) No power to oat switch (5VDC) or not reading oat switch
3. Float Switcha) Float does not move freely.
4. Inlet Water Valvea) Clogged or defective.
1. Bin Controla) Large balance plate sticking.
2. Control Boarda) Defective.
a) Bulb loose.
b) Operating erratically.
b) Defective coil.
c) Defective control board.
Rell
condition.
b) No power to inlet water valve (24VAC).
b) Defective.
Shutdown
b) Microswitch defective.
27
Page 28
2. Ice/Water Dispensing
Ice Dispense-Push Button
1. Power Supplya) Off, blown fuse, or tripped breaker.
2. Control Boarda) No power from control board to ice dispense switch (5VDC) or
not reading signal.
b) No power to ice dispense solenoid or dispense relay (115VAC).
3. Ice Dispense Switcha) Defective.
4. Ice Dispense Solenoida) Defective or loose connection.
5. Ice Dispense Relaya) Defective.
6. Gear Motora) Defective.
7. Shutter Assemblya) Defective.
Ice Dispense-Opti-Serve
1. Power Supplya) Off, blown fuse, or tripped breaker.
2. Control Boarda) No power from control board to OS sensor (5VDC) or not reading
signal.
b) No power to ice dispense solenoid or dispense relay (115VAC).
3. OS Sensor (infrared)a) Defective.
4. Ice Dispense Solenoida) Defective or loose connection.
5. Ice Dispense Relaya) Defective.
6. Gear Motora) Defective.
7. Shutter Assemblya) Defective.
Water Dispense-Push Button
1. Power Supplya) Off, blown fuse, or tripped breaker.
2. Control Boarda) No power from control board to water dispense switch (5VDC) or
not reading signal.
b) No power to dispense water valve (24VAC).
3. Water Dispense Switcha) Defective.
4. Water Dispense Valvea) Water supply turned off.
b) Defective.
Water Dispense-Opti-Serve
1. Power Supplya) Off, blown fuse, or tripped breaker.
2. Control Boarda) No power from control board to OS sensor (5VDC) or not reading
signal.
b) No power to water dispense valve (24VAC).
3. OS Sensor (infrared)a) Defective.
4. Water Dispense Valvea) Water supply turned off.
b) Defective.
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III. Controls and Adjustments
• A Hoshizaki exclusive control board is employed in Hoshizaki icemakers.
• All models are pre-tested and factory adjusted.
• For a control board check procedure, see "II.C. Control Board Check."
NOTICE
• The control board is fragile; handle very carefully.
• 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
icemaker before handling or replacing the control board.
• Do not touch the electronic devices on the control board or the back of the control
board.
• Do not change wiring and connections. Do not misconnect terminals.
• Do not short out power supply to test for voltage.
• Always replace the whole control board assembly if it goes bad.
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A. Control Board Layout
1. DCM-270BAH
Control Switch
#1 to #2 (W/BK)
"ICE"-Open-5VDC
"DRAIN"-Closed-0VDC
Upper Float Switch
#6 (R)
Open-5VDC to #5 black
Closed-0VDC to #5 black
Lower Float Switch
#7 (BU)
Open-5VDC to #5 black
Closed-0VDC to #5 black
• K7 Connector
OS Ice Sensor #1 (W/R)
Ice Dispense #2 (Y)
5VDC
Ice Dispense Output
#3 (W/BK)
115VAC Input
1 (BK)
LED Legend:
COMP-compressor
FLUSH (Drain)-drain valve
GM-gear motor
ICE-dispense motor
WTRDP-water dispense valve
WTRIN-inlet water valve
• S1 Dip Switch
5VDC Ground (GND) Terminals
• "POWER OK" LED
Fig. 9b
31
OS Water Sensor GND
#7 (R)
Water Dispense Signal
#8 (P)
OS Water Sensor
Output #9 (BK)(+)
• K6 Connector
Open
Page 32
B. LED Lights and Audible Alarm Safeties
The "POWER" LED indicates proper control voltage and will remain on unless a control
voltage problem occurs. For further details, see "II. Sequence of Operation and Service
Diagnosis."
Icemaking Sequence
Sequence StepLED
Fill CycleWTRINWVOn until UFS closes.
Ice Purge Cycle GMGM5 min.5 min.
Freeze Cycle
(with rell)
Drain CycleFLUSH (Drain)DV2 sec.10 min.
Sequence StepLED
Ice Dispense
Activation
GM, WTRIN* (rell),
COMP
ICEGM, **IDSV Factory set for
Energized
ComponentsMin.Max.
Alarm sounds after 90 sec.
GM, Comp,
FM, WV*
(rell)
Dispensing Sequence
Energized
Components
Time LEDs are on
20 sec.
*On until UFS closes.
Alarm sounds after 90 sec.
**Dispense Mode
Continuous
IDSV de-energizes on internal
overload after 3 to 4min.
Resets when cool
Dispense Water
Valve Activation
WTRDPDispWV
The built-in alarm safeties shut down the appliance.
No. of Beeps
(every 5 sec.)
1Low Water Safety
UFS open > 90 seconds after WV energized.
2Control Switch
In "DRAIN" position longer than 15 minutes.
3High-Pressure Switch
First and second activation in 1 hour.
4High-Pressure Switch
Third activation in 1 hour.
5Freeze Timer
WV off > 30 minutes since last WV activation.
6Low Voltage
(92Vac ±5% or less)
7High Voltage
(147Vac ±5% or more)
8Gear MotorManual reset. Turn power off and on again.
9Bin Control (Infrared Sensor)
(S1 dip switch 7) (Not used on this model)
Type of AlarmReset Options
Automatic reset once water supply is restored
and UFS closes.
Automatic reset once the control switch is
moved to the "ICE" position.
Automatic reset once pressure drops
below the high pressure threshold and the
high-pressure switch closes.
Call for service. To avoid possible catastrophic
failure, it is recommended to leave the
appliance off until this alarm is resolved.
Manual reset. Turn power off and on again.
Manual reset. Turn power off and on again.
"POWER OK" LED turns off if voltage
protection operates.
The control voltage safeties automatically
reset when voltage is corrected.
Manual reset. Turn power off and on again.
Legend: Comp–compressor; DispWV–dispense water valve; DV–drain valve;
The S1 dip switch settings are factory-set to the following positions:
Dip Switch No.12345678910
DCM-270BAH(-OS) OFF OFF OFF OFFONOFF OFF OFF OFF OFF
Normally off (factory use)
Bin Control Shutdown Delay (mechanical) and Periodic Agitation
of Storage Bin
Bin Control Selector
Continuous Dispensing Timer
(Do not adjust on DCM-270BAH-OS)
Drain Frequency Control
Bin Control Shutdown Delay (infrared sensor)
2. Bin Control Shutdown Delay (Infrared Sensor) (S1 dip switch 1, 2, 3)
NOTICE
Do not adjust. Setting not used on this model. When dip switch 7 is off, 1, 2, and 3
are ignored.
Factory set. DCM-270BAH(-OS) does not use a bin control with an infrared sensor.
The appliance uses a bin control with a mechanical microswitch for ice level control.
3. Drain Frequency Control (S1 dip switch 4)
The appliance is factory set for optimum performance with the 1-in-1 drain cycle (S1 dip
switch 4 in the "OFF" position). This setting allows for removal of sediment from the
evaporator without interrupting the icemaking process. 1-in-12 drain cycle is available.
The factory setting allows ice to be dispensed continuously for 20 sec. The DCM-270BAH
may be adjusted to other dispense time options.
NOTICE! On DCM-270BAH-OS, do not adjust S1 dip switch 5 & 6 out of the factory
default position.
S1 Dip Switch Setting
No. 5No. 6
OFFOFFNo Limit
ONOFF20 Seconds
OFFON60 Seconds
ONONNo Limit
Dispense Time
Note: The ice dispense solenoid has an internal overload protector. When set to "No
Limit" the internal protector may open if ice dispense solenoid is energized longer than
3to 4 min. at one time.
5. Bin Control Selector (S1 dip switch 7)
The appliance is factory set with mechanical bin control operation. No adjustment is
required. Inthe factory default position (S1 dip switch 7 in the off position), the gear
motor delay after the upper oat switch closes is 5 seconds. WARNING! Do not adjust
S1 dip switch 7 out of the factory default position. This dip switch must be left in
the factory default position or the appliance will not operate correctly.
S1 Dip Switch
Setting
No. 7
OFFBin Control (Mechanical)5 seconds
ON
Bin Control (Infrared Sensor) with
Mechanical Bin Control Backup
Bin Control ApplicationGear Motor Delay
30 seconds
6. Bin Control Shutdown Delay and Storage Bin Agitation Timer (S1 dip switch 8)
Factory set for normal operation. No adjustment is required. The shutdown delay is the
time between the bin control microswitch opening and the control board shutting off the
appliance. A 2-second periodic agitation occurs every 90 minutes.
S1 Dip Switch
Setting
No. 8
OFF0.25 Seconds2 Seconds
ON6.7 SecondsNo Agitation
Bin Control #1
Shutdown Delay
Storage Bin
Periodic Agitation
7. Factory Use (S1 Dip Switch 9 & 10)
Factory set for optimum performance. Do not adjust.
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Page 35
D. Switches
The power switch and control switch are used to control the operation of this icemaker.
1. Power Switch
The power switch has 2 positions, "OFF" and "ON."
2. Control Switch
The control switch is a double-pole double-throw switch with 3 positions, "ICE," "OFF,"
and "DRAIN."
a) ICE
When the control switch is in the "ICE" position, the control switch closes a 5VDC
circuit from control board K4 connector pin #3 (W/R) to control board K4 connector
pin#4 (W/R). When the control board receives 5VDC on K4 connector pin #4 (W/R),
the control starts the icemaking process.
b) OFF
When the control switch is in the "OFF" position, the 5VDC circuits used for ice and
drain are open and the unit is off.
c) DRAIN
When the control switch is in the "DRAIN" position, the control switch closes a 5VDC
circuit from control board K4 connector pin #1 (W/BK) to control board K4 connector
pin #2 (W/BK). When the control board receives 5VDC on K4 connector
pin #2 (W/BK), the control board directs 24VAC to the drain valve and the drain valve
energizes.
35
Page 36
IV. Removal and Replacement of Components
WARNING
• This icemaker should be diagnosed and repaired only by qualied service
personnel to reduce the risk of death, electric shock, serious injury, or re.
• Move the power switch to the "OFF" position and turn off the power supply to the
icemaker before servicing. Lockout/Tagout to prevent the power from being turned
back on inadvertently.
• CHOKING HAZARD: Ensure all components, fasteners, and thumbscrews are
securely in place after the equipment is serviced. Make sure that none have fallen
into the storage bin.
• Make sure all food zones in the icemaker and storage bin are clean after
the icemaker is serviced. For cleaning procedures, see "VI. Cleaning and
Maintenance."
• When replacing evaporator assembly and water circuit components, make sure
there are no water leaks after the repair is complete.
A. Service for Refrigerant Lines
WARNING
• Repairs requiring the refrigeration circuit to be opened must be performed by
properly trained and EPA-certied service personnel.
• Always recover the refrigerant and store it in an approved container. Do not
discharge the refrigerant into the atmosphere.
• Use an electronic leak detector or soap bubbles to check for leaks. Add a trace of
refrigerant to the system (if using an electronic leak detector), and then raise the
pressure using nitrogen gas (140 PSIG). Do not use R-404A as a mixture with
pressurized air for leak testing.
NOTICE
• Do not leave the system open for longer than 15 minutes when replacing or
servicing parts. The Polyol Ester (POE) oils used in R-404A units can absorb
moisture quickly. Therefore it is important to prevent moisture from entering the
system when replacing or servicing parts.
• Always install a new drier every time the sealed refrigeration system is opened.
• Do not replace the drier until after all other repair or replacement has been made.
Install the new drier with the arrow on the drier in the direction of the refrigerant
ow.
• When brazing, protect the drier by using a wet cloth to prevent the drier from
overheating. Do not allow the drier to exceed 250°F (121°C).
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Page 37
1. Refrigerant Recovery
This icemaker is provided with refrigerant access valves. Using proper refrigerant
practices, recover the refrigerant from the service valves and store it in an approved
container. Do not discharge the refrigerant into the atmosphere.
2. Brazing
WARNING
• R-404A itself is not ammable at atmospheric pressure and temperatures up to
176°F (80°C).
• R-404A itself is not explosive or poisonous. However, when exposed to high
temperatures (open ames), R-404A can be decomposed to form hydrouoric
acid and carbonyl uoride both of which are hazardous.
• Do not use silver alloy or copper alloy containing arsenic.
• Use an electronic leak detector or soap bubbles to check for leaks. Add a trace of
refrigerant to the system (if using an electronic leak detector), and then raise the
pressure using nitrogen gas (140 PSIG). Do not use R-404A as a mixture with
pressurized air for leak testing.
1) Braze all ttings while purging with nitrogen gas owing at a pressure of 3 to 4 PSIG.
NOTICE
• Always install a new drier every time the sealed refrigeration system is opened.
• Do not replace the drier until after all other repair or replacement has been made.
Install the new drier with the arrow on the drier in the direction of the refrigerant
ow.
• When brazing, protect the drier by using a wet cloth to prevent the drier from
overheating. Do not allow the drier to exceed 250°F (121°C).
2) Use an electronic leak detector or soap bubbles to check for leaks. Add a trace of
refrigerant to the system (if using an electronic leak detector), and then raise the
pressure using nitrogen gas (140 PSIG). Do not use R-404A as a mixture with
pressurized air for leak testing.
3. Evacuation and Recharge (R-404A)
1) Attach a vacuum pump to the system. Be sure to connect charging hoses to both high
and low-side access valves.
IMPORTANT
The vacuum level and vacuum pump may be the same as those for current
refrigerants. However, the rubber hose and gauge manifold to be used for
evacuation and refrigerant charge should be exclusively for POE oils.
2) Turn on the vacuum pump. Open the gauge manifold valves. Never allow the oil in the
vacuum pump to ow backwards.
3) Allow the vacuum pump to pull down to a 29.9" Hg vacuum. Evacuating period depends
on pump capacity.
37
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4) Close the low-side valve and high-side valve on the gauge manifold.
5) Disconnect the gauge manifold hose from the vacuum pump and attach it to a
refrigerant service cylinder. Remember to loosen the connection and purge the air from
the hose. See the rating label inside the icemaker for the required refrigerant charge.
Hoshizaki recommends only virgin refrigerant or reclaimed refrigerant which meets ARI
Standard 700 (latest edition) be used.
6) A liquid charge is required for charging an R-404A system (to prevent fractionation).
Place the service cylinder on the scales: if the service cylinder is not equipped with
a dip tube, invert the service cylinder, then place it on the scales. Open the high-side
valve on the gauge manifold.
7) Allow the system to charge with liquid until the proper charge weight is met.
8) If necessary, add any remaining charge to the system through the low-side.
NOTICE! To prevent compressor damage, use a throttling valve or liquid
dispensing device to add the remaining liquid charge through the low-side
access valve with the icemaker running.
9) Close the high and low-side gauge manifold valves, then disconnect the gauge manifold
hoses.
10) Cap the access valves to prevent a possible leak.
B. Important Notes for Component Replacement
NOTICE
When replacing a component listed below, see the notes to help ensure proper
operation.
ComponentNotes
CompressorInstall a new drier, start capacitor, and start relay.
Expansion Valve • Install a new drier.
• Attach the expansion valve bulb to the suction line in the same location as the previous
bulb.
• The bulb should be between the 10 and 2 o'clock positions on the tube.
• Secure the bulb with the clamp and holder, then insulate it.
Upper and
Lower Bearings
Evaporator• Install a new drier.
Gear MotorInstall a new gear motor capacitor.
• Inspect the upper bearing for wear. See "IV.C.1. Upper Bearing Wear Check." Replace if
necessary.
• When replacing the upper bearing it is advised to also change the lower bearing at the
same time.
• Inspect the mechanical seal and O-ring prior to installing the new evaporator. If worn,
cracked, or scratched, the mechanical seal should also be replaced.
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Page 39
Drip Ring
Evaporator Assembly
Cutter
Extruding Head
(Upper Bearing)
Auger
Cover
"O"-Ring
Seal Bolt
Evaporator
Socket Head Cap Screw
Ring
Mechanical Seal
"O"-Ring
Housing
(Lower Bearing)
Gear MotorSpline Coupling
Fig. 8
Socket Head Cap Screw
39
Page 40
C. Icemaking Unit
1. Upper Bearing Wear Check
To ensure that the bearing inside the extruding head does not exceed the wear tolerance
of .02", follow the instructions below. See Fig. 3.
1) Move the control switch to the "OFF" position, then turn off the power supply. Remove
the front and top panels, then move the power switch to the "OFF" position.
2) Remove the top of the storage bin, then remove the agitator
by turning it counter clockwise. Next, lift the drip pan out of
the storage bin area.
3) Grasp the top of the auger and move the
auger towards you, then try to insert a
.02" round stock or pin gauge in between
Drip Ring
the back side of the auger shaft and the
bearing surface. Check several locations
around the auger shaft. If the gauge goes
.02" Round Stock
or Pin Gauge
between the shaft and the bearing at
any point or if the bearing is scratched
or cracked, both the top bearing in the
extruding head and the lower bearing in the
housing should be replaced. Instructions for
removing the extruding head and housing
are located later in this procedure.
Extruding
Head
Note: Replacing the bearing requires a
bearing press adaptor. If one is not
available, replace the whole extruding
head and housing.
Agitator
Auger
Fig. 3
4) Replace the drip pan, agitator, and top of the storage bin in their correct positions.
5) Move the power switch to the "ON" position, then replace the panels in their correct
positions.
6) Turn on the power supply, then move the control switch to the "ICE" position to start the
automatic icemaking process.
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Page 41
2. Removal and Replacement of Extruding Head
1) Move the control switch to the "DRAIN" position and drain all of the water from the
evaporator.
2) After the water has stopped draining, move the control switch to the "OFF" position,
then turn off the power supply. Remove the front and top panels, then move the power
switch to the "OFF" position.
3) Remove the front cover of the storage bin. Remove spout B, then remove spout A and
the cutter. See Fig. 2.
4) Remove the apron panel, then remove the left side panel.
5) Remove the allen head cap screws and lift off the extruding head.
6) Place the new extruding head in place and tighten down the allen head cap screws.
7) Replace the cutter in its correct position.
8) Replace spout A, spout B, and the front cover of the storage bin in their correct
positions.
9) Move the power switch to the "ON" position, then replace the panels in their correct
positions.
10) Turn on the power supply, then move the control switch to the "ICE" position to start the
automatic icemaking process.
3. Removal and Replacement of Auger
1) Move the control switch to the "DRAIN" position and drain all of the water from the
evaporator.
2) After the water has stopped draining, move the control switch to the "OFF" position,
then turn off the power supply. Remove the front and top panels, then move the power
switch to the "OFF" position.
3) Remove the front cover of the storage bin. Remove spout B, then remove spout A.
See Fig. 2.
4) Remove the apron panel, then remove the left side panel.
5) Remove the allen head cap screws securing the extruding head. Using the cutter, lift out
the auger assembly.
6) Remove the cutter, extruding head, and upper part of the mechanical seal from the
auger and place them on the new auger. NOTICE!To help prevent water leaks, be
careful not to damage the surfaces of the O-ring or mechanical seal.
7) Install the new auger assembly with the upper part of the mechanical seal attached and
tighten down the allen head cap screws.
8) Replace spout A, spout B, and the front cover of the storage bin in their correct
positions.
9) Move the power switch to the "ON" position, then replace the panels in their correct
positions.
10) Turn on the power supply, then move the control switch to the "ICE" position to start the
automatic icemaking process.
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Page 42
4. Removal and Replacement of Evaporator
NOTICE
• Always install a new drier every time the sealed refrigeration system is opened.
• Do not replace the drier until after all other repair or replacement has been made.
Install the new drier with the arrow on the drier in the direction of the refrigerant
ow.
• When brazing, protect the drier by using a wet cloth to prevent the drier from
overheating. Do not allow the drier to exceed 250°F (121°C).
1) Move the control switch to the "DRAIN" position and drain all of the water from the
evaporator.
2) After the water has stopped draining, move the control switch to the "OFF" position,
then turn off the power supply. Remove the front and top panels, then move the power
switch to the "OFF" position.
3) Remove the apron panel, then remove the left side panel.
4) Recover the refrigerant and store it in an approved container.
5) Remove the front cover of the storage bin. Remove spout B, then remove spout A.
See Fig. 2.
6) Remove the allen head cap screws securing the extruding head. Using the cutter, lift out
the auger assembly.
7) Remove the evaporator bracket and disconnect the water hoses.
8) Disconnect the inlet and outlet tubing.
9) Remove the allen head cap screws securing the evaporator to the lower housing.
10) Lift off the evaporator.
11) Inspect the mechanical seal and O-ring prior to installing the new evaporator. The
mechanical seal consists of two parts. One moves along with the auger, and the other
is xed on the lower housing. NOTICE! If the contact surfaces of these two parts
are worn, cracked, or scratched, the mechanical seal may cause water leaks and
should be replaced. Instructions for removing the mechanical seal and lower housing
are located later in this procedure.
12) Make sure the lower mechanical seal is in place, then place the new evaporator in
position. Secure the evaporator to the lower housing using the allen head cap screws.
13) Remove the drier, then place the new drier in position.
14) Braze all ttings while purging with nitrogen gas owing at a pressure of 3 to 4 PSIG.
42
Page 43
15) Use an electronic leak detector or soap bubbles to check for leaks. Add a trace of
refrigerant to the system (if using an electronic leak detector), and then raise the
pressure using nitrogen gas (140 PSIG). Do not use R-404A as a mixture with
pressurized air for leak testing.
16) Evacuate the system, and charge it with refrigerant. See the nameplate for the required
refrigerant charge.
17) Install the auger assembly with the upper part of the mechanical seal attached and
tighten down the allen head cap screws.
18) Replace the evaporator bracket and reconnect the water hoses.
19) Replace spout A, spout B, and the front cover of the storage bin in their correct
positions.
20) Move the power switch to the "ON" position, then replace the panels in their correct
positions.
21) Turn on the power supply, then move the control switch to the "ICE" position to start the
automatic icemaking process.
5. Removal and Replacement of Mechanical Seal and Lower Housing
5a. Mechanical Seal
1) Move the control switch to the "DRAIN" position and drain all of the water from the
evaporator.
2) After the water has stopped draining, move the control switch to the "OFF" position, then
turn off the power supply. Remove the front and top panels, then move the power switch
to the "OFF" position.
3) Remove the front cover of the storage bin. Remove spout B, then remove spout A.
See Fig. 2.
4) Remove the apron panel, then remove the left side panel.
5) Remove the extruding head heater and the allen head cap screws securing the
extruding head.
6) Using the cutter, lift out the auger assembly, then remove the evaporator bracket.
7) The mechanical seal consists of two parts. One moves along with the auger, and the
other is xed on the lower housing. NOTICE!If the contact surfaces of these two
parts are worn, cracked, or scratched, the mechanical seal may cause water leaks
and should be replaced.
8) Remove the allen head cap screws securing the evaporator to the lower housing.
9) Raise the evaporator up to access the lower housing.
10) Remove the mechanical seal from the housing. If only replacing the mechanical seal,
proceed to step 13. NOTICE! To help prevent water leaks, be careful not to damage
the surfaces of the O-ring or mechanical seal.
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Page 44
5b. Lower Housing
11) Remove the O-ring and the bolts securing the housing to the gear motor and remove
the housing from the gear motor. If inspection of the upper bearing inside the extruding
head (see "IV.C.1. Upper Bearing Wear Check") indicates that it is out of tolerance,
replace both it and the bearing inside the lower housing.
Note: Replacing the bearing requires a bearing press adaptor. If one is not available,
replace the whole extruding head and housing.
12) Install the O-ring and mount the lower housing on the gear motor.
13) Install the lower part of the mechanical seal on the lower housing.
14) Lower the evaporator down and secure it to the lower housing.
15) Install the auger assembly with the upper part of the mechanical seal attached.
16) Replace the evaporator bracket in its correct position.
17) Replace spout A, spout B, and the front cover of the storage bin in their correct
positions.
18) Move the power switch to the "ON" position, then replace the panels in their correct
positions.
19) Turn on the power supply, then move the control switch to the "ICE" position to start the
automatic icemaking process.
44
Page 45
6. Removal and Replacement of Gear Motor
1) Move the control switch to the "DRAIN" position and drain all of the water from the
evaporator.
2) After the water has stopped draining, move the control switch to the "OFF" position, then
turn off the power supply. Remove the front and top panels, then move the power switch
to the "OFF" position.
3) Remove the front cover of the storage bin. Remove spout B, then remove spout A.
See Fig. 2.
4) Remove the apron panel, then remove the left side panel.
5) Remove the evaporator bracket.
6) Remove the bolts securing the lower housing to the gear motor. Lift the evaporator up
slightly.
7) Remove the 3 gear motor bolts.
8) Disconnect the wiring from the gear motor, then remove the gear motor.
9) Remove the spline coupling from the old gear motor and attach to the new gear motor.
10) Place the new gear motor in the drain pan.
11) Secure the gear motor.
12) Connect the gear motor wires.
13) Lower the evaporator down and secure it to the gear motor.
14) Replace the evaporator bracket in its correct position.
15) Replace spout A, spout B, and the front cover of the storage bin in their correct
positions.
16) Move the power switch to the "ON" position, then replace the panels in their correct
positions.
17) Turn on the power supply, then move the control switch to the "ICE" position to start the
automatic icemaking process.
45
Page 46
V. Maintenance
The maintenance schedule below is a guideline. More frequent maintenance may be
required depending on water quality, the appliance's environment, and local sanitation
regulations.
WARNING
• Only qualied service technicians should service the appliance.
• Move the control switch and power switch to the "OFF" positions, then turn off the
power supply before servicing. Lockout/Tagout to prevent the power supply from
being turned back on inadvertently.
Maintenance Schedule
Frequency AreaTask
Every 2
Weeks
MonthlyExternal Water
Every 6
Months
YearlyInlet Water Valve
After
3 Years,
then Yearly
Air FilterInspect. Wash with warm water and neutral cleaner if dirty.
Check for proper pressure and change if necessary.
Filters
Appliance Exterior Wipe down with a clean, soft cloth. Use a damp cloth containing a neutral
cleaner to wipe off oil or dirt build up. Clean any chlorine staining (rust
colored spots) using a non-abrasive cleaner.
Icemaker and
Storage Bin
Evaporator
Condensate Drain
Pan and Gear
Motor Drain Pan
Icemaker, Storage
Bin, and Drip Tray
Drains
and Drain Valve
Water HosesInspect the water hoses and clean/replace if necessary.
CondenserInspect. Clean if necessary by using a brush or vacuum cleaner.
ApplianceInspect for oil spots, loose components, fasteners, and wires.
Upper Bearing
Clean and sanitize per the cleaning and sanitizing instructions provided in
the instruction manual or maintenance label on the appliance.
Wipe down with a clean cloth and warm water. Dilute 0.82 . oz. (25 ml) of a
5.25% sodium hypochlorite solution (chlorine bleach) with 1.6 gal. (6.0 l) of
warm water. Slowly pour one cup of sanitizing solution into the evaporator
condensate drain pan. Be careful not to overow the pan. This solution will
ow down to the gear motor drain pan and out the drain line to sanitize
these areas. Repeat with a cup of clean water to rinse.
Check to make sure they are clear.
Close the water supply line shut-off valve and drain the water system. Clean
the inlet water valve screen and clean and inspect the drain valve.
Check for wear using .02" round stock or pin gauge. Replace both upper
bearing and lower bearing if wear exceeds factory recommendations. See
"IV.C.1. Upper Bearing Wear Check".
Inspect. Replace both upper bearing and lower bearing if wear exceeds
factory recommendations. Replace the mechanical seal if the seal's contact
surfaces are worn, cracked, or scratched.
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Page 47
VI. Preparing the Icemaker for Periods of Non-Use
NOTICE
When storing the icemaker for an extended time or in sub-freezing temperatures,
follow the instructions below to prevent damage.
When the icemaker is not used for two or three days under normal conditions,
it is sufficient to only move the power switch to the "OFF" position. When storing
the icemaker for extended time or in sub-freezing temperatures, follow the
instructions below.
1) Close the icemaker water supply line shut-off valve and open the icemaker water supply
line drain valve.
2) Remove the louver and air lter, then move the control switch to the "DRAIN" position.
Allow the water system to drain for 5minutes.
3) Dispense all of the ice from the storage bin.
4) Attach a compressed air or carbon dioxide supply to the icemaker water supply line
drain valve.
5) While engaging the water dispense switch, blow out the water dispense valve using the
compressed air or carbon dioxide supply. After blowing out the water dispense valve,
leave the compressed air or carbon dioxide supply owing. Move the control switch to
the "ICE" position to open the inlet water valve and briey blow out the inlet water valve.
After blowing out the inlet water valve, move the control switch to the "OFF" position.
6) Close the icemaker water supply line drain valve.
7) Move the power switch to the "OFF" position, then unplug the icemaker from the
electrical outlet.
8) Remove the storage bin cover. Clean the storage bin liner and the storage bin cover
using a neutral cleaner. Rinse thoroughly after cleaning. Replace the storage bin cover,
front panel, air lter, and louver in their correct positions.
Control
Switch
Power
Switch
Fig. 4
47
Page 48
VII. Disposal
This icemaker contains refrigerant and must be disposed of in accordance with
applicable national, state, and local codes and regulations. Refrigerant must be
recovered by properly certied service personnel.
48
Page 49
VIII. Technical Information
We reserve the right to make changes in specications and design without prior notice.
A. Specication and Performance Data
Pressure data is recorded at 5 min. into freezing cycle. The data not in bold
should be used for reference only.
1. DCM-270BAH
SPECIFICATION SHEET
AC SUPPLY VOLTAGE115/60/1
AMPERAGE8.5 A [AT 104°F(40°C)/WT 80°F(27°C)]
MINIMUM CIRCUIT AMPACITYN/A
MAXIMUM FUSE SIZEN/A
ELECTRIC & WATER CONSUMPTION90/70°F70/50°F
ELECTRIC W (kWH/100 lbs.)686 (8.16)641 (5.5)
WATER gal./24HR (gal./100 lbs.)25.6 (12)32.8 (12)
APPROXIMATE STORAGE CAPACITY8.8 lbs
REFRIGERANT CHARGER-404A14.8 oz. (420g)
WEIGHTNet 152 lbs. ( 69 kg ), Shipping 170 lbs. ( 77 kg )
PERFORMANCE DATA
APPROXIMATE ICE AmbientWater Temp. (F)
PRODUCTION PER 24 HR.Temp. (F)
3532 BTU/h (AT 90°F / WT 70°F)TOTAL HEAT OF REJECTION
689689-
50
Page 51
B. Wiring Diagrams
1. DCM-270BAH(-OS)
a) Serial Number: C10508L to D00829A (except C17634M and C17641M)
WIRE COLOR CODE
BK -BLACK
BR -BROWN
BU -BLUE
DBU -DARK BLUE
GR -GREEN
GY -GRAY
LBU -LIGHT BLUE
O -ORANGE
P -PINK
R -RED
V -VIOLET
W -WHITE
Y -YELLOW
W/BK -WHITE BLACK
W/BR -WHITE BROWN
W/BU -WHITE BLUE
W/O -WHITE ORANGE
W/R -WHITE RED
W/O
BR
BR
W/O
W/O
BR
BR
BR
W/O
DCM-270BAH-OS
P
ICE
DISPENSE
SENSOR
P
W/O
W/O
(BR)
L
2
POWER
SWITCH
3
BR
DBU
DBU
BR
WATER
DISPENSE
SENSOR
BK
LBU
LBU
LBU
BR
LBU
DISPENSE
VALVE
LBU
(BK)
(NO)
COMPRESSOR
CONTROL RELAY
1
3
5
7
BK
BK
INLET
WATER
VALVE
WATER
BR
BK
(BK)
(W)
(R)
(W)
(R)
WATER
SWITCH
(COM)
2
4
6
8
DISPENSE RELAY
1
3
5
7
DBU
BK
DBU
LBU
GND
BK
O
BK
O
W/O
BK
DBU
BR
W/R
BR
P
R
W/BK
W/BK
ICE
SWITCH
(NO)
W/BK
W/BK
2
4
6
8
DRAIN
W/DBU
W/DBU
Y
Y
W
W/R
BK
BR
W
VALVE
W/R
O
O
W/R
W/R
W
W
BR
W/DBU
W
R
BK
CAP.
10MFD
BK
DBU
BR
W/R
FUSE (1A)
W/DBU
W/DBU
W/DBU
BU
DCM-270BAH
115/60/1
COMP.
C
INTERNAL
PROTECTOR
R
Y
W
(DBU)
W
FAN MOTOR
BR
LBU
BR
W/R
BR
BK
R
GY
(R)
UPPER
(BU)
LOWER
FLOAT SWITCH
(Y)
R
GY
S
R
120VAC
BK
BK
LBU
START CAP.
145-174MFD
GY
GEAR MOTOR
(GY)
(BK)
(BK)
LBU
24VAC
BR
W/R
(BU)
(BK)
GY
INTERNAL
PROTECTOR
(BK)
O
(R)
(GY)
DISPENSE
SOLENOID
W
CONTROL
TRANSFORMER
R
W/R
R
W/BK
Y
Y
W/O
W/O
BIN
CONTROL
W/O
W/O
START
RELAY
4
1
2
W
EXTERNAL
PROTECTOR
W
W
LBU
ICE
OFF
DRAIN
ICE
OFF
DRAIN
CONTROL
SWITCH
HI-PRESS.
SWITCH
5
BK
R
W
W/BK
(W)
GR
N
GND
W
W
W
W
R
BK
W
W
BK
W
BK
W
R
BK
LBU
BK
R
W/R
W/R
W/R
LBU
51
Page 52
2. DCM-270BAH(-OS)
a) Serial Number: C17634M, C17641M, and D00833A and Later
52
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