Hoshizaki DCM-271BAH User manual

Models
DCM-270BAH(-OS)
F-A & F-C Control Boards
Cubelet Icemaker/Dispenser
Service Manual
Number: 73202
Issued: 5-6-2014
Revised: 5-10-2016
hoshizakiamerica.com

2
WARNING
Only qualied service technicians should install and service the icemaker. 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 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 qualied service technicians in the
service and maintenance 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: [email protected]
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.

3
CONTENTS
Important Safety Information ................................................................................................. 4
I. Construction and Water Refrigeration Circuit Diagrams ..................................................... 6
A. Construction.................................................................................................................. 6
B. Water/Refrigeration Circuit Diagrams............................................................................ 7
II. Sequence of Operation and Service Diagnosis................................................................. 8
A. Sequence of Operation Flow Chart............................................................................... 8
B. Service Diagnosis ......................................................................................................... 9
C. Control Board Check................................................................................................... 14
D. Bin Control Check ....................................................................................................... 23
E. Float Switch Check and Cleaning ............................................................................... 25
F. Diagnostic Tables......................................................................................................... 27
III. Controls and Adjustments............................................................................................... 31
A. Control Board Layout .................................................................................................. 32
B. LED Lights and Audible Alarm Safeties....................................................................... 34
C. Settings and Adjustments............................................................................................ 35
1. Default Dip Switch Settings .................................................................................... 35
2. Bin Control Shutdown Delay (Infrared Sensor) (S1 dip switch 1, 2, 3) .................. 35
3. Drain Frequency Control (S1 dip switch 4) ............................................................ 35
4. Continuous Dispensing Timer (S1 dip switch 5 & 6).............................................. 36
5. Bin Control Selector (S1 dip switch 7) ................................................................... 36
6. Bin Control Shutdown Delay, Agitation, and Ice Purge Timer (S1 dip switch 8)..... 36
7. Bin Control Shutdown Delay (S1 dip switch 9) (F-C CB Only)................................ 37
8. Factory Use (S1 Dip Switch 10)............................................................................. 37
D. Switches...................................................................................................................... 37
IV. Refrigeration Circuit and Component Service Information.............................................. 38
A. Refrigeration Circuit Service Information .................................................................... 38
B. Component Service Information.................................................................................. 41
C. Icemaking Unit ............................................................................................................ 43
V. Maintenance .................................................................................................................... 49
VI. Preparing the Appliance for Periods of Non-Use ............................................................ 50
VII. Disposal......................................................................................................................... 51
VIII. Technical Information.................................................................................................... 52
A. Specication and Performance Data Sheets............................................................... 52
1. DCM-270BAH ........................................................................................................ 52
2. DCM-270BAH-OS ................................................................................................. 53
B. Wiring Diagrams.......................................................................................................... 54
1. DCM-270BAH(-OS): .............................................................................................. 54
Serial Number: C10508L to D00829A (except C17634M and C17641M) ............. 54
2. DCM-270BAH(-OS): ............................................................................................. 55
Serial Number: C17634M, C17641M, and D-00998A and Later ........................... 55
IMPORTANT
This manual should be read carefully before the appliance 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
appliance. Retain this booklet for any further reference that may be necessary.

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 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 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5-15 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
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 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.
• 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.

6
I. Construction and Water Refrigeration Circuit Diagrams
A. Construction
1. DCM-270BAH(-OS)
Power
Switch
Ice Storage Bin
Control Box B Right Side Panel
Compressor
Condenser
Control Box A
Right Side Louver
Air Filter
Control Box A
Cover
DCM-270BAH
Front Panel
DCM-270BAH-OS
Front Panel
DCM-270BAH-OS
Apron Panel
Control Switch
Gear Motor
External Protector
Control Board
Control Transformer
Fuse
(AGC-1A, 250VAC)
Icemaking Unit
Top Panel
Shutter
Assembly
Bin Control Switch
Inlet Water Valve
Dispensing Water Valve
Reservoir
DCM-270BAH
Apron Panel
Bin Top Cover

7
B. Water/Refrigeration Circuit Diagrams
Inlet Water Valve
Dispense Water Valve
Drain Valve
Float
Switch
Water Level
To Drain
Evaporator
Bin
Thermostatic
Expansion Valve
Gear Motor
Overow
Reservoir
Water
Supply
Drier
Air-Cooled Condenser
Fan
High-Pressure Switch
Compressor
Refrigeration Circuit
Water Circuit
DCM-270BAH(-OS)
To Drain
Bin Drain
Hose
Evaporator Water
Supply Hose
Bin Top Cover
Agitator

8
II. Sequence of Operation and Service Diagnosis
A. Sequence of Operation Flow Chart
"F-A" & "F-C" Control Board Sequence Flow Chart
DCM-270B_H(-OS)
1-in-1 drain cycle. DV energizes for 2 seconds every hour (S1 Dip Switch 4). Does not affect operation.
GM energized UFS open
LFS open FT starts (90 sec.) WV energized Comp energized FM energized GM energized
1. Startup
2. Ice Purge Cycle
Comp energized FM energized GM energized
Power Switch "ON" Control Switch in "ICE" "POWER OK" LED on
1. Fill Cycle 3. Freeze Cycle
LFS closed UFS closed FT terminates WV de-energized Comp energized FM energized GM energized
Low Water Safety
1-beep alarm sounds PT starts UFS open Comp de-energized FM de-energized WV 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
4. 1-in-12 Drain Cycle - The factory default is 1-in-1 drain cycle. IMPORTANT! Do not adjust for 1-in-12 drain cycle sequence on this model.
Rell
Maximum 90 seconds
90 sec. FT exceeded 1-beep alarm sounds 90 sec. PT starts
When UFS closes, alarm resets and 2. Ice Purge Cycle starts.
1-beep alarm continues WV energized GM de-energized
90 seconds
FT exceeded
PT terminates
To bypass, press the "SERVICE" button after GM starts.
*1-min. or 5-min.
5 sec.
Maximum 90 seconds
LFS closed UFS closed FT terminates WV de-energized
WV energized FT starts (90 sec.)
If Fill> 90 sec. FT 1-beep alarm sounds WV energized When UFS closes alarm resets and 2. Ice Purge Cycle starts.
to "2. Ice Purge Cycle" above if UFS closed. to "1. Fill Cycle" above if UFS open.
1. Bin Full
GM energized Comp de-energized FM de-energized
GM de-energized
3. Icemaker Off
BC open Comp energized FM energized GM energized
2. Ice Purge Cycle 4. Icemaker
Restart
150-sec. Shutdown Sequence
BC closed
BC open (BC large balance plate engaged)
2.Icemaker Off
2. Bin Control
Shutdown & Restart 1. Bin Full 3. Icemaker Restart
All Components de-energized
Ice level lowered
6 to 10 sec.
BC closed (BC large balance plate disengaged)
A. "F-A" E-0 (G) and
Earlier Dip Switch 8 "ON"
B. "F-A" E-0 (H) and Later
Dip Switch 8 "OFF"
C. "F-C" Dip Switch
8 and 9 "OFF"
to "2. Ice Purge Cycle" above if UFS closed. to "1. Fill Cycle" above if UFS open.
BC open (BC large balance plate engaged)
90 sec. 60 sec.
*"F-A" E-0 (G) and Earlier dip switch 8 on - 5 min. *"F-A" E-0 (H) and Later and "F-C" dip switch 8 off - 1 min. and a 2-second periodic agitation was added to occur every 90 min.

9
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. 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 ice storage bin. Once ice begins to ll the bin, start a 10 min. timer. After
10min., 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 20sec. 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 144for the total production in 24 hr. Replace
the control box cover and bin top cover in their correct positions and secure. Replace all
panels in their correct positions and secure. Move the power switch to the "ON" position
to start the automatic icemaking process.

10
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 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). If24VAC 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). If5VDC 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.

11
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 (O) 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 CCR energize. CCR cannot energize unless GM circuit is complete
(GM external protector and GM internal protector). Once CCR energizes, CB K9
#5W/O and CB K9 #6 W/O 5VDC circuit closes and ice purge timer starts (1-min.
"F-A" CB E-0 (H) and later and "F-C" CB dip switch 8 off or 5-min. "F-A" CB E-0 (G)
and earlier dip switch 8 on). See "II.C.3)c. Compressor Control Relay (Ice Purge Timer
Circuit)." If CCR 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 the "SERVICE" button on CB during
the 5-sec. GM delay time.
Diagnosis CB: Check that UFS closed, WV LED turned off and WVde-energized.
IfUFS is closed, "WV" LED is off, and "GM" LED is off, replace CB. If "GM" LED is
on and GM is off, conrm 115VAC at CB K1 #2 (BR) to neutral(W). If115VAC 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). If115VAC is not present, replace CB.
Diagnosis GM: If115VAC is present at CB K1 #3 (BK) to neutral(W), check GM fuse,
GM capacitor, GM windings, and GM coupling between auger and GM.
Diagnosis CCR: See "II.C.3)c. Compressor Control Relay (Ice Purge Timer Circuit)."
Once ice purge timer terminates (1-min. "F-A" CB E-0 (H) and later and "F-C" CB dip
switch 8 off or 5-min. "F-A" CB E-0 (G) and earlier dip switch 8 on) or the "SERVICE"
button is pressed, freeze cycle begins.

12
6) Freeze Cycle – "COMP" LED is on. ice purge timer terminates (1-min. "F-A" CB
E-0 (H) and later and "F-C" CB dip switch 8 off or 5-min. "F-A" CB E-0 (G) and earlier
dip switch 8 on) or the "SERVICE" button is pressed. "COMP" LED turns on. "GM" LED
remains on. Comp and FM energize. GM and CCR 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, conrm ice purge timer has terminated (1-min. "F-A" CB E-0 (H) and later
and "F-C" CB dip switch 8 off or 5-min. "F-A" CB E-0 (G) and earlier a dip switch 8 on).
Check for 0VDC across CB K9 #3 (W/O) and CB K9 #5 (W/O). If5VDC is present,
CCR contacts are open. Check for 115VAC at CCR #7 (R) to CCR #8 (W). If115VAC
is present, check CCR continuity between CCR #3 (W/O) and CCR #5 (W/O). If open,
replace CCR. If closed and"COMP" LED remains off, replace CB. If"COMP" LED is
on and Comp is off, check for 115VAC at CB X1 brown (BR) wire to neutral(W) and CB
X1red (R) wire to neutral (W). If115VAC is present on CB X1 brown (BR) wire and not
on CB X1 red (R) wire, replace CB. If115VAC is present on CB X1 red (R) wire, check
Comp external protector, motor windings, start relay, and capacitors.
Note: If CCR 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, motor windings, and
bearings.
7) Rell 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, CCR, 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 CCR continue to clear ice from the evaporator. 90-sec. ice purge timer
terminates, GM and CCR 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 rell 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 icemaker and sounds a 5-beep alarm every 5 sec. See "II.B. LED
Lights and Alarm Safeties."

13
10) Shutdown
a) "F-A" E-0 (H) and Earlier Dip Switch 8"ON" CB Shutdown – Bin lls with ice
activating BC micro-switch. Within 6 to 10 sec. CB shutsdown appliance.
b) "F-A" E-0 (H) and Later Dip Switch 8 "OFF" Shutdown – Bin lls with ice
activating BC micro-switch. CB starts 90-sec. Comp shutdown timer. Once
90-sec. Comp shutdown timer terminates, Comp and FM de-energize and 60-sec.
GM shutdown timer starts. Once 60-sec. GM shutdown timer terminates, GM
de-energizes and icemaker is off.
c) "F-C" Dip Switch 8 and 9"OFF" CB – Bin lls with ice activating BC micro-switch.
CB starts 90-sec. Comp shutdown timer. Once 90-sec. Comp shutdown timer
terminates, Comp and FM de-energize and 60-sec. GM shutdown timer starts. Once
60-sec. GM shutdown timer terminates, GM de-energizes and icemaker is off.
Shutdown Diagnosis: Check that BC large balance plate is activated and not
sticking. Check BC micro-switch continuity. When BC large balance plate is down
(icemaking), BC micro-switch is closed. When BC large balance plate is up BC
micro-switch is open. If not, replace BC micro-switch. If BC micro-switch is open and
Comp, FM, and GM do not de-energize, replace CB. See "II.C. Control Board Check
Procedure."
Legend: BC–bin control; CB–control board; CCR–compressor control relay;
Comp–compressor; CT–control transformer; DV–drain valve; FM–fan motor;
GM–gear motor; LFS–lower oat switch; UFS–upper oat switch; WV–inlet water
valve

14
C. Control Board Check
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 is good and 115VAC 3A GM external protector is closed.
NOTICE! Control Board Change:
• "F-A" control board 2A4296-01 no longer available.
• "F-C" control board 2A8054-01 new and replaces 2A4296-01.
• 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
7determines bin control application. WARNING! Do not adjust S1 dip switch 4, 7, 8,
or 9 dip switches out of their factory default positions. These dip switches 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 CBred K4 connector pin closest to CB black
K3connector for DC ground (GND).

15
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. Diagnosis: Checkthat "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 K8connector pin #1 (W/R) to CB K8 connector pin #2(LBU).
If24VAC 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 control relay (CCR).
b) 2 circuits at CB K8 connector: Bincontrol (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
Component Pin # (Wire Color)
Control Switch "DRAIN" Position #1 (W/BK) and #2 (W/BK)
High-Pressure Switch (HPS) #3 (Y) and #4 (Y)
Compressor Control Relay (CCR)
(CCR relay terminals #3 W/O and #5 W/O)
#5 (W/O) and #6 (W/O)
Red positive test lead to
redK4 connector pin closest
to black K3 connector
Fig. 1
Control Board K9 Connector
Red Positive
Test Lead
Black Negative
Test Lead
Multimeter
5VDC
"DRAIN" Position on
Control Switch
(W/BK)
High-Pressure Switch (HPS) (Y)
Compressor Control Relay (CCR)
CCR Terminals #3 (W/O) and #5 (W/O)

16
2a) 5VDC CB K9 Connector Continued:
a) Control Switch"DRAIN" Position
CB K9 connector pins #1 (W/BK) and #2 (W/BK):
• "ICE" Position: When the control switch is in the "ICE" position, CB K9 connector
pin#1and pin #2are open. 5VDC is present between CB K9 connector
pin #1(W/BK) and pin #2 (W/BK). If not, check control switch position and
continuity (open). Replace as needed. Next, conrm 5VDC between pin
#1 (W/BK) and CBred K4 connector, pin closest to CBblack K3connector. 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. 0VDC is present between pin
#1(W/BK) and pin#2 (W/BK). If not, check control switch position and continuity.
Next, conrm 5VDC is present between both CB K9 connector pin #1(W/BK) and
pin #2 to CBred K4connector, pin closest to CB black K3 connector. If5VDC is not
present on both pins, 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. If5VDC is not present on pin #3 (Y) or pin
#4(Y), replace CB. If 5VDC is present on CBK9connector pin #3 (Y) and not on CB
K9connector 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 Control Relay (CCR)
CB K9 connector pins #5 (W/O) and #6(W/O): When CCR is de-energized (GM off),
CCRterminals #3 and #5 are open and 5VDC is present between CBK9connector
pin #5 (W/O) and CBK9connector pin #6(W/O). If5VDC is not present, check CCR
continuity between terminals #3 and #5. If open, replaceCB. When CCR is energized,
CCR terminals #3 and #5close 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 K3connector and CB K9 connector
pin #6 (W/O) to CB red K4 connector pin closest to CB black K3connector. If GM is
energized and CCR terminals #3& #5 are open, an 8-beep alarm occurs. See "III.B.
LED Lights and Audible Alarm Safeties." If CCR terminals #3 and #5 are closed and
0VDC is present between CB K9 connector pin #5 (W/O) and pin #6(W/O), Comp
delay timer starts. IfComp does not energize after Comp delay timer terminates
(1-min. "F-A" CB E-0 (H) and later and "F-C" CB dip switch 8 off or 5-min. "F-A" CB
E-0(G) and earlier dip switch 8 on), replace CB.

17
2b) 5VDC CB K8 Connector: See Fig. 2.
5VDC CB K8 Connector
Component Pin # (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
Fig. 2
Red Positive
Test Lead
Black Negative
Test Lead
Multimeter
5VDC
Control Board K8 Connector
Bin Control (GY)
Upper Float Switch (UFS) (R)
Float Switch (FS) Common (BK)
Lower Float Switch (LFS) (BU)
2b) 5VDC CB K8 Connector Continued:
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. If5VDC 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 #7LFS (BU): 5VDC is
present between CB K8 connector pin #5common (BK) and CB red K4connector pin
closest to CB black K3connector at all times. If 5VDC is not present, replace CB. For
further oat switch diagnostics, see "II.E. Float Switch Check and Cleaning."

18
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 (Y) or (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, conrm 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
Component Pin # (Wire Color) To CB VDC Ground Disengaged Engaged
5VDC Power Supply #3 (W/BK)
To
Red K4 pin closest
to black K3
5VDC 5VDC
Water Dispense Signal #8 (Y) or (P) 0VDC 5VDC
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
Red Positive
Test Lead
Black Negative
Test Lead
Multimeter
5VDC
Control Board K7 Connector
Water Dispense (Y) or (P)
(switch signal)
Fig. 3
Water Dispense (W/BK)
(5VDC power supply)

19
2. Opti-Serve Model
CB K8 connector pins #7 (R), #8 (Y) or (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, conrm 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.
5VDC CB K7 Connector
Component Pin # (Wire Color) To CB VDC Ground Disengaged Engaged
VDC Sensor Ground #7 (R)
To Red K4 pin closest
to black K3
0VDC 0VDC
Water Dispense Signal #8 (Y) or (P) 0VDC 5VDC
5VDC Power Supply #9 (BK) 5VDC 5VDC
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
Fig. 4
Red Positive
Test Lead
Black Negative
Test Lead
Multimeter
5VDC
Control Board K7 Connector
Water Dispense (Y) or (P)
(switch signal)
Water Dispense (R)
(VDC GND)
Water Dispense (BK)
(5VDC power)

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
Component Pin # (Wire Color) To CB VDC Ground Disengaged Engaged
5VDC Power Supply #3 (W/BK)
To
Red K4 pin closest
to black K3
5VDC 5VDC
Ice Dispense Signal #2 (Y) 0VDC 5VDC
Red positive
test lead to red
K4 connector
pin closest
to black K3
connector
Fig. 5
Red Positive
Test Lead
Black Negative
Test Lead
Multimeter
5VDC
Control Board K7 Connector
Ice Dispense (W/BK)
(5VDC power supply)
Ice Dispense (Y)
(ice dispense signal)