Hoshizaki DCM-751BAH User manual

Hoshizaki
“A Superior Degree
of Reliability”
www.hoshizaki.com
Models
DCM-751BAH(-OS)
DCM-751BWH(-OS)
Cubelet Icemaker/Dispenser
Hoshizaki America, Inc.
Number: 73184
Issued: 8-31-2012
SERVICE MANUAL

2
WARNING
Only qualied service technicians should install and service the appliance. To
obtain the name and phone number of your local Hoshizaki Certied Service
Representative, visit www.hoshizaki.com. No service should be undertaken until
the technician has thoroughly read this Service Manual. Failure to service and
maintain the appliance in accordance with this manual will adversely affect safety,
performance, component life, and warranty coverage 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
IMPORTANT
This manual should be read carefully before the appliance is serviced. Read
the warnings and guidelines contained in this manual carefully as they provide
essential information for the continued safe use, service, and maintenance of the
appliance. Retain this manual for any further reference that may be necessary.
CONTENTS
Important Safety Information ................................................................................................. 5
I. Construction and Water/Refrigeration Circuit Diagrams ..................................................... 7
A. Construction.................................................................................................................. 7
1. DCM-751BAH(-OS).................................................................................................. 7
2. DCM-751BWH(-OS) ................................................................................................ 8
3. Ice Making Unit........................................................................................................ 9
B. Water/Refrigeration Circuit Diagrams.......................................................................... 10
1. DCM-751BAH(-OS)................................................................................................ 10
2. DCM-751BWH(-OS) ..............................................................................................11
II. Sequence of Operation and Service Diagnosis............................................................... 12
A. Sequence of Operation Flow Chart............................................................................. 12
B. Service Diagnosis ....................................................................................................... 13
C. Control Board Check................................................................................................... 18
D. Bin Control Check ....................................................................................................... 26
E. Float Switch Check and Cleaning ............................................................................... 27
F. Diagnostic Tables......................................................................................................... 29
1. No Ice Production................................................................................................... 29
2. Ice/Water Dispensing............................................................................................. 31
III. Controls and Adjustments............................................................................................... 32
A. Control Board Layout .................................................................................................. 33
1.DCM-751B_H......................................................................................................... 33
2.DCM-751B_H-OS.................................................................................................. 34
B. LED Lights and Audible Alarm Safeties....................................................................... 35
C. Settings and Adjustments............................................................................................ 36
1. Default Dip Switch Settings .................................................................................... 36
2. Infrared Sensor Shutdown Delay (S1 dip switch 1, 2, 3) ....................................... 36
3. Drain Frequency Control (S1 dip switch 4) ............................................................ 36
4. Continuous Dispensing Timer (S1 dip switch 5 & 6).............................................. 37
5. Bin Control Selector (S1 dip switch 7) ................................................................... 37
6. Bin Control Shutdown Delay (S1 dip switch 8) ...................................................... 37
7. Factory Use (S1 Dip Switch 9 & 10) ....................................................................... 37
D. Power Switch, Control Switch, and Dispense Mode Switch ....................................... 38
IV. Removal and Replacement of Components ................................................................... 40
A. Service for Refrigerant Lines....................................................................................... 40
1. Refrigerant Recovery ............................................................................................. 41
2. Brazing .................................................................................................................. 41
3. Evacuation and Recharge (R-404A)...................................................................... 41

4
B. Important Notes for Component Replacement............................................................ 42
C. Icemaking Unit ............................................................................................................ 44
1. Upper Bearing Wear Check .................................................................................. 44
2. Removal and Replacement of Extruding Head...................................................... 45
3. Removal and Replacement of Auger ..................................................................... 45
4. Removal and Replacement of Evaporator ............................................................. 46
5. Removal and Replacement of Mechanical Seal and Lower Housing ................... 47
6. Removal and Replacement of Gear Motor ............................................................ 48
D. Dispense Components................................................................................................ 49
1. Dispense Auger and Agitator.................................................................................. 49
2. Dispense and Agitating Motors .............................................................................. 49
V. Maintenance .................................................................................................................... 50
VI. Preparing the Appliance for Periods of Non-Use ............................................................ 51
VII. Disposal......................................................................................................................... 53
VIII. Technical Information.................................................................................................... 54
A. Specication Sheets.................................................................................................... 54
1. DCM-751BAH ....................................................................................................... 54
2. DCM-751BAH-OS ................................................................................................. 55
3. DCM-751BWH....................................................................................................... 56
4. DCM-751BWH-OS ................................................................................................ 57
B. Performance Data ....................................................................................................... 58
1. DCM-751BAH(-OS)................................................................................................ 58
2. DCM-751BWH(-OS) .............................................................................................. 59
C. Wiring Diagrams.......................................................................................................... 60
1.DCM-751B_H......................................................................................................... 60
2.DCM-751B_H-OS.................................................................................................. 61

5
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
•Electricalconnectionmustbehard-wiredandmustmeetnational,state,andlocal
electrical code requirements. Failure to meet these code requirements could result
in death, electric shock, serious injury, re, or damage to equipment.
•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. Failure to properly ground the appliance
could result in death, serious injury, or damage to equipment.
•Toreducetheriskofelectricshock,donottouchthepowerswitchorcontrolswitch
with damp hands.
•Beforeservicing,movethepowerswitchandcontrolswitchtothe"OFF"position,
then turn off the power supply. Lockout/Tagout to prevent the power supply from
being turned back on inadvertently.
•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.

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WARNING, continued
•Childrenshouldbeproperlysupervisedaroundtheappliance.
•Donotclimb,stand,orhangontheapplianceorallowchildrenoranimalstodoso.
Serious injury could occur or the appliance could be damaged.
•Donotusecombustiblesprayorplacevolatileorammablesubstancesnearthe
appliance. They might catch re.
•Keeptheareaaroundtheapplianceclean.Dirt,dust,orinsectsintheappliance
could cause harm to individuals or damage to the appliance.
NOTICE
•Followtheinstructionsinthismanual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"V.D.PreparingtheApplianceforPeriods
ofNon-Use."
•Keepventilationopenings,intheapplianceenclosureorinthebuilt-instructure,
clear of obstruction.
•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
1. DCM-751BAH(-OS) Storage Bin
Inlet Water Valve
Reservoir
Control Box
Air-Cooled Condenser
Spout Cover
Evaporator Assembly
Compressor
Dispensing Motor
Agitator (L)
Dispense Auger
Dispense Water Valve
Spout B
Float Switch
Shutter Assembly
Power Switch
Spout A
Drain Valve
Thermostatic Expansion Valve
Safety Switch (Door)
Agitator (R)
Agitating Motor (L)
Agitating Motor (R)
Gear Motor
Bin Control Switch
CONTROL
DISPENSE MODE
4A1038-014
ICE
OFF
DRAIN
PORTION
CONTINUOUS

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2. DCM-751BWH(-OS)
Water-Cooled Condenser
Storage Bin
Inlet Water Valve
Reservoir
Control Box
Spout Cover
Evaporator Assembly
Compressor
Dispensing Motor
Agitator (L)
Dispense Auger
Dispense Water Valve
Spout B
Float Switch
Shutter Assembly
Power Switch
Spout A
Drain Valve
Thermostatic
Expansion Valve
Safety Switch (Door)
Agitator (R)
Agitating Motor (L)
Agitating Motor (R)
Gear Motor
Bin Control Switch
CONTROL
DISPENSE MODE
4A1038-014
ICE
OFF
DRAIN
PORTION
CONTINUOUS
Water Regulating Valve

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3. Ice Making Unit
Cubelet Cutter
Allen Head Cap Screw
Gear Motor
O-Ring
Mechanical Seal
Extruding Head
and Upper Bearing
Hex Head Bolt
with Washer
Auger
Evaporator
Housing and
Lower Bearing
Cylinder
Insulation
Allen Head Cap Screw
with Washer
Washer
Extruding Head Heater

10
Inlet Water Valve
Dispense Water Valve
Drain Valve
Float
Switch
Water Level
To Drain
Evaporator
Spout
Thermostatic
Expansion Valve
Gear Motor
Overow
Reservoir
Water Supply
Drier
Air-Cooled Condenser
Fan
High-Pressure Switch
Compressor
Refrigeration Circuit
Water Circuit
B. Water/Refrigeration Circuit Diagrams
1. DCM-751BAH(-OS)

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Inlet Water Valve
Dispense Water Valve
Drain Valve
Float
Switch
Water Level
To Drain
Evaporator
Spout
Thermostatic
Expansion Valve
Gear Motor
Overow
Reservoir
Water Supply
Drier
Water-Cooled Condenser
Compressor
Water In
Water Out
Refrigeration Circuit
Water Circuit
Water Regulating
Valve
High-Pressure Switch
2. DCM-751BWH(-OS)

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II. Sequence of Operation and Service Diagnosis
A. Sequence of Operation Flow Chart
BC open (BC actuator paddle engaged)
"F-A" Control Board Sequence Flow Chart
DCM-751B_H(-OS)
1-in-1 drain cycle. DV energizes for 2 seconds every hour (S1 Dip Switch 4). Does not affect operation.
GM energized GMPR energized
3. 1-in-12 Drain Cycle
&Restart(optional)
2.Icemaker Off
UFS open LFS open FT starts (90 sec.) WV energized Comp energized FM energized GM energized GMPR energized
1. Startup
2. Ice Purge Cycle
Comp energized FM energized GM energized GMPR energized
PowerSwitch"ON" ControlSwitchin"ICE" Safety Switch closed "POWEROK"LEDon
2. Bin Control
Shutdown & Restart
1. Bin Full
Comp de-energized FM de-energized GM energized GMPR energized
1. Fill Cycle 3. Freeze Cycle
LFS closed UFS closed FT terminates WV de-energized Comp energized FM energized GM energized GMPR energized
Low Water Safety
1-beep alarm sounds PT starts UFS open WV energized Comp de-energized FM de-energized GM energized GMPR energized
DV energized GM de-energized GMPR de-energized
10-min. DT terminates DV de-energized 1-in-12 DT reset
3. Icemaker Restart
5 minutes
4. Icemaker Restart
2.Ice Purge Cycle 3.10-Minute Drain
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 GMPR-gear motor protect relay LFS-loweroatswitch PT-purge timer UFS-upperoatswitch WV-inlet water valve
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)."
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 GMPR de-energized
1. DT Initiates DC
to"1.FillCycle"above
90 seconds
(S1 dip switch 4)
FT exceeded
PT terminates
To bypass, press the "SERVICE"buttonafter GM starts.
5 minutes5 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.
All Components de-energized
to"2.IcePurgeCycle"above
Ice level lowered
6 to 10 sec.
BC closed (BC actuator paddle disengaged)

13
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 production, prepare a bucket or pan to catch the ice and a set of scales to
weigh the ice. After the appliance has operated for 10 to 20 minutes, catch the ice
production for 10 minutes. Weigh the ice to establish the batch weight. Multiply the batch
weight by 144 to calculate 24hr production. When conrming production or diagnosing
lowproduction,see"VIII.B.PerformanceData."
2. Diagnostic Procedure
This diagnostic procedure is a sequence check that allows you to diagnose the electrical
system and components. Before proceeding, check for correct installation, proper
voltage per unit nameplate, and adequate water supply. Check that the 24VAC 1Afuse
and GM 115VAC 3A fuse are good. When checking high-voltage (115VAC), always
choose a neutral (W) to establish a good neutral connection. When checking low-voltage
(24VAC), always choose a neutral (LBU) from CT to establish a good neutral connection.
When checking CB DC-voltage (5VDC), use CB red K4 connector pinclosest to CB
blackK3connectorforDCground(GND).CB"POWER"LEDremainsonunless
powersupplyisinterrupted.CheckCBusingthestepsin"II.C.ControlBoardCheck."
IMPORTANT!Appliance will not start unless the safety switch is engaged.
1)Turnonthepowersupply.Removethefrontpanel.Movethepowerswitchtothe"ON"
position,thenmovethecontrolswitchtothe"DRAIN"position.Engagethesafety
switch.
2) Allow the water system to drain for 5 minutes. If water does not drain, see step 12.
3)Disengagethesafetyswitch,thenmovethecontrolswitchtothe"OFF"position.
4)Movethepowerswitchtothe"OFF"position.
5) Remove the control box cover.
6) Engage the safety switch.

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7) Startup–"POWER OK" LED is on:Movethepowerswitchtothe"ON"position,
thenmovethecontrolswitchtothe"ICE"position.CB"POWEROK"LEDison.
"POWEROK" LED Diagnosis:CheckthatCB"POWER"LEDison.Ifnot,checkfor
proper power supply voltage (115VAC) input to CT. If 115VAC is not present, check the
breaker, power switch, and safety switch. Next, check that the power protect relay is
de-energized and contacts between terminals #6(BR) and #2(BK) are closed. Check
for proper control voltage (24VAC) output from CT. Next, check the 24VAC 1A fuse. If
open, replace. Check for 24VAC at CB K8connector pin #1 (W/R) to CB K8 connector
pin #2 (LBU). If24VAC is not present at CB K8 connector pin #1 (W/R) but is present at
1A fuse (W/R), check continuity of control switch. If open, replace. If24VAC is present
betweenCBK8connectorpin#1(W/R)andpin#2(LBU),and"POWEROK"LEDis
off, replace CB.
BC Diagnosis: Check that the actuator paddle is properly positioned. Check for
continuity across BC proximity switch. When BC proximity switch is closed 0VDC is
read across CB K8 connector pin #3(GY) and #4 (GY). 5VDC is present between CB
K8 connector pin #3 (GY) or #4(GY) to CB red K4 connector pin closest to CB black K3
black connector (5VDC GND). If 5VDC is not present, replace CB.
HPS Diagnosis: HPS automatically resets when refrigeration circuit high-side pressure
is within an acceptable range. 5VDC is supplied from CB K9connector pin #3 (Y) and
back onto CB K9 connector pin #4 (Y). If 5VDC is not present at CB K9 connector pin
#3 (Y) to CB red K4 connector pin closest to CB black K3 connector (5VDC GND)
andCB"POWEROK"LEDison,replaceCB.Ifrefrigerantpressureshavereturned
to an acceptable range and HPS does not close, replace HPS. Ifpressures have not
equalized, and refrigeration circuit high-side pressure does not drop, recover, evacuate,
and recharge if necessary. On air-cooled model, check that the condenser is not dirty
or clogged, check for proper FMoperation and fan blade for binding. On water-cooled
model,checkWRVandwaterowinandoutofcondenser.Checkforrefrigeration
circuit refrigerant restriction (TXVand drier).
8) Fill Cycle–"WTRIN" LED is on: WV energizes. 90-sec. FT starts. LFScloses. Nothing
happens at this time. Reservoir continues to ll. UFS closes, WV de-energizes, 90-sec.
FT terminates. Diagnosis:Ifthereservoirisempty,LFSopen,"WTRIN"LEDon,and
WV off, check for 24VAC at CB K2connector pin #8(W/BR) to a neutral(LBU).
If 24VAC is not present, conrm 24VAC power supply at CB K2connector pin #7 (W/R)
to a neutral (LBU). If 24VAC is not present on CB K2connector pin #7 (W/R), check
wiring connections from CT. If24VAC is present on CB K2 connector pin #7 (W/R)
and not on CB K2 connector pin #8 (W/BR), replace CB. If 24VAC is present on CB
K2connector pin #8 (W/BR), check for 24VAC at WV solenoid. If 24VAC is present,
replace WV. If WV is energized and ll/rell exceeds 90-sec. FT with no water in the
reservoir, check for clogged WV screen or DVleaking. Note: IfUFS remains open
90seconds after LFS opens (WV energized), a 1-beep alarm sounds (90 sec. FT). This
alarmresetsautomaticallyonceUFScloses.Ifreservoirisfullandoverowing,check
foropenUFS.See"II.E.FloatSwitchCheckandCleaning."IfWVde-energizesand
water continues to ll the reservoir, replace WV.

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9) Ice Purge Cycle–"GM" LED is on.UFScloses(WVde-energizes)and"WTRIN"
LED turns off. 5-sec. GM delay timer and 30-min. FZT start. 5-sec. GM delay timer
terminates. GM and GMPR energize. 5-min. IPT starts. GM runs for 5 min. to clear
any ice from the evaporator. Diagnosis:If"GM"LEDisoff,checkthatUFSclosed.
IfUFSisclosedand"GM"LEDdoesnotturnon,replaceCB.If"GM"LEDisonand
GM is off, conrm 115VAC at CB K1 connector pin #2 (BR) to neutral (W). Check for
115VAC at CB K1connector pin#3 (DBU) to a neutral (W). If no voltage is present at
CB K1 connector pin #2 (BR), check wiring connections. If no voltage is present at CB
K1connector pin#3 (DBU), replace CB. If115VAC is present, check 115VAC 3A GM
fuse, GM internal protector, GM windings, capacitor, and GM coupling between auger
and GM. If GM internal protector is open, allow to cool and reset. If reset does not
occur, replace GM. If Comp energizes at the same time GM energizes, check CB.
See"II.C.ControlBoardCheck."
10) Freeze Cycle–"COMP" and "GM" LEDs are on. 5 min. IPT terminates. GM continues.
CB conrms GM operation through GMPR terminal #3 (W/O) and terminal #5(W/O).
Comp and FM energize. Ice production begins 4to 6min. after Comp and FM energize
depending on ambient and water temperature conditions. Diagnosis:5 min. after GM
energizes, conrm Comp LED turns on and Comp and FM energize. If not, check
that GMPR is energized (115VAC). Next, check continuity between GMPR terminal
#3(W/O) and terminal #5 (W/O). If open, GMPR is de-energized or defective. If closed,
and"COMP"LEDisnoton,replaceCB.If"COMP"LEDturnsonandCompandFM
do not energize, conrm 115VAC at CB Comp X1 relay (BR) to a neutral (W). If 115VAC
is not present, check connections. If 115VAC is present, conrm 115VAC at CB Comp
X1relay(R)toaneutral(W).If115VACisnotpresentand"COMP"LEDison,replace
CB. If 115VAC is present, check Comp external protector (overload), allow to cool and
reset. If reset does not occur, replace external protector. Check Comp start and run
capacitors, Comp start relay, and Comp windings. If FM does not energize, check FM
run capacitor, that the fan blade is not binding, and that FM windings are good.
11) Rell/Low Water Safety–"COMP," "GM," and "WTRIN" are on. As ice is produced,
the water level in the reservoir drops. UFS opens. Nothing happens at this time. When
LFS opens, 90-sec. FTstarts. WV energizes. Comp, FM, and GM continue. As water
lls the reservoir, LFS closes. Nothing happens at this time. When UFS closes, WV
de-energizes, 90-sec. FT terminates, and 30-min. FZT resets. This continues until BC
shuts down the appliance or power is turned off to the appliance. Diagnosis: Conrm
thatthewaterlevelhasdroppedandUFSandLFSareopen.See"II.E.FloatSwitch
CheckandCleaning."Checkfordirtyorstickingoatswitches,cloggedWVscreen,
defective WV coil, or DV leaking by. If UFS remains open 90 seconds after LFS opens
(WV energized), a 1-beep alarm sounds (90 sec. FT). This alarm resets automatically
once UFS closes. Comp and FM de-energize. GM de-energizes 90 sec. later. WV and
alarm continue until UFS closes.
Note: Each time UF/S closes, 30-minute FZT starts. 30-minute FZT resets when UF/S
closes again. If UF/S does not close again within 30 minutes, CB shuts down the
applianceandsoundsa5-beepalarmevery5seconds.See"III.B.LEDLights
andAudibleAlarmSafeties."

16
12) Drain Cycle–"FLUSH" (drain) LED is on. IMPORTANT! Drain valve will not energize
unless the safety switch is engaged. The appliance is factory set to drain the
evaporator and reservoir once every hour for 2 seconds. A manual drain is provided
whencleaningtheappliancebymovingthecontrolswitchfromthe"ICE"positiontothe
"DRAIN"position.A1-in-12draincycleisalsoavailable.Forfurtherdetails,see"III.C.3.
DrainFrequencyControl(S1dipswitch4)."
a) Automatic Drain Cycle: A drain cycle occurs once every hour for 2seconds.
DCTterminates and DVT starts. Once DVT terminates, DCTresets and DV
de-energizes. DCT resets every time the power supply is turned off and on again.
Diagnosis: Once DCT terminates, DV energizes. If not, check for 24VAC from
K2connector pin #10 (W/BU) to a neutral (LBU). If 24VAC is not present, replace CB.
If 24VAC is present, check for 24VAC at DV. If 24VAC is present and DV does not
energize, check DV solenoid continuity.
b) Manual Drain:Movecontrolswitchtothe"OFF"position,pausemomentarily,then
movetothe"DRAIN"position.DVenergizes.
DVcontinuesuntilcontrolswitchismovedto"OFF"or"ICE"positionorpoweris
turned off.
Note:a)Amomentarypauseinthe"OFF"positionisnecessarytode-energizethe
controlboardwhenmovingthecontrolswitchbetween"ICE"and"DRAIN."
Otherwise there is a delay of several minutes before the new selection takes
effect.
b)Ifthecontrolswitchisleftinthe"DRAIN"positionfor10minutesormore,a
2-beep alarm sounds every 5 seconds. Move the control switch out of the
"DRAIN"positiontoclearthealarm.
Diagnosis: DV energizes. If not, check for 24VAC at CBK2connector pin
#10(W/BU) to a neutral (LBU). If 24VAC is not present, conrm 24VAC power
supply to CB K2connector pin #9(W/R) to a neutral (LBU). If 24VAC is present on
CB K2 connector pin #9(W/R) and not on CB K2 connector pin #10(W/BU), check
for 5VDC at CB K9 connector pin #1 (W/BK) to CBred K4 connector pin closest to
CBblack K3connector. If 5VDC is not present on CB K9 connector pin #1 (W/BK),
replace CB. If 5VDC is present on CB K9 connector pin #1 (W/BK), check for 5VDC
at CB K9 connector pin #2 (W/BK) to CBred K4 connector pin closest to CBblack
K3connector. If 5VDC is not present on pin #2 (W/BK), check continuity of control
switch.Ifopen,placein"DRAIN"positionorreplacecontrolswitch.
If 24VAC is present at CB K2 connector pin #10 (W/BU), check for 24VAC at DV. If
24VAC is present and DV does not energize, check DV solenoid continuity.

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13) Shutdown–Bin lls and ice engages BC actuator paddle. 6 to 10-sec. shutdown
sequence begins. Diagnosis: Check that BC actuator paddle is activated and not
sticking. Check BC proximity switch continuity to conrm BC proximity switch is open.
If BC actuator is engaged and BC proximity switch is closed, replace BC proximity
switch. If BC proximity switch is open and Comp, FM, and GM do not de-energize,
replaceCB.See"II.C.ControlBoardCheck."
Legend: AM–agitating motor; BC–bin control; CB–control board; Comp–compressor;
CT–control transformer; DCT–drain cycle timer (1-hr.); DV–drain valve;
DVT–drain valve timer (2-sec.); FM–fan motor; FT–ll timer (90-sec. low water
safety); FZT–freeze timer; GM–gear motor; GMPR–gear motor protect relay;
HPS–high-pressure switch; IPT–ice purge timer; LFS–loweroatswitch;
TXV–thermostatic expansion valve; UFS–upperoatswitch;   
WRV–water regulating valve; WV–inlet water valve

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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 and 115VAC 3A GM fuse 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
7determines 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CBredK4connectorpinclosesttoCBblack
K3connector for DC ground (GND).
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: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.

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2) 5VDC Output Checks: Thereareseven5VDCcircuitsontheappliance,"DRAIN"
position through control switch, high-pressure switch (HPS), gear motor protect
relay(GMPR),bincontrol(BC),oatswitch(FS),icedispenseswitch,andwater
dispense switch.
•5VDC CB K9 Connector: See Fig. 1.
5VDC CB K9 Connector
Component Pin # (Wire Color)
"DRAIN"PositionThroughControlSwitch #1 (W/BK) and #2 (W/BK)
High-Pressure Switch (HPS) #3 (Y) and #4 (Y)
Gear Motor Protect Relay (GMPR)
(terminals #3 and #5)
#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)
Gear Motor Protect Relay (GMPR)
Terminals #3 and #5 (W/O)
a. "DRAIN" Position on Control Switch
CB K9 connector pins #1 and #2 (W/BK):
•When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, 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.
•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 K9 connector
pin #1(W/BK) and pin#2 (W/BK) to CBred K4connector, 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. 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.

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c. Gear Motor Protect Relay (GMPR)
CB K9 connector pins #5 (W/O) and #6(W/O): When GMPR is de-energized,
GMPR terminals #3 and #5 are open and 5VDC is present between
CBK9connector pin #5 (W/O) and CB red K4connector pin closest to CBblack
K3 connector. If 5VDC is not present, replace CB. When GMPR is energized, GMPR
terminals #3 and #5are closed and 5VDC is present between CB K9 connector
pin #5 (W/O) and pin #6(W/O) to CB red K4 connector pin closest to CB black
K3connector. If GM is energized and GMPR terminals #3 & #5 are open, an 8-beep
alarmoccurs.See"III.B.LEDLightsandAudibleAlarmSafeties."
•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 (DBU)
d. Bin Control (BC)
CB K8 connector pins #3 (GY) and #4 (GY): When BC is closed (calling for ice),
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."
e. Float Switch (FS): CB K8 connector pins #5 common (BK), #6 UFS (R), and
#7LFS (DBU): 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."
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) (DBU)