Scotsman MXG 327 User manual

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Scotsman Ice Srl
Via Lainate, 31 - 20010 Pogliano M.se - Milano - Italy
Tel. [phone] (Aut. Sel.)- Telefax [phone]
Direct Line to Service & Parts:
Phone [phone] - Fax [phone]
Website: www.scotsman-ice.it
E-Mail: [email protected]
ISO 9001 - Cert. n. 0080
MXG 327
MXG 427
MXG 437
R 290
Electronic
modular cubers
REV. 07/2018
SERVICE MANUAL

LED STATUS REASON WHY-SIGNIFICATION-SIGNIFICATO
ON STEADY
FIXE
FISSO
UNIT UNDER POWER
SOUS TENSION
IN TENSIONE
ON STEADY
FIXE
FISSO
FREEZING CYCLE
EN RÉFRIGÉRATION
IN CONGELAMENTO
BLINKING
CLIGNOTANT
LAMPEGGIANTE
60 MINUTES DELAY AT START UP – JUMPER J3 OUT
60 MINUTES DE RETARD AU DEMARRAGE – CAVALIER J3 OUVERTE
60 MINUTI RITARDO PARTENZA – CONTATTI J3 APERTI
ON STEADY
FIXE
FISSO
TOO HI DISCHARGE PRESSURE/TEMP
COUPURE HP
FERMATA ALTA TEMP. CONDENSAZIONE
BLINKING
CLIGNOTANT
LAMPEGGIANTE
TOO HI EVAP. TEMP. (> 0C°) AFTER 15' FROM START UP
COUPURE BP (0°C LU PAR LA SONE EVAP, NON ATTEINTE APRES 15' FONCT.)
TEMP. EVAP >0 °C DOPO 15' DA INIZIO CONGELAMENTO
ON STEADY
FIXE
FISSO
UNIT OFF AT BIN FULL
CABINE PLEINE
CONTENITORE PIENO
BLINKING SLOW
CLIGNOTANT LENT
LAMPEGGIANTE LENTO
I/R BEAM CUTTED
FAISCEAU INFRA ROUGE CELLULE NIVEAU GLACE INTERROMPU
RAGGIO INFRAROSSO INTERROTTO
BLINKING FAST
CLIGNOTANT RAPIDE
LAMPEGGIANTE VELOCE
I/R ON AFTER TRIP OFF AT BIN FULL
FAISCEAU INFRA ROUGE CELLULE NIVEAU GLACE ETABLI
RAGGIO INFRAROSSO RIPRISTINATO DOPO FERMATA A CONT. PIENO
ON STEADY
FIXE
FISSO
I/R CALIBRATION DONE
CALIBRATION FAISCEAU INFRA ROUGE CELL. NIVEAU GLACE REALISE’
CALIBRAZIONE RAGGIO INFRAROSSO EFFETTUATA
BLINKING
CLIGNOTANT
LAMPEGGIANTE
UNIT IN CLEANING MODE OR TRIPPING OFF AFTER TEST – JUMPER TEST IN
MACHINE EN MODE DETARTRAGE OU ARRETE APRES LE TEST – CAVALIER TEST FERME’
MACCHINA NELLA FASE LAVAGGIO O FERMA DOPO IL TEST – PONTICELLO TEST CHIUSO
ON STEADY
FIXE
FISSO
BLINKING
CLIGNOTANT
LAMPEGGIANTE
CONDENSER SENSOR OUT OF ORDER
SONDE CONDENSEUR HS
SONDA CONDENSATORE MALFUNZIONANTE
EVAPORATOR SENSOR OUT OF ORDER
SONDE EVAPORATEUR HS
SONDA EVAPORATORE MALFUNZIONANTE
BLINKING ALTERNATIVELY
CLIGNOTANT ALTERNE’
LAMPEGGIO ALTERNATO
I/R SENSOR OUT OF ORDER
SONDE INFRA ROUGE CELLULE NIVEAU GLACE HS
SONDA ALL’INFRAROSSO LIVELLO GHIACCIO MALFUNZIONANTE
PUSH
PUSH > 5" DURING WATER FILLING TO MOVE THE UNIT INTO FREEZING
PUSH > 5" DURING FREEZING TO MOVE THE UNIT INTO DEFROST
PUSH > 5" DURING DEFROST TO MOVE THE UNIT INTO FREEZING
PUSH 2" < 5" DURING WATER FILLING TO MOVE THE UNIT INTO CLEANING
PUSH DURING THE 60 MIN START UP DELAY TIME TO BY-PASS IT
APPUI > 5" EN REMPLISSAGE POUR BASCULER LA MACHINE EN REFRIGERATION
APPUI > 5" EN CONGELATION POUR BASCULER LA MACHINE EN DEGIVRAGE
APPUI > 5" EN DEGIVRAGE POUR BASCULER LA MACHINE EN CONGELATION
APPUI 2"< 5" EN REMPLISSAGE POUR BASCULER LA MACHINE EN DETARTRAGE
APPUI PENDANT LE RETARD AU DEMARRAGE POUR LE BY-PASSER
PREMERE > 5" DURANTE CARICAMENTO ACQUA PER METTERE LA MACCHINA IN CONGELAMENTO
PREMERE > 5" DURANTE CONGELAMENTO PER METTERE LA MACCHINA IN SBRINAMENTO
PREMERE > 5" DURANTE SBRINAMENTO PER METTERE LA MACCHINA IN CONGELAMENTO
PREMERE 2" < 5" DURANTE CARICAMENTO ACQUA PER METTERE LA MACCHINA IN LAVAGGIO
PREMERE DURANTE IL RITARDO ALLA PARTENZA PER BY-PASSARLO
PC BOARD 620462 06/11 – NEW RELEASE – NUOVELLE VERSION – NUOVA VERSIONE

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TABLE OF
CONTENTS Table of contents
Specifications MXG 327
Specifications MXG 427
Specifications MXG 437
GENERAL INFORMATION AND INSTALLATION
Introduction
Unpacking and Inspection - Ice maker
Unpacking and Inspection - Storage bin
Location and levelling
Electrical connections
Water supply and drain connections
Final check list
Installation practice
OPERATING INSTRUCTIONS
Start up
Operatiobnal checks
OPERATING PRINCIPLES (How it works)
Freezing cycle
Harvest cycle
Control sequence
Component description
ADJUSTMENT, REMOVAL AND REPLACEMENT PROCEDURES
Adjustment of the cube size
Wiring diagram
Service diagnosis
MAINTENANCE AND CLEANING INSTRUCTIONS
General
Icemaker
Cleaning instructions of water system
2
3
5
7
17
19
20
21
26
27
29
31
31
32
12
13
9
9
9
9
10
10
11
11

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ice making capacity
SPECIFICATIONS
ELECTRONIC CUBER MODEL MXG 327
NOTE.Thedailyice-makingcapacityisdirectlyrelatedtothecondenserairinlettemperature,water
temperature and age of the machine.
TokeepyourSCOTSMAN MODULAR CUBER atpeakperformancelevels,periodicmaintenance
checks must be carried out as indicated on maintenance section of this manual.
Production charts shown are indicating the production of "M" (medium) and "L" (large) models. For
"S" (small) models ice production is approx. 10% lower.
I mportant operating requirements:
MIN.
Air temperature 10°C (50°F)
Water temperature 5°C (40°C)
Water pressure 1 bar (14 psi)
Electr. voltage variations
from voltage rating
specified on nameplate -10%
MAX.
40°C (100°F)
35°C (90°F)
5 bars (70 psi)
+10%
32
38
10
21
154
152
150
148
146
144
142
140
138
136
134
132
130
128
126
124
122
120
118
116
114
112
110
108
106
104
102
100
98
96
94
92
90
88
Kg.
10 °C
27 21 15
AIR COOLED MODELS
WATER TEMPERATURE
AMBIENT TEMPERATURE
ICE PRODUCED PER 24 HRS.
32

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Basic electr. Amps Watts N. of wires Amps. fuse
220230/50/1/50/1 4.9 N.A 1150 21.2 3 x 1.5 mm216 3 x
-230/50/1 7 3 x
SPECIFICATIONS
MXG 327 - MACHINE SPECIFICATIONS
Starts Electric power cons.
amps. Kwh x 24 HR
Cubes per harvest: 72 Large - 106 Medium - 198 Small
* At 21°C (70°F) water temperature
MXG 327 AS 6 Air Stainless steel 480*
MXG 327 WS 6 Water Stainless steel
Model Cond. unit Finish Water req. - lt/24 HR

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ice making capacity
SPECIFICATIONS
ELECTRONIC CUBER MODEL MXG 427
NOTE.Thedailyice-makingcapacityisdirectlyrelatedtothecondenserairinlettemperature,water
temperature and age of the machine.
TokeepyourSCOTSMAN MODULAR CUBER atpeakperformancelevels,periodicmaintenance
checks must be carried out as indicated on maintenance section of this manual.
Production charts shown are indicating the production of "M" (medium) and "L" (large) models. For
"S" (small) models ice production is approx. 10% lower.
I mportant operating requirements:
MIN.
Air temperature 10°C (50°F)
Water temperature 5°C (40°C)
Water pressure 1 bar (14 psi)
Electr. voltage variations
from voltage rating
specified on nameplate -10%
MAX.
40°C (100°F)
35°C (90°F)
5 bars (70 psi)
+10%
32
38
10
21
172
170
168
166
164
162
160
158
156
154
152
150
148
146
144
142
140
138
136
134
132
130
128
126
124
122
120
118
116
114
Kg.
10 °C
27 21 15
AIR COOLED MODELS
WATER TEMPERATURE
AMBIENT TEMPERATURE
ICE PRODUCED PER 24 HRS.
32

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220-230/50/1 7 1400 26.65 3 x
Basic electr. Amps Watts N. of wires Amps. fuse
230/50/1N5 39 3 x 1.5 m/m216
N
MXG 427 AS 6 Air Stainless steel
MXG 427 WS 6 Water Stainless steel
Model Cond. unit Finish Water req. - lt/24 HR
SPECIFICATIONS
432*
MXG 427 - MACHINE SPECIFICATIONS
Starts Electric power cons.
amps. Kwh x 24 HR
Cubes per harvest: 72 Large - 106 Medium - 198 Small
* At 21°C (70°F) water temperature

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ice making capacity
SPECIFICATIONS
ELECTRONIC CUBER MODEL MXG 437
NOTE.Thedailyice-makingcapacityisdirectlyrelatedtothecondenserairinlettemperature,water
temperature and age of the machine.
TokeepyourSCOTSMAN MODULAR CUBER atpeakperformancelevels,periodicmaintenance
checks must be carried out as indicated on maintenance section of this manual.
Production charts shown are indicating the production of "M" (medium) and "L" (large) models. For
"S" (small) models ice production is approx. 10% lower.
I mportant operating requirements:
MIN.
Air temperature 10°C (50°F)
Water temperature 5°C (40°C)
Water pressure 1 bar (14 psi)
Electr. voltage variations
from voltage rating
specified on nameplate -10%
MAX.
40°C (100°F)
35°C (90°F)
5 bars (70 psi)
+10%
32
38
10
21
172
170
168
166
164
162
160
158
156
154
152
150
148
146
144
142
140
138
136
134
132
130
128
126
124
122
120
118
116
114
Kg.
10 °C
27 21 15
AIR COOLED MODELS
WATER TEMPERATURE
AMBIENT TEMPERATURE
ICE PRODUCED PER 24 HRS.
32

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220-230/50/1 7 1400 26.65 3 x
Basic electr. Amps Watts N. of wires Amps. fuse
230/50/1N5 39 3 x 1.5 m/m216
N
SPECIFICATIONS
MXG 437 - MACHINE SPECIFICATIONS
Starts Electric power cons.
amps. Kwh x 24 HR
Cubes per harvest: 72 Large - 106 Medium - 198 Small
* At 21°C (70°F) water temperature
MXG 437 AS 6 Air Stainless steel
MXG 437 WS 6 Water Stainless steel
Model Cond. unit Finish Water req. - lt/24 HR
432*

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A. INTRODUCTION
This manual provides the specifications and the
step-by-stepproceduresfortheinstallation,start-
up and operation, maintenance and cleaning for
the SCOTSMAN MODULAR CUBERS.
The Electronic Modular Cubers are quality
designed, engineered and manufactured.
Their ice making systems are thoroughly tested
providing the utmost in flexibility to fit the needs
of a particular user.
These icemakers have been engineered to our
own rigid safety and performence standards.
NOTE.Toretainthesafetyandperformance
built into this icemaker, it is important that
installation and maintenance be conducted
in the manner outlined in this manual.
Storage Bin
Since the MXG series Modular Cubers do not
have their own attached ice storage bins, it is
necessary to use an auxiliary bin such as:
SB 193
SB 322
SB 393
SB 530.
B. UNPACKING AND INSPECTION
Modular Cuber
1. CallyourauthorizedSCOTSMANDistributor
or Dealer for proper installation.
2. Visually inspect the exterior of the packing
and skid. Any severe damage noted should be
reportedtothedeliveringcarrierandaconcealed
damage claim form filled in subjet to inspection
of the contents with the carrier’s representative
present.
3. a)Cutandremovetheplasticstripsecuring
the carton box to the skid.
b) Remove the packing nails securing the
carton box to the skid.
c)Cutopenthetopofthecartonandremove
the polystyre protection sheet.
d) Pull out the polystyre posts from the
corners and then remove the carton.
4. Remove top and sides panels of the unit
and inspect for any concealed damage. Notify
carrier of your claim for the concealed damage
as stated in step 2 above.
5. Loosetwo nutson leftand rightsside ofthe
unit base and remove it from the skid. Save the
two bolts and nuts to mount the machine on
storage bin or on top of another Modular Cuber.
GENERAL INFORMATION AND INSTALLATION
6. Remove all internal support packing and
masking tape and the hardware package.
7. Check that refrigerant lines do not rub
againstor touchother linesor surfaces,and that
the fan blade moveS freely.
8. Checkthat the compressor fits snugly onto
all its mounting pads.
9. See data plate on the rear side of the unit
and check that local main voltage corresponds
with the voltage specified on it.
CAUTION. Incorrect voltage supplied to
the icemaker will void your parts
replacement program.
10. Remove the manufacturer’s registration
card from the inside of the User Manual and fill-
in all parts including: Model and Serial Number
taken from the data plate.
Forward the completed self-addressed
registration card to Scotsman Ice srl.
C. LOCATION AND LEVELLING
WARNING. This Ice Cuber is designed
for indoor installation only. Extended
periods of operation at temperature
exceedingthe followinglimitations will
constitute misuse under the terms of
theSCOTSMANManufacturer’sLimited
Warrantyresulting in LOSS of warranty
coverage.
1. Position the Bin in the selected permanent
location.Criteriaforselectionoflocationinclude:
a)Minimumroomtemperature10°C(50°F)
and maximum room temperature 40°C (100°F).
b) Water inlet temperatures: minimum 5°C
(40°F) and maximum 35°C (90°F).
c) Well ventilated location for air cooled
models.
d) Service access: adequate space must
be left for all service connections through the
rearoftheicemaker.Aminimumclearanceof15
cm (6") must be left at the sides of the unit for
routingcooling airdrawninto andexhausted out
of the compartment to maintain proper
condensing operation of air cooled models.
2. Level the Storage Bin Assy in both the left
to right and front to rear directions by means of
the adjustable legs.

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D. ELECTRICAL CONNECTIONS
See data plate for current requirements to
determine wire size to be used for electrical
connections.AllSCOTSMAN icemakersrequire
a solid earth wire.
All SCOTSMAN ice machines are supplied from
thefactorycompletelypre-wiredandrequireonly
electrical power connections to the wire cord
providedattherearoftheunit.Makesurethatthe
ice machine is connected to its own circuit and
individually fused (see data plate for fuse size).
Themaximumallowablevoltagevariationshould
not exceed -10% and +10% of the data plate
rating. Low voltage can cause faulty functioning
and may be responsible for serious damage to
the overload switch and motor windings.
NOTE. All external wiring should conform to
national, state and local standards and
regulations.
Check voltage on the line and the ice maker’s
data plate before connecting the unit.
E. WATER SUPPLY AND DRAIN
CONNECTIONS
General
When choosing the water supply for the ice
modularcuber consideration shouldbe given to:
a) Length of run
b) Water clarity and purity
c) Adequate water supply pressure
Sincewateristhemostimportantsingleingredient
in producting ice you cannot emphasize too
much the three items listed above.
Low water pressure, below 1 bar may cause
malfunction of the ice maker unit.
Water containing excessive minerals will tend to
produce cloudy coloured ice cubes, plus scale
build-up on parts of the water system.
Water supply
Connectthe3/4"GASmale fittingofthesolenoid
water inlet valve, using flexible tubing or a 3/8"
O.D. copper pipe, to the cold water supply line
with regular plumbing fitting and a shut-off valve
installed in an accessible position between the
water supply line and the unit.
Water supply - Water cooled models
The water cooled versions of SCOTSMAN Ice
Makersrequiretwoseparateinletwatersupplies,
one for the water sprayed for making the ice
cubes and the other for the water cooled
condenser.
Connect the 3/4" GAS male fitting of the water
inlet, using the flexible tubing or a 3/8" O.D.
copper pipe, to the cold water supply line with
regular plumbing fitting and a shut-off valve
installed in an accessible position between the
water supply line and the unit.
3. InspecttheStorageBintopmountinggasket
which should be flat with no wrinkles, to provide
a good sealing when the Modular Cuber is
installed on top of it.
4. Place the Modular Cuber on top of
Storage bin using care not to wrinkle or tear
the gasket.
5. LiftalittlebittheModularCuberrightsidein
order to be able to mount the ice level control
bracket taking care to align the hole located on
unit base to mate with the one on the top of the
Bin.
6. Remove the PVC plastic plug closing the
round hole located on the side of the ice chute
opening.
7. Tracetheicelevelcontrolassy,securedfor
the transport of the Modular Cuber, and direct it
down through the round hole into the Storage
Bin.
8. Fasten the ice level control assy on its
bracketby means ofthe two screwsfoundin the
hardware package supplied with the unit.
9. Make a cut (shear) in the PVC plastic plug
that goes from its edge to the center; insert the
ice level control cable in the center of the plastic
plugso toprevent itfrom any sortof contactwith
the unit frame, then place again the PVC plug in
the round hole keeping the cable exceeding
portion inside the unit.
10. Place ice level sensor and related bracket
as per below figure.
11. SecuretheModularCuberonthetopofthe
StorageBinusingthetwoboltsanddiberwasher
foundinthehardwarepackagesuppliedwiththe
unit.

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Water drain
The recommended drain tube is a plastic or
flexible tube with 18 mm (3/4") I.D. which runs to
an open trapped and vented drain. When the
drain is a long run, allow 3 cm pitch per meter
(1/4" pitch per foot).
Aventattheunitdrainconnectionisalsorequired
for proper sump drainage.
Water drain - Water cooled models
Connectthe3/4"GASmalefittingofthecondenser
waterdrain,usingasecondflexibletubingora3/
8" O.D. copper tubing, to the open trapped and
vented drain.
NOTE.Thewatersupplyandthewaterdrain
must be installed to conform with the local
code. In some case a licensed plumber and/
or a plumbing permit is required.
F. FINAL CHECK LIST
1. Is the unit in a room where ambient
temperatures are within a minimum of 10°C
(50°F) even in winter months?
2. Is there at least a 15 cm (6") clearance
around the unit for proper air circulation?
3. Is the unit level? (IMPORTANT)
4. Have all the electrical and plumbing
connectionsbeen made,and isthe watersupply
shut-off valve open?
5. Has the voltage been tested and checked
against the data plate rating?
6. Has the water supply pressure been
checked to ensure a water pressure of at least 1
bar (14 psi).
7. Havetheboltsholdingthecompressordown
been checked to ensure that the compressor is
snugly fitted onto the mounting pads?
8. Checkallrefrigerant linesand conduitlines
to guard against vibrations and possible failure.
9. Have the bin liner and cabinet been wiped
clean?
10. Has the owner/user been given the User
Manualandbeeninstructedontheimportanceof
periodic maintenance checks?
11. Has the Manufacturer’s registration card
been filled in properly? Check for correct model
and serial number against the serial plate and
mail the registration card to the factory.
G. INSTALLATION PRACTICE
1. Hand shut-off valve
2. Water filter
3. Water supply line (flexible hose)
4. 3/4" gas male fitting
5. Power line
6. Main switch
7/9. Drain fitting
8/10. Vented drain line
11. Open trapped vented drain
WARNING. This icemaker is not designed for outdoor installation and will not function in
ambient temperatures below 10°C (50°F) or above 40°C (100°F).
This icemaker will malfunction with water temperatures below 5°C (40°F) or above 35°C (90°F).

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OPERATING INSTRUCTIONS
16
15
14
13
2
1
7
8
9
10
3
4
5
6
11
12
Rx Tx
WATER IN VALVE
HOT GAS VALVE
CONTACTOR COIL
FAN MOTOR
WATER PUMP
- EVAPORATOR
- AMBIENT
- CONDENSER
TEMPERATURE SENSORSBINCOMPRESSOR
TRANSF.
DATA
PROCESSOR
ELECTR.
TIMER
DIP
SWITCH
ELECTRONIC CARD
L
N
RELAYS
RELAY
TRIAC
WATER DRAIN VALVE
FIG. 1
START UP
Afterhavingcorrectlyinstalledtheicemakerand
completed the plumbing and electrical
connections,performthefollowing“Start-up”pro-
cedure.
A. Give power to the unit to start it up by
switching "ON" the power line main disconnect
switch.
NOTE. Every time the unit returns under
power, after having been switched off, the
water inlet valve, the hot gas valve and the
water drain valve get energized for a period
of 5 minutes, thus to admit new water to the
machine sump reservoir to fill it up and,
eventually,towash-offanydirtthatcanhave
deposited in it during the unit off period
(Fig.1).
B. During the water filling operation, check to
seethattheincomingwaterdribbles,throughthe
evaporator platen dribbler holes, down into the
sump reservoir to fill it up and also that the
incoming surplus of water flows out through the
overflow pipe into the drain line.
During the water filling phase the components
energized are:
THE WATER INLET SOLENOID VALVE
THE HOT GAS SOLENOID VALVE
THE WATER DRAIN SOLENOID VALVE/S
for the first 30 seconds.
NOTE . If in the 5 minutes length of the water
filling phase the machine sump reservoir
does not get filled with water up to the rim of
the overflow pipe, it is advisable to check:
1.Thewaterpressureofthewatersupplyline
thatmustbeatleast1bar(14psig)Minimum
(Max 5 bar-70 psig).
2.The filtering device installed in the water
line that may reduce the water pressure
below the Minimum value of 1 bar (14 psig).
3. Any clogging situation in the water circuit
like the inlet water strainer and/or the flow
control.

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16
15
14
13
2
1
7
8
9
10
3
4
5
6
11
12
Rx Tx
WATER IN VALVE
HOT GAS VALVE
CONTACTOR COIL
FAN MOTOR
WATER PUMP
- EVAPORATOR
- AMBIENT
- CONDENSER
TEMPERATURE SENSORSBINCOMPRESSOR
TRANSF.
DATA
PROCESSOR
ELECTR.
TIMER
DIP
SWITCH
ELECTRONIC CARD
L
N
RELAYS
RELAY
TRIAC
WATER DRAIN VALVE
FIG. 2
C. At completion of the water filling phase(5
minutes) the unit passes automatically into the
freezing cycle with the start up of:
COMPRESSOR
WATER PUMP
FANMOTOR/S(inaircooledversion)controlled
by the condensing temperature sensor located
within the condenser fins (Fig.2).
OPERATIONAL CHECKS
D. If necessary install the refrigerant service
gauges on both the high side and low side
Schräder valves to check the compressor head
and suction pressures.
NOTE. On air cooled models, in case of
condensercloggingsuchtopreventtheproper
flowofthecoolingairor,incasethefanmotor
isoutofoperationorshortageofwaterinthe
watercooledcondenser,thecondensertem-
perature rises and when it reaches 70 ° C
(160 ° F) - for air cooled version - or 60 ° C
(140 ° F) - for water cooled version - the
condenser temperature sensor shuts-off the
icemakerwiththeconsequentlight-upof the
RED WARNING LED (Fig.3).
Afterhavingdiagnosedthereasonoftherise
of temperature and removed its cause, it is
necessarytounplug (waitfewseconds)and
plug in again the unit, thus to put the
machine in condition to initiate a new
freezing cycle.
Themachinerestartswiththeusual5minutes
waterfillingphaseinordertoprovideenough
water into the sump tank.
E. Check to see through the ice discharge
opening that the self propeller spray bar is
correctly rotating and that the water jets
uniformely reach the interior of the inverted
mold cups and there is not excessive water
spilling through it.
F. Theicemakingprocesstakesplacethereby,
with the water sprayed into the molds that gets
graduallyrefrigeratedbytheheatexchangewith
the refrigerant flowing into the evaporator
serpentine.

Page 14
Page 14
16
15
14
13
2
1
7
8
9
10
3
4
5
6
11
12
Rx Tx
WATER IN VALVE
HOT GAS VALVE
CONTACTOR COIL
FAN MOTOR
WATER PUMP
- EVAPORATOR
- AMBIENT
- CONDENSER
TEMPERATURE SENSORSBINCOMPRESSOR
TRANSF.
DATA
PROCESSOR
ELECTR.
TIMER
DIP
SWITCH
ELECTRONIC CARD
L
N
RELAYS
RELAY
TRIAC
WATER DRAIN VALVE
FIG. 4
16
15
14
13
2
1
7
8
9
10
3
4
5
6
11
12
Rx Tx
WATER IN VALVE
HOT GAS VALVE
CONTACTOR COIL
FAN MOTOR
WATER PUMP
- EVAPORATOR
- AMBIENT
- CONDENSER
TEMPERATURE SENSORSBINCOMPRESSOR
TRANSF.
DATA
PROCESSOR
ELECTR.
TIMER
DIP
SWITCH
ELECTRONIC CARD
L
N
RELAYS
RELAY
TRIAC
WATER DRAIN VALVE
FIG. 3

Page 15
Page 15
16
15
14
13
2
1
7
8
9
10
3
4
5
6
11
12
Rx Tx
WATER IN VALVE
HOT GAS VALVE
CONTACTOR COIL
FAN MOTOR
WATER PUMP
- EVAPORATOR
- AMBIENT
- CONDENSER
TEMPERATURE SENSORSBINCOMPRESSOR
TRANSF.
DATA
PROCESSOR
ELECTR.
TIMER
DIP
SWITCH
ELECTRONIC CARD
L
N
RELAYS
RELAY
TRIAC
WATER DRAIN VALVE
FIG. 5
Duringthefreezingprocess,whentheevaporator
temperature falls below an established value, to
the evaporator temperature sensor supplies a
lowvoltagepowersignaltotheelectroniccontrol
device (P.C.BOARD) in order to activate an
electronic timer.
This one takes over the control of the freezing
cycle up to the complete formation of the ice
cubes (Fig.4).
NOTE. Thelengthoftheentirefreezingcycle
is governed by the evaporator temperature
sensorwhichhas its brobe placed in contact
with the evaporator serpentine (Non
adjustable)incombinationwiththeelectronic
timer (Adjustable) incorporated in the P.C.
BOARD).
The timer adjustment is factory set in
considerationoftheicemakermodel,cooling
version and ice cube size (Small, Medium,
Large).
It is possible, however, to modify the timed
length of the freezing cycle, by changing the
DIP SWITCH keys setting.
In Table B of PRINCIPLE OF OPERATION
areshownthevarioustimeextensionsofthe
freezingcycle second phase, inrelationwith
the different DIP SWITCH keys settings.
G. After about 17-20 minutes from the
beginning of the freezing cycle, in an hypothetic
ambient temperature of 21°C , the defrost cycle
takes place with the hot gas and the water inlet
valves being simoultaneously activated (Fig.5).
The electrical components in operation are:
COMPRESSOR
WATER PUMP for the first 30 seconds
WATER INLET SOLENOID VALVE
HOT GAS VALVE
WATER DRAIN SOLENOID VALVE/S
NOTE. The length of the defrost cycle is
related to the length of the second phase of
freezing cycle T2. (Time to drop the
evaporating temperature from 0 ° C (32 ° F) -
small Red LED blinking-to-15 ° C (5 ° F) small
Red LED ON steady.
Itispossibletoextendthelengthofthedefrost
cyclebychangingthesettingofDIPSWITCH
7 and 8 as shown on table at page 28.
H. Check, during the defrost cycle, that the
incomingwaterflowscorrectlyintosumpreservoir
in order to refill it and that the surplus overflows
through the overflow drain tube.

Page 16
Page 16
16
15
14
13
2
1
7
8
9
10
3
4
5
6
11
12
Rx Tx
WATER IN VALVE
HOT GAS VALVE
CONTACTOR COIL
FAN MOTOR
WATER PUMP
- EVAPORATOR
- AMBIENT
- CONDENSER
TEMPERATURE SENSORSBINCOMPRESSOR
TRANSF.
DATA
PROCESSOR
ELECTR.
TIMER
DIP
SWITCH
ELECTRONIC CARD
L
N
RELAYS
RELAY
TRIAC
WATER DRAIN VALVE
FIG. 6
I. Checkthetextureoficecubesjustreleased.
They have to be in the right shape with a small
depression of about 5-6 mm in their crown.
Ifnot,waitfor thecompletionofthesecondcycle
before performing any adjustment.
If required, the length of the timed freezing cycle
can be modified by changing the DIP SWITCH
keys setting as illustrated in OPERATING
PRINCIPLE.
If the ice cubes are shallow and cloudy, it is
possible that the ice maker runs short of water
during the freezing cycle second phase or, the
quality of the supplied water requires the use of
an appropriate water filter or conditioner.
J. Tobesureofthecorrectoperationoficelevel
controldevice,placesomeicecubesbetweenits
sensing “eyes” to interrupt the light beam.
TheBin FullYELLOW LED starts blinkingfillthe
endofdefrostcycleafterward,theunitstopswith
the simultaneous glowing of the same LED to
monitor the BIN FULL situation (Fig.6).
Remove ice cubes out from the ice level control
sensors to allow the resumption of the light
beam. Water inlet valve is energized for 45
secondstorefillthesump,theBINFULLYELLOW
LEDblinksfastandafterapproximately6seconds
the ice maker resume its operation with the
immediate glowing of the FIRST YELLOW LED
indicating UNIT IN OPERATION and the
extinguishingofthe“BINFULL”YELLOWLED.
NOTE. The ICE LEVEL CONTROL
(INFRAREDSYSTEM)isindependentofthe
temperature however, the reliability of its
detection can be affected by external light
radiations or by any sort of dirt and scale
sediment which may deposit directly on the
light source and on the receiver.To prevent
any possible ice maker malfunction, due to
negative affection of the light detector, it is
advisable to locate the unit where it is not
reached by any direct light beam or light
radiation,alsoitisrecommendedtokeepthe
bin door constantly closed and to follow the
instructions for the periodical cleaning of
thelightsensorelementsasdetailedinthe
MAINTENANCE AND CLEANING PRO-
CEDURES.
K. Remove, if previously installed, the
refrigerant service gauges and re-fit the unit
service panels previously removed.
L. Instruct the owner/user on the general
operation of the ice machine and about the
cleaning and care it requires.

Page 17
Page 17
PRINCIPLE OF OPERATION
How it works
In the SCOTSMAN Modular Cubers the water
used to make the ice is kept constantly in
circulationbyanelectricwaterpumpwhichprimes
it to the self propeller spray bar nozzles from
whereitisdivertedintotheinvertedmoldcupsof
the evaporator (Fig. B).
Asmallquantityofthesprayedwaterfreezesinto
ice; the rest of it cascades by gravity into the
sump assembly below for recirculation.
FREEZING CYCLE (Fig. A)
The hot gas refrigerant discharged out from the
compressorreachesthecondenserwhere,being
cooled down, condenses into liquid.
Flowing into the liquid line it passes through the
drier filter, then it goes all the way through the
capillarytubewhere,duetotheheatexchanging
action, it looses some of its heat content so that
its pressure and temperature are lowered as
well.
Next the refrigerant enters into the evaporator
serpentine (which has a larger I.D. then the
capillary) and starts to boil off; this reaction is
emphasized by the heat transferred by the
sprayed water.
The refrigerant then increases in volume and
changes entirely into vapor.
The vapor refrigerant then passes through the
suction accumulator (used to prevent that any
small amount of liquid refrigerant may reach the
compressor) and through the suction line.
In both the accumulator and the suction line it
exchanges heat with the refrigerant flowing into
the capillary tube (warmer), before to be sucked
in the compressor and to be recirculated as hot
compressed refrigerant gas.
Thefreezingcycleiscontrolledbytheevaporator
temperaturesensor(whichhasitsprobeincontact
with the evaporator serpentine) that determines
the length of its first portion of the cycle.
When the temperature of the evaporator
serpentinedropstoapre-setvalue,theevaporator
sensor probe changes its electrical resistance
allowingalowvoltagecurrent(12volts)toflowto
the P.C. BOARD which in turn activates an
electronic timer.
The timer, which is built-in the P.C. BOARD,
takes over from the evaporator temperature
sensor, the control of the freezing cycle up to its
completion.
NOTE. Thechangeoftheelectricpotentialof
the evaporator sensor with the consequent
activationofthetimer(Timemode)issignalled
by the glowing-up of the RED LED located
besidetheFREEZINGyellowoneinthefront
of the P.C. BOARD.
MXG-S 327 A
MXG-S 327 W
MXG-M 327 A ON ON OFF ON OFF ON ON ON OFF ON
MXG-M 327 W
MXG-M 327 W
MXG-L 327 A
MXG-L 327 W
MXG-S 427-437 A
MXG-S 427-437 W
MXG-M 427-437 A ON ON OFF ON OFF ON ON ON OFF ON
MXG-M 427-437 W
MXG-L 427-437 A
MXG-L 427-437 W
TAB. A
DIP SWITCH FACTORY SETTING COMBINATIONS PER MODEL AND VERSION
DIP SWITCH 12345678910
FREEZING CYCLE DEFROST
CYCLE DEFR. CYCLE
ADD. TIME 15/30°AIR
WATER

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