Scotsman MXG Series, MXG 438 A/W, MXG 638 A/W, MXG 938 A/W, MXG 328 A/W Technical Service Training

TECHNICAL SERVICE TRAINING

Welcome to another Scotsman technical service presentation

This one will cover the electronic MXG series Ice Cube Machines

MXG SERIES

CUBERS

MXG SERIES

MXG 328 A/W

Max. Ice Production = 150 Kg/24h*
* 10/10°C= Air & Water Inlet Temperature

NEW MXG SERIES

MXG 428 A/W

Max. Ice Production = 195 Kg/24h*
* 10/10°C= Air & Water Inlet Temperature

NEW MXG SERIES

MXG 438 A/W

Max. Ice Production = 195 Kg/24h
*10/10°C = Air & Water Inlet Temperature

NEW MXG SERIES

MXG 638 A/W

Max. Ice Production = 340 Kg/24h
*10/10°C = Air & Water Inlet Temperature

NEW MXG SERIES

MXG 938 A/W

Max. Ice Production = 400 Kg/24h
*10/10°C = Air & Water Inlet Temperature

NEW MXG SERIES

TOPICS

On the next slides are shown the following steps by steps
procedures:

• UNPACKING

• INSTALLATION

• START UP AND OPERATIONAL CHECKS

• OPERATING PRINCIPLES and COMPONENTS

• MAINTENANCE

• SERVICE ANALYSIS

NEW MXG SERIES

UNPACKING

NEW MXG SERIES

The machines are supplied
in a carton box secured by
two plastic strips to a
wooden base. Check first
the outside conditions of
carton box and wooden base
then cut the two plastic
strips, remove the tape and
then the carton box.

UNPACKING

NEW MXG SERIES

Slip away – remove
plastic strip

UNPACKING

NEW MXG SERIES

Remove front panel
air filter (AC version
only)

UNPACKING

NEW MXG SERIES

Remove front panel
screws and the
panel

UNPACKING

NEW MXG SERIES

Remove top panel
screws and the
panel

UNPACKING

NEW MXG SERIES

Remove I/R bracket
installation
instruction and
water inlet and
outlet hoses

UNPACKING

NEW MXG SERIES

Remove side
panels screws and
the panels

UNPACKING

NEW MXG SERIES

UNPACKING

NEW MXG SERIES

…..unscrew

the unit

frame from

the wooden

base….

The Modular Cuber machines
require for the installation the
use of a companion storage
bin to store the ice produced.

Perfect “matching” storage
been are:

SB 193 – 322 for MXG 328-428
SB 393 – 530 for MXG 438-638-938

UNPACKING

NEW MXG SERIES

Due to design reason MXG
series can not be stacked:

• Ice chutes not aligned

• Not enough space for
Service over the bottom unit
top evaporator

• Not possible to remove
bottom unit front panel

UNPACKING

NEW MXG SERIES

INSTALLATION

NEW MXG SERIES

After having installed the
ice maker on top of chosen
bin, remove polystyrene
block form ice chute top
and remove the ice chute.

locate I/R and its bracket,
release the same from
clamps

INSTALLATION

NEW MXG SERIES

Cut the unit base
gasket , pass the
I/R sensor through
the same reaching
the inner bin area.

INSTALLATION

NEW MXG SERIES

Fix the IR
by
supplied
screws to
related
bracket

INSTALLATION

NEW MXG SERIES

Fix IR bracket at
ice chute
discharge area by
stainless steel
screw

INSTALLATION

NEW MXG SERIES

Once installed optical level
sensor, re-install ice chute
previously removed paying
attention to hang the same
to its hook rim point.

INSTALLATION

NEW MXG SERIES

Note different
location
according to
MXG models

INSTALLATION

NEW MXG SERIES

MXG 328-428-438-938

MXG 638

Check the data plate
of the machine
located on the rear
panel for correct
voltage as well as
for the proper
wiring/fuse size.

Remember that all
machines require a
solid earth wire.

INSTALLATION

NEW MXG SERIES

Check for the correct water and ambient conditions that
should be:

• Min. ambient temperature 10ºC (50F)

• Max. ambient temperature 40ºC (100F)

• Min. water temperature 5ºC (40F)

• Max. water temperature 35ºC (90F)

• Min. water pressure 1 bar (14 PSI)

• Max. water pressure 5 bar (70 PSI)

INSTALLATION

NEW MXG SERIES

Adequate space must
be left for proper water
and electrical
connections on the rear
side of the machine. A
minimum clearance of
15 cm on both sides for
best routing air.

INSTALLATION

NEW MXG SERIES

Min. space 15 cm

NEW MXG SERIES

Air

filter

Air

filter

INSTALLATION

328 – 428 - 438 air flow

NEW MXG SERIES

Air

filter

INSTALLATION

638 air flow

Air

filter

NEW MXG SERIES

Air

filter

Air

filter

INSTALLATION

938 air flow

Level the unit on
both directions front
to rear and right to
left side using the
adjustable legs.

STACKING INSTALLATION

NEW MXG SERIES

Install, on the cable
supply with the
machine, an
adequate electrical
plug according to
the local standards
and regulations.

Maximum voltage
variation should be
±10%.

Machine must be
individually fuse
protected.

INSTALLATION - ELECTRICAL

NEW MXG SERIES

Connect the water inlet 3/4” male
threat of the water inlet solenoid valve
to the water supply line by means of
the rubber hose provided with
machine.Install on water supply line
closed to the machine a water valve
(tap).

Connect the 20 mm O.D. fitting of the
water drain with the flexible hose
supply with the machine securing it by
proper

INSTALLATION – WATER PIPING

NEW MXG SERIES

AIR COOLED VERSION

TYPICAL INSTALLATION

NEW MXG SERIES

POWER

WATER INLET

WATER DRAIN

HAND DISCONNECT

SWITCH

WATER
FILTER

WATER
VALVE

WATER DRAIN

On the water
cooled version
there are two
separate 3/4”
male thread
water inlet
fittings…..

INSTALLATION

NEW MXG SERIES

…..a second separate
drain hose must be
connected to the outlet
3/4” male fitting located
on the upper side of the
water regulating valve.

INSTALLATION

NEW MXG SERIES

WATER COOLED VERSION

TYPICAL INSTALLATION

NEW MXG SERIES

POWER

WATER INLET

WATER DRAIN

HAND DISCONNECT

SWITCH

WATER
FILTER

WATER
VALVE

WATER DRAIN

START UP AND

OPERATIONAL

CHECKS

NEW MXG SERIES

Open the water tap/valve and Switch ON the power on the
electrical supply line.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

Green Lighted
Master Push
Switch located in
the front panel.

By pushing it is
possible to Switch
ON and OFF the
machine.

NEW MXG SERIES

START UP AND OPERATIONAL CHECKS

Push the Green
Push Button
Switch to Start
Up the machine

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

A start-up delay is
factory set at 60’ on the
models MXG 638 - 938
with the Yellow LED
blinking.

This delay can be set
up with the Jumper n.3

Jump IN = 0’
Jump OUT = 60’

FREEZING CYCLE

BIN FULL

POWER

TOO HI EVAP TEMP

TOO HI COND TEMP

PUSH

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

Once the start delay is elapsed the Ice Machine will start up automatically
through the 5 minutes of “Water Filling Phase”.

The components energized
during this period are:

• PC Board

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Water Inlet Solenoid Valve

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• W ater drain

valve

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Hot Gas

Solenoid
Valve

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

During the first 5’ the water
goes through the Water Inlet
Valve then…

….flows into the small
orifice of the “Flow Control”
located on the outlet port of
the same.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

Following the plastic inlet
hose the incoming water
arrive on the upper side of
the evaporator….

.... where it flows onto the

plastic evaporator platen
dribbling down through the
holes located on the corners.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

Dribbled water is
collected down into
the water sump
where is located
the overflow that
assures the proper
water level and
quantity for the next
freezing cycle.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

START UP AND OPERATIONAL CHECKS

NEW MXGSERIES

Once the start delay is elapsed the Ice Machine will start up automatically
through the 5 minutes of “Water Filling Phase”.

After the first 5’ of water filling
phase the machine start up
automatically on freezing cycle
with the following electrical
components in operation:

• Compressor

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Water Pump

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Fan Motor (on air cooled

version only)

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Contactor

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

The operation of the

fan motor is controlled
by a condenser
temperature sensor
located within the fins
of condenser that
transmit a signal to
the PC Board to
activate in ON-OFF
mode the fan motor
so to keep between
two pre-set values the
condenser
temperature and
pressure.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

On PC Board the LED energized are:

• Power

FREEZING CYCLE

BIN FULL

POWER

TOO HI EVAP TEMP

TOO HI COND TEMP

PUSH

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

On PC Board the LED energized are:

• Power

• Freezing

FREEZING CYCLE

BIN FULL

POWER

TOO HI EVAP TEMP

TOO HI COND TEMP

PUSH

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

Water is
circulating by
the water pump
into the
inverted tin
plated copper
molds of the
evaporator….

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

….while the
refrigerant is
flowing into the
serpentine
welded on the
upper side of
the tin plated
copper molds.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• EVAPORATOR
SENSOR

NEW MXG SERIES

After
approximately 5
minutes since the
start up of the
freezing cycle, the
temperature of
the evaporator
serpentine drops
down to 0ºC….

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

0ºC

….with the blinking of the small RED LED located in the center
of PC Board.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

After
approximately 10
minutes from the
start up of the
freezing cycle, the
temperature of
the evaporator
serpentine drops
down to - 15ºC….

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

-15ºC

….with the light ON steady of the small RED LED located in the
center of PC Board.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

The machine
remains in the
freezing cycle till its
completion for an
additional time
according to the
set up of the first
four DIP SWITCH
of the PC Board.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

Once completed the freezing

cycle the machine enters into
the defrost or harvest cycle
with the following electrical
components in operation:

• Compressor

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Water Inlet Solenoid valve

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Water Drain

Solenoid Valve

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

• Hot Gas Valve

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

The length of the defrost or
harvest cycle is controlled
by the PC Board according
to the setting of the DIP
SWITCH 5 and 6 and it is
related to the time that the
machine takes to drop the
evaporating temperature
from 0ºC to -15ºC (time T2)
as shown on the table.

A

SWITCH 5 AND 6

D

BC

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

LENGTH OF HARVEST CYCLE ACCORDING TO THE TIME TO DROP THE

EVAP. TEMPERATURE FROM 0ºC TO -13ºC

LENGTH PROGRAMS

HARVEST

CYCLE A B C D

180” Up to 6’ *** Up to 9’ ***
165” 6’-7’ Up to 3’ 9’-10’ ***
150” 7’-8’ 3’-3’15’ 10’-11’ ***
135” 8’-9’ 3’15”-3’30” 11’-12’ ***
120” 9’-10’ 3’30”-4’30” 12’-13’ Up to 3’
105” 10’-12’ 430”-6’ 13’-15’ 3-4’

90” >12’ >6’ >15’ >4’

It’s possible to extend the length of the defrost cycle by
means of the DIP SWITCH 7 and 8 as per below chart.

ADDITIONAL DEF ROST TIME

78

ON ON 0

OFF ON 30"

ON OFF 60"

OFF OFF 90"

D I P SWITCH

START UP AND OPERATIONAL CHECKS

WATER PUMP OFF

NEW MXG SERIES

During the defrost or
harvest cycle the
combined action of
refrigerant in Hot Gas
state and incoming
Water are going to
partially melt the ice
cubes in contact with
the tin plated copper
molts with the
dropping down of the
same through the
curtain.

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

Ice maker turns OFF just when
bin is full by ice and cubes cut
the I/R beam.

It is possible to test I/R
operation by keeping some ice
cubes between lenses during
a defrost ……...

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

The Bin Full YELLOW LED starts to blink slow.

FREEZING CYCLE

BIN FULL

POWER

TOO HI EVAP TEMP

TOO HI COND TEMP

PUSH

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

..till defrost cycle is elapsed thus to release all ice cubes from
inverted mold cups; after that the machine will stop at bin full
condition with the yellow LED steady ON

FREEZING CYCLE

BIN FULL

POWER

TOO HI EVAP TEMP

TOO HI COND TEMP

PUSH

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

As soon as the ice is removed between transmitter and received
the infrared beam is resumed immediately with fast a blinking of
the Yellow LED, then the machine restart with 45” of recharging
water

FREEZING CYCLE

BIN FULL

POWER

TOO HI EVAP TEMP

TOO HI COND TEMP

PUSH

START UP AND OPERATIONAL CHECKS

NEW MXG SERIES

OPERATING

PRINCIPLES

and

COMPONENTS

NEW MXG SERIES

Compressor

Evaporator

Air cooled

condenser

Hot

gas

valve

OPERATING PRINCIPLES - FREEZE

NEW MXG SERIES

Compressor

Evaporator

Air cooled

condenser

Hot

gas

valve

OPERATING PRINCIPLES - HARVEST

NEW MXG SERIES

OPERATING PRINCIPLES 938

NEW MXG SERIES

Liquid valves

Liquid valves
hot gas valves

TXV
valves
factory
setting,
full
opening
(countercl
ockwise
then 1 turn
clockwise

OPERATING PRINCIPLES 938

NEW MXG SERIES

OPERATING PRINCIPLES 938

NEW MXG SERIES

Evaporator
sensor location

OPERATING PRINCIPLES 938

NEW MXG SERIES

Condenser
sensor
location
air cooled
version

OPERATING PRINCIPLES 938 - FREEZE

NEW MXG SERIES

Condenser
sensor
location
water
cooled
version

SWEP
water
cooled
condenser

OPERATING PRINCIPLES 938

NEW MXG SERIES

DANFOS
S water
regulating
valve set
at 17 bar

WATER SYSTEM – FREEZING CYCLE

NEW MXG SERIES

WATER SYSTEM – HARVEST CYCLE

FIRST PORTION 30”

NEW MXG SERIES

WATER SYSTEM – HARVEST CYCLE

SECOND PORTION

NEW MXG SERIES

OPERATING PRINCIPLES – PC BOARD

NEW MXG SERIES

SWITCH 9

OPERATING TIME

OF WATER PUMP

DURING HARVEST

OFF = 15”

ON = 30”

SWITCH 7 AND 8

EXTENTION TIME OF

HARVEST CYCLE BY 0”, 30”,

60” OR WATER PUMP OFF

SWITCH 5 AND 6

LENGTH OF THE

HARVEST CYCLE

ACCORDING TO THE

TIME T

2

SWITCH 1, 2, 3 AND 4

SETTING OF THE

TIMED PORTION OF

FREEZING CYCLE

SWITCH 10

CONDENSER

SAFETY CUT OUT

TEMPERATURE

(60ºC WATER -

OFFAND 70ºC AIR

- ON)

OPERATING PRINCIPLES – DIP SWITCHES

NEW MXG SERIES

OPERATING PRINCIPLES – JUMPERS

NEW MXG SERIES

Time T

1

From start
up of
freezing
cycle till
the blinking
of 0°C Red
LED

OPERATING PRINCIPLES – PC BOARD

NEW MXG SERIES

Time T

2

From
blinking of
Red LED
till the light
ON steady
of -15°C
Red LED

OPERATING PRINCIPLES – PC BOARD

NEW MXG SERIES

Time T

a

Added time controlled
by the PC Board
according to the setting
of the DIP SWITCH
1, 2, 3 and 4.

LENGTH OF TIMED PORTION OF FREEZING

CYCLE – FIRST 4 SWITCHES

25’

13’

19’

11’

17’

3’

9’

15’

21’23’

7’ 5’

OPERATING PRINCIPLES – PC BOARD

NEW MXG SERIES

Time T

s

Harvest Time TSis
controlled by the PC
Board and it is inversely
proportional to the Time
T2of the Freeze Cycle
(from 0ºC to -13ºC) as
per the combination A
of the Table.

Time TSis NOT
adjustable.

LENGTH OF HARVEST CYCLE ACCORDING TO THE TIME

TO DROP THE EVAP. TEMPERATURE FROM 0ºC TO -13ºC

LENGTH PROGRAMS

HARVEST

CYCLE A B C D

180” Up to 6’ *** Up to9’ ***
165” 6’-7’ Upto 3’ 9’-10’ ***
150” 7’-8’ 3’-3’15’ 10’-11’ ***
135” 8’-9’ 3’15”-3’30” 11’-12’ ***
120” 9’-10’ 3’30”-4’30” 12’-13’ Up to 3’
105” 10’-12’ 430”-6’ 13’-15’ 3-4’

90” >12’ >6’ >15’ >4’

OPERATING PRINCIPLES – PC BOARD

NEW MXG SERIES

It’s possible to extend the length of the harvest cycle (Te)
by means of the DIP SWITCH 7 and 8 as per below chart.

ADDITIONAL DEF ROST TIME

78

ON ON 0

OFF ON 30"

ON OFF 60"

OFF OFF 90"

D I P SWITCH

OPERATING PRINCIPLES – PC BOARD

WATER PUMP OFF

NEW MXG SERIES

Time T

a

Time T1+T

2

Time

T

s

Freezing = T1+ T2+ T

a

Defrost/Harvest = Ts + T

e

0°C

-15°C

T

e

OPERATING PRINCIPLES – PC BOARD

NEW MXG SERIES