Scotsman NW458, NW608, NW1008 Service Manual













SERVICE MANUAL

NW458
NW608

NW1008

Electronic Modular Cubers



98020303-00 Version A

2



TABLE OF CONTENTS

Table of contents

Specifications

2-3
4-9

FOR THE INSTALLER

Introduction 10
Storage bin 10
Standard legs 10
Important operating requirements 10
Select location 11
Storage bin 11
Ice machine 11
Stacking instructions 12

FOR THE PLUMBER

Conform to all applicable codes
Water inlet

13

Drains 13

For the electrician

Electrical connections 14

Final check list

15

START-UP

Start-up cycle 16
Freezing cycle 16
Harvest cycle 17

OPERATION

Refrigeration during freeze 18
Water system 19
Refrigeration system during harvest 20
Water system 20
Control sequence 20
Alarm conditions 21
PC Board set up 22

SERVICE SPECIFICATIONS

Component 23
Operating characteristics 23

COMPONENT DESCRIPTION

Component description

24-26

3



WIRING DIAGRAM

NW 458/608 27
NW 1008 28

SERVICE DIAGNOSIS

Service diagnosis 29

MAINTENANCE & CLEANING INSTRUCTION

Icemaker 30
Ice storage bin 30
Cabinet exterior 30
Cleaning (Icemaker) 30-31

4



SPECIFICATIONS



MODULAR CUBER NW 458





Ice Making Capacity











NOTE. To keep your Modular cuber performing at its maximum capacity, it is necessary to perform periodic
maintenance as outlined on page 29 of this manual.

5



SPECIFICATIONS

MODULAR CUBER NW 458





Air Cooled



6





SPECIFICATIONS

MODULAR CUBER NW 608



Ice Making Capacity







NOTE. To keep your Modular cuber performing at its maximum capacity, it is necessary to perform periodic
maintenance as outlined on page 29 of this manual.

7





SPECIFICATIONS

MODULAR CUBER NW 608



Air Cooled



8



SPECIFICATIONS

MODULAR CUBER NW 1008

Ice Making Capacity



NOTE. To keep your Modular cuber performing at its maximum capacity, it is necessary to perform periodic
maintenance as outlined on page 29 of this manual.

9



SPECIFICATIONS

MODULAR CUBER NW 1008

Air Cooled

10



FOR THE INSTALLER



INTRODUCTION

These instructions provide the specifications
and the step-by-step procedures for the
installation, start up and operation for the
SCOTSMAN Model NW 458-608-1008
Modular Cubers. The Models NW 458-608­1008 Modular Cubers are quality designed,
engineering and constructed, and are
thoroughly tested ice making systems,
providing the utmost in flexibility to fit the
needs of a particular user.

STORAGE BIN

NW 458 608 1008 stack onto SCOTSMAN bin
model NB 393/530/948.

Refrigerant R 404 A

Charge per nameplate rating.
STANDARD LEGS: Furnished with storage

bin. Four legs screw into mounting sockets on
cabinet base. Provide 18.5 cm. (7’’) minimum
heights including adjustable leveling foot.

IMPORTANT OPERATING REQUIREMENTS

Air Temperature

MINIMUM
10　C
(50　F)

MAXIMUM
40　C
(100　F)

Water Temperature

5　C

(40　F)

35　C

(90　F)

Water Pressures

1 bar

gauge

5 bar

gauge

Electrical Voltage
Variations Voltage
rating specified
on nameplate

-10% +10%

Extended periods of operation exceeding
these limitations constitute misuse under the
terms of Manufacturer’s Limited Warranty,
resulting in a loss of warranty coverage.

INSTALLATION NOTE: Allow 15 cm minimum
space at sides and back for ventilation and utility
connections.



SE

L

Th

e

sel

e

will
sp

o

- i

nexc

limi

- t

h

incl

- t

hmacand

ST

O

Th

e393

Ot

h

var

ybacsup

Sta
sm

a

wit

h

IC

E

Th

e

for
Re

m

Pla
the
pa

cuse

sid

e

Se

e

Re

mmasDef

ECT LO

C

first ste

p

ct the lo

c

have a d

e

t to insur

e

doors, in
eed the
tations for

at the

n

uding the

c

at there

hine for

s

rear for

a

RAGE B

Scotsma

, NB530

a

er bins

m

the stor

a

k, using
port it, sc

r

nd the bin

ll tears i

n

food gra

d

MACHIN

use of a
lifting the

ove fron

t

ce the uni

t

back of

kage, tak

e

them to

s of the b

illustrati

o

ove all

s

king

lector/eva

ATION

in installi

ation. Th

e

sired spot
that it is:

an envir

o

air an

d

the equip

m

ecessary

orrect vo

l

be spac

e

ervice, 15
ir-cooled

m

IN

n bins for

nd NB94

8

ay be av

a

ge capa

c

cardboar

d

ew in the

l

upright, a

the ma

c

e silicone

E

mechani

c

uncrated

, top and

s

directly o

the bin.

out two

secure th

e

in.
n below.

hipping

m

tapes

porator co

v

ng the eq

u

purchas

e

in mind,

c

nment t

h

water

ent.

utilities

a

tage elect

r

around
cm. mini

m

odels.

these uni

t

.

ilable wit

h

ity. Lay t

h

from t

h

egs.

nd correct

hine mo

u

sealant.

al lift is r

e

icemaker

ides pan

e

nto the bi

n

Locate t

h

mounting

Icemak

e

aterial a

s

from

er.

ipment i

s

r of the

u

heck out t

at does

temperat

u

re availa
ical powe

the instal

um left, ri

g

s are the

bin top

s

e bin on

e carton

any possi

nting gas

commen

d

onto the

b

ls.

, align it

w

e hardw

a

screws,

a

r to the

t

well as

t

the

11

to

nit

hat
not

re

ble
r.
led

ht,

NB

to

its

to

ble
ket

ed

in.

ith

re

nd

wo

he

ice

R

e

th

e

se

move firs

t

n the ma

nsor.

the ice d

e

sking tap

e

flector/ev

a

from the

porator c

o

ice thick

n

ver

ess

12



Page 15

AIR BAFFLE

Install on the back side of the machine the air
baffle as per instruction provided with it.

STACKING INSTALLATION

To stack a second NW onto the present one,
first remove the top panel from the lower
machine. Add a bead of food grade silicone
sealant to the top edges of the lower units
freezing compartment. Lift the top machine
onto the bottom machine, (the use of a
mechanical lift is recommended for this step).
Align the two machines cabinets, and using
the 2 screw from the top units, hardware
package, fasten the two units together at the
side cabinets.
Then make use of the Stacking Kit KSC 450,
and KSC 1000, to be mounted as per fitting
instructions included in their package,
respectively on NW 458, NW608, NW1008
located in the bottom for proper conveying, of
the ice cubes made by the top unit, into the
storage bin.
With food grade silicone perfectly seal the
edge between the freezing compartment of the
upper machine and of the bottom machine so
to avoid any possible leak of water through the
clearance in between.

13



FOR THE PLUMBER

CONFORM TO ALL APPLICABLE CODES
WATER INLET

AIR-COOLED MODELS: The recommended

water supply is cold water connected to the ­3/4'’ gas - male fitting at the back of the
cabinet. Install a hand valve near the machine
to control the water supply.

1) Plug receptacle

2) Electrical plug

3) Water inlet

4) Shut-off valve

5) Water filter

6) Water inlet line

7) Water outlet line

8) Bin water outlet line

9) Open vented water drain
When choosing the water supply for the NW

Cuber, consideration should be given to:
A. Length of run.
B. Water clarity and purity.
C. Adequate water supply pressures.

Since water is the most important single
ingredient in producing ice you cannot over
emphasize the three items listed above. Low
water pressure, below 1 bar may cause
malfunction, of the icemaker unit. Water
containing excessive minerals will tend to
produce cloudy colored ice cubes, plus scale
build-up on parts in the water system.
Heavily chlorinated water can be controlled
using charcoal or carbon filters.

DRAINS
AIR-COOLED MODELS: There is one 20 mm.

dia sump drain fitting at the back of the cabinet.
Insulations in high humidity areas is recom­mended. The ideal drain receptacle would be
a trapped and vented floor drain.
STORAGE BIN: A separate gravity type drain
needs to be run, similar to the air-cooled sump
drain. Insulation of this drain line is
recommended.

14



FOR THE ELECTRICIAN

ELECTRICAL CONNECTIONS

The unit comes equipped with an electrical
cord for power supply. The lead wires must be
connected to an electrical plug that
corresponds to the local electrical codes and
requirements or to a separate two poles
disconnect box with opening to the contacts of
about 3 millimeters. The disconnect box
should be placed close to the selected ice
maker location to be easily and prompt
reached.
Undersized wiring or improperly installed
electrical circuit will result in major problems
and malfunctions. Voltage variations should
not exceed ten percent.

NOTE: All SCOTSMAN Cubers require a
neutral wire and a solid earth ground wire
to prevent possible severe Electrical
Shock Injury to individuals or extensive
damage to equipments.

IMPORTANT - All plumbing and electrical
connections must be made by licensed
plumbers and electricians, this one must
follow the electrical specifications printed
on the ice maker nameplate.

15



FINAL CHECK LIST

1. Is the cabinet/bin level?

2. Is the cuber in a location where ambient
temperatures are a minimum of 10　C (50-de­grees F.) all year around and to not exceed a
maximum of 40　C. (100　F.)

.3. Is there at least a 15 cm. clearance behind
and around the cabinet for all connections and
for proper air circulation?

4. Have all electrical and piping connections
been made?

5. Has the electrical power supply wiring been
properly connected and the voltage tested and
checked against the nameplate rating? Has
the unit properly grounded?

6. Is the water supply line shutoff valve
installed and opened and has the inlet water
supply pressure been checked to insure a
minimum of 1 bar without exceeding a
maximum of 5 bar.

7. Have the compressor hold down bolts been
checked to be sure the compressor is snug on
the mounting pads.

8. Check all refrigerant lines and conduit lines
to gard against vibration and possible failure.

9. Has the cuber and the bin been wiped clean
with clean damp cloths?

10. Has the owner/user been given the User
Manual and instructed on how to operate the
icemaker and the importance of periodic

maintenance?

11. Has the owner/user been given the name
and telephone number of the Authorized
SCOTSMAN Distributor or Service Agency
serving him?

12. Has the Manufacturer’s Registration Card
been properly filled out?

Check for correct Model and Serial Numbers
from nameplate, then mail the completed card

to the Manufactured.

TYPICAL STACKING INSTALLATION

KIT STACKING KSC 450: TO STACK 2 NW 458
KIT STACKING KSC 450: TO STACK 2 NW 608
KIT STACKING KSC 1000: TO STACK 2 NW 1008

16



START-UP

START-UP CYCLE

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

2. The models NW 458, 608
enter in the Start Up mode with
the PC Board energized as well
as the Green LED of the
machine under power while the
models NW 1008 enter in 90
minutes delay time controlled by
a special Start-up Delay PC
Board.
The Green LED of machine in
operation is energized too,
blinking fast for 40 seconds.

3. During the Start Up cycle the
components in operation are:

• Hot gas valve

• Water Drain Valve

• Water Pump

FREEZING CYCLE

1. After the Start Up cycle the machine enters
directly into the Freezing cycle with the
following components energized:

• Water Inlet valve

• Compressor

• Fan motor (in continuous operation for the
first 3 minutes).

2. The LED energized are:

• Machine under power

• Machine in operation (steady)

3. Water is coming into the water through the
Water Inlet Solenoid Valve till the water
reservoir if filled up to the maximum level
controlled by a Water Level Sensor.

4. 30 seconds later, the Water Pump starts up.

5. After few minutes (3-5) from the start up of
the freezing cycle, the Water Inlet Solenoid
Valve is activated again for few seconds to re­fill the water reservoir up to the maximum level
so to reduce any possibility of slush ice
formation.

6. In the meantime the condenser sensor
starts to transmit the current to the PC Board
keeping in operation the Fan Motor in ON-OFF
mode or continuously according to the
condenser temperature.

7. The machine remains in the freezing cycle
with the ice that become thicker till the two
metal plates of the Ice Thickness Sensor are
covered by the water cascading through the
front surface of the ice plate.

8. When the Power is transmitted back to the
PC Board continuously through the metal
plates of the Ice Thickness Sensor for more
than 6", the machine enters in the Pre-Harvest
or directly into the Harvest Cycle mode
according to:

• FAN MOTOR IN ON-OFF MODE DURING
THE PREVIOUS FREEZING CYCLE

RISE UP THE CUT IN TEMPERATURE OF
THE CONDENSER SENSOR TO 38　C (FAN
MOTOR OFF) AND EXTEND THE LENGTH
OF FREEZING CYCLE BY 30" MORE THEN
GO INTO HARVEST CYCLE

• FAN MOTOR ALWAYS IN OPERATION
DURING THE PREVIOUS FREEZING CYCLE

GO STRAIGHT TO THE HARVEST CYCLE

9. First freezing time will range between 15
and 20 minutes. Longer time for temperature

NOTE: Do not remove the evaporator
deflector cover as it will cause the switching
off of the machine at "STORAGE BIN
FULL".

NOTE: The models NW 1008 is equipped
with a compressor crankcase heater and a
Start up Delay PC Board set up at 90
minutes. During the first 90 minutes only
the compressor crankcase heater is
energized warning up the compressor.

17



above 25℃ and shorter time required when
temperature are below 25 ℃ . Average
complete cycle time is about 22 min.

HARVEST CYCLE

1. During the harvest cycle the components in
operation are:

• Hot Gas valve

• Water Drain/Purge Valve

• Water Pump for the first 40"

• Compressor
and both

• Machine Under Power

• Machine in Operation

2. 30 seconds after the beginning of the
Harvest Cycle, the Water Inlet Solenoid Valve
is energized for 10 seconds only in order to
have a short flush of fresh water into the sump
while the Water Pump is still in operation.

3. The Fan Motor remains in OFF mode
unless the Condenser Sensor probe rise up to
more then 38℃ (same set up as per end of
freezing cycle).

4. When the ice plate is falling down from the
evaporator, the magnetic switch is activated
for a while providing the signal to the PC
Board to restart a new freezing cycle.

5. Observe first ice cube harvest and check
size of ice cubes; if an adjustment is required
thread down or out screw NO.1 as shown on
below illustration.

This screw position determines the distance
between the sensor reeds and the egg-crate
evaporator thus keeping the ice cube at a
proper thickness.

6. Observe second and third cube harvest.
Check if size and shape combination is correct.
In areas where extreme problem water
conditions exist, filtering or purifying
equipment is recommended.

7. Check operation of magnetic switch
controlling it by keeping open the bottom end
of plastic deflector for more than 30 seconds.
The machine must switch off at storage bin full.
Release the plastic deflector. The machine
should restart in the freezing cycle mode
within few seconds going through a 3' delay
time.

8. Place again all cabinet panels and screws
previously removed.

9. Thoroughly explain to owner/user the
significant specifications of the ice maker start­up, reset and operation, going through the
procedures in the operating instructions.
Answer all questions about the ice maker by
the owner and inform the owner himself of the
name and telephone number of the authorized
service agency serving him.

NOTE: To assure a correct operation of the
machine the water must have a minimum
electrical conductivity of 20 us.

NOTE: If water used is too soft,
"demineralized" the ice thickness sensor
might not be able to sense the water on its
reeds, thereby it will not switch the unit on
harvest cycle.
A safety system built in the P.C. Board
switches the unit on harvest cycle whenever
the freezing period gets longer than 30' or
40'.

NOTE: This type of machine produce an
"ICE PLATE" that breaks when falls down
into the storage bin. Setting the ice thickness
sensor in order to have single ice cubes may
cause malfunction of the machine.



O

P

RE

F

Thi

scon

eit

h

A

t

co

m

pre
Th

e

the
co

o

wit

h

te

m

If

wcon

thr

o

by

t

Afte

givi
int

o

thr

o

a t

h

Th

emuc

ERATI

O

RIGERA

T

ice ma

densing

m

er one is

a

the herm

pressed

ssure gas

.

gas mov

e

condens

e

led, the

d

the he

perature.

ater-cool

trolled b

y

ugh the

c

he water

r

r the ga

ng up mu

c

a high p

ugh the li

ermostati

c

thermos

t

h liquid r

e

N

ION DU

R

chine em

edia, the

follows:

etic com

p

into a h

s throug

h

r, air o

r

ischarge

at load
ed, the

d

the am

o

ondenser

egulating

v

s is cool

h of its h

e

ressure li

q

quid line

t

expansi

o

atic expa

n

frigerant i

REF

R

ING FRE

E

ploys eit

h

refrigerati

o

ressor,

R

igh temp

e

the disch
water-c

o

pressure

and the

ischarge
unt of

w

- which i

s

alve.

ed in th

e

at, the g

a

uid. This

o the me

t

n valve.

sion valv

e

s to be all

o

FR

E

IGERATI

O

ZE:

er air a

s

n system

efrigerant

rature, h

arge line i

oled. If

a

will cha

n

ambient

pressure

ater flow

determi

n

conden

s

s conden

s

liquid tra

v

ering devi

meters h

wed into

t

18

EZE CY

C

N SYST

E

a

for

is

igh
nto

ir­ge
air

is

ing

ed
er,

es

els

ce,

ow

he

e

vThTXma

If

tref

(c

o

a

nref

T

h

wi

l

e

v

hi

genthe

su
T

hforexref

su
hi

g

a

n

LE

M SCHE

M

aporator

s

is is dete

r

V sensin

g

nifold, at

t

he bulb

s

rigerant i

mmon at

d when t

h

rigerant i

s

is is why
l decline t

aporator,

t

h pressu

vironment

evapora

ch as wat

e

e low pr

e

ced throu

g

cess liqui

d

rigerant

v

ction tub

e

h pressu

d the cycl

e

ATIC

ection of t

h

mined by
bulb, lo

c

he outlet

o

enses a

w

s allowe

d

the begin

n

e temper

a

allowed t

h

the sucti

o

hroughou

t

he liquid

r

re, boils

o

and abs

o

tor surfac

e

r.

ssure re

f

h the he

a

refrigera

n

apor to

, where

i

re, high

t

repeats.

P

e refrige

r

the temp

ated on t

h

f the eva

p

arm suct

into th

e

ing of th

e

ture begi

n

rough.

n side g

a

the freez

e

efrigerant

ff in the

rbs heat

,

and an

y

rigerant

v

t exchan

g

t boils-off

enter th

e

t is reco

m

emperatu

age 19

ation syst

e

erature of

e suction

orator.

ion line,

m

evapor

a

freeze c

y

s to fall,

uge pres

s

cycle. A

t

released

f

low pres

s

thus co

o

thing ne

a

apor the

n

er where

, allowing

o

compre

s

pressed

re gas a

g

m.

the

line

ore
tor,

cle)

less

ure

the

rom

ure

ling

r it,

is

any

nly

sor

into

ain

19



FREEZE CYCLE

WATER SYSTEM

A combination of a solenoid water inlet valve
with a water level sensor is used to control the
level of the water into the reservoir/sump.
A pump, running continuously, after the first
30" of freezing cycle, forces the water to the
top of the evaporator, where it is distributed
through a water tube and then cascades down

the evaporator surface by gravity. As it flows
across the refrigerated evaporator, some of
the water will be chilled enough to change
form, turn to ice, and stay frozen onto the
evaporator cells. Most of the water returns to
the reservoir, to be sucked back into the pump,
and re-pumped over the evaporator.

20



HARVEST (DEFROST) CYCLE

REFRIGERATION SYSTEM SCHEMATIC

REFRIGERATION SYSTEM DURING
HARVEST

The refrigeration system performs the harvest
of ice by use of a hot gas bypass valve. When
the time comes to de-ice the evaporators, the
hot gas valve is energized, and the high
temperature, high pressure gas bypasses the
condenser, and is allowed directly into the
evaporator. The high pressure gas is cooled
by the cold evaporator so it condenses into a
liquid, giving up its heat as it does so. This
heat warms the evaporator and the ice frozen
onto the evaporator surface melts, releasing
the frozen cubes. Ice then falls by gravity into
the storage bin.
The liquid refrigerant goes through the suction
line into the heat exchanger where it boils-off
so that only refrigerant vapor is drawn into the
suction tube of the compressor.

WATER SYSTEM

During the harvest cycle, the electric water
drain valve is energized thereby opening the
drain line.

All water remained in the reservoir at the end
of freezing cycle is pumped-out, to the waste,
through the water solenoid and drain line
during the first 40 seconds of the defrost cycle
eliminating any possible build-up and
accumulation of minerals concentration and
impurities in the water reservoir.
The water inlet valve is energized during the
last 10" of the operation of the water pump so
to rinse the water tank with new fresh water.
When the released ice cubes drop into the bin,
they open-up for a fraction of a seconds the
bottom end of plastic deflector.
This deflector swinging motion is enough to
reset the contact of the magnetic switch which

- via electronic control board de-energizes the
water drain valve allowing the unit to initiate a
new freezing cycle. The harvest cycle lasts
about 1.5-2 minutes.

CONTROL SEQUENCE

At the start of the freezing cycle, the contacts
of the magnetic switch mechanically operated
by the actuator plate of the deflector cover are
closed, thereby - via electronic control board -

21



closing the circuit to the main contactor coil
and consequently to the compressor and fan
motors and 30" later, to the water pump
motors.
Then, as the ice thickness reaches the value
that corresponds to the full cube size, the film
of water that constantly cascades over the
slab of ice formed on the evaporator, arrives to
establish a contact between the two fingers
(energized at low voltage) of the ice sensor
control, located on the front upper right side of
the evaporator. If the contact between the two
fingers of the ice sensor remains established ­by the film of water – for more than 10
seconds, a small relay of the electronic board,
get energized, controlling - simultaneously
both the hot gas valve and the water drain
valve.

At this point, the unit initiates the defrost cycle.
The hot gas circulating into the evaporator
serpentine causes a slight melting of ice cubes
which get released from their molds. Once
entirely released the ice cubes drop
simultaneously into the ice storage bin below;
by doing so they move apart from the
evaporator bottom end the plastic deflector.
This plastic deflector has on its side a
magnetic switch that on account of the
deflector swinging motion, caused by the ice
while dropping in the bin, opens and closes
their contacts. This will, in turn, deactivates the
relay contacts that controls the hot gas and
water drain valve which get de-energized
allowing the unit to start a new freezing cycle.
When the ice bin is full of ice, the last batch of
ice cubes released from the evaporator
accumulates to keep the bottom end of the
plastic deflector in open position; with the
magnetic switch contacts open for longer than
30'’ the entire unit stops with the glowing of the
corresponding LED.
The machine will restart when the ice deflector
will be back in its normal vertical position
provided that 3' are elapsed from unit stop. If
not the machine will delay its restart till 3' are
elapsed with the blinking of the green LED.

ALARM CONDITIONS

Both the last two Red LED are
ON STEADY: Condenser Sensor
OUT OF ORDER.
Both the last two Red LED are
BLINKING SLOW: WATER
ERROR Water level inside the
water sump too low after 3' from
the activation of the Water Inlet
Valve.
Both the last two Red LED are
BLINKING FAST.
RESET MODE: Charging water
through the Water inlet Solenoid
Valve after the tripping OFF on
WATER ERROR.
The fourth Red LED is ON
STEADY: Harvest Cycle longer
than 3' 30".
The fourth Red LED is BLINKING
SLOW: TOO HI CONDENSING
TEMPERATURE. The condenser
sensor detected a temperature >
65℃.
The fourth Red LED is BLINKING
FAST.
RESET MODE: Condenser
Sensor < 50 ℃ Fan motor in
operation for 3' then back on
Start Up Cycle Mode
The fifth Red LED is ON
STEADY: TOO HI DISCHARGE
PRESSURE > 33 bar 460 PSI
The fifth Red LED is BLINKING
FAST:
RESET MODE: FOR THE FIRST
2 TIMES, MACHINE WILL
AUTOMATIC RESET, THE
MACHINE WILL STOP WHEN
HIGH PRESSURE OCCURS
THE THIRD TIME.

The PC Board is also checking the maximum
time of the freezing cycle that changes
according to the operation of the fan motor
during the freezing cycle (room temperature):

• Fan motor in: Max. freezing cycle length
ON-OFF mode: equal to 30'

• Fan motor ON: Max. freezing cycle length
All the time: equal to 40'
Whenever the machine remains in the
Freezing Cycle for the Maximum time (30 or
40 minutes), the PC Board moves the unit
directly into the Harvest Cycle.

NOTE: in case of failure of ice level sensor,
the P.C. Board turns - on automatically the
unit into the defrost cycle when the freezing
cycle reaches 30 or 40 minutes according
to the operation of the fan motor during the
freezin

g cy

cle.



P

C

Th

e

• M
for
har

v

- J

U

• M
a s
har

vcyc

- J

U

BOAR

D

PC Boar

d

anual res

e

a short ti

m

est cycle

MP IN J2

anual res

e

hort time

o

est cycle

les - Rec

o

MP IN th

e

SET U

P

can be s

e

t mode a

n

e only a

t

- Sugges

t

t mode a

n

nly at be

plus a ful

l

mmende

d

first TW

O

t up for:

d water

p

beginnin

g

ed for soft

d water p

ginning of

water pu

r

for norma

contacts

urge out

of every
water

urge out f

o

every

ge every

s

l /hard wat
of J1

22

ix

er

•
e

vwa- J

•

-

Manual r

e

ery harve

s

ter

UMP IN t

h

A

utomati

c

JUMP O

U

set mod

e

t cycle -

e second

reset

T

and full

Recomm

e

TWO con

t

water p

u

nded for

h

acts of J1

rge
ard

23



SERVICE SPECIFICATION

In servicing a machine, it is often, useful to
compare that individual unit operating
characteristics to those of a normally operating
machine. The data that follows gives those
characteristics; however, be aware that these
values are for NEW, CLEAN machine
operating at 21℃ ambient and 15 ℃C water.

USE THESE NUMBERS AS A GUIDELINE
ONLY.

COMPONENT
Reservoir level

NW 458/NW608 ......................... 80~85 mm

NW 1008 ............................. 100~105 mm

Cube Size Control Ice Sensor - distance
from evaporator 3~5 mm

High Pressure Safety Switch.

NW 458-608-1008: Cut IN 23 bar - Cut OUT
33 bar

OPERATING CHARACTERISTICS

On air-cooled models during the freezing cycle,
the discharge pressure is maintained between
two preset values by means of fan control
(condenser sensor); and at the same time, the
suction pressure will also decline reaching its
lowest point just before harvest. Compressor
amps experience a similar drop.
On water-cooled, the discharge pressure is
constantly, maintained during the freeze cycle
by the water regulating valve. However,
suction pressure and compressor amps, will
still decline as the machine freezes ice.

MODEL

Disch.

Pressure

Freeze

max

Disch.

Pressure

Freeze

min

Hi

Pressure

CUT
OUT

Suction

Pressure

Beginning

Freeze

Suction

Pressure

end

Freeze

Freezing

time

Amps

Compressor

Beginning

Freeze

Amps

Compressor

end

Freeze

NW 458 A 17,0 bar 15,0 bar 33 bar 3,6 bar 2,3 bar 16' 4,2 3,4
NW 608 A 18,0 bar 16,0 bar 33 bar 2,9 bar 1,7 bar 11' 7,0 5,2

NW 1008 A 18,0 bar 15,5 bar 33 bar 3,2 bar 1,7 bar 11' 30" 4,0 3,1

Refrigerant charge R 404A
MODEL NW 458 NW 608 NW1008

Air cooled 50 Hz 700 850 1300

Refrigerant metering device

Thermostatic expansion valve.

NOTE: Always check nameplate on individual ice machine for special refrigerant charge before
charging the refrigeration system. Such refrigerant charge is the average charge for the NW
Modular Cubers. However it is important to check nameplate for each machine.

24



COMPONENT DESCRIPTION

1. Front Console Panel

NW SERIES

2. P.C. Board

Located in the control box, this board is the
brain of the system as it governs the ice
machine cyclematic through sensors, relays
and switches. It consists of two separated
printed circuits one at high and the other at
low voltage integrated with a fuse, of four
connectors for the sensors/switches
(condenser sensor - BLACK -, magnetic switch

- GREEN - ice thickness sensor - RED - water
level sensor - BLUE), of two jumpers (one J1
for factory use only - and the second J2 for the
selection between manual or automatic reset
mode), of one outlet connector (front LED
display- black) one serial port connector (black)

and of four plug in terminals for input and
output power. With J2 closed the P.C. Board is
set up for Manual reset mode, when J2 is
open on Automatic Reset mode.
The P.C. Board is equipped by an electronic
safety timer that turns-on automatically the unit
to defrost cycle when freezing cycle is longer
than 30 or 40 minutes and trips-off completely
unit when defrost cycle is longer than 3,5
minutes (2nd Red LED ON).
A trimmer, located close to the transformer,
can change the current received back from the
Ice Thickness Sensor according to the
Electrical Conductivity of the water.

BUTTON A
Reset/Washing

LED No. 1

A

larm high pressure

LED No. 2

A

larm

LED No. 3

Tank full./Washing

LED No. 4

Operation

LED No. 5

Electrical power supply

A

1

2

3

4

5

25



3. Compressor Contactor

Located in the control box, the compressor
contactor functions to carry the compressor
line current. The contactor is wired to receive
power from the P.C. Board.

4. Ice Thickness Sensor

Located in the front upper right side off the
evaporator, the sensor is made with two metal
reeds in which passes power at low voltage.
The two metal reeds, which are individually
insulated, are set through a setting screw, to
maintain a minimum clearance from the
evaporator (3~5 mm). Once ice is formed into
each mold and is thick enough to fill-up that
minimum clearance existing between the two
sensor reeds and the evaporator, the water
that cascades over the ice has gradually
approached to make contact between the two
sensor reeds.
It is enough that this contact remains there for
about 10 seconds that the P.C. Board receives
the signals to put the ice machine on defrost.

5. Magnetic Switch

Located in the front of the evaporator plastic
curtain, this switch sends a pulse to the P.C.
Board which switches the machine back in the
freezing cycle.

6. Hot Gas Solenoid Valve

The Hot Gas Solenoid Valve functions only
during the Harvest Cycle, to divert the hot
discharge gas from the Compressor,
bypassing the Condenser and thermostatic
expansion valve, for direct flow to the
Evaporator Plate Assembly to release ice
cubes from the ice cube molds.
The Hot Gas Solenoid Valve is comprised of
two parts, the Body & Plunger and the Coil
assembles.
Installed in the discharge line of the
Compressor, the energized solenoid coil lifts
the valve stem within the valve body to cause
the hot discharge gas to be diverted when the
ice Thickness sensor has signaled to the P.C.
Board to start the Harvest Cycle.

7. Condenser temperature sensor

The condenser temperature sensor probe
(located in contact with the condenser tube
coil) detects the condenser temperature
variations and signals them by supplying

current, at low voltage, to the P.C. BOARD.
In the air cooled versions, in relation to the
different current received, the micro processor
of the P.C. BOARD supplies, through a TRIAC,
the power at high voltage to the fan motor so
to cool the condenser and to reduce its
temperature.
In case the condenser temperature rises and
reaches 65℃ (150 F) the current arriving to
the micro processor is such to cause an
immediate and total stop of the machine
operation with the blinking of the Red LED.

8. High Pressure Control

The high Pressure Control, a safety control, is
factory set to cut-out, at 33 bars and cut-in at
22 bars. The high Pressure Control is
automatic reset with a monitoring light on the
Front Console Panel.

9. Water Regulating Valve

(Water Cooled Models)
The Water Regulating Valve functions
maintain a constant Compressor head
pressure, by regulating the amount of
incoming water flow through the Condenser,
on water-cooled models. The valve operates
through the refrigerant system high side
pressure. Rotating the adjusting screw located
on top of the valve, can INCREASE or
DECREASE the water flow through the water­cooled Condenser, which in turn, will
DECREASE or INREASE the Compressor
operating head pressure.

10. Water Distribution System

The Water Distribution System functions to
even supply water to all cells of the evaporator
plate. The water pump pumps water from the
sump to the tee. From there water is
channeled through the vertical Teflon tube to
the water distributors, above the evaporator
plate, and from the holes in the distributor tube
water flows to the cells on one side of the
evaporator plate.
Gravity flow returns the unfrozen excess
portion of water to the sump reservoir for
recirculation.

11. Water Drain Solenoid Valve

The Water Outlet Solenoid Valve functions in
conjunction with the water pump to flush-out
the sump assembly at the beginning (first 40")

26



of every harvest cycle. This action cleans-up
and rinses the sump during each harvest cycle
preventing dangerous water minerals
concentration.

12. Thermostatic Expansion Valve

The Thermostatic Expansion Valve regulates
the flow of refrigerant to the evaporator and
reduces pressure of liquid refrigerant from
condensing pressure to evaporating pressure.

13. Water pump

The water pump primes the water from the
sump to the water distributor tube and through
the distributing holes it cascades down onto
the evaporator cells by gravity so to be frozen
into clear ice cubes. The water pump remains
off during the first 30" seconds of the freezing
cycle (to avoid any cavitation problem) while
it's kept running during the first 40" of
defrost/harvest cycle to drain out (purge) the
remaining water from the sump (reach in
mineral salts).

14. Water inlet solenoid valve - 3/4" male
fitting

The Water Inlet Solenoid valve is energized by
the P.C. Board during the beginning of the
freezing cycle till the water reaches the
maximum level into the sump (controlled by
the Water Level Sensor).
After 3 minutes, from the start up of the
freezing cycle, the Water Inlet Valve is
energized again for a short period to re-fill the
sump with water till again to the maximum
level so to minimize any possibility of slush ice

formation
A flow control, fitted into its outlet port, reduces

the pressure of the water flow.

15. Water level sensor

The Water Level Sensor, located on the upper
right side of the water sump, works in
conjunction with the P.C. Board in order to
control the water level at beginning of the
freezing cycle by receiving a low power current
passing through the water. When the current
reaches the PC Board, the water inlet solenoid
valve is de-energized.
In case the PC Board doesn’t receive any
signal (current) from the Water Level Sensor
within the
first 3 minutes of the freezing cycle, the PC
Board trips OFF the operation of the machine
with the switching ON of the Water Error LEDs.

16. Start up delay PC Board

Located in the back side of the unit it delays
the start up of the entire machine by 90' so to
avoid that compressor can start up w/out be
pre-heated.

17. Start up delay PC Board by-pass switch

Located in the back side of the machine allows
to by-pass the delay time controlled by the
delay PC Board.

WARNING: It is IMPERATIVE to by-pass the
delay time only when sure of proper warm up
of compressor.

27





Page 28

NW 458/608 - WIRING DIAGRAM

220 V. 50 Hz. 1 ph.
m = brown
bc = light blue

gv = yellow green b = white
n = black r = red
a = orange

A - Input terminal board
B - Compressor contactor
C - Compressor
D - Ice sensor
E - End defrosting switch
F - Water level sensor
G - Condenser temperature probe
H - Led card
I - PC Board
J - Hi pressure switch

K - Manual/Automatic reset jumper
L - Water pump
M - Water inlet valve
N - Water drain/purge valve
O - Hot gas valve
P - Fan Motor (only AIR cooled unit)
Q - Fan Motor (only WATER cooled unit)
RC - Compressor relay
CS - Start capacitor
CM - Run capacitor

28



NW 1008 - WIRING DIAGRAM

400 V. 50 Hz. 3 ph.
m = brown

bc = light blue

gv = yellow green
b = white n = black
r = red
a = orange v = purple

A - Input terminal board
B - Compressor remote control switch
C - Compressor
D - Ice sensor
E - End defrosting switch
F - Water level sensor
G - Condenser temperature probe
H - Led card
I - Electronic card
J - Max pressure switch

K - Automatic reset switch
L - Water pump
M - Water inlet valve
N - Water discharge valve
O - Hot gas valve
P1 - Fan Motor 1 (only AIR cooled unit)
P2 - Fan Motor 2 (only AIR cooled unit)
R - Crankcase heater
S - Delay by pass switch
T - Start delay electronic board

29





Page 30

SERVICE DIAGNOSIS

The table below is intended as a quick
reference to aid the Service Agent in
determining the cause of a particular type of
malfunction, as well as the recommended
repair. It is not intended to be an exclusive list.

Reference to other portions of this manual,
including wiring diagrams, installation, and
operation are recommended to better
determine the cause of a problem.

SYMPTOM POSSIBLE CAUSE CORRECTION

Warning Red LED ON See page 20 See page 20

No warning LED/LIGHT ON P.C. Board inoperative. Remove board and check.
No power to unit. Check electrical source.

Bin full Yellow LED ON Bin Full of ice. Nome.

Magnetic switch
inoperative.

Check and replace.

Machine runs, compressor
does not.

P.C. Board compressor
relay open.

Test and replace.

Compressor contactor
open.

Test and replace.

Compressor relay open. Test and replace.
Compressor winding open. Test and replace.

Machine runs, makes ice,
does not try to harvest.

Ice thickness control open. Check sensor fingers if are not

covered with scale sediment.

Too soft water. Water electrical conductivity must be

higher then 20 S. Machine can't run
with demineralized water.

Built-in relay on

Check and replace P.C. Board.

P.C. Board open.

Machine runs, makes and
harvests ice but very slowly.

Low refrigerant charge. Check system for correct refrigerant

charge. Check for leak weight in
charge.

Low ice capacity. High discharge pressure

due to not-condensable or
overcharge.

Evacuate and weigh in charge.

Inefficient compressor. Replace.
Condenser dirty. Clean.
Low water flow

(Water-cooled).

Check and repair.

High air temperature
(air-cooled).

Check temperature of air entering
condenser.

Machine makes irregular ice. Plugged water distributor. Clean water distributor.
TXV superheat wrong. Adjust or replace.

Refrigerant charge low.

Adjust-check for leak.
Recharge.

30



MAINTENANCE & CLEANING & SANITATION INSTRUCTIONS

A SCOTSMAN Ice System represents a
sizable investment of time and money in any
company’s business. In order to receive the
best return for that investment, in MUST
receive periodic maintenance.
It is the USER’S RESPONSIBILITY to see that
preferable, and less costly in the long run, to
avoid possible down time by keeping it clean,
adjusting it as needed and by replacing worn
parts before they can cause failure. The
following is a list of recommended
maintenance that will help keep your machine
running with a minimum of problems.
Maintenance and Cleaning should be
scheduled at MINIMUM twice per year while
sanitation once per month.

ICEMAKER

THE FOLLOWING MAINTENANCE SHOULD
BE SCHEDULED AT LEAST TWO TIMES
PER YEAR ON THIS ICEMAKER. CALL
YOUR AUTHORIZED SCOTSMAN SERVICE
AGENCY.

1. Check and clean or service any optional
water treatment devices, if any installed.

2. Clean water strainer.

3. Check that the cabinet is level, in the side­to-side and front-to-back directions.

4. Clean/Sanitise the water system, evaporator
plate and sump assembly, using a solution ot
Ice Machine Cleaner/Sanitiser. Refer to
CLEANING - Icemaker.

5. Check and tighten all bolts and screws.

6. Check for water leaks and make corrections.

7. Check the bin control to test shut-off.
Holding the evaporator deflector in open
Position for more that 30", should cause the
ice maker to shut-off.
Once the evaporator deflector is released in its
closed position, the ice maker will restart.

8. Check cube size; adjust if required through
setting screw of ice thickness control sensor.

9. With unit out of operation, clean the
condenser using vacuum, cleaner, wisk broom
or brush. Instruct customer to clean condenser
frequently
DO NOT USE A WIRE BRUSH.

ICE STORAGE BIN

The interior liner of the bin is in contact with a
food product, ice, and should be cleaned and
sanitised regularly. Once a week sanitise it
with a commercial food grade sanitiser
complying with the manufacturer dilution.

CABINET EXTERIOR

Wipe clean unit and bin cabinet exterior with a
clean cloth or disposable paper wipers,
soaked in warm water with mild detergent
solution.

CLEANING - Ice maker

1. Empty bin of ice.

2. Remove front panel.

3. Wait till the end of the defrost/harvest cycle
then push the RESET BUTTON for 6-8

WARNING - Ice Machine Cleaner contains
Phosphoric and Hydroxyacetic acids. These
compounds are corrosive and may cause
burns. If swallowed, DO NOT induce
vomiting. Give large amounts of water or
milk. Call physician immediately. In case of
external contact, flush with water. KEEP OUT

OF THE REACH OF CHILDREN.

NOTE: Cleaning/Sanitising requirements

vary according to local water conditions and
individual user operation.
Continuous check of the clarity of ice cubes
and visual inspection of the water system
parts, evaporator plates and the sump
assembly before and after cleaning will
indicate frequency and procedure to be
followed in local areas.

31



Page 32

seconds. The machine should stop with the
blinking of the Yellow LED (slow blink).

4. Pour on

- NW 458-600 250 cc

- NW 1008 350 cc
of Scotsman Ice Machine Cleaner directly into
the reservoir then push again the RESET
BUTTON for a while. The water pump starts to
operate with the fast blinking of the Yellow
LED while the water inlet valve will be
energized till the fill up of the water sump.

5. After 15 minutes push the RESET BUTTON
for a while. The P.C. Board puts the machine
in automatic rinsing mode with the special
blinking (blink twice and repeat) of the Yellow
LED.

6. At the end of the 7th Rinsing cycle the P.C.
Board stops the operation of the machine with
the blinking (slow) of the Yellow LED.

7. Pushing the RESET BUTTON for 6-8
seconds the machine restarts in the freezing
cycle.

8. Replace the evaporator cover deflector and
front panel.

9. Check the next batch of cubes to be sure all
the cleaner is gone (no sour taste).

10. Pour hot water into the storage bin melt
the cubes, and to also clean the bin drain.



CAUTION - DO NOT use ice cubes
produced from the cleaning solution. Be
sure none remains in the bin.

NOTE: RINSING mode consists of:
a) Energize the water drain valve and the
water pump for 40 seconds to empty the
reservoir
b) De-energize the water drain valve and
the water pump for 1 minute
c) Energize the water inlet valve till the fill
up of the water sump
d) Energize the water pump for 1.5
minutes. The above sequence is repeated
7 times so to be sure to have removed any
possible trace of Ice Machine Cleaner.

32



Scotsman Ice Systems (Shanghai) Co., Ltd.

Room 2505, Building 2, No. 20 Xuhong Middle Rd.,
Xuhui District,Shanghai, China

Postcode：200235
Tel：[phone]
Fax：[phone]

Email：[e-mail]

[e-mail]
Hotline：[phone]
Website：www.scotsman-china.com