Scotsman ND550 User manual

INTRODUCTION
To the owner or user: The service manual you are
reading is intended to provide you, and the
maintenance or service technician with the
information needed to install, start up, clean,
maintain, and service this ice maker-dispenser.
The ND550 is a combination nugget ice maker and
countertop dispenser, with the option of wall
mounting. A water station may be added, if desired.
The ND550 ice making section is equipped with
the following features: electronic controls for bin
level and low water; thermostatic expansion valve;
front service for most components; and R502
refrigerant. The ice dispensing section is a
seamless plastic storage bin, with a stainless steel
ice agitator at the bottom to sweep the ice into the
dispensing chute.
TABLE OF CONTENTS
For the Installer
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Environmental Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Wall Mount Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Glass Filler Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Soda Valve Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
For the Plumber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
For the Electrician . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Final Check List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Component Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Electrical Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Maintenance and Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Service Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Removal and Replacement
Water Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Bin Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Breaker and Bearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Auger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Water Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Evaporator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Gearmotor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Electronic Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Parts Lists and Wiring Diagrams are printed on yellow paper in the center of this manual.
ND550
December, 1988
Page 1

FOR THE INSTALLER: Specifications
This ice maker-dispenser is designed to be
mounted on a machine stand, or a countertop, or
using wall mounting kit KWB3, hung from a wall.
The sink may be retained, or removed and the
optional longer splash panel (KSP1B) installed in
place of the original. Instructions for each kit are
included in this service manual.
Before beginning the installation, check that all the
materials and kits required are available at the
installation location.
SPECIFICATIONS
+ Minimum Circuit Ampacity is used to figure wire size and type per National Electric Code.
ND550AE-1A
ND550WE-1A
ND550AS-1A
ND550WS-1A
41 x 26 x 22.5
same
same
same
NUGGET
same
same
same
Air
Water
Air
Water
115/60/1
115/60/1
115/60/1
115/60/1
16.7
16.2
16.7
16.2
20
20
20
20
Maximum
Fuse
Size
Minimum
Circuit
Ampacity+
Basic
Electrical
Condenser
Type
Ice
Type
Dimensions
(w/o stand)
H" x W" x D"
Model Number Cabinet
Finish
Painted
Painted
Stainless
Stainless
14.06" 1.88"dia
20.5"
22.5"
2.56"
Optional for water and
drain lines
NAMEPLATE
on inside of
right side panel
ELECTRCIAL JUNCTION BOX
3/8" FPT
Condenser
Water Inlet
(Water Cooled)
1/2" FPT
Cond. Drain
(Water Cooled)
3/4" FPT
Drain
12.27"
1.12"
3.12"
5.12"
6.43"
4.5"
3.54"
3/8" Flare
Potable Water Inlet
ND550
August, 1989
Page 2

FOR THE INSTALLER: Environmental Limitations
Installation Limitations
This ice system is designed to be installed indoors,
in a controlled environment.
Minimum Maximum
Air Temp 500F. 1000F.
Water Temp 400F. 1000F.
Water Pressure 20 PSI 80 PSI
Voltage 104 126
Operating the machine outside of the above
limitations, or outdoors, is potentially damaging to
the machine; also it is misuse of the machine,
which may void the warranty.
Scotsman Ice Systems are designed and
manufactured with the highest regard for safety
and performance. They meet or exceed the
standards of UL, NSF, and CSA.
Scotsman assumes no liability or responsibility of
any kind for products manufactured by Scotsman
that have been altered in any way, including the
use of any part and/or other components not
specifically approved by Scotsman.
Scotsman reserves the right to make design
changes and/or improvements at any time.
Specifications and design are subject to change
without notice.
Water Limitations
An ice machine is a food manufacturing plant; it
takes a raw material, water, and turns it into a food
product, ice. The purity of the water is very
important in obtaining pure ice and in maximizing
product life. This section is not intended as a
complete resource for water questions, but it does
offer these general recommendations:
1. Filter the water used to produce ice. That is the
water going to the "potable" water connection.
Water filters vary greatly in ability and function.
Install one that filters out suspended solids to a
dimension of 5 microns or smaller. The finer the
filter the better, but finer filters will clog sooner
than course ones. It may be necessary to add a
course filter ahead of the fine filter to prolong filter
life.
2. Check with a water treatment specialist for a
water test, and recommendations regarding filters
and treatment.
Service Limitations
Do not install in a location where the top of the
machine is within 6" of a fixed ceiling. Do not install
air cooled models in a location where there is less
than 6" clearance to the left and right of the
cabinet.
WALL
CUT AWAY
CEILING
CUT AWAY
6" SPACE
FOR AIR
(AIR COOLED)
SPACE
ABOVE
FOR
SERVICE
6" SPACE
FOR AIR
(A/C)
SPACE
FOR
UTILITIES
ND550
December, 1988
Page 3

FOR THE INSTALLER
Location
After uncrating and inspection, the unit is ready for
installation. It is important that the machine be
installed in a location where it has enough space
above and behind it for service. Air cooled models
require a minimum of 6 inches to the left and right
of the machine for air circulation.
Machine Stand Installation
Tip the stand on it’s back and install the legs,
return the stand to the upright position. Adjust leg
levelers so that the stand does not "rock".
Counter Top or Machine Stand Installation
The base of the icemaker-dispenser must be
sealed to the object it rests upon. Food grade
silastic sealant such as Scotsman part number
19-0529-01 is recommended.
Place a bead of the sealant on the machine stand
or counter top to match the outside edge of the
cabinet base and sink.
The icemaker-dispenser is heavy: use of a
mechanical hoist is recommended to lift it to the
height required to install it.
The DMS machine stand has holes in the top that
match up with "feet" on the icemaker-dispenser.
Place the cabinet onto the machine stand, so that
the unit "snaps" into place.
In both counter top and machine stand
installations, wipe off and neatly smooth any
excess sealant. Level the machine stand and
cabinet.
Unpack and install the sink brackets. Fit the sink
assembly onto the two sink brackets, and press
onto the bead of sealant. Wipe off and neatly
smooth any excess sealant from under the sink
edge.
SEAL THE
UNIT TO
THE
COUNTER
OR STAND
ND550
August, 1989
Page 4

FOR THE INSTALLER: Wall Mount Kit
/////////////////////////WARNING///////////////////////////////
It is recommended that the wall mounting
installation be done by an experienced contractor.
The weight of the machine when in use may
exceed 350 pounds. The unit should be mounted
on a solid, rigid wall with proper fasteners for that
type of wall and of adequate strength to support
the weight of the machine when in use.
/////////////////////////////////////////////////////////////////////////
Clearance between the wall and the icemaker is a
maximum of 1 inch. Check utility connections first.
The electrical junction box will have to be
removed, and the electrical connections made
inside the cabinet in compliance with local codes.
The plumbing connections may be made through
the base, or at either side through the pre-punched
holes, using standard plumbing practices.
Interior plumbing lines must be disconnected from
the original connections and plugged when routing
through the side or base.
1. Remove machine top. Attach bracket "A" to
machine using (3) nuts, (3) flat washers, (3)
lockwashers, and (3) 5/16-18 bolts received with
the kit.
2. Mount brackets "B" and "C" to the wall at the
dimensions shown for the unit. (hardware for this is
not included).
/////////////////////////////////////////////////////////////////////////
Use fasteners and wall of sufficient strength to
carry the use and weight of the
icemaker-dispenser.
/////////////////////////////////////////////////////////////////////////
3. Lift unit up and hook bracket "A" over bracket
"B". Slide unit until the two remaining holes are
aligned and secure with the remaining (2) 1/4-20
bolts, flat washers and lockwashers.
30"
7.58"
SIDE
ROUTING
BASE
HOLE
DO NOT LIFT ON SINK
1" CLEARANCE
B
A
C
16"
16"
12"
12"
ND550
December, 1988
Page 5

FOR THE INSTALLER: Water Glass Filler Kit
Installation Instructions for KWGF
///////////////////////////CAUTION////////////////////////////////
Shut off potable water supply to icemaker -
dispenser.
/////////////////////////////////////////////////////////////////////////
///////////////////////////WARNING////////////////////////////
Disconnect electrical power to icemaker -
dispenser.
//////////////////////////////////////////////////////////////////////////
1. Remove screws, and remove top panel
2. Remove screws, and remove both front panels.
3. Remove screws, and remove the filler
plate-scrap the plate.
4. Locate water solenoid valve assembly and two
red wires in the kit. Attach the (2) red wires to the
solenoid terminals.
5. Locate the water line assembly and the water
line adapter. Connect to water solenoid valve.
Fitting size will determine location.
6. Remove plug from potable water line.
7. Install valve plate and switch assembly to the
dispenser, replace the filler plate removed in step
3.
8. Attach the water solenoid
assembly to the underside of the
upper compartment using (2)
screws and lockwashers into the
threaded holes provided.
9. Attach the water line adapter
and solenoid valve assembly to
water line where plug was removed
in step 6.
10. Attach clamp and #8-32 x 3/4
phillips machine screw to secure
the water line assembly.
11. Insert glass filler lever through
the square slot in the valve plate
and switch assembly. Attach to
dispenser with (2) arm clamps and
(2) #6-32 x 1/2 machine screws.
12. Check and adjust the
microswitch so that the glass filler
lever pushes the micro-switch
button.
13. Attach the glass filler lever
spring to glass filler lever. The large
hook goes to the filler lever, the
small one to the hole in the
dispenser base directly below.
14. Attach the red wire connected to the solenoid
to the switch on the valve plate. Attach the blue
wire to the switch on the valve plate.
••Route the free red wire from the solenoid,
attach to the terminal strip to the second
terminal from the left.
••Route the blue wire from the switch to the
control box, attach the red wire to the terminal
strip and attach the blue wire to the leftmost
terminal.
15. Turn on water, check for leaks. Replace
panels, switch on power supply, check operation.
TOP PANEL
ARM CLAMPS
SWITCH
PLATE
ASSEMBLY
CLAMP
WATER
LINE
ADAPTER
PLUG
SPRING
FILLER
PLATE
VALVE
ND550
August, 1989
Page 6

FOR THE INSTALLER: Soda Valve Kit
Installation Instructions
Note: Carbonator and carbonated product cooling
system are not included.
//////////////////////////WARNING////////////////////////////
Disconnect electrical power to the icemaker -
dispenser.
////////////////////////////////////////////////////////////////////////
1. Remove cabinet top panel, front panel, and
splash panel.
2. Remove screws and remove filler plate from the
ice maker dispenser.
3. Remove large plug from base of
icemaker-dispenser.
4. Install valve assembly in the ice machine with
two screws through the same holes that held on
the valve cover plate. Install 1-3/8" ID insulation
tube over the syrup and carbonated lines.
5. Route product lines through the hole in the base.
6. Make all required connections soda line
connections, using field supplied materials. All
lines should be insulated. A carbonated water
recirculating line is provided and recommended to
insure that high quality drinks are dispensed.
7. Install transformer in upper compartment of
icemaker-dispenser, using screws provided. It may
be necessary to pre-drill holes.
8. Route drink valve assembly electrical leads up
to the transformer.
9. Connect wire leads from the drink valves to the
24 volt output side of the transformer.
10. Locate a 115 volt continuous power source
from within the icemaker control box. Route white
and black leads from the 115 volt input side of the
transformer and connect to the 115 volt power
source.
11. Turn on power and soda equipment, check
operation and check for leaks. Adjust valves for
proper mixture.
115 VOLT
CONNICTION
SODA
LINES
SODA VALVES
TRANSFORMER
24 VOLTS
ATTACH DRINK VALVE
ASSEMBLY HERE
ND550
December, 1988
Page 7

FOR THE PLUMBER
CONFORM TO ALL APPLICABLE CODES
Water Inlet
Air Cooled Models: The recommended water
supply is clean, cold water. Use 3/8" O.D. copper
tubing, connect to the 3/8" male flare at the back
of the cabinet. Install a hand valve near the
machine to control the water supply.
Water Treatment: In most areas, a water filter of
some type will be useful. In areas where the water
is highly concentrated with minerals the water
should be tested by a water treatment specialist,
and the recommendations of the specialist
regarding filtration and/or treatment should be
followed.
Water Cooled Models: A separate 3/8" O.D.
copper line is recommended, with a separate hand
valve to control it. It is connected to a 3/8" FPT
condenser inlet at the back of the cabinet. The
water pressure to all lines must always be above
20 psig, and below 120 psig.
Drains
Air Cooled Models: There is one 3/4" FPT drain
at the back of the cabinet, the drain line is of the
gravity type, and 1/4 inch per foot fall is an
acceptable pitch for the drain tubing. There
should be a vent at the highest point of the drain
line, and the ideal drain receptacle would be a
trapped and vented floor drain. Use only 3/4" rigid
tubing.
Water Cooled Models: In addition to the above
mentioned drain, a separate condenser drain must
be installed. Connect it to the 1/2" condenser drain
connection at the back of the cabinet.
WATER INLET
CABINET
DRAIN
OPTIONAL
WATER
FILTER
WATER INLET
SHUT OFF
VALVE
VENTED
DRAIN TUBE
FLOOR DRAIN
WATER COOLED DETAIL
CONDENSER
WATER INLET
POTABLE
WATER INLET CONDENSER
DRAIN
CABINET
DRAIN
ND550
August, 1989
Page 8

FOR THE ELECTRICIAN
CONFORM TO ALL APPLICABLE CODES
The electrical power to the unit is
supplied through the junction box at the
rear of the machine.
Check the nameplate (located on the
back panel) for the voltage
requirements, and for the minimum
circuit ampacity. The machine requires
a solid chassis to earth ground wire.
The ice maker should be connected to
its own electrical circuit so it would be
individually fused. Voltage variation
must remain within design limitations,
even under starting conditions.
All external wiring must conform to
national, state, and local electrical
codes. The use of a licensed
electrician is required to perform the
electrical installation.
JUNCTION
BOX
ELECTRICAL
POWER
ND550
December, 1988
Page 9

FOR THE INSTALLER: Final Check List
1. Is the icemaker-dispenser installed indoors, in a
location where the air and water temperatures are
controlled, and where they do not go beyond
design limitations?
2. is there an electrical service disconnect within
sight of the installed machine? Is the machine on a
separate circuit? Has the voltage been checked
and compared to nameplate requirements?
3. Have all of the plumbing connections been
made and checked for leaks?
4. Has the machine been leveled?
5. Is there a minimum of 6 inches of clearance at
the left and right sides of an air cooled machine?
6. Is there a minimum of 6 inches of clearance at
the top and back of the machine for service and
utility connections?
Wall mounted only: Is the machine properly
installed and secured to the wall?
7. Is there a water shut off valve installed near the
machine?
8. Have all of the shipping blocks been removed?
BACK VIEW OF COMPLETED INTSTALLATION
ICEMAKER
DISPENSER
MACHINE
STAND
ELECTRICAL?
LEVELED?
PLUMBING?
ND550
August, 1989
Page 10

INITIAL START UP
Pre Start Inspection
1. Remove the two front panels.
2. Check that all shipping blocks have been
removed.
3. Remove any and all packing tape (check inside
the storage bin).
4. Inspect the interior of the machine for loose
screws or wires. Check that no refrigerant lines are
rubbing each other. Check that the fan blade on air
cooled models turns freely.
5. Check that the machine is installed correctly
according to the final check list.
Start Up
1. Go through the pre start inspection.
2. Open the water hand valve, observe that water
enters the water reservoir, fills the tube from the
reservoir to the evaporator and then shuts off.
Check for leaks.
3. Switch the master switch on. The electrical start
up sequence is now on automatic:
A. There will be a short (15 second) delay before
the gearmotor starts.
B. After the gearmotor starts, the compressor will
start.
4. On air cooled models, warm air will begin to flow
from the condenser. Water cooled models will
begin to discharge warm water down the drain.
5. The unit should soon be making ice. If desired,
the low side pressure may be checked: it should
be 30 PSIG + or - 4 PSIG.
The air cooled discharge pressure will depend
upon air and water temperatures, but should be
between 200 PSIG and 280 PSIG.
Water cooled discharge pressure should be about
220 PSIG. If needed, adjust the water regulating
valve.
The above numbers are for new, clean machines.
Field values may be somewhat higher or lower.
6. There are no adjustments to make, so replace
the panels.
7. Check ice dispensing by pushing in on the glass
filler lever. Ice dispenses are portion controlled; by
turning a knob, the length of time the unit
dispenses when the glass filler lever is pushed
(and the amount of ice dispensed) is adjusted.
8. Switch off the icemaker-dispenser, remove the
top panel and the top of the ice storage bin.
Sanitize the interior of the ice storage bin by wiping
it with a mixture of 1 ounce of household bleach to
1 gallon of water, allow to air dry. Replace all
covers and panels. Switch the icemaker-dispenser
back on.
9. Give the owner/user the service manual, instruct
him/her in the operation and maintenance
requirements of the unit. Make sure they know
who to call for service.
10. Fill out the warranty registration card, and mail
it in to Scotsman.
11. Fill out the field Quality Audit form, and mail it
to Scotsman.
ND550
December, 1988
Page 11

COMPONENT DESCRIPTION
Control Box: Contains the electrical controls that
operate the machine.
High Pressure Cut Out Switch: A manual reset
switch sensing the high side refrigeration pressure.
It is set to shut the machine off, and illuminate the
reset switch light if the discharge pressure should
ever exceed 450 psig.
Evaporator: A vertical stainless steel tube,
refrigerated, and water filled. In it there is a
stainless steel auger.
Reservoir: Float operated, it maintains the water
level in the evaporator at a constant level, it also
contains the water level sensor.
Water Level Sensor: Senses if there is water in
the reservoir to make ice out
of. Will shut the machine off it
there is none.
Ice Level Sensor: An
electronic "eye", it senses the
presence of ice in the bottom of
the ice discharge chute.
Operates to turn the ice
machine on and off
automatically as the level of ice
in the bin changes.
Drain Tube: When uncapped
and lowered, drains the
evaporator.
Condenser: Air or water
cooled, where the heat
removed in ice making is
discharged.
Ice Storage Bin Assembly: A
plastic lined, insulated cylinder
that receives, stores and
dispenses the ice. Fresh ice
enters at the top, and when the
bin is full enough the ice will be
between the ice level sensors,
and the icemaking will stop. Ice
is dispensed through a chute at
the bottom front when the
agitator assembly sweeps the
ice over the chute.
Glass Filler Lever: Pushing in
on this lever causes the ice
dispensing cycle to occur.
Portion Control Knob:
Turning this knob adjusts the
length of time of dispense.
Low Pressure Cut Out
Switch: A manual reset
control that shuts off the ice machine when the low
side pressure drops below a preset point, 0-4 psig.
ICE LEVEL SENSORS WATER LEVEL
SENSOR
RESERVOIR
EVAPORATOR
ICE STORAGE BIN
GLASS FILLER LEVER
PORTION
CONTROL
LOW PRESSURE
CUT OUT
CONDENSER
DRAIN TUBE
CONTROL
BOX
HIGH PRESSURE
CUT OUT
ND550
August, 1989
Page 12

COMPONENT DESCRIPTION
Evaporator: A refrigerated vertical tube filled with
water and containing a water seal and auger.
Auger: A solid stainless steel double spiral auger,
it pushes the ice crystals up to the top of the
evaporator.
Water Seal: A two part "face" seal, the top half
rotating with the auger, the bottom half stationary,
the sealing action being where the two seal "faces"
meet.
Ice Sweep: A plastic cap with "fingers". It revolves
with the auger to "sweep" the ice into the ice chute.
Breaker: Where the ice is compressed and much
of the extra water is squeezed out of it before it is
discharged into the bin.
Motor: A permanent split capacitor motor that
drives the gear reducer.
Thrust Bearing: As the ice is pushed up the
evaporator, the auger is thrust down, and pressure
from the auger thrust is taken up by this bearing.
EVAPORATOR
AUGER
WATER SEAL
ICE SWEEP
BEARING
BREAKER
MOTOR
ND550
December, 1988
Page 13

COMPONENT DESCRIPTION: Control Box
Contactor: A definite
purpose contactor connecting
the compressor to the power
supply.
Circuit Board: Controlling
the ice machine through
sensors and relays. The
sensors are for ice level and
water level. The relays are for
the gear motor (with a built in
time delay to clear the
evaporator of ice when the
unit turns off) and for the
compressor. The reset switch
is mounted on the circuit
board.
On/Off Switch: Manual
control for the machine.
Transformer: Supplies low
voltage to the circuit board.
Potential Relay: The
compressor start relay.
Reset Switch: Part of Circuit
Board, manual reset. Lights up
when unit shuts off from: ice
discharge chute being
overfilled (opening the
microswitch at the top of the
chute); low or high pressure
switches opening.
Portion Control Module:
Controls the amount of time
the dipensing drive motor is
on. The time is varied by
adjustine the portion control
knob.
PORTION
CONTROL
MODULE
CONTACTOR
RESET
SWITCH
CIRCUIT
BOARD
TRANSFORMER
POTENTIAL
RELAY
ON-OFF SWITCH
ND550
August, 1989
Page 14

ELECTRICAL SEQUENCE
Refer the wiring diagram as needed.
If the machine is switched off at the master switch,
but is otherwise ready to go, switching the master
switch to on does the following:
••The bin empty light on the circuit board goes on
••There is a 15 second delay
••If there is enough water in the reservoir, the
circuit board will allow the machine to start up.
Start up consists of:
••The compressor relay and auger motor relay
become energized, connecting power to the
windings of the auger motor.
••The auger motor starts, and the centrifugal
switch closes, connecting power to the
compressor contactor coil.
••The contactor is energized, connecting power
to the compressor, and the compressor starts.
••As ice goes past the ice level sensors, the bin
empty light will stay on, and the machine will
continue to run, unless the ice stays between
the sensors for more than 15 seconds (bin full).
At that point, the bin empty light goes out, and
the machine shuts down.
Shut Down consists of:
••The compressor relay opens.
••The compressor contactor opens
••The compressor stops
••The auger motor is run by the circuit board for
2.5 more minutes, clearing out ice in the
evaporator, and then
••The auger motor relay opens, and the auger
motor stops.
If the ice level sensor is clear (bin empty) for more
than 15 seconds, the machine will start up again.
Another purpose of the circuit board is to turn the
machine off if there is not enough water in the
machine.
••When the water level in the reservoir falls
below the water level sensor, the machine will
"shut down"
••When the water refills the reservoir, the
machine will start up again.
Separate from the circuit board:
••If the high pressure control (cut out switch)
opens, the machine will stop immediately
(through the relays on the circuit board) and
cause the reset switch on the circuit board to
light up. It must be manually reset at the
control and at the reset switch on the circuit
board.
••If the low pressure control (cut out switch)
opens, the machine will stop immediately
(through the relays on the circuit board) and
cause the reset switch on the circuit board to
light up. It must be manually reset at the
control and at the reset switch on the circuit
board.
••If the spout switch opens, the machine will stop
immediately (through the relays on the circuit
board) and cause the reset switch on the circuit
board to light up. After it re-closes the reset
switch on the circuit board must be manually
reset.
••The master switch is the manual control for the
complete machine, but it is not a service
disconnect.
Ice Vending
••When the glass filler lever is pushed in the vend
switch closes. That energizes the portion
control module, which, depending upon the
setting of the portion control knob, will power
the agitator drive motor for a set length of time.
••Holding the glass filler lever in will not cause
additional dispensing. Releasing and
re-pushing the glass filler lever will repeat the
dispense cycle.
ND550
December, 1988
Page 15

OPERATION: Water
Water enters the machine through the 3/8" male
flare at the rear of the cabinet, goes to a strainer
and then to the water reservoir which it enters
through the float valve. The water then goes out
the bottom of the reservoir tank to the bottom of
the evaporator.
Reservoir overflow, evaporator condensation and
water in the sink are all routed to the drain. Water
cooled models have a separate water circuit for
the cooling water: it enters the fitting at the rear,
goes to the water regulating valve, then to the
water cooled condenser and down the drain.
Those models with a water dispensing station
have an additional water circuit to an electric valve.
When the water station glass filler lever is pushed,
a switch closes a circuit to the electric water valve,
and water is dispensed.
WATER RESERVOIR
WATER INLET
WATER DRAIN
WATER LINE FOR
OPTIONAL WATER
STATION
Adjustment of the Water Level
WATER
LEVEL
ND550
August, 1989
Page 16

OPERATION: Refrigeration
Beginning at the compressor, the refrigerant 502 is
compressed into a high temperature gas. The
discharge line directs this gas to the condenser. At
the condenser (air or water cooled) the gas is
cooled by either air or water and it then condenses
into a liquid. This high pressure liquid then goes
through the liquid line to the expansion valve. The
thermostatic expansion valve meters liquid
refrigerant into the evaporator, the volume of liquid
refrigerant depending upon the temperature of the
evaporator; warmer evaporators get more
refrigerant and colder evaporators get less.
At the evaporator, the refrigerant enters an area of
relatively low pressure, where it can easily "boil
off" or evaporate. As it evaporates, it absorbs heat
from the evaporator and whatever is in contact
with it (such as the water inside it). After the
evaporator, the refrigerant, now a low pressure
vapor, goes through the suction line back to
compressor, where the cycle is repeated.
CONDENSER HIGH
PRESSURE
CUT OUT
COMPRESSOR
THERMOSTATIC
EXPANSION VALVE
EVAPORATOR
SUCTION LINE
DISCHARGE
LINE
LIQUID LINE
REFRIGERATION
SCHEMATIC
ND550
December, 1988
Page 17

OPERATION: Ice Vending
When the ice dispensing glass
filler lever is pushed, an electrical
circuit is made to the portion
control module in the control box.
That module will energize the
agitator drive motor for a certain
length of time, depending upon the
setting of the portion control knob.
The dispensing takes place when
the agitator sweeps the ice over
the ice dispensing chute: ice will
continue to discharge out this
chute as long as the agitator is
turning. It stops when the agitator
stops.
AGITATOR
BIN BOTTOM
DRIVE MOTOR
ICE CHUTE
VEND SWITCH
GLASS FILLER
LEVER
SINK
ND550
August, 1989
Page 18

MAINTENANCE AND CLEANING
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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, it MUST receive periodic
maintenance.
It is the USER’S RESPONSIBILITY to see that the unit is properly maintained. It is always
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 the machine running with a minimum of
problems.
Maintenance and Cleaning should be scheduled at a minimum of twice per year.
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/////////////////////////////WARNING////////////////////////////
Electrical power will be ON when doing in
place cleaning. Switch it OFF before
completing the cleaning procedures.
///////////////////////////////////////////////////////////////////////////
ICEMAKING SYSTEM: In place cleaning
1. Check and clean any water treatment devices, if
any are installed.
2. Remove screws and remove the upper front
panel.
3. Move the ON-OFF switch to OFF.
4. Remove the cover to the ice storage bin, and
remove the ice.
5. Remove the cover to the water reservoir and
block the float up.
6. Drain the water reservoir and freezer assembly
using the drain tube attached to the freezer water
inlet. Return the drain tube to its normal upright
position and replace the end cap.
///////////////////////////WARNING//////////////////////////////
Scotsman 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.
//////////////////////////////////////////////////////////////////////////
7. Prepare the cleaning solution: Mix eight ounces
of Scotsman Ice Machine Cleaner with three
quarts of hot water. The water should be between
90-115 degrees F.
8. Slowly pour the cleaning solution into the water
reservoir until it is full. Wait 15 minutes, then
switch the master switch to ON.
9. As the ice maker begins to use water from the
reservoir, continue to add more cleaning solution
to maintain a full reservoir.
10. After all of the cleaning solution has been
added to the reservoir, and the reservoir is nearly
empty, switch the master switch to OFF.
11. After draining the reservoir, as in step 6, wash
and rinse the water reservoir.
12. Remove the block from the float in the water
reservoir.
13. Switch the master switch to ON
14. Continue ice making for at least 15 minutes, to
flush out any cleaning solution. Check ice for acid
taste - continue icemaking until ice tastes sweet.
//////////////////////////////WARNING///////////////////////////
DO NOT USE any ice produced from the
cleaning solution.
Be sure no ice remains in the bin.
///////////////////////////////////////////////////////////////////////////
15. Remove all ice from the storage bin.
16. Add warm water to the ice storage bin and
thoroughly wash and rinse all surfaces within the
bin.
17. Sanitize the bin interior with an approved
sanitizer using the directions for that sanitizer.
18. Replace the ice storage bin cover, and the
front panel.
ND550
December, 1988
Page 19

MAINTENANCE AND CLEANING
///////////////////////////WARNING/////////////////////////////
Disconnect electrical power before beginning.
//////////////////////////////////////////////////////////////////////////
1. The ice machine senses water level by a probe
located in the water reservoir. At least twice a
year, the probe should be removed from the
reservoir, and the tip wiped clean of mineral
buildup.
2. The bin control uses devices that sense light,
therefore they must be kept clean enough so that
they can "see". At least twice a year, remove the
bin control sensors from the grommets in the ice
chute, and wipe them clean.
3. The bearing in the breaker should also be
checked at least two times per year.
A. Check the bearing by:
••removing the ice chute cover
••unscrewing the ice sweep
••removing the water shed
••using a spanner wrench and unscrewing the
breaker cover.
••unscrewing the auger stud
Inspect the assembly, looking for wear.
See Removal and Replacement to replace
bearing or seals. Reverse to reassemble.
4. Check and tighten all bolts and screws.
CLEAN WATER
SENSOR PROBE
////////CAUTION//////
THE TIP IS
MADE OF GLASS
//////////////////////////////
ICE SWEEP
BIN
CONTROL
SENSOR
BIN TOP
BIN CONTROL
SENSOR
ND550
August, 1989
Page 20