Scotsman FME1200R User manual

INTRODUCTION
To theowneror user: Theservicemanual youare
reading is intendedtoprovideyou, and the
maintenance or servicetechnician, with the
information neededtoinstall, start up, clean,
maintain, andservicethis icesystem.
Theicemachines coveredin this manual are a
remote condenser typemodularice system that
fits a variety ofScotsmanstoragebins. They
feature: front servicefor thefreezer, gearmotor,
control box, water reservoir, andbin control; an
electronic circuitformonitoringiceandwater level;
a thermostatic expansion valve;and R-404A as
the refrigerant.
TABLEOF CONTENTS
FOR THEINSTALLER .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page2
REMOTECONDENSER SPECIFICATIONS. .. . . .. . . .. . . .. . . .. . . .. . . .Page3
FOR THEINSTALLER .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page4
FOR THEINSTALLER: RemoteCondenser . .. . . .. . . .. . . .. . . .. . . .. . . .Page5
FOR THEINSTALLER: PrechargedLines . . .. . . .. . . .. . . .. . . .. . . .. . . .Page6
FOR THEINSTALLER: Location. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page7
FOR THEPLUMBER . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page8
FOR THEELECTRICIAN. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page9
FOR THEELECTRICIAN: Fan Relay Kit . . . .. . . .. . . .. . . .. . . .. . . .. . . .Page10
FOR THEELECTRICIAN: Fan Relay Kit Phasing (DoAfter StartUp) .. . . .. . . .. . . .Page11
FOR THEINSTALLER: CompletedInstallation.. . . .. . . .. . . .. . . .. . . .. . . .Page12
FOR THEINSTALLER: Final Check List. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page13
START UP. . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page14
COMPONENT DESCRIPTION.. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page15
COMPONENT DESCRIPTION: Control Box . .. . . .. . . .. . . .. . . .. . . .. . . .Page16
ELECTRICALSEQUENCE . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page17
OPERATION: Water. .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page18
OPERATION: Refrigeration. . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page19
MAINTENANCEAND CLEANING . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page21
SERVICE DIAGNOSIS: Condition - NoIceBeing Produced. .. . . .. . . .. . . .. . . .Page24
SERVICE DIAGNOSIS: Condition - Low Ice Production. . . .. . . .. . . .. . . .. . . .Page27
REMOVALAND REPLACEMENT: Water Reservoir &Bin Controls . .. . . .. . . .. . . .Page28
REMOVALAND REPLACEMENT: BearingAnd Breaker . . .. . . .. . . .. . . .. . . .Page29
REMOVALAND REPLACEMENT: Auger . . .. . . .. . . .. . . .. . . .. . . .. . . .Page30
REMOVALAND REPLACEMENT: Water Seal.. . . .. . . .. . . .. . . .. . . .. . . .Page31
REFRIGERATION SYSTEMSERVICE.. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page32
REMOVALAND REPLACEMENT: Evaporator .. . . .. . . .. . . .. . . .. . . .. . . .Page33
REMOVALAND REPLACEMENT: Gear motor Assembly . . .. . . .. . . .. . . .. . . .Page34
CIRCUITBOARD TESTING. .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .Page35
Parts Lists and Wiring Diagrams are located in the center of this manual, printed on
yellow paper.
This ManualWas PrintedOn
Recycled Paper
NME950R & FME1200R
February 1995
Page 1

FOR THE INSTALLER
Either the FME1200R or the NME950R is
designed to fit the following Scotsman storage bins:
••B90 and extensions, with bin top KBT18.
••BH800 using bin top KBT15 (one unit).
••BH800 if using two units, no bin top needed.
••BH900 using bin top KBT24 (one unit)
••BH900 with bin top KBT25 (two units side by
side
••BH550 or HTB500 using bin top KBT14.
When installing a new system, check to be sure
that you have everything you need before
beginning:
••Correct Bin
••Correct Ice Machine
••Correct Bin Top
••All kits, legs, and information required for the
specific job.
Back View
Liquid Line
Connection
Discharge Line
Connection
Remote Condenser
Junction Box
Electrical
Inlet
Water Inlet
3/8" Flare
Drain
3/4" FPT
2.96"
3" 5.25"
20.84"
Allow 6" above
machine for service.
The Standard Finish is Enamel - Gray. There is an optional stainless steel panel kit, SPKFM21 available to
convert the unit to Stainless Steel. It is field installed.
Model Number
FME1200RE-32A
FME1200RE-3A
NME950RE-32A
NME950RE-3A
Dimensions
(w/o bin)
H X W X D
27" x 21" x 24"
same
same
same
Basic
Electrical
208-230/60/1
208-230/60/3
208-230/60/1
208-230/60/3
Ice Type
FLAKE
same
Nugget
same
Cond.
Type
R/Air
R/Air
R/Air
R/Air
SPECIFICATIONS: ICE MAKER
Refrigerant Charge*
208 ounces of R-404A
* Always go by the nameplate
charge.
NME950R & FME1200R
December 1995
Page 2

REMOTE CONDENSER SPECIFICATIONS
Other Required Items:
RTE25 Precharged line set, 25’, R-404A or
RTE40. Precharged line set, 40’, R-404A.
KCMR230. Fan Relay Kit used when two 230 volt (-32) ice makers are on one 230 volt (-32) two circuit
condenser.
ICE MAKER NAMEPLATE
LOCATED ON BACK PANEL
SERIAL PLATE LOCATED
BEHIND FRONT PANEL
Model Use with Basic Electrical
RCE501-32 1 FME1200R OR 1 NME950R 208-230/60/1
ERC151-32 SAME SAME
RCE502-32 1 or 2 FME1200Rs or NME950Rs SAME
ERC302-32 SAME SAME
19 7⁄8"
23 13⁄16"
ERC DIMENSIONS
A B F G
33 3⁄8"10 3⁄4"16 3⁄4"11 5⁄8"
NME950R & FME1200R
December 1995
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
around it to be accessible for service, usually a
minimum of 6 inches. Try to avoid hot, dirty and
crowded locations. Be sure that the location for the
machine is within the limitations described on page
3. Storage Bin
Tip the storage bin on its back, using parts of the
carton to protect the exterior finish. Install the legs
into the threaded holes in the bottom of the bin.
Turn the leg levelers all the way in preparation for
leveling later. Return the bin to the upright position,
remove paper covering the bin gasket.
Install the bin top according to the directions with
the bin top.
Note: Do not push bin into position, but lift it there.
Pushing a bin, especially one with ice in it, can
cause damage to the legs and the leg mounts.
Ice Maker
The machine is heavy, so the use of a mechanical
lift is recommended for lifting the machine high
enough to install on top of the bin. After the unit is
placed on the bin, line it up so it is even with the
back side. Secure the machine to the bin with the
hardware provided with the machine.
Remove the front panel and remove any shipping
blocks.
Note: Be sure to allow a 6" minimum space above
the top of the machine for service.
Installation Limitations:
This ice system is designed to be installed indoors,
in a controlled environment: Min Max
Air Temperature 500F100
0
F
(Not including the remote condenser)
Water Temperature 400F100
0
F
Water Pressure 20 PSIG 80 PSIG
Voltage -5% +10%
(Compared to the nameplate)
Operating the machine outside of the limitations is
misuse and can 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 CUL.
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.
NME950R & FME1200R
December 1995
Page 4

FOR THE INSTALLER: Remote Condenser
Location
Limited to a 40 foot or a 25 foot length of
precharged refrigerant tubing connecting the ice
maker to the remote condenser. The condenser
must be above or level with the ice maker.
Select the best available location, protecting the
condenser from extremes of dirt, dust, and sun.
Meet all applicable building codes. Usually the
services of a licensed electrician are required.
Roof Attachment
1. Install and attach the remote condenser to the
roof of the building, using the methods and
practices of construction that conform to the local
building codes, including having a roofing
contractor secure the condenser to the roof.
2. Have an electrician connect the remote
condenser fan motor to the ice maker, using the
junction box at the back of the ice maker.
PRECHARGED LINE ROUTING
CAUTION
Do not connect precharged tubing until all routing
and forming of the tubing is complete. See the
coupling instructions, page for connecting
instructions.
1. Each set of precharged refrigerant lines (either
25 foot or 40 foot) consists of a 3/8 inch diameter
liquid line and a 1/2 inch diameter discharge line.
Both ends of each line have quick connect
couplings, one end has a schrader valve
connection, that end goes to the condenser.
Note: The openings in the building ceiling or wall,
listed in the next step, are the minimum sizes
recommended for passing the refrigerant lines
through.
2. Have the roofing contractor cut a minimum hole
for the refrigerant lines of 1 3/4 inch. Check local
codes, a separate hole may be required for the
electrical power to the condenser.
CAUTION
DO NOT KINK OR CRIMP REFRIGERANT
TUBING WHEN INSTALLING IT.
3. Route the refrigerant lines through the roof
opening.
Follow straight line routing whenever possible.
Any excess tubing MUST be retained within the
building.
4. Spiral the excess length of pre charged tubing
inside the building. Use a horizontal spiral (as
illustrated) to avoid any traps in the lines.
5. Have the roofing contractor seal the holes in
the roof per local codes.
Note: Precharged tubing contains a R-404A
holding charge. The entire refrigerant charge
required for the system is contained in the ice
machine.
Tubing illustration shows tight spiral; a spiral in the
field depends on tubing limitations. Tight spiral not
required.
Traps in tubing not required, they are included as
part of the Scotsman condenser and ice machine.
REMOTE CONDENSER
LOCATE REMOTE
CONDENSER
ABOVE ICE MAKER
SPIRAL
EXCESS
TUBING
INSIDE
BUILDING
NME950R & FME1200R
December 1995
Page 5

COUPLING INSTRUCTIONS
CAUTION
The couplings on the sets of precharged lines are
self sealing when installed properly. Carefully
follow the instructions:
Initial Connections:
1. Remove the protector caps and plugs. Wipe the
seats and threaded surfaces with a clean cloth to
be certain that no foreign matter remains on them.
2. Lubricate the inside of the couplings, especially
the O-Rings with refrigerant oil.
••The 1/2 inch discharge line (schrader valve
end) goes to the remote condenser fitting
marked "discharge line".
••The 3/8 inch liquid line (schrader valve end)
goes to the remote condenser fitting marked
"liquid line".
••The 1/2 inch discharge line goes to the ice
maker fitting marked "discharge line".
••The 3/8 inch liquid line goes to the ice maker
fitting marked "liquid line".
Final Connections:
3. Begin tightening the couplings together by
hand, then using two wrenches (it is important that
ONLY the nut on the precharged lines be turned,
the other parts of the couplings must NOT be
allowed to turn or the process will tear out the
diaphragms and they will be loose in the
refrigeration system) tighten the coupling until it
bottoms out or a definite increase in resistance is
felt.
4. Using a marker or pen, mark a line lengthwise
from the coupling union nut to the bulkhead. Then
tighten the coupling and additional 1/4 turn. As the
nut turns, the line will show when 1/4 turn is made.
5. After all connections are made, and after the
king valve has been opened, check the couplings
for leaks.
FOR THE INSTALLER: Precharged Lines
SCHRADER
VALVE NO SCHRADER
VALVE
TO REMOTE
CONDENSER TO ICE MAKER
3/8" LIQUID LINE
1/2" DISCHARGE
LINE
SERVICE PORTS
REMOTE CONDENSER
NME950R & FME1200R
December 1995
Page 6

FOR THE INSTALLER: Location
TWO UNITS ON ONE
CONDENSER
REMOTE
CONDENSER
EXCESS
PRECHARGED
TUBING INSIDE
BUILDING ICE MAKERS
SERVICE
ACCESS
SERVICE ACCESS
SIDE AND BACK
ROOF
CUTAWAY
WALL
CUTAWAY
NME950R & FME1200R
December 1995
Page 7

FOR THE PLUMBER
CONFORM TO ALL APPLICABLE CODES
Water Inlet
The recommended water supply is
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.
Drains
The cabinet has a 3/4" FPT drain.
connection. The drain is 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.
Storage Bin: A separate gravity type
drain needs to be run. Insulation of
this drain line is recommended.
FLOOR DRAIN
VENT BIN DRAIN
3/4" FPT
VENT ICE
MAKER
DRAIN,
3/4" FPT
WATER INLET
3/8" MALE
FLARE
FIELD
SUPPLIED
WATER FILTER
HAND SHUT
OFF VALVE
CONNECT TO
COLD WATER
NME950R & FME1200R
December 1995
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.
Electrically the remote condenser fan motor is
connected to the ice maker at the contactor
terminals for the compressor and the fan motor
operates whenever the compressor operates.
Electrical connections are made at the junction
box at the back of the ice maker and at the
junction box on the remote condenser.
The remote condenser must be wired to the ice
maker in accordance with local and national
electrical codes with a minimum of 18 Awg. wire
with an ground bonding wire connected to the
ground screws provided in both the condenser and
machine field wiring boxes. All outdoor wiring
must be in rain proof conduit.
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.
TERMINAL STRIP
FOR REMOTE
CONDENSER
ICE MAKER
JUNCTION BOX
POWER
SUPPLY
GROUND
THE
CHASSIS
RAIN PROOF
CONDUIT
NME950R & FME1200R
December 1995
Page 9

WARNING
Do all wiring with the electrical power
disconnected.
To install the KCMR230 fan relay kit when using
(2) 230 VOLT ice makers and one 230 volt, two
circuit remote condenser.
See the remote condenser nameplate for
current requirements to determine wire size
to be used for electrical hookup. Refer to
wiring diagram.
All external wiring should conform to the national,
state and local electrical codes. Usually an
electrical permit and services of a licensed
electrician will be required.
1. Mount the control box in a convenient location.
2. Attach a solid earth ground wire to the ground
screw.
3. Route connecting wires from the first ice maker
junction box
(marked condenser fan) and connect it to the
KCMR230 terminal strip marked: NO. 1 ICE
MACHINE.
4. Route connecting wires from the second
machine junction box
(marked condenser fan) and connect it to the
KCMR230 terminal strip marked: NO. 2 ICE
MACHINE.
5. Route connecting wires from KCMR230
terminal strip marked: TO REMOTE FAN and
connect at the remote condenser junction box.
6. Check phasing of the electrical circuit as follows:
A. The phasing of the wiring MUST now be
checked, as incorrect phasing will result in a failure
of the kit relay.
POSSIBLE LOCATION
FOR KCMR230
CONTROL BOX
FOR THE ELECTRICIAN: Fan Relay Kit
NME950R & FME1200R
December 1995
Page 10

Below is an illustration of the KCMR230 terminal
strip. Note that each terminal is marked:
1-2-3-4-5-6. For proper phasing:
Terminals #1 and #3 must be connected to the
same side of the line (such as L1)
Terminals #2 and #4 must be connected to the
same side of the line (such as L2).
B. Make a test with a volt meter as follows:
1. Switch on ice maker #1 first, then switch on ice
maker #2.
(The compressors must be operating for this test.
Do this after start up.)
2. Test with a volt meter between terminals #2
and #4, then between terminals #1 and #3.
Compare the readings obtained to the ones in the
following list:
C. Test terminals 1-2 = Full Voltage (208-230)
Test terminals 1-3 = No voltage
Test terminals 2-3 = Full Voltage
Test terminals 2-4 = No voltage
Test terminals 3-4 = Full voltage
Test terminals 1-4 = Full voltage
D. If there is full voltage where there should be no
voltage, turn off ice maker #2, (both switches)
Then turn off ice maker #1 (both switches). The
connections at the KCMR230 terminal strip
marked ice maker #1 must be reversed (put the
wire that was on 1 on 2 and the wire that was on 2
on 1). WARNING
Do all wiring with the electrical power
disconnected.
FOR THE ELECTRICIAN: Fan Relay Kit Phasing (Do After Start Up)
NME950R & FME1200R
December 1995
Page 11

FOR THE INSTALLER: Completed Installation
ROOF
CUT-AWAY
INSULATED
PRECHARGED
REFRIGERANT
TUBING
A typical installation should generally appear as
illustrated below. The remote condenser must be
located above the ice maker and the precharged
lines installed per the instructions on page 6.
NME950R & FME1200R
December 1995
Page 12

FOR THE INSTALLER: Final Check List
1. Is the ice system installed
indoors in a location where the
air and water temperatures are
controlled, and where they do
not exceed the design
limitations?
2. Is there an electrical service
disconnect within sight of the
installed machine? Has the
voltage been checked, and
compared to nameplate
requirements?
3. Have all the plumbing
connections been made and
checked for leaks?
4. Has the machine and bin been
leveled?
5. Is there a minimum of 6"
clearance at the rear, left, and
right of the machine for proper
service access and air
circulation?
6. Is the water pressure a
minimum of 20 psig?
7. Has the machine been
secured to the bin?
8. If two units on one condenser,
has the relay kit been installed?
9. Is there a water shut off valve
installed near the machine?
10. Is the remote condenser
installed per local building codes,
and in a place where it has
adequate ventilation and minimal
solar heat gain?
11. Has all shipping material and
literature (inside the front panel)
been removed from the units?
12. Have the remote condenser
and precharged lines been
properly installed?
13. Has the electrical connection
between the ice maker and the
condenser been made?
14. Verify that the master switch is in the OFF
position. 15. Switch on the electrical power.
16. Refer to Pre-Start instructions, the next page.
ROOF
HOLES
SEALED?
POWER
SUPPLY?
LEVELED?
PLUMBING?
REMOTE
CONDENSER
SECURED?
NME950R & FME1200R
December 1995
Page 13

START UP Pre-Start Inspection
1. Remove the front, left, and right side service
panels.
2. Check that any styrofoam shipping blocks have
been removed.
3. 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
turns freely (remote condenser).
4. Check that the refrigerant lines are properly
installed.
5. Check that the electrical power has been on for
at least 4 hours and that the compressor dome is
warm.
6. Check that the unit is installed correctly
according to the final check list on page 13.
Start Up
1. Go through the pre-start inspection.
2. Open the 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. Open the King Valve.
4. Turn the master switch on.
The electrical start up sequence is now on
automatic.
A. There should be a short (15 second) delay
before the gear motor starts.
B. After the gear motor starts, the liquid line valve
will open, the low pressure control will close and
the compressor will start.
5. The remote condenser fan turns, and the
condenser begins to discharge warm air.
6. The unit should soon be making ice, if desired
the low side pressure may be checked, it should
be 32 psig + or - 2 psig. The discharge pressure
will depend upon air and water temperatures, but
should be between 200 psig and 280 psig.
7. THERE ARE NO ADJUSTMENTS TO MAKE,
so replace the panels.
8. Clean and/or sanitize the storage bin interior,
wipe off the exterior with a clean, damp cloth.
9 Give the owner/user the service manual, instruct
him/her in the operation of the unit, and make sure
they know who to call for service.
10. Fill out the warranty registration, and mail it to
the Scotsman Factory.
NME950R & FME1200R
December 1995
Page 14

COMPONENT DESCRIPTION
Control Box: Contains the electrical controls that
operate the machine.
High Pressure Cut Out: A manual reset switch
sensing the high side refrigeration pressure. It is
set to shut the machine off at 400 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 Discharge Chute: Directs the ice produced
by the evaporator into the storage bin.
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.
Gear Motor: An oil filled, speed reduction
gearbox, driving the auger.
Cleaning Drain Tube: When uncapped and
lowered, drains the evaporator.
Compressor: The refrigerant vapor pump.
Expansion valve: The refrigerant metering
device.
CONTROL BOX
EXPANSION VALVE
WATER LEVEL
SENSOR
RESERVOIR
CLEANING
DRAIN TUBE
EVAPORATOR
GEAR MOTOR
ICE LEVEL
SENSOR
HIGH PRESSURE
CUT OUT
COMPRESSOR
ICE CHUTE
NME950R & FME1200R
December 1995
Page 15

COMPONENT DESCRIPTION: Control Box
Contactor: A definite purpose contactor
connecting the compressor and the remote
condenser fan motor to the power supply.
Circuit Board: Controlling the ice machine
through sensors and relays. The sensors are: 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 liquid line valve.
Transformer: Supplies low voltage to the circuit
board.
Pump Down Control: An automatic reset
pressure switch connected to the low side of the
refrigeration system. Controls the compressor.
Potential Relay: The compressor start relay.
On/Off Switch: Manual control for the machine.
CONTACTOR
ON/OFF SWITCH
PUMP DOWN CONTROL
POTENTIAL RELAY
TRANSFORMER
CIRCUIT
BOARD
NME950R & FME1200R
December 1995
Page 16

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 liquid line relay and auger motor relay
become energized, connecting power to the
liquid line solenoid coil and to the windings of
the auger motor.
••The liquid line solenoid opens, raising the low
side pressure.
••The pump down control closes.
••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 liquid line solenoid closes, lowering the
suction pressure.
••The pump down control opens.
••The compressor contactor opens
••The compressor stops
••The auger motor is run by the circuit board for 2
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:
••The high pressure control will stop the machine
immediately if it opens. It is manually reset at
the control.
••The master switch is the manual control for the
complete machine, but it is not a service
disconnect.
ELECTRICAL SEQUENCE NME950R & FME1200R
December 1995
Page 17

OPERATION: Water
Water enters the machine through the 3/8" male
flare at the rear of the cabinet, goes to the water
reservoir which it enters through the float valve.
The water them goes out the bottom of the
reservoir tank to the bottom of the evaporator.
Reservoir overflow or evaporator condensation is
routed to the drain.
RESERVOIR DRAIN TUBE
WATER LEVEL
WATER
INLET
DRAIN
NME950R & FME1200R
December 1995
Page 18

OPERATION: Refrigeration
Beginning at the compressor, the refrigerant is
compressed into a high temperature gas. The
discharge line directs this gas to the condenser.
At the remote condenser the gas is cooled by air
and it then condenses into a liquid. This high
pressure liquid then goes through the liquid line to
the head pressure control valve, into the receiver,
through the liquid line valve and then through 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.
REMOTE CONDENSER
DETAIL OF HEAD
PRESSURE CONTROL
VALVE
EVAPORATOR
DISCHARGE
LINE LIQUID LINE
HEAD
PRESSURE
CONTROL
VALVE
RECEIVER COMPRESSOR
Refrigeration Schematic
KING
VALVE SUCTION
LINE
THERMOSTATIC
EXPANSION
VALVE
LIQUID LINE
VALVE
System Information @ 90oF. air and 70oF. water.
••Suction pressure: 35 PSIG
••Discharge pressure: 255 PSIG
••Minimum Discharge pressure (low temp): 180 PSIG
Compressor Amps
••3 Phase - 2.8
••Single Phase - 4.3
NME950R & FME1200R
December 1995
Page 19

OPERATION: Refrigeration
Low Condensing Temperature
The refrigeration system under low condenser air
temperatures is much the same as it is under
higher temperatures, with the exception that the
resulting low head pressures cause the head
pressure control to close off the liquid line between
the condenser and the receiver. This forces more
refrigerant into the condenser (with a small amount
of discharge gas going into the receiver to
maintain pressure until the head pressure is built
back up to the rated gauge pressure of 180 psig).
At that pressure the valve opens up the liquid line
from the condenser to the receiver.
OPERATION: Refrigeration PUMP DOWN
During the pump down cycle (usually initiated by
the circuit board de-energizing the liquid line valve)
the discharge gases flow through their normal path
to the remote condenser, through the head
pressure control, and into the receiver. At this
point the refrigerant flow is stopped by the closed
liquid line valve. This action forces the refrigerant
into the receiver and keeps it out of the
compressor. The pump down continues until the
low pressure control turns the compressor off.
SCHEMATIC OF DISCHARGE PRESSURE
CONTROL VALVE, Normal Temperature
From
Condenser
To Receiver
From
Compressor
Valve
Disk
From
Condenser
From
Compressor
To Receiver
SCHEMATIC OF DISCHARGE PRESSURE
CONTROL VALVE, Low Temperature
NME950R & FME1200R
December 1995
Page 20