Scotsman CME256 Service Manual

Introduction:

CME256, 506, 656, 806: AutoIQ™ Cubers

This product manual contains the information
needed for the setup, installation, initial start up,
sanitation and maintenance of this ice machine.
Keep it for future reference.

All series of these 4 models are covered in this
manual:

CME256, a 115 volt, single evaporator

•

machine
CME506, a 115 volt, dual evaporator

•

machine (115 volt if 60 Hz, 230 volt if 50 Hz)
CME656 and CME806, 230 volt, dual

•

evaporator machines

Table of Contents

Specifications: ................. page 2

Pre-Installation ................ page 3

Location & Assembly: ............. page 4

Stacking: ................... page 5

Plumbing: ................... page 6

Electrical: ...................page 7

After Utility Connections: ........... page 8

Component Location and Function: ...... page 9

AutoIQ Controller: ............... page 10

Initial Start Up: ................. page 11

Adjustments: ................. page 12

Adjustments: ................. page 13

How To Operate The AutoIQ Controller . . . page 14

How The Electronic Cuber Works ....... page 15

Technicians Only: Freeze Cycle Operational Sequence

.........................page 16

Be certain that the information applies to the
model in question. If no model is listed, the
information applies to all models, including A
through H series.

This manual is organized in the same way as the
expected use of the machine, it begins with
specifications, goes thru unpacking and setup,
shows where everything is; continues with initial
start up, then describes how it works. After that is
the sanitation section, followed by service
diagnosis and repair.

Additional Maintenance: Water Distributors . page 20

Additional Maintenance: Inlet Water Valve Screen

.........................page 21

Additional Maintenance: Bin Controls, Condenser

.........................page 22

Service Diagnosis: Controller Diagnostic Light Analysis

.........................page 23

Service Diagnosis ............... page 24

Service Diagnosis: Components ....... page 25

PTCR Diagnosis ............... page 26

Operational Characteristics: CME256 .... page 27

Operational Characteristics: CME506 .... page 28

Operational Characteristics: CME656 .... page 29

Operational Characteristics: CME806 .... page 30

Removal and Replacement .......... page 31

Removal and Replacement .......... page 32

Removal and Replacement: Sensors ..... page 33

Technicians Only: Harvest Cycle Operational Sequence

.........................page 17

Sanitation and Cleaning ............ page 18

Additional Maintenance ............ page 19

June 2007

Page 1

Removal and Replacement: Fan Blade and/or Fan

Motor .....................page 34

Access Valves: ................ page 35

Before

Calling for Service ........... page 36

Printed on Recycled Paper.Parts lists are in the center section.

CME256, 506, 656, 806: AutoIQ™ Cubers

Specifications:

These ice machines are designed to be installed
indoors, in a controlled environment. They can
operate satisfactorily under a wide variety of
conditions. However, Do NOT operate the
machine where it has not been designed for. Do
NOT operate the machine in temperatures it has
not been designed for. Do NOT operate the
machine above or below the voltage limits for the
particular model. Do NOT operate the machine
with too little or too much water pressure.

CME256 or CME506 Operational Limits

Minimum Maximum

Air Temperature 50oF. 100oF.
Water Temperature 40oF. 100oF.
Water Pressure 20 psi 80 psi
Voltage (115 volt model) 103 126
Voltage (208-230 volt mdl) 198 253
Voltage (230 volt model) 207 253

CME656 or CME806 Operational Limits

Minimum Maximum

Air Temperature 50oF. 100oF.

Water Temperature 40oF. 100oF.

Water Pressure 20 psi 80 psi

Voltage (60 Hz model) 198 253

Voltage (50 Hz model) 207 253

All models will fit a standard, 30" wide Scotsman
Ice Storage Bin. Some examples are:

BH550; HTB555; HTB350; HTB250

•

The CME256 and CME506 are the typical models
used in hotel applications and they fit the
Scotsman HD30 dispenser without an adapter. All
models fit the ID200 or ID250 dispensers which
require a KBT44 adapter. Check Scotsman’s sales
literature for other application information.

Note: These machines fill the bin very full, up to
the base of the ice machine. Bin Model BH550
may need kit KBaffle1. In some cases the ice
level in the bin may be too high for a customer's
needs. A thermostat kit is available to lower the ice
level, its part number is A37749-001.

A stacking kit, for like models

,isKSCME6-30.

Scotsman reserves the right to make design
changes and/or improvements at any time.
Specifications and designs are subject to change
without notice.

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 parts and/or other components not
specifically approved by Scotsman.

BASIC INFORMATION

Current Model
Number

CME256AS-1H 30 x 24 x 27 115/60/1 Air Cooled 16 20
CME256WS-1H same 115/60/1 Water Cooled 16 20
CME256AS-32H same 208-230/60/1 Air Cooled 7.9 15
CME506AS-1H same 115/60/1 Air Cooled 19 20
CME506WS-1H same 115/60/1 Water Cooled 19 20
CME506AS-6H same 230/50/1 Air Cooled 7.9 15
CME506WS-6H same 230/50/1 Water Cooled 7.1 15
CME506AS-32H same 208-230/60/1 Air Cooled 8.9 15
CME656AS-32H same 208-230/60/1 Air Cooled 13.6 20 36 ounces
CME656WS-32H same 208-230/60/1 Water Cooled 12.7 20 26 ounces
CME656AS-3H same 208-230/60/3 Air Cooled 6.6 15 36 ounces
CME656WS-3H same 208-230/60/3 Water Cooled 5.8 15 26 ounces
CME656AS-6H same 230/50/1 Air Cooled 13.4 20 36 ounces
CME656WS-6H same 230/50/1 Water Cooled 12.6 20 26 ounces
CME806AS-32H same 208-230/60/1 Air Cooled 17.5 20 32 ounces
CME806WS-32H same 208-230/60/1 Water Cooled 16.0 20 24 ounces
CME806AS-6H same 230/50/1 Air Cooled 17.6 20 32 ounces
CME806WS-6H same 230/50/1 Water Cooled 16.2 20 24 ounces

Dimensions
W"xD"xH"
(w/o bin)

Basic
Electrical

Condenser
Type

Minimum
Circuit
Ampacity

Maximum
Fuse Size

Refrigerant
Charge
(R-404A)

see page

27

see page

28

February 2007

Page 2

CME256, 506, 656, 806: AutoIQ™ Cubers

Pre-Installation

Other Applications:

Models CME256 or CME506 may be placed on
certain Ice Dispensers, including Scotsman
models: HD30, ID200 and ID250.

Check with other dispenser manufacturers for
recommendations regarding application.

Check the nameplate for electrical requirements.
The nameplate is located on the back of the ice
machine. While the model and serial number are
on the nameplate, a serial number plate is located
at the front of the machine, below the metal control
box.

Water:

There is no such thing as pure water. There are
two ways water can contain impurities: in
suspension or in solution. Suspended solids can
be filtered out. In solution or dissolved solids must
be diluted or treated. Water filters are
recommended to remove suspended solids. Some
filters have treatment in them for suspended
solids. Check with a water treatment service for a
recommendation.

Location of Nameplate

(on the back, plus a serial plate

is behind the front panel)

Nameplate

Cube Ice machines use more water than what
ends up in the bin as ice. While most water is used
during ice making, a portion is designed to “rinse”
out the water system to keep hard water scale
from clogging up the machine. That water rinse,
combined with water filters, prolongs the times
between needed water system cleaning.

Note: All Scotsman CM3models, like those
described in this manual, feature Scotsman’s
AutoIQ™ control system and ReliaClean™ water
system cleaning process.

Service Technicians
factory at a “standard” water rinse, which is
compatible with typical water conditions. The
ReliaClean™ water system provides an
adjustment method so to the amount of water
rinsed per cycle can be changed. If the prior ice
machine worked acceptably well with the local
water conditions, leave the machine at the factory
setting. If severe water conditions are present, and
water filters do not solve the problem acceptably,
adjust the machine to use more water. If water
conditions are excellent, adjust the machine to use
less water. See the Adjustments section.

: All models are set by the

Back View Diagram (air cooled)

Top View Diagram

Note: Water use adjustments are customer
convenience adjustments; they are NOT factory
defects and are NOT covered by warranty.

July 2004

Note: Although the machine will function, ice capacity of
air cooled machines will be significantly reduced with
only 6 inches of clearance at the sides, back and top.

Page 3

CME256, 506, 656, 806: AutoIQ™ Cubers

Location & Assembly:

Air cooled models take room temperature air in
from the left and right sides, and discharge warm
air out the back. If installed in a corner or with
another cabinet next to the right side, an air baffle
could be installed on the back of the cabinet to
minimize air re-circulation.

A 6 inch minimum clearance on the back, left and
right sides is required for operation and service of
this machine.

Air Flows in the Sides

and Out the Back

Cabinet Panel Removal:

Note: The top panel holds the upper edges of the
side panels in place.

1. Front Panel, “A” series: Remove the front
panel by removing the four screws connecting the
front panel to the left and right sides.

Remove

Second

Note: Although the machine will function, ice
capacity of air cooled machines will be
significantly reduced with only 6 inches of
clearance at the sides, back and top.

Unpacking and Assembly:

Begin with unpacking the ice storage bin. Remove
the carton, and using part of the carton as a
cushion, tip the bin on its back to remove the skid
and attach the legs or casters. Note: Stacked
applications may not use casters.

Return the bin to an upright position. Check the bin
top gasket for gaps and tears, fill any in with food
grade sealant prior to placing the ice machine on
the bin.

If the ice machine has not been unpacked, do so
now. Remove the carton from the skid. Lift the ice
machine off the skid directly onto the bin.

Note: The machine is heavy! Use a mechanical
hoist if necessary.

Remove

First

Removal of Panels

Front Panel “C thru H” Series: Remove top two
screws, and pull the bottom of the panel away
from the machine to unsnap it from the machine.

2. Remove 2 screws at the front edge of the top
panel, and pull the top panel forward until it
releases from the tabs connecting it to the back
panel.

3. Remove the screws at the front edge of each
side panel, and pull them forward until they
release from the tabs connecting them to the back
panel.

Secure the ice machine to the bin with the
hardware provided (two metal straps and 4 bolts).

July 2007

Page 4

CME256, 506, 656, 806: AutoIQ™ Cubers

Stacking:

Models CME256, CME506, CME656 and CME806
may be stacked together in any combination. Use
kit number KSCME6-30:

1. Remove the front, left side and top panels from
the bottom machine. Discard the top panel.

2. Remove the front and left side panels from
the top machine.

3. Place the upper machine onto the lower
machine. Check that the tabs on the top of the
freezing compartment in the lower machine
engage the slot in the base of the upper
machine (around the cube port).

4. Fasten the upper cabinet to the lower
cabinet with the hardware (two metal straps
and four bolts) provided with the machine.

5. Knock out 1 hole in the upper left (viewed
from the front) corner of the lower unit’s back
panel. Knock out the hole in the lower left
(viewed from the front) corner of the upper
unit’s back panel.

Mounting Strap,

Machine to

Machine

6. Position the strain reliefs over the wrapped
portion of the stacking kit wire harness.

Route the Stacking Kit Wire Harness from the
back to the top and bottom machines thru the
holes made in step 5. The harness is marked
which end goes to which machine. Push the
strain reliefs into place from the back of the
machines.

Follow local electrical codes for 24 volt wire.

In the lower unit, route the wire behind the
suction line and thru the snap bushing just
below the Controller. Tape any excess wire to
the insulated suction line.

In the upper unit, route the harness thru the
snap bushing just below the System
Controller.

Plug one end into each Controller connection
number 7.

7. Place insulation pad from the kit over the
reservoir drain tubing in the upper machine.
Make certain that the insulation is in contact
with the tubing.

Mounting Strap,

Machine to Bin

Wire Harness from

Stacking Kit

8. Return all panels to their normal places.

Stacking Like Models

July 2002

Page 5

CME256, 506, 656, 806: AutoIQ™ Cubers

Plumbing:

All models require an adequate potable water
supply and a gravity drain. The recommendations
for tubing are: Water supply to be

3

“ OD. Drain to

8

be ¾ “ OD.

Supply:

Air cooled models have 1 water supply connection,

3

a

“ male flare at the back of the cabinet. Water

8

cooled models have an additional
condenser inlet connection at the back of the
cabinet.

Potable Water

Inlet

Condenser
Water Inlet

3

” FPT

8

Water Cooled

Plumbing

Connections

Drain:

Air cooled models have 1 gravity drain connection,
a ¾ “ FPT fitting at the back of the cabinet.

It must be vented at the back of the cabinet.

Water cooled models have an additional
condenser drain, it isa½“FPTfitting at the back
of the cabinet. Do not vent this drain.

The ice storage bin will have a drain out the back
or base, depending upon the model. Note:
Scotsman HTB555 (shown in this manual) may be
drained either out the back or the base.

Condenser

Drain

Potable

Water Inlet

Optional

Filter

Reservoir

Drain, Must

Be Vented

Separate

Drains for

Bin and

Machine

Plumbing

Connections

July 2002

HTB555

Drains

Insulation is recommended for the ice machine
reservoir and bin drains.

Follow all applicable codes

Page 6

CME256, 506, 656, 806: AutoIQ™ Cubers

Electrical:

All models must be installed with the correct wire
size and type per the National Electric Code.
Locate the nameplate on the back of the cabinet
and find the numbers for Voltage, Phase, Minimum
Circuit Ampacity and Maximum Fuse Size. Either
fuses or HACR type circuit breakers may be used.

Electrical connections are made in the junction box
in the back of the cabinet.

1. Remove the junction box cover.

2. Knock out 1 hole for a field supplied strain relief.

3. Install wires and strain relief per code.

4. Connect to wires and secure ground wire to
ground screw inside junction box.

Follow all Local, State and National codes.

Junction Box

Electrical Access

Electrical Connection

July 2002

Page 7

CME256, 506, 656, 806: AutoIQ™ Cubers

After Utility Connections:

1. Level the cabinet, use the leg levelers on the
end of the legs to adjust the cabinet height.

2. Wash out the bin. If desired, the interior of the
bin could be sanitized.

3. Locate the ice scoop (if supplied) and have it
available for use when needed.

Final Check List:

1. Is the unit located indoors in a controlled
environment?

2. Is the unit located where it can receive
adequate cooling air?

3. Has the correct electrical power been supplied
to the machine?

4. Have all the water supply connections been
made?

5. Have all the drain connections been made?

6. Has the unit been leveled? The unit must be
leveled at the water reservoir.

7. Have all unpacking materials been removed?

8. Is the water pressure adequate?

9. Have the drain connections been checked for
leaks?

10. Has the bin interior been wiped clean or
sanitized?

11. Have any water filter cartridges been
replaced?

July 2002

Page 8

CME256, 506, 656, 806: AutoIQ™ Cubers

Component Location and Function:

Reservoir: Contains the water charge used for
every batch of ice.

Water Inlet Valve: Opens to allow water into the
reservoir.

Water Level Sensor: Controls the size of the ice
cube by measuring how much water is used in a
cycle. It consists of a float, stem and electric eye.
The stem will move slightly when the pump is on,
this is normal. As the machine makes ice the
reservoir water level will fall and the visible portion
of the stem will slide down thru the slot in the
sensor body.

AutoIQ Controller: Controls the complete
operation of the ice machine. Turns it on and off;
switches it between cycles; shows information via
indicator lights; and shuts the machine down if
there is a problem.

Evaporators/Freezing Compartment: Location of
the evaporators. Ice forms on the evaporators and
is released when warmed up during the harvest
cycle. The freezing compartment is fully insulated
for maximum efficiency.

Cube Deflector: The slots in the inclined deflector
let the water falling from the evaporators back into
the reservoir, but when ice falls during harvest, the
ice slides off into the bin.

Refrigeration Service Access Valves: Only to be
used by a certified technician. Allows access to the
refrigeration system for diagnostic information.

Water Pump: Forces the water from the reservoir
to the top of the evaporator(s). The motor is
separated from the reservoir water to minimize
contact with the water.

Compressor: The refrigerant vapor pump, it
forces the refrigerant to flow thru the refrigeration
system tubing.

Hot Gas Valve: Closed during freeze, it opens
during harvest to divert hot discharge refrigerant
gas into the inlet of the evaporators.

Condenser: Either air or water cooled, discharges
the heat produced in ice making.

Access Valves

AutoIQ

Controller

Compressor

Water Pump

Water Level

Sensor

Reservoir

Evaporators

Cube

Deflector

Inlet Water

Valve

July 2002

Page 9

Component Location

CME256, 506, 656, 806: AutoIQ™ Cubers

1

2

3

4

5

6

7

89

BIN FULL

FREEZE

HARVEST

CLEAN

OFF

WATER

REFRIGERATION

Reservoir Water

Level Sensor

Bin Control Sensor

Bin Control Sensor

Reservoir & Discharge

Line Thermistors

Low Voltage In/out

Water Valve

Hot Gas Valve

Contactor Coil

Stacking

Future Use

Factory Use

Push Button

Control Switches

Hi Voltage In/out

Water Pump

Air Cooled Fan Motor

Indicator Lights:

Diagnostic Lights

AutoIQ Controller:

Indicator Lights:

Bin Full: On when bin is full, goes on and

•

off as ice falls during a harvest cycle.
Freeze: On when the unit is in the Freeze

•

cycle, blinks when a freeze mode is
pending.

Harvest: On when the unit is in the Harvest

•

cycle.
Clean: On when the unit is in the Clean

•

cycle, blinks when preparing for a clean
mode.

Off: On when the unit has been switched

•

off, blinks when the machine is preparing to
shut off.

Water Error: On when the controller has

•

identified a problem with the water system.
Refrigeration Error: On when the controller

•

has identified a problem with the
refrigeration system.

Cycle Definitions:

Freeze: The refrigeration system is

•

operating to remove heat from the
evaporators. The compressor, fan motor (if
air cooled) and water pump are ON.

Harvest: The refrigeration and water

•

systems are operating to harvest the ice
cubes. While the compressor is on for the
full cycle, the water pump will be off at the
beginning and inlet water valve will switch
off before the end.

Clean: The Inlet Water Valve opens to fill

•

the reservoir, The Water Pump starts. The
Clean indicator light is switched ON. A
manually initiated rinse flushes the system.

AutoIQ Controller: Wire Connections, Push Buttons, and Indicator Lights

July 2002

Page 10

Initial Start Up:

CME256, 506, 656, 806: AutoIQ™ Cubers

1. Remove the front panel.

2. Locate the AutoIQ Controller.

3. Switch on the electrical power. Note that the

indicator lights all flashed on briefly.

4. Open the water supply valve.

5. Push and release the Freeze cycle push button

(the Freeze indicator light will blink until the
compressor starts). The next several operations
are automatic.

Initial Start Sequence

The Freeze light is blinking.

•

The Hot Gas Solenoid valve is open.

•

The inlet water valve opens to fill the

•

reservoir. The inlet water valve will shut off
when the reservoir is full.

The water pump starts to pump water.

•

The inlet water valve opens again to refill the

•

reservoir.
After 30 seconds the compressor starts.

•

After 5 seconds the hot gas valve closes.

•

Freeze Cycle:

•

The Freeze indicator light will come on. The
machine will stay in a Freeze cycle for many
minutes. Slush may appear in the reservoir,
it is temporary and normal.

•

Under certain conditions, the pump may
stop for a few seconds. After that the inlet
water valve will refill the reservoir.

•

The fan motor (of air cooled models) will
begin to turn and soon warm air will be
forced out the back of the cabinet.

•

The freeze cycle will continue until the water
level in the reservoir drops to its factory set
point, then the Harvest Cycle will begin.

Harvest Cycle:

•

The Harvest indicator light will be ON,

•

The hot gas valve will open.

•

The water pump will stop. It will restart in
less than a minute.

•

The Inlet water valve will open. The machine
will fill the reservoir and overflow it for a
specified number of seconds then shut off.
The harvest cycle may still be in progress.

•

The Bin Full indicator light will go on and off
as ice falls from the evaporators.

6. Machines are shipped from the factory with the
purge level set to accommodate average water
conditions. See page 13 for purge adjustment
instructions.

24 hours of run time may be need to attain full ice
making capacity.

7. The machine’s correct
ice falling from the evaporator in vertical strips of 8

- 10 cubes; the top 2 cubes might fall individually.

8. After a few minutes the machine will return to a
freeze cycle.

9. Fill out the Customer Evaluation and Warranty
Registration. Send it to Scotsman.

10. Replace the front panel.

11. Inform the user of the location and telephone
number of the local service company. Also inform
the user of the required maintenance of the
machine.

cube size should result in

Notes On Operation:

1. The electric eyes signal the ice machine to shut
off whenever the bin becomes full. After the eyes
sense that there is ice between them, the ice
machine will shut off at the end of the next harvest
cycle. This last harvest cycle will be longer than
the rest.

2. After the bin has filled the ice machine will not
be able to restart for 4 minutes. However, if
needed, the Freeze button may be pushed and the
unit will restart.

For example: If ice is removed from the bin
immediately after the machine has filled up and
shut off, the machine will not restart for 4 minutes.

3. If the bin controls sense a bin full signal before
any water is used (float stem up), the machine will
shut off on bin full.

July 2004

Page 11

CME256, 506, 656, 806: AutoIQ™ Cubers

Adjustments:

If there was a problem during Initial Start
Up:

If an error light came on, check the following.

1. Water error.

A water error could have been determined by the
System Controller if the inlet water valve does not
fill the reservoir, or if the water pump does not start
and lower the water level.

2. Refrigeration error.

A refrigeration error could have been determined
by the System Controller if the water temperature
did not drop during the freeze cycle. The controller
will next check the compressor discharge
temperature, If the discharge temperature is too
low, the refrigerant error light will be switched on,
and the machine will Shut Down.

Note: Reset and restart the machine by pushing
and releasing the Off push button switch, and then
pushing and releasing the freeze push button
switch.

How to Adjust Cube Size (Reference Only)

The adjustment is done by moving the long screw
located in the floating stem at the front of the
machine.

Note: Units manufactured beginning 3/97 do not
have a cube size adjustment screw; their cube
size is fixed.

Cube Size

Adjustment

Screw

Adjustment of

Cube Size

1. Remove the front panel.

2. Locate adjustment screw, and

To increase the cube size, turn the screw out
(counter clockwise)

To decrease the cube size, turn the screw in
(clockwise)

Turn the screw 2 turns at a time.

3. Check cube size after the next freeze cycle,
repeat step 2 if needed.

Cube Size Diagram

Side View, Cube

should be 1/2" thick

at the center

July 2002

Page 12

Front View,

Cube is 1.5" x 1.4"

Adjustments:

CME256, 506, 656, 806: AutoIQ™ Cubers

How to adjust the water cooled discharge
pressure

Water cooled models use a water regulating valve
to control how much cooling water flows thru the
water cooled condenser. At the top of that valve,
located in the right rear corner of the ice machine,
is an adjustment stem.

To Adjust:

1. Attach a refrigeration manifold gage to the

discharge access valve.

2. While the unit is in the freeze cycle, determine

the discharge pressure, it should be about 245
PSIG.

3. If needed, rotate the adjustment stem to

increase or decrease the pressure:

Water

Regulating

Valve

Adjustment

Screw

Adjusting Water Cooled

Discharge Pressure

A. To increase discharge pressure (reduce water
flow) rotate the stem counter-clockwise.

B. To decrease the discharge pressure (increase
water flow) rotate the stem clockwise.

Remove the manifold when done. Note: The water
outlet temperature should be between 100-110
when the valve is properly set.

Thermostatic Expansion Valve:

The TXV is not adjustable, do not attempt to adjust
it.

How to Adjust the Amount of Water Purge

Adjustment is done by use of the control buttons
on the AutoIQ Controller. Examine the next section
to become familiar with the Controller before
beginning.

1. If the machine is on, push and hold the OFF
button for more than 3 seconds, then release it.
This switches the machine Off.

2. Push and hold the OFF button for more than 3
seconds (just until all lights flash on) then release
it. Do not hold it in it too long.

3. Examine the green lights. They should have all
flashed once, then certain ones will have turned on
to indicate which purge level the machine is set at.
There are 5 levels of purge available:

1. Maximum Purge is when All 5 lights are

•

ON. Use for extreme water conditions. Note:
This setting may extend the Harvest cycle
and reduce capacity.

2. Heavy Purge is when these 4 lights are

•

ON: Freeze
severe water conditions.

, Harvest, Clean,Off. Use for

• 3. Standard Purge (factory setting) is when

these 3 lights are ON: Harvest
Use for moderate to severe water
conditions.

•

4. Moderate Purge is when these 2 lights
are ON: Clean
conditions.

•

5. Minimum Purge is when this light is ON:
Off

. For excellent water conditions.

Adjust by pushing and releasing the Freeze
button. Pushing and releasing the Freeze button
increases the purge one level up to the maximum,
then it goes to the minimum.

4. The machine will automatically restart after 60
seconds of no switch inputs, or restart the machine
by pushing in and holding the Off button for more
than 3 seconds, then releasing it. The unit will then
be Off. From there the machine may be placed in
a freeze cycle by pushing and releasing the
Freeze button.

,Off. This is for typical water

, Clean,Off.

July 2002

Page 13

CME256, 506, 656, 806: AutoIQ™ Cubers

1

2

3

4

5

6

7

89

BIN FULL

FREEZE

HARVEST

CLEAN

OFF

WATER

REFRIGERATION

Push Buttons

Indicator Lights

Diagnostic Lights:

How To Operate The AutoIQ Controller

The AutoIQ Controller is a
microprocessor based device that
receives input from several sources
and switches various components on
and off.

Its manual control is thru the use of
the Push Button Control Switches

1. Freeze Button. Pushing and
releasing this button starts or restarts
the machine. The System Controller
remembers what cycle it was last in
and returns to that cycle.

2. Harvest Button: Pushing and
releasing this button will cause the
machine to go directly to a Harvest
Cycle. Can be done from Freeze or
Off. The machine will switch Off at the
end of the Harvest cycle.

3. Clean Button: Pushing and
releasing this button will cause the
machine to only power the water
pump for circulation of ice machine
cleaner. After the ice machine
cleaner has circulated for about 10
minutes a second push of this button
will switch on the rinsing system to
flush out the dissolved scale and ice
machine cleaner.

4. Off Button: Pushing and releasing
this button will switch the machine
OFF at the end of the next cycle. If the
button is pushed and HELD for more
than 3 seconds, the unit will switch off
immediately.

To Reset Machine (machine off, error
light on): First push and release the
Off button, then push and release the
Freeze button.

To Recall the last two diagnostic codes: Push
and hold the Off button until the machine shuts off.
Then push and hold the Off button again until the
green lights flash on. Push and release the
Harvest button to recall the most recent diagnostic
code. Push and release the Harvest button again
to recall the second to last diagnostic code (the bin
full light will be on when the second to last code is
displayed). If no code is displayed, there was none
recorded. Push and release the off button again to
return to the normal setting.

Controller Indicator Light Description

July 2004

Page 14

CME256, 506, 656, 806: AutoIQ™ Cubers

How The Electronic Cuber Works

This section is intended for the technician. It is not
necessary for the normal operation and
maintenance of the machine.

The AutoIQ Controller operates the ice machine by
monitoring several input measures and switching
various loads on and off.

Water System:

Water flows into the ice machine during the
harvest cycle thru the inlet water valve. The water
valve will NOT be open the complete length of the
harvest cycle. The water pump forces water to the
top of the evaporators, both in the Freeze and
Harvest cycles. Un-frozen water falls thru the cube
deflector and back into the reservoir. As water is
turned into ice, the water level in the reservoir falls,
and at the point where the cubes are fully formed,
the Water Level Sensor indicates to the Controller
that it is time to begin the Harvest cycle.

During the Harvest cycle, water again enters the
water reservoir, and overfills it to rinse the
reservoir of accumulated minerals. It does
NOT overflow for a fixed
time, but for a time determined by
the Controller.

amount of

Refrigeration System:

The refrigeration system is similar to that of most
commercial cube ice machines. Heat is removed
from the water and discharged out the condenser
during the freeze cycle. As liquid refrigerant
passes thru the Thermostatic Expansion Valve(s),
it enters the bottom of the evaporators, and will
form on the bottom first. Later CME506 models
have check valves to help direct the flow of
refrigerant to the correct distributor.

When cubes need to be released (Harvest) the
Hot Gas Bypass Valve is opened and hot
discharge gas flows directly from the compressor
to the evaporator inlets. This warms up the
evaporators and the surface of the ice frozen to
the evaporator surface melts. Ice then falls into the
bin.

Hot Gas Valve

Thermostatic

Expansion Valve

Water

Distributors

The water pump will be off
for a short period of
time at the beginning
of harvest.

Compressor

Water Cooled

Condenser

Reservoir

Evaporators

Cube

Deflector

Drain

Water Pump

July 2007

Page 15

Inlet Water Valve

Water and Refrigeration

Schematic - Note: CME506 E Has

Two Expansion Valves

CME256, 506, 656, 806: AutoIQ™ Cubers

Technicians Only: Freeze Cycle Operational Sequence

Assuming the machine has been operational, the
Freeze cycle begins with the end of the Harvest
Cycle:

Reservoir is full

•

Condenser fan is OFF

•

Water Inlet Valve is OFF

•

Water Pump is ON

•

Compressor is ON

•

Hot Gas Valve is ON

•

Controller Operation, Beginning freeze:

1. Switches on the Freeze indicator light and shuts
off the hot gas valve.

2. Measures and stores the discharge
temperature.

3. Starts the fan motor (air cooled only). Some
early units have a fan control switch, it shuts the
fan off if the discharge pressure drops below 190
PSIG. Machines built beginning in August 1996 do
not have a fan control switch, instead the
Controller checks the discharge temperature and
cycles the fan every 30 seconds if the temperature
is low (below 125oF. or more than 3381 ohms).

If the discharge temperature exceeds the design
maximum (250oF. or less than 377 ohms), shuts
the machine down on a Refrigeration Error.

4. Checks for a “bin full" signal throughout the
cycle.

5. Measures the reservoir water temperature. If the
machine is operating correctly, the reservoir water
temperature will fall at a standard rate. The
Controller will be checking to see if the water
temperature fall matches that rate.

6. Once per cycle the machine may
water pump. It only does this when the water
temperature reaches a preset minimum (38oF. or
27835 ohms). The pump will only be off for a few
seconds. After the pump restarts, the inlet water
valve opens to refill the reservoir.

7. As the machine makes ice, the water level in the
reservoir will ultimately fall to the Harvest Level
(when the top electric eye in the water level sensor
is disrupted by the adjustment screw).

Note: If the freeze cycle exceeds the preset
Maximum (50 minutes), the Controller will Shut
Down on a Refrigeration Error.

8. The end of Freeze cycle will see the machine in
this state:

Water level = below harvest position

•

Condenser fan will be off

•

Water inlet valve will be off

•

Water pump will be ON

•

Compressor will be ON

•

Hot gas valve will be off

•

At this point Harvest begins and the Controller
switches the Harvest indicator light ON.

Note: If there is a power interruption, the system
controller will automatically restart the machine
with a process that begins with getting the
machine back to a normal state: water re-fills, the
unit freezes for 30 seconds and then goes into a 4
minute harvest. It will then proceed to a new
Freeze cycle. While in an electrical restart mode,
the controller’s Freeze light will be blinking - even
when the machine is in harvest.

shut off the

If not, it re-checks the discharge line temperature.
If too low, it Shuts Down on a Refrigeration Error.
If the discharge temperature is acceptable, the
water system is checked by shutting off the water
pump and determining if the water level goes up
enough. If it does not, it is assumed that there is a
water pump problem and the machine Shuts Down
on a Water Error.

If the water level does “measure up" the water
pump is restarted and the controller then
measures how long it takes to lower the water
level. If the water level does not fall, the machine
Shuts Down on a Water Error.

July 2002

Page 16

CME256, 506, 656, 806: AutoIQ™ Cubers

Technicians Only: Harvest Cycle Operational Sequence

Harvest

The (air cooled model) fan is off.

The water valve opens and fills the reservoir to the
Full level.

The water pump shuts off, it will restart in less than
a minute.

Note: Machines built after August 1996:

If the machine remains in the harvest cycle

•

for longer than between 6 to 9 minutes
(depending upon the regular harvest cycle’s
length) the water pump will be switched off
until the next freeze cycle.

When the bin is full and the unit is in a

•

harvest cycle, the pump will be switched off.

The Controller checks how long it takes to fill the
reservoir and if it was too much time, the machine
Shuts Down on Water Error.

Note: The machine will automatically attempt to
restart after shutting down because of a lack of
water. The time between restarts is about 20
minutes.

The inlet water valve will stay on and open for a
predetermined fraction of the time it took to fill the
reservoir. This overflows and rinses the reservoir
water.

During the Harvest Cycle, ice will be falling from
the evaporators and between the bin control’s
electric eyes. The Controller monitors the ice
falling and stays in the Harvest Cycle until ice quits
going thru the electric eyes.

The maximum harvest time is 10 minutes. The first
Harvest after a restart will be a long one to
establish a base line, then the actual time it took to
release the ice is used to determine the length of
the next harvest cycle.

Stacked Units:

If the bottom unit is in harvest and receives a
signal from the top unit that it is also in Harvest,
the bottom unit will stay in harvest for its Maximum
Harvest Time.

Diagnostic Lights and Manual Resets

The controller will shut the machine off if a
malfunction is sensed. Controllers up to 17-1 will
shut the machine off after the first malfunction.
Controllers marked 17-1 and up will restart the
machine 2 times, with a 50 minute interval
between restarts.

If a malfunction is still present after the second
restart, the machine will then shut off and must be
manually reset. During the restart interval, the
machine will be off and a diagnostic code
indicated.

An exception to this is lack of water. When
switched off because of lack of water, the machine
will always try to re-fill the reservoir every 20
minutes.

Another exception is a harvest error. As before,
there must be two consecutive harvest errors to
trigger a machine shut-down. With this change, the
controller will still shut down and restart the
machine after two consecutive harvest errors.
However, if the errors repeat two more
consecutive times, the controller will shut down
and restart the machine again. If the machine
registers two more consecutive harvest errors, the
machine will again shut down and must be
manually reset.

Production of units with Controllers 17-1 began
approximately March 1997. Higher numbers may
be expected after that date.

If no cubes fall (or are sensed) by the end of
Maximum Harvest Time, the machine senses a
refrigeration error. If the next cycle also produces
a refrigeration error, the machine Shuts Down.

Note: Machines built up to August 1996: The last
Harvest cycle before shutting off on Bin Full will be
10 minutes long. Machines built beginning

August 1996 have a last harvest cycle that is
4-6 minutes long.

Note: The machine will not restart for 4 minutes
after switching off on Bin Full, unless the freeze
button is pressed.

July 2002

Page 17