Cornelius I Series Installation guide

I-SERIES ICE MACHINE
TRAINING MANUAL
CARBON DIOXIDE
WATER
SYRUP/CONCENTRATE
MECHANICAL
REFRIGERATION
CONTROLS & ELECTRICAL
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I-Series Ice Machine Training Manual
I-Series Ice Machine
Training Manual
The products, technical information, and instructions contained in this manual are subject
to change without notice. These instructions are not intended to cover all details or varia-
tions of the equipment, nor to provide for every possible contingency in the installation,
operation or maintenance of this equipment. This manual assumes that the person(s) work-
ing on the equipment have been trained and are skilled in working with electrical, plumb-
ing, pneumatic, mechanical, and refrigeration equipment. It is assumed that appropriate
safety precautions are taken and that all local safety and construction requirements are
being met, in addition to the information contained in this manual.
To inquire about current revisions of this and other documentation or for assistance with
any Cornelius product contact:
Trademarks and copyrights:
Aurora, Cornelius, Decade, Hydro Boost, Sitco, Spirit, UF-1, Vanguard, Venture, Olym-
pus, and Vista are registered trademarks of IMI Cornelius Inc.
Optifill trademark is pending.
This document contains proprietary information and it may not be
reproduced in any way without permission from Cornelius.
Printed in U.S.A.
Copyright © 2001, All Rights Reserved, IMI Cornelius Inc.
IMI Cornelius Inc.
Corporate Headquarters
One Cornelius Place
Anoka, MN 55303-6234
U.S.A.
Internet:
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Email:
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phone: [phone]
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phone: [phone]
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I-Series Ice Machine Training Manual
NOTES:
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I-Series Ice Machine Training Manual
TABLE OF CONTENTS
TABLE OF CONTENTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -1
INTRODUCTION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3
Preview Questions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3
Key Things To Know / Do - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -4
Overview - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -5
Product Description - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -5
Dimensions & Capacities - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -6
Ice Machine: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -6
SYSTEM DETAILS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -7
Carbon Dioxide/Air - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -7
Water - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -7
Dump Valve - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -8
Syrup - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -8
Mechanical - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -8
Sealing Ice Bin - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -8
Refrigeration - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -9
Air Cooled Condensers - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -9
Water Cooled Condensers - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -9
Water Regulating Valve - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10
Remote Cooled Ice Machines - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11
Refrigeration System - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11
Expansion Valve - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11
Low Refrigerant- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11
Refrigerant Charge/Recharge- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12
Thermal Expansion Valve (TXV)- - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12
Hot Gas Defrost Valve - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12
Compressor Start Windings - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13
Thermal Overload Protector- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13
Head Pressure Control - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13
Suction Line Thermistor Replacement - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
Controls and Electrical - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 16
Controls Board Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 16
TROUBLE SHOOTING - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
Issues Affecting All Circuit Boards - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
Reset Operation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
Evaporator Proximity Switches - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
TABLE OF CONTENTS

I-Series Ice Machine Training Manual
- 2 - © 2001, IMI Cornelius Inc.
Harvest Safety Termination - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
Stacking Cable - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
Ice Bridge Thickness Adjustment - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
Condenser Fan Cycling Control - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 18
Sensor - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 18
Circuit Board Overview (red & yellow boards) - - - - - - - - - - - - - - - - - - - - - - - - 19
Sensors - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19
Red & Yellow Boards (LEDs) Descriptions - - - - - - - - - - - - - - - - - - - - - - - - 20
Red & Yellow Board Diagnostics - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 22
Check Circuit Board - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 23
Check Thermistor Sensor(s) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 23
Green Circuit Board Overview - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 24
Green Board Test Plug - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 24
Green Board Sensors - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 25
Green Board Voltage Check - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 25
Green Board Voltage Selector Switch - - - - - - - - - - - - - - - - - - - - - - - - - - - - 25
Green Board Ice Bridge Thickness Potentiometer (POT) Factory Reset - - - - - 25
Green Board Dump Cycle Options - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26
Green Board Thermistor Sensor Diagnostics - - - - - - - - - - - - - - - - - - - - - - - - 27
Check Circuit Board- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27
Check Thermistor Sensor(s)- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27
Green Board Diagnostics - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 28
Erratic Component Operation- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 28
Check Circuit Board- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 28
APPENDIX - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 29
Appendix A — Service Tips - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 29
Appendix B — Installation Tips - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 29
REVIEW - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 30
TABLE OF CONTENTS

I-Series Ice Machine Training Manual
© 2001, IMI Cornelius Inc. - 3 -
INTRODUCTION
1. PREVIEW QUESTIONS
Check your current knowledge by taking a few minutes to answer the following questions:
1. Does the ice machine need to be level?
_____ Yes _____ No?
2. What is the recomended clearance for a air cooled machine? ____________________
____________________________________________________________________
____________________________________________________________________
3. What kind of cleaner should be used when cleaning this ice machine?_____________
____________________________________________________________________
____________________________________________________________________
4. Water filters are required in most installations.
_____ True _____ False?
5. Water regulators are required in most installations.
_____ True _____ False?
INTRODUCTION

I-Series Ice Machine Training Manual
- 4 - © 2001, IMI Cornelius Inc.
2. KEY THINGS TOKNOW / DO
• The sealant should be added before the unit is placed on the dispenser on
bin. Always seal the ice maker to the bin (with a gasket or food grade
sealant). Sealing prevents melted ice from running out the joint between
the ice machines!
• Choose the proper condenser for the application:
Air — with sufficient clean air circulation
Water — high ambient temperature or dusty environment, restricted air
flow, or where extra BTUs are unwanted
Remote — when heat or noise are a problem!
• Always refer to serial plate for electrical power requirements and refrig-
eration charge and type of refrigerant!
Note serial plate locations. Lower lefthand corner of cabinet inside the
unit, on the bulkhead between the evaporator and the compressor.
• Always use proper size and type of water conditioning equipment (filter,
chlorine, etc.)!
• Do NOT use softened or reverse osmosis water!
• Premature harvest is normally caused by a defect in suction line sensors!
“I” series units only.
• Installation of a bin thermostat control is required in some installations,
such as ice drink dispensers or ice drink units!
• Bin stat is available to lower ice level! Part No. 630000-408
INTRODUCTION

I-Series Ice Machine Training Manual
© 2001, IMI Cornelius Inc. - 5 -
3. OVERVIEW
3.1 Product Description
The normal sequence of events for starting the I-Series Ice Machine is as follows:
1. The ON-OFF-CLEAN switch is switched ON.
2. Controller board does a startup check.
3. After 4 seconds the contactor closes and the compressor starts.
4. When the condenser thermistor reaches 100° F (38° C), the fan starts. The fan
stops when the thermistor drops to 88° F (31° C).
5. When the suction line thermistor reaches 20° F (-7° C), the water pump starts.
Ice Machine
Ice Bin
ON/OFF/CLEAN and
DUMP switches
INTRODUCTION

I-Series Ice Machine Training Manual
- 6 - © 2001, IMI Cornelius Inc.
6. Ice builds on the evaporator
to about 1/8” (.32cm) bridge
thickness (center measure,
adjustable). When the hot-gas
defrost valve opens, the water
dump valve opens, and the
pump motor runs for 15 sec-
onds to expel the waste water.
NOTE: The hot-gas defrost
valve opens at approxi-
mately 0° F (-18° C),
and can be adjusted by
turning the ice thick-
ness potentiometer.
7. Ice drops from the evaporator
and opens the curtain proximity switch.
8. After the ice drops into the bin, the curtain proximity switch close. The defrost
stops and the ice making process starts over.
9. If the ice does not drop into the bin because the bin is full, the defrost will con-
tinue for approximately 8 seconds and stop. The ice machine then waits for the ice
to fall into the bin and the curtain and proximity switches to close.
3.2 Dimensions & Capacities
Ice Machine:
Ambient operating temperature:- - - - - - - - - - - - - - - 50-100° F (10-38° C)
Water: - - - - - - - - - - - - - - - -20-50 psi (1.4-3.45 BAR) at the ice machine.
- - - - - - If the water pressure exceeds 50 p.s.i. install a water pressure regulator
Electrical: - - - - - - - - - - - - - - - - - - - - - - - - - see unit’s name plate
Top row
3/8 - 5/8”
(.95 - 1.59 cm)
dimple
Center
1/8”(.32 cm)
bridge
Bottom 2 rows
3/16 - 1/4”(.48 -
.64 cm) bridge
1/8”(.32 cm)
bridge
Ice slab
INTRODUCTION

I-Series Ice Machine Training Manual
© 2001, IMI Cornelius Inc. - 7 -
SYSTEM DETAILS
1. CARBON DIOXIDE/AIR
Not applicable for this product.
2. WATER
+NOTE: Water related issues are the cause of the
majority of ice maker problems.
NOTE: Always use the proper type and size of water filter
Inlet pressure should be 20 to 50 psi (1.4-3.45 BAR) at the
ice machine.
Water goes first to a strainer. The strainer screen should be
removed and cleaned at least once per year.
There is a rubber flow control washer in the base of the
float valve. This flow control can be become plugged or
deteriorated by chloramine. It should be checked at least
once per year, and replaced if necessary. Be sure to install
the flow control washer flat side up.
NOTE: The flow control should be removed when the
water pressure is below 20 psi (1.4 BAR).
NOTE: If water pressure is above 50 psi (3.45 BAR) add a pressure regulator.
The operating water level can be changed by bending the
float arm.
NOTE: Make sure the float moves up and down freely
after it has been reinstalled.
A splash shield has been installed above the float on all
machines built since June of 1998. A splash shield kit is available for older machines (part
number for 1 evaporator = 630000234, 2 evap. = 630000232, 4 evap. = 630000233). See
Service Bulletin # TB97108 for additional information.
Water
strainer
Flow
control
Float
arm
SYSTEM DETAILS

I-Series Ice Machine Training Manual
- 8 - © 2001, IMI Cornelius Inc.
2.1 Dump Valve
It is important to make sure that the dump valve is
functioning properly. This valve dumps mineral laden
water out the dump hose.
The ice may become mushy if the valve does not
open properly. If the valve sticks open, it will cause a
longer freeze cycle.
1. Remove wire harness from the solenoid coil.
2. Remove blue cap and lift coil off.
3. Check coil resistance. It should be 140 ohms ± 10%.
4. Remove valve body stem by twisting counter-
clockwise about 1/8 turn.
5. Disassemble valve body components and check
for scale, etc.
6. Clean as necessary and reassemble the valve.
NOTE: A diaphragm kit is available, p/n 165637018.
3. SYRUP
Not applicable for this product.
4. MECHANICAL
4.1 Sealing Ice Bin
If the ice bin is full, new ice will not be able to
drop. Instead it blocks the evaporator curtain
open and no additional ice is made. This new
ice may start to melt and the resulting liquid
can leak out of the joint between the ice
maker and bin. To prevent this problem, seal
the joint with food grade silicon sealant.
Cap
Wire
harness
Dump
hose
Coil
Twist
counterclock
wise 1/8 turn
Valve Body
Stem
Spring Diaphragm
SYSTEM DETAILS

I-Series Ice Machine Training Manual
© 2001, IMI Cornelius Inc. - 9 -
NOTE: A bin thermostat is recommended for dispenser applications. When the bin
thermostat is satisfied, the ice maker will finish the cycle it is in and shut-
down. Part No. bin stat 630000-413
5. REFRIGERATION
5.1 Air Cooled Condensers
Air cooled ice machines add heat to the surrounding environment. In some situations
this may over tax the air conditioning system or cause other problems.
Adequate air flow is necessary, including 6 inches (15.2 cm) clearance on the right
side and back.
A louvered front and top panel is available for special applications.
A louvered front and top panel is available for special applications.Air cooled ice
machines are not a good choice for industrial applications, or in greasy or dusty envi-
ronments that could lead to plugged condensers.
On some ice machines a condenser filter is available to trap airborne particles.
5.2 Water Cooled Condensers
Water cooled condensers will significantly increase water and sewer costs.
Water cooled condensers require a dedicated water line with 3/8” (.95 cm) i.d. inlet
supplying 20-50 psi (1.4-3.45 BAR) at the ice machine. There should be dedicated
water lines for the ice machine and the condenser. These lines should not be teed off
of one line..
Name 322/522 330/530 630/830 1030/1230
Top Panel 164874-016 630200-614 630200-614 630200-614
Front Panel 164873-022 164873-019 164873-020 164873-021
Electrical Service
Line
Shut-Off Valve
Shut-Off Valve
Manual Disconnect Switch
Water Filter
Electrical Service Line
Manual Disconnect Switch
Shut-Off Valve
Water Filter
Condenser Water Inlet
Strain Relief
must be used
Strain Relief
must be used
Dump Valve
Drain Tube
Dump Valve
Drain Tube
Condenser Water
Drain Tube
Floor Drain
Floor Drain
Bin Drain Tube
Bin Drain
Tube
SYSTEM DETAILS

I-Series Ice Machine Training Manual
- 10 - © 2001, IMI Cornelius Inc.
Use separate lines for the bin drain and the dump valve drain.
It is usually not necessary to filter incoming condenser water.
Follow standard procedures for cleaning condenser lines of scale and deposits.
Water Regulating Valve
The water regulating valve is used on water-cooled ice machines only. The
valve is installed in the condenser outlet water line. Its function is to con-
trol the proper operating head pressure by regulating the amount of water
flowing through the condenser. The valve is adjustable and factory set to
maintain condenser discharge water temperature at 108/112° F (42 - 44°
C). Setting the water regulating valve to maintain discharge water tempera-
ture eliminates the need to enter the sealed refrigeration system. When
checking the valve, the water temperature should be taken as close to the
condenser discharged as possible. The water temperature will equate to
operating head pressure of approximately 275 psi (19.0 BAR).
Should adjustment be required, the valve has an adjustment stem on the
top. After allowing the ice machine to operate for 10 minutes in the ice
making mode to balance the system, turning the adjustment stem clockwise
will increase the discharge water temperature, and counterclockwise will
decrease the discharge water temperature.
The water regulating valve must close off condenser water flow com-
pletely during the hot gas harvest cycle. There should be no discharge
water flowing out of the condenser during the harvest cycle. Should the
valve fail to close during the harvest mode, the condenser will continue to
condense the compressor discharge vapor needed for the harvest cycle, and
this will result in long harvest times.
Leaking (bypassing) water regulating valves are normally the result of
scale buildup on the valve diaphragm. The valve should be flushed, not
replaced. To flush the valve, open the adjusting stem fully counterclock-
wise (or force the valve spring up with a screwdriver) and open and close
the water supply to the condenser, resulting in the flushing action. Should
this not correct the problem, replace the valve diaphragm. This should be
done without entering the sealed refrigeration system.
Damage to the water regulating valve may also be caused by a water ham-
mer. Water hammering will result from the condenser inlet and outlet water
lines being reversed or defective valve stops in the water supply line.
Proper installation of water cooled equipment should always include an
anti-water hammer standpipe in the supply inlet line, as close to the ice
machine as possible.
SYSTEM DETAILS

I-Series Ice Machine Training Manual
© 2001, IMI Cornelius Inc. - 11 -
5.3 Remote Cooled Ice Machines
Refer to I Series Ice Cube Machine Service Manual & Maintenance Guide for
remote condenser installation information and correct refrigeration procedures.
NOTE: When installing a remote ice maker, always open the receiver valve after
connecting refrigerant lines.
5.4 Refrigeration System
Expansion Valve
The expansion valve is factory set at 6° F (-14° C) superheat (difference between
evaporator inlet and outlet). It is non-adjustable. DO NOT REPLACE WITH AN
ADJUSTABLE VALVE.
Low Refrigerant
Observe ice production. If the
refrigerant is low, some of the
top evaporator rows do not form
ice and freeze times are longer.
For optimum ice production and
maximum cube separation, the
ice connecting the individual
cubes should be a minimum of
1/8 inch (.32cm) thick at the cen-
ter area of the evaporator.
It is normal for the ice slab to be
slightly thicker at the bottom and
taper off in a slight wedge pat-
tern at the top. The top row of
cubes must have a complete pat-
tern of ice on all four sides and the back wall. Remember, when you operate the
product with the panels off during testing the additional heat at the top of the evapo-
rator will cause thinner ice at the top.
Should a different thickness of the bridge be desired, it will be required to adjust the
potentiometer (POT), located on the circuit board.
1. Thinner Bridge - turn the ice thickness POT adjustment screw clockwise one full
turn. Allow two cycles before determining if additional adjustments are required.
2. Thicker Bridge - turn the ice thickness POT adjusting screw counterclockwise
one full turn. Allow two cycles before determining if additional adjustments are
required.
Top row
3/8 - 5/8”
(.95 - 1.59 cm)
dimple
Center
1/8”(.32 cm)
bridge
Bottom 2 rows
3/16 - 1/4”(.48 -
.64 cm) bridge
1/8”(.32 cm)
bridge
Ice slab
SYSTEM DETAILS

I-Series Ice Machine Training Manual
- 12 - © 2001, IMI Cornelius Inc.
NOTE: Never judge the thickness of the ice from the first batch of the ice pro-
duced — the first cycle is a balance cycle. Always wait for the second
cycle before making any adjustments.
Refrigerant Charge/Recharge
The refrigeration system is critically charged to within ± 1/2 ounces (14.8 ml), and
does not use an accumulator. DO NOT use gauges until all other tests have been per-
formed. Time the freeze cycle and refer to the charts in the I Series Ice Cube Machine
Service Manual & Maintenance Guide.
NOTE: If water is leaking from the dump valve, warm water is introduced which will
increase freeze time.
After conducting all other tests attach gauges and
check head and suction pressures.
The ice machine should freeze within ± 10% of the
times indicated in the service guide. If the times are
longer, find and fix the leak. Then evacuate and
recharge the system BY WEIGHT.
NOTE: The R404A refrigerant used in the I-Series ice machines is a blend of several
refrigerants. These can fractionate in the refrigeration system. This is why it
is so important to completely evacuate the system before recharging.
NOTE: Always recharge R404A systems in a liquid state (not in a gas state).
NOTE: ALWAYS install a new dryer whenever the refrigeration system has been
opened (replace with an EK 404A dryer).
Thermal Expansion Valve (TXV)
Check the TXV by disconnecting the capillary valve
from the suction line. Warm the bulb in your hand
and watch to see that the valve opens and the suction
pressure gauge increases. Cooling the bulb closes the
valve.
Hot Gas Defrost Valve
Check that the Hot Gas Defrost Valve is not leaking
during the freeze cycle.
NOTE: The best way to detect a small weeping hot-
gas valve, use an electronic sight glass.
Alternately, touch the outlet line. If it is warm/hot, it is leaking.
Test
ports
Thermal Expansion Valve
Bulb
Hot gas
defrost
valve
SYSTEM DETAILS

I-Series Ice Machine Training Manual
© 2001, IMI Cornelius Inc. - 13 -
Compressor Start Windings
Check the compressor start windings.
1. With the power disconnected use an ohm meter to
check each pair of terminals. There should NOT
be an open circuit.
2. Take an amp reading from the red wire during
defrost mode. The amps should match those on the
name plate. Low amps indicate low refrigerant.
3. Check the voltage at the compressor terminals while the compressor is trying to
start. The voltage should be at least 90% of line voltage.
4. Refer to the I Series Ice Cube Machine Service Manual & Maintenance Guide for
additional compressor starting tests.
Thermal Overload Protector
Check the Thermal Overload Protector by discon-
necting one of the wires and checking for continuity
(make sure the compressor has cooled).
Head Pressure Control
The Cornelius "I" series
remote systems use an Alco
Head Pressure Control, nor-
mally referred to as a head-
master. This control is
mounted in the remote con-
denser with a fan cycling
control switch. Using both
these controls gives the sys-
tem positive operation under a wide range of condensing temperatures.
The normal flow pattern through the headmaster is from the condenser port to the
receiver port. When this flow pattern is unable to maintain a receiver outlet pressure
equal to or above the dome pressure setting of the valve, the dome pressure will force
the valve port to change, closing the condenser port and opening the bypass port
from the compressor discharge line. This allows the high pressure vapor from the
discharge port to "buck" the receiver pressure back up. With the condenser port
closed, the refrigerant is backed up in the condenser, basically reducing the con-
denser size, assisting in maintaining the discharge port flow, and increasing the head
pressure.
Red wire
Terminals
Thermal overload protector
SYSTEM DETAILS

I-Series Ice Machine Training Manual
- 14 - © 2001, IMI Cornelius Inc.
The head pressure control valve (headmaster) maintains adequate condensing pres-
sure during periods of low ambient temperature. The I-Series ice makers are charged
with R404A refrigerant. The headmaster valve is set to maintain a condensing pres-
sure of 200 psig (13.8 BAR) down to an operating temperature of -20°F (-6.7° C).
Touching the lines of the headmaster will determine the flow path the headmaster is
in; condenser to receive, or bypass to receiver. Installing a gauge at the receiver out-
let valve will determine if the headmaster is functioning to maintain the proper oper-
ating pressure. It should be less than 15 psi (1.0 BAR). Less pressure indicates low
refrigerant or kinked lines.
Refer to the I Series Ice Cube Machine Service Manual & Maintenance Guide for
additional head pressure control information.
SYSTEM DETAILS

I-Series Ice Machine Training Manual
© 2001, IMI Cornelius Inc. - 15 -
5.5 Suction Line Thermistor Replacement
NOTE: The following procedure may be the easiest, but, it is not the only way
replace the thermistor.
1. Unplug the ice machine and remove the top and front panels.
2. Remove plastic rivets from the
electrical box mounting bracket using a
punch and side cutters. Save the rivets
for reinstallation.
3. Remove and retain four screws on top
of bracket and two on gauge port bracket.
4. Move electrical box out of the
way and cut insulation from
around the thermistor.
5. Replace thermistor. Be sure to clean the surface
of the suction line.
Punch thru
center of rivet
Side cutters to lift
rivets Do Not Cut
Remove 2 screws
Remove 4 screws
Thermistor
Groove
in line
Thermistor
SYSTEM DETAILS

I-Series Ice Machine Training Manual
- 16 - © 2001, IMI Cornelius Inc.
6. CONTROLS AND ELECTRICAL
6.1 Controls Board Features (Red and Yellow Boards)
• 4 second power-up sequence, adjusts board to correct voltage and Hertz before
the compressor starts
• Push button test mode
• 8 inline power connectors
• Bridge adjustment range indicator
• Dip switch selectors for curtain switches 1-4
• Dip switch selector for dump cycles
• Circuit board will retrofit for service replacements
6. Reassemble, making sure the new thermistor is in the proper location. Replace the
insulation around the thermistor or the ice machine will not function properly.
SYSTEM DETAILS