Technician’s
Handbook
This manual is updated as new information and models are
released. Visit our website for the latest manual.
www.manitowocice.com
America’s #1 Selling Ice Machine
Manitowoc
Undercounter
Ice Machines
Part Number STH042 3/14
Safety Notices
As you work on Manitowoc equipment, be sure to pay
close attention to the safety notices in this handbook.
Disregarding the notices may lead to serious injury
and/or damage to the equipment.
Throughout this handbook, you will see the following
types of safety notices:
!
Warning
Text in a Warning box alerts you to a potential
personal injury situation. Be sure to read the
Warning statement before proceeding, and work
carefully.
!
Caution
Text in a Caution box alerts you to a situation in
which you could damage the equipment. Be sure
to read the Caution statement before proceeding,
and work carefully.
Procedural Notices
As you work on Manitowoc equipment, be sure to read
the procedural notices in this handbook. These notices
supply helpful information which may assist you as
you work.
Throughout this handbook, you will see the following
types of procedural notices:
NOTE: Text set off as a Note provides you with simple,
but useful, extra information about the procedure you
are performing.
Important
Text in an Important box provides you with
information that may help you perform a
procedure more efficiently. Disregarding this
information will not cause damage or injury, but it
may slow you down as you work.
Read These Before Proceeding:
!
Caution
Proper installation, care and maintenance are
essential for maximum performance and troublefree operation of your equipment. Visit our
website www.manitowocfsg.com for manual
updates, translations, or contact information for
service agents in your area.
Important
Routine adjustments and maintenance
procedures outlined in this handbook are not
covered by the warranty.
! Warning
Read this manual thoroughly before operating,
installing or performing maintenance on the
equipment. Failure to follow instructions in this
manual can cause property damage, injury or
death.
! Warning
Do not use electrical appliances or accessories
other than those supplied by Manitowoc for your ice
machine model.
!
Warning
Two or more people or a lifting device are
required to lift this appliance.
! Warning
This equipment contains high voltage electricity
and refrigerant charge. Installation and repairs are
to be performed by properly trained technicians
aware of the dangers of dealing with high voltage
electricity and refrigerant under pressure.The
technician must also be certified in proper
refrigerant handling and servicing procedures. All
lockout and tag out procedures must be followed
when working on this equipment.
!
Warning
Do not damage the refrigeration circuit when
installing, maintaining or servicing the unit.
!
Warning
Do not operate equipment that has been misused,
abused, neglected, damaged, or altered/modified
from that of original manufactured specifications.
This appliance is not intended for use by persons
(including children) with reduced physical, sensory
or mental capabilities, or lack of experience and
knowledge, unless they have been given
supervision concerning use of the appliance by a
person responsible for their safety. Do not allow
children to play with this appliance.
!
Warning
All covers and access panels must be in place
and properly secured, before operating this
equipment.
!
Warning
Do not obstruct machine vents or openings.
! Warning
Do not store gasoline or other flammable vapors
or liquids in the vicinity of this or any other
appliance.
!
Warning
Do not clean with water jet.
! Warning
It is the responsibility of the equipment owner to
perform a Personal Protective Equipment Hazard
Assessment to ensure adequate protection
during maintenance procedures.
! Warning
Two or more people are required to move this
equipment to prevent tipping.
! Warning
When using electric appliances, basic
precautions must always be followed, including
the following:
a. Read all the instructions before using
the appliance.
b. To reduce the risk of injury, close
supervision is necessary when an
appliance is used near children.
c. Do not contact moving parts.
d. Only use attachments recommended or
sold by the manufacturer.
e. Do not use outdoors.
f. For a cord-connected appliance, the
following must be included:
• Do not unplug by pulling on cord. To
unplug, grasp the plug, not the cord.
• Unplug from outlet when not in use
and before servicing or cleaning.
• Do not operate any appliance with a
damaged cord or plug, or after the
appliance malfunctions or is dropped
or damaged in any manner. Contact
the nearest authorized service facility
for examination, repair, or electrical
or mechanical adjustment.
g. Follow applicable lock out tag out
procedures before working on
equipment.
h. Connect to a properly grounded outlet
only.
We reserve the right to make product
improvements at any time. Specifications and
design are subject to change without notice.
Part Number STH042 3/14 9
Table of Contents
GENERAL INFORMATION
Model Numbers . . . . . . . . . . . . . . . . . . . . . 13
How to Read a Model Number . . . . . . . . . 14
Ice Machine Warranty Information . . . . . 15
Residential Warranty Coverage . . . . . 17
INSTALLATION
Location of Ice Machine . . . . . . . . . . . . . . 21
Ice Machine Clearance Requirements . . 22
Ice Machine Heat of Rejection . . . . . . . . . 22
Leveling the Ice Machine . . . . . . . . . . . . . 23
Electrical Requirements . . . . . . . . . . . . . . 24
Electrical Specifications . . . . . . . . . . . . . 25
Water Service/Drains . . . . . . . . . . . . . . . . 27
Water Supply . . . . . . . . . . . . . . . . . . . . 27
Water Inlet Lines . . . . . . . . . . . . . . . . . 27
Drain Connections . . . . . . . . . . . . . . . . 28
Cooling Tower Applications . . . . . . . . . 28
MAINTENANCE
Interior Cleaning and Sanitizing . . . . . . . 31
General . . . . . . . . . . . . . . . . . . . . . . . . 31
Cleaning and Sanitizing Procedure . . . 31
Touch Pad Operation . . . . . . . . . . . . . 32
Remove Parts for Cleaning . . . . . . . . . 36
Preventative Maintenance Cleaning . . . . 41
Ice Machine Inspection . . . . . . . . . . . . . . 42
Cleaning the Condenser . . . . . . . . . . . . . 43
Removal from Service/Winterization . . . 44
Bin Removal . . . . . . . . . . . . . . . . . . . . . . . 45
10 Part Number STH042 3/14
OPERATION
Touch Pad Features . . . . . . . . . . . . . . . . 47
On/Off . . . . . . . . . . . . . . . . . . . . . . . . . 47
Delay . . . . . . . . . . . . . . . . . . . . . . . . . 48
Clean . . . . . . . . . . . . . . . . . . . . . . . . . 48
Bin Full . . . . . . . . . . . . . . . . . . . . . . . . 49
Service . . . . . . . . . . . . . . . . . . . . . . . . 49
Ice Making Sequence of Operation . . . . 50
Control Board Timers . . . . . . . . . . . . 51
Safety Limits . . . . . . . . . . . . . . . . . . . . 52
Energized Parts Chart . . . . . . . . . . . . 54
Operational Checks . . . . . . . . . . . . . . . . . 56
Ice Thickness Check . . . . . . . . . . . . . 56
Ice Thickness Adjustment . . . . . . . . . . 56
TROUBLESHOOTING
Control Board Test Mode . . . . . . . . . . . . 57
Operating Ice Machine with bin and touch
pad removed. . . . . . . . . . . . . . . . . . . . 57
Diagnosing an Ice Machine that Will Not Run
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Ice Machine Does Not Cycle Into Harvest
when Water Loses Contact with the Harvest
Float Switch . . . . . . . . . . . . . . . . . . . . . . . 59
Ice Machine Cycles Into Harvest Before Water
loses Contact with the Harvest Float Switch
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Ice Production Check . . . . . . . . . . . . . . . 63
Installation/Visual Inspection Checklist 64
Water System Checklist . . . . . . . . . . . . . 65
Ice Formation Pattern . . . . . . . . . . . . . . . 66
Safety Limit Feature . . . . . . . . . . . . . . . . 68
Analyzing Discharge Pressure . . . . . . . . 75
Analyzing Suction Pressure . . . . . . . . . . 77
Harvest Valve . . . . . . . . . . . . . . . . . . . . . . 81
Comparing Evaporator Inlet/Outlet
Temperatures . . . . . . . . . . . . . . . . . . . . . . 85
Discharge Line Temperature Analysis . 86
Refrigeration Component Diagnostics . 88
Final Analysis . . . . . . . . . . . . . . . . . . . 90
Refrigeration Component Diagnostic Chart
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Part Number STH042 3/14 11
COMPONENT CHECK PROCEDURES
Main Fuse . . . . . . . . . . . . . . . . . . . . . . . . . 95
Bin Switch . . . . . . . . . . . . . . . . . . . . . . . . . 96
Touch Pad . . . . . . . . . . . . . . . . . . . . . . . . . 98
Float Switch . . . . . . . . . . . . . . . . . . . . . . . 100
Compressor Electrical Diagnostics . . . . 102
Fan Cycle Control . . . . . . . . . . . . . . . . . . . 104
High Pressure Cutout (HPCO) Control . . 105
Filter-Driers . . . . . . . . . . . . . . . . . . . . . . . . 106
Refrigerant Recovery/Evacuation . . . . . . 108
Definitions . . . . . . . . . . . . . . . . . . . . . . 108
Refrigerant Re-use Policy . . . . . . . . . . 109
Recovery and Recharging Procedures 111
System Contamination Cleanup . . . . . . . 114
Determining Severity of Contamination 114
Mild System Contamination Cleanup
Procedure . . . . . . . . . . . . . . . . . . . . . . 116
Severe System Contamination Cleanup
Procedure . . . . . . . . . . . . . . . . . . . . . . 117
Replacing Pressure Controls without
Removing Refrigerant Charge . . . . . . . 118
Total System Refrigerant Charge . . . . . . 120
12 Part Number STH042 3/14
CHARTS
Cycle Times, 24 Hr. Ice Production and
Refrigerant Pressure Charts . . . . . . . . . . 121
U0140 Self-contained Air-cooled . . . . 122
U0140 Self-contained Water-cooled . . 123
U0190 Self-contained Air-cooled . . . . 124
U0240 Self-contained Air-cooled . . . . 125
U0240 Self-contained Water-cooled . . 126
U0310 Self-contained Air-cooled . . . . 127
U0310 Self-contained Water-cooled . . 128
DIAGRAMS
Wiring Diagrams . . . . . . . . . . . . . . . . . . . 129
Wiring Diagram - All Models . . . . . . . . 130
Electronic Control Board . . . . . . . . . . . 131
Tubing Schematic - U0140 . . . . . . . . . . . 132
Tubing Schematic - U0190/U0240/U0310 133
Part Number STH042 3/14 13
General Information
Model Numbers
This manual covers the following models:
Self-contained
Air-cooled
Self-contained
Water-cooled
UD0140A UD0140W
UD0140AE UD0140WE
UY0140A UY0140W
UY0140AE UY0140WE
UR0140A --
UR0140AE --
UD0190A --
UD0190AE --
UY0190A --
UY0190AE --
UR0190A --
UR0190AE --
UD0240A UD0240W
UD0240AE UD0240WE
UY0240A UY0240W
UY0240AE UY0240WE
UR0240A --
UR0240AE --
UD0310A UD0310W
UD0310AE UD0310WE
UY0310A UY0310W
UY0310AE UY0310WE
UR0310A --
UR0310AE --
14 Part Number STH042 3/14
How to Read a Model Number
! Warning
An ice machine contains high voltage electricity
and refrigerant charge. Repairs are to be
performed by properly trained refrigeration
technicians aware of the dangers of dealing with
high voltage electricity and refrigerant under
pressure.
A - Air-cooled
W - Water-cooled
Series
Condenser
Type
Capacity
U D 0140 A E
R - Regular
D - Dice
Y - Half-dice
Cube Size
E - WRAS 50Hz
Part Number STH042 3/14 15
Ice Machine Warranty Information
Owner Warranty Registration Card
General
Warranty coverage begins the day the ice machine is
installed.
If the OWNER WARRANTY REGISTRATION CARD is
not returned, Manitowoc will use the date of sale to the
Manitowoc Distributor as the first day of warranty
coverage for your new ice machine.
Commercial Warranty Coverage
General
The following Warranty outline is provided for your
convenience. For a detailed explanation, read the
warranty bond shipped with each product.
Contact your local Manitowoc representative or
Manitowoc Ice, if you need further warranty
information.
Parts
1. Manitowoc warrants the ice machine against
defects in materials and workmanship, under
normal use and service for three (3) years from
the date of original installation.
2. The evaporator and compressor are covered by
an additional two (2) year (five years total)
warranty beginning on the date of the original
installation.
Labor
1. Labor required to repair or replace defective
components is covered for three (3) years from
the date of original installation.
2. The evaporator is covered by an additional two(2) year (five years total) labor warranty beginning
on the date of the original installation.
Important
Complete and mail the OWNER WARRANTYREGISTRATION CARD as soon as possible to
validate the installation date.
16 Part Number STH042 3/14
Exclusions
The following items are not included in the ice
machine’s warranty coverage:
1. Normal maintenance, adjustments and cleaning
as outlined in this manual.
2. Repairs due to unauthorized modifications to the
ice machine or use of non-standard parts without
prior written approval from Manitowoc Ice.
3. Damage caused by improper installation of the ice
machine, electrical supply, water supply or
drainage, or damage caused by floods, storms, or
other acts of God.
4. Premium labor rates due to holidays, overtime,
etc.; travel time; flat rate service call charges;
mileage and miscellaneous tools and material
charges not listed on the payment schedule.
Additional labor charges resulting from the
inaccessibility of equipment are also excluded.
5. Parts or assemblies subjected to misuse, abuse,
neglect or accidents.
6. Damage or problems caused by installation,
cleaning and/or maintenance procedures
inconsistent with the technical instructions
provided in this manual.
7. This warranty is intended exclusively for
commercial application. No warranty is extended
for personal, family, or household purposes.
Authorized Warranty Service
To comply with the provisions of the warranty, a
refrigeration service company qualified and authorized
by your Manitowoc distributor, or a Factory Authorized
Servicer must perform the warranty repair.
Service Calls
Normal maintenance, adjustments and cleaning as
outlined in this manual are not covered by the
warranty.
Part Number STH042 3/14 17
RESIDENTIAL WARRANTY COVERAGE
What Does this Limited Warranty Cover?
Subject to the exclusions and limitations below,
Manitowoc Ice (“Manitowoc”) warrants to the original
consumer that any new ice machine manufactured by
Manitowoc (the “Product”) shall be free of defects in
material or workmanship for the warranty period
outlined below under normal use and maintenance,
and upon proper installation and start-up in
accordance with the instruction manual supplied with
the Product.
How Long Does this Limited Warranty Last?
Who is Covered by this Limited Warranty?
This limited warranty only applies to the original
consumer of the Product and is not transferable.
What are MANITOWOC ICE’S Obligations Under
this Limited Warranty?
If a defect arises and Manitowoc receives a valid
warranty claim prior to the expiration of the warranty
period, Manitowoc shall, at its option: (1) repair the
Product at Manitowoc’s cost, including standard
straight time labor charges, (2) replace the Product
with one that is new or at least as functionally
equivalent as the original, or (3) refund the purchase
price for the Product. Replacement parts are
warranted for 90 days or the balance of the original
warranty period, whichever is longer. The foregoing
constitutes Manitowoc’s sole obligation and the
consumer’s exclusive remedy for any breach of this
limited warranty. Manitowoc’s liability under this limited
warranty is limited to the purchase price of Product.
Additional expenses including, without limitation,
service travel time, overtime or premium labor
charges, accessing or removing the Product, or
shipping are the responsibility of the consumer.
Product Covered Warranty Period
Ice Machine Twelve (12) months
from the sale date
18 Part Number STH042 3/14
What Is Not Covered?
This limited warranty does cover, and you are solely
responsible for the costs of: (1) periodic or routine
maintenance, (2) repair or replacement of the Product
or parts due to normal wear and tear, (3) defects or
damage to the Product or parts resulting from misuse,
abuse, neglect, or accidents, (4) defects or damage to
the Product or parts resulting from improper or
unauthorized alterations, modifications, or changes;
and (5) defects or damage to any Product that has not
been installed and/or maintained in accordance with
the instruction manual or technical instructions
provided by Manitowoc. To the extent that warranty
exclusions are not permitted under some state laws,
these exclusions may not apply to you.
EXCEPT AS STATED IN THE FOLLOWING SENTENCE,
THIS LIMITED WARRANTY IS THE SOLE AND EXCLUSIVE
WARRANTY OF MANITOWOC WITH REGARD TO THE
PRODUCT. ALL IMPLIED WARRANTIES ARE STRICTLY
LIMITED TO THE DURATION OF THE LIMITED
WARRANTY APPLICABLE TO THE PRODUCTS AS
STATED ABOVE, INCLUDING BUT NOT LIMITED TO, ANY
WARRANTY OF MERCHANTABILITY OR OF FITNESS
FOR A PARTICULAR PURPOSE.
Some states do not
allow limitations on how long an implied warranty lasts,
so the above limitation may not apply to you.
IN NO EVENT SHALL MANITOWOC OR ANY OF ITS
AFFILIATES BE LIABLE TO THE CONSUMER OR ANY
OTHER PERSON FOR ANY INCIDENTAL,
CONSEQUENTIAL OR SPECIAL DAMAGES OF ANY KIND
(INCLUDING, WITHOUT LIMITATION, LOSS OF PROFITS,
REVENUE OR BUSINESS) ARISING FROM OR IN ANY
MANNER CONNECTED WITH THE PRODUCT, ANY
BREACH OF THIS LIMITED WARRANTY, OR ANY OTHER
CAUSE WHATSOEVER, WHETHER BASED ON
CONTRACT, TORT OR ANY OTHER THEORY OF
LIABILITY.
Some states do not allow the exclusion or
limitation of incidental or consequential damages, so
the above limitation or exclusion may not apply to you.
Part Number STH042 3/14 19
How State Law Applies
This limited warranty gives you specific legal rights,
and you may also have rights that vary from state to
state or from one jurisdiction to another.
Registration Card
To secure prompt and continuing warranty service, this
warranty registration card must be completed and sent
to Manitowoc within thirty (30) days from the sale date.
Complete the following registration card and send it to
Manitowoc at the address shown above. Retain a copy
for your records.
HOW TO OBTAIN WARRANTY SERVICE
To obtain warranty service or information regarding
your Product, please contact us at:
MANITOWOC ICE
2110 S. 26
th
St.,
P.O. Box 1720
Manitowoc, WI 54221-1720
Telephone: 920-682-0161 Fax: 920-683-7585
www.manitowocice.com
20 Part Number STH042 3/14
This Page Intentionally Left Blank
Part Number STH042 3/14 21
Installation
Location of Ice Machine
The location selected for the ice machine must meet
the following criteria. If any of these criteria are not
met, select another location.
• The location must be indoors.
• The location must be free of airborne and other
contaminants.
• Air temperature: Must be at least 40°F (4°C) but
must not exceed 110°F (43.4°C).
• The location must not be near heat-generating
equipment or in direct sunlight.
• The location must be capable of supporting the
weight of the ice machine and a full bin of ice.
• The location must allow enough clearance for
water, drain, and electrical connections in the rear
of the ice machine.
• The location must not obstruct airflow through or
around the ice machine (condenser airflow is in
and out the front). Refer to the chart below for
clearance requirements.
• The ice machine must be protected if it will be
subjected to temperatures below 32°F (0°C).
Failure caused by exposure to freezing
temperatures is not covered by the warranty.
22 Part Number STH042 3/14
Ice Machine Clearance Requirements
*NOTE: The ice machine may be built into a cabinet.
There is no minimum clearance requirement for the
top or left and right sides of the ice machine. The listed
values are recommended for efficient operation and
servicing only.
Ice Machine Heat of Rejection
* B.T.U./Hour
** Because the heat of rejection varies during the ice making cycle,
the figure shown is an average.
Ice machines, like other refrigeration equipment, reject
heat through the condenser. It is helpful to know the
amount of heat rejected by the ice machine when
sizing air conditioning equipment where self-contained
air-cooled ice machines are installed.
Self-contained
Air-cooled
Self-contained
Water-cooled
Top/Sides 5" (127 mm)* 5" (127 mm)*
Back 5" (127 mm)* 5" (127 mm)*
Series
Ice Machine
Heat of Rejection*
Air Conditioning** Peak
U140 2400 2900
U190 2200 2600
U240 2400 3400
U310 3800 6000
Part Number STH042 3/14 23
Leveling the Ice Machine
1. Screw the leveling legs onto the bottom of the ice
machine.
2. Screw the foot of each leg in as far as possible.
3. Move the ice machine into its final position.
4. Level the ice machine to ensure that the siphon
system functions correctly. Use a level on top of
the ice machine. Turn each foot as necessary to
level the ice machine from front to back and side
to side.
Leg Installation
!
Caution
The legs must be screwed in tightly to prevent
them from bending.
THREAD
LEVELING LEG
INTO BASE OF
CABINET
THREAD “FOOT”
IN AS FAR AS
POSSIBLE
SV1606
24 Part Number STH042 3/14
Electrical Requirements
Voltage
The maximum allowable voltage variation is ±10% of
the rated voltage on the ice machine model/serial
number plate at start-up (when the electrical load is
highest).
Fuse/Circuit Breaker
A separate fuse/circuit breaker must be provided for
each ice machine.
Total Circuit Ampacity
The total circuit ampacity is used to help select the
wire size of the electrical supply.
The wire size (or gauge) is also dependent upon
location, materials used, length of run, etc., so it must
be determined by a qualified electrician.
Part Number STH042 3/14 25
Electrical Specifications
Air-cooled Ice Machine
NOTE: * Indicates preliminary data
Ice Machine
Voltage
Phase Cycle
Max. Fuse/
Circuit
Breaker
Total
Amps
U140
115/1/60 15 5.0
208-230/1/60 15 2.5
230/1/50 15 2.5
U190
115/1/60 15 6.0
208-230/1/60 15 2.5
230/1/50 15 2.5
U240
115/1/60 15 7.0
208-230/1/60 15 4.0
230/1/50 15 4.0
U310
115/1/60 15 10.0
208-230/1/60 15 4.5
230/1/50 15 4.5
26 Part Number STH042 3/14
Water-cooled Ice Machine
NOTE: * Indicates preliminary data
Ice Machine
Voltage
Phase Cycle
Max. Fuse/
Circuit
Breaker
Total
Amps
U140
115/1/60 15 5.0
208-230/1/60 15 2.5
230/1/50 15 2.5
U240
115/1/60 15 7.0
208-230/1/60 15 4.0
230/1/50 15 4.0
U310
115/1/60 15 10.0
208-230/1/60 15 4.5
230/1/50 15 4.5
! Warning
All wiring must conform to local, state and national
codes.
! Warning
The ice machine must be grounded in accordance
with national and local electrical code.
Part Number STH042 3/14 27
Water Service/Drains
WATER SUPPLY
Local water conditions may require treatment of the
water to inhibit scale formation, filter sediment, and
remove chlorine odor and taste.
WATER INLET LINES
Follow these guidelines to install water inlet lines:
• Do not connect the ice machine to a hot water
supply. Be sure all hot water restrictors installed for
other equipment are working. (Check valves on
sink faucets, dishwashers, etc.)
• If water pressure exceeds the maximum
recommended pressure, 80 psig (5.5 bar) obtain a
water pressure regulator from your Manitowoc
distributor.
• Install a water shut-off valve for ice making potable
water.
• Insulate water inlet lines to prevent condensation.
Important
If you are installing a Manitowoc water filter
system, refer to the Installation Instructions
supplied with the filter system for ice making
water inlet connections.
!
Warning
For ice making, connect to a potable water supply
only.
28 Part Number STH042 3/14
DRAIN CONNECTIONS
Follow these guidelines when installing drain lines to
prevent drain water from flowing back into the ice
machine and storage bin:
• Drain lines must have a 1.5-inch drop per 5 feet of
run (2.5 cm per meter), and must not create traps.
• The floor drain must be large enough to
accommodate drainage from all drains.
• Install a tee to vent the ice machine drain to the
atmosphere.
• Insulate drain lines to prevent condensation.
COOLING TOWER APPLICATIONS
Water Cooled Models Only
A water-cooling tower installation does not require
modification of the ice machine. The water regulator
valve for the condenser continues to control the
refrigeration discharge pressure.
It is necessary to know the amount of heat rejected,
and the pressure drop through the condenser and
water valves (inlet to outlet) when using a cooling
tower on an ice machine.
• Water entering the condenser must not exceed
90°F (32.2°C).
• Water flow through the condenser must not
exceed 5 gallons (19 liters) per minute.
• Allow for a pressure drop of 7 psig (.48 bar)
between the condenser water inlet and the outlet
of the ice machine.
• Water exiting the condenser must not exceed
110°F (43.3°C).
!
Caution
Plumbing must conform to state and local codes
Part Number STH042 3/14 29
WATER SUPPLY AND DRAIN LINE SIZING/
CONNECTIONS
Tubing S ize Up t o
Ice Machine
Fitting
3/8" (9.5 mm) min.
inside diameter
3/8" (9.5 mm) min.
inside diameter
3/8" (9.5 mm) min.
inside diameter
Ice Machine
Fitting
3/8" Female
Pipe Thread
3/8" Female
Pipe Thread
3/8" Female
Pipe Thread
Water
Pressure
20 psi (1.38 bar) min.
80 psi (5.5 bar) max.
20 psi (1.38 bar) min.
150 psi (10.3 bar) max.
—
Water
Temperature
33°F (0.6°C) min.
90°F (32.2°C) max.
33°F (0.6°C) min.
90°F (32.2°C) max.
—
Location
Ice Making
Water Inlet
Condenser
Water Inlet
Condenser
Water Drain
30 Part Number STH042 3/14
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Part Number STH042 3/14 31
Maintenance
Interior Cleaning and Sanitizing
GENERAL
Clean and sanitize the ice machine every six months
for efficient operation. If the ice machine requires more
frequent cleaning and sanitizing, consult a qualified
service company to test the water quality and
recommend appropriate water treatment.
The ice machine must be taken apart for cleaning and
sanitizing.
CLEANING AND SANITIZING PROCEDURE
Ice machine cleaner is used to remove lime scale and
mineral deposits. Ice machine sanitizer disinfects and
removes algae and slime.
!
Caution
Use only Manitowoc approved Ice Machine
Cleaner (part number 94-0546-3) and
Sanitizer (part number 94-0565-3). It is a
violation of Federal law to use these solutions
in a manner inconsistent with their labeling.
Read and understand all labels printed on
bottles before use.
32 Part Number STH042 3/14
TOUCH PAD OPERATION
Pressing and holding the clean button for 3 seconds
starts the clean cycle. The Clean & On/Off lights
energize indicating the clean cycle has started and ice
making will automatically start when the Clean cycle is
complete.
• Setting the ice machine to stop after the clean
cycle: Press the On/Off button. The On/Off light
will de-energize indicating the ice machine will
stop after the clean cycle.
• Pausing the cleaning cycle: Press the Clean
button. The clean light will flash indicating the
clean cycle has paused. Pressing the Clean button
again will restart the clean cycle.
Step 1 Press the On/Off button after ice falls from the
evaporator at the end of a Harvest cycle. Or, press the
On/Off button and allow the ice to melt off the
evaporator.
Step 2 Remove all ice from the bin.
.
!
Caution
Never use anything to force ice from the
evaporator. Damage may result.
! Warning
Wear rubber gloves and safety goggles
(and/or face shield) when handling Ice
Machine Cleaner or Sanitizer.
Part Number STH042 3/14 33
Step 3 To start a cleaning cycle, press the Clean
button. Water will flow through the water dump valve
and down the drain. Wait until the water trough refills,
then add the proper amount of ice machine cleaner to
the water trough.
Wait until the clean cycle is complete (approximately
22 minutes) then press the On/Off button and
disconnect power and water supplies to the ice
machine.
Step 4 Remove parts for cleaning.
Refer to the proper parts removal for your machine.
Continue with step 6 when the parts have been
removed.
!
Caution
Do not mix Ice Machine Cleaner and Sanitizer
solutions together. It is a violation of Federal
law to use these solutions in a manner
inconsistent with their labeling.
Model Amount of Cleaner
U0140 2 ounces (60 ml)
U0190 5 ounces (150 ml)
U0240 5 ounces (150 ml)
U0310 5 ounces (150 ml)
34 Part Number STH042 3/14
Step 5 Mix a solution of cleaner and warm water.
Depending on the amount of mineral buildup, a larger
quantity of solution may be required. Use the ratio in
the table below to mix enough solution to thoroughly
clean all parts.
Use half of the cleaner/water solution to clean all
components. The cleaner solution will foam when it
contacts lime scale and mineral deposits; once the
foaming stops use a soft bristle brush, sponge or cloth
(not a wire brush) to carefully clean the parts. Soak the
parts for 5 minutes (15 – 20 minutes for heavily scaled
parts). Rinse all components with clean water.
Step 6 While components are soaking, use half of the
cleaner/water solution to clean all foodzone surfaces
of the ice machine and bin. Use a nylon brush or cloth
to thoroughly clean the following ice machine areas:
• Evaporator plastic parts – including top, bottom
and sides
• Bin bottom, sides and top
• Rinse all areas thoroughly with clean water.
Solution Type Water Mixed with
Cleaner 1 gal. (4 l) 16 oz (500 ml) cleaner
Part Number STH042 3/14 35
Step 7 Mix a solution of sanitizer and warm water.
Use half of the sanitizer/water solution to sanitize all
removed components. Use a spray bottle to liberally
apply the solution to all surfaces of the removed parts
or soak the removed parts in the sanitizer/water
solution. Do not rinse parts after sanitizing.
Step 8 Use half of the sanitizer/water solution to
sanitize all foodzone surfaces of the ice machine and
bin. Use a spray bottle to liberally apply the solution.
When sanitizing, pay particular attention to the
following areas:
• Evaporator plastic parts - including top, bottom and
sides
• Bin bottom, sides and top
Do not rinse the sanitized areas.
Step 9 Replace all removed components, wait 10
minutes, then reapply power and water to the ice
machine
Step 10 Press the Clean button. Water will flow
through the water dump valve and down the drain.
Wait until the water trough refills, then add the proper
amount of ice machine sanitizer to the water trough.
Wait until the sanitize cycle is complete (approximately
22 minutes) then press the Ice button to start ice
making.
Solution Type Water Mixed With
Sanitizer 3 gal. (12 l) 2 oz (60 ml) sanitizer
Model Amount of Sanitizer
U0140 1 ounces (30 ml)
U0190 2 ounces (60 ml)
U0240 2 ounces (60 ml)
U0310 2 ounces (60 ml)
36 Part Number STH042 3/14
REMOVE PARTS FOR CLEANING
A. Remove the Harvest Float Switch and Ice
Thickness Float Switch
• Pull forward on the bottom of the bracket until clear
of the tab, then slide bracket upward to remove the
bracket and float as an assembly. At this point, the
float switch’s can easily be cleaned. If complete
removal is desired follow the wires to the bulkhead
grommet (exit point) in the back wall. Pull the wire
connector through the bulkhead grommet, then
disconnect the wire leads from the connector.
NOTE: The wire from the top grommet goes to the ice
thickness float switch (front switch). The wire from the
bottom grommet goes to the Harvest float switch (side
switch).
! Warning
Disconnect electric power to the ice machine
at the electric switch box before proceeding.
Part Number STH042 3/14 37
WIRE CONNECTORS ARE LOCATED BEHIND BULKHEAD
PULL THROUGH GROMMET TO DISCONNECT
ICE THICKNESS FLOAT
SWITCH & BRACKET
HARVEST FLOAT
SWITCH & BRACKET
DISCONNECT WIRES
FOR COMPLETE
REMOVAL
38 Part Number STH042 3/14
B. Remove the Water Trough
• Remove the upper thumbscrew.
• While supporting the water trough remove the
thumbscrew from beneath the water trough.
• Remove the water trough from the bin area.
UPPER THUMBSCREW
LOWER THUMBSCREW
Part Number STH042 3/14 39
C. Remove the Ice Damper
• Remove thumbscrew from bin switch cover.
• Support ice damper and then pull bin switch cover
and ice damper forward to remove.
2. SUPPORT ICE DAMPER THEN
SLIDE RIGHT SIDE FORWARD TO REMOVE
1. REMOVE THUMBSCREW
40 Part Number STH042 3/14
D. Remove the Water Distribution Tube
• Distribution tube thumbscrews are retained to
prevent loss. Loosen thumbscrews but do not pull
thumbscrews out of distribution tube.
• Loosen the two outer screws and pull forward on
the distribution tube to release.
NOTE: For ease of assembly when reinstalling the
water distribution tube, install the top edge first
.
2. PULL DISTRIBUTION TUBE
FORWARD TO REMOVE
1. LOOSEN THUMBSCREWS
Part Number STH042 3/14 41
Preventative Maintenance Cleaning
This cleaning procedure can be performed
between the bi-annual cleaning and sanitizing
cycles. This procedure does not require
removing the ice from the bin.
Step 1 Press the On/Off button after ice falls from the
evaporator at the end of a Harvest cycle. Or, press the
On/Off button and allow the ice to melt off the
evaporator.
.
Step 2 To start a cleaning cycle, press the Clean
button. Water will flow through the water dump valve
and down the drain. Wait until the water trough refills,
then add the proper amount of ice machine cleaner to
the water trough.
Wait until the clean cycle is complete (approximately
22 minutes) then press the On/Off button.
!
Caution
Never use anything to force ice from the
evaporator. Damage may result.
!
Warning
Wear rubber gloves and safety goggles
(and/or face shield) when handling Ice
Machine Cleaner or Sanitizer.
Model Amount of Cleaner
U0140 2 ounce (60 ml)
U0190 5 ounces (150 ml)
U0240 5 ounces (150 ml)
U0310 5 ounces (150 ml)
42 Part Number STH042 3/14
Ice Machine Inspection
Check all water fittings and lines for leaks. Also, make
sure the refrigeration tubing is not rubbing or vibrating
against other tubing, panels, etc.
Do not put anything (boxes, etc.) in front of the ice
machine. There must be adequate airflow through and
around the ice machine to maximize ice production
and ensure long component life.
Exterior Cleaning
Clean the area around the ice machine as often as
necessary to maintain cleanliness and efficient
operation.
Sponge any dust and dirt off the outside of the ice
machine with mild soap and water. Wipe dry with a
clean, soft cloth.
A commercial grade stainless steel cleaner/polish can
be used as necessary.
Cleanup any fallen ice or water spills as they occur.
Part Number STH042 3/14 43
Cleaning the Condenser
General
A dirty condenser restricts airflow, resulting in
excessively high operating temperatures. This
reduces ice production and shortens component life.
• Clean the condenser at least every six months.
• Shine a flashlight through the condenser to check
for dirt between the fins.
• Blow compressed air or rinse with water from the
inside out (opposite direction of airflow).
• If dirt still remains call a service agent to clean the
condenser.
! Warning
Disconnect electric power to the ice machine
head section and the remote condensing unit
at the electric service switches before cleaning
the condenser.
!
Warning
The condenser fins are sharp. Use care when
cleaning them.
44 Part Number STH042 3/14
Removal from Service/Winterization
1. Clean and sanitize the ice machine.
2. Press the On/Off button to turn off the ice
machine.
3. Turn off the water supply, disconnect and drain
the incoming ice-making water line at the rear of
the ice machine and drain the water trough.
4. Energize the ice machine, wait one minute for the
water inlet valve to open and blow compressed air
in both the incoming water and the drain openings
in the rear of the ice machine to remove all water.
5. Press the On/Off button and disconnect the
electric power at the circuit breaker or the electric
service switch.
6. Fill spray bottle with sanitizer and spray all interior
food zone surfaces. Do not rinse and allow to air
dry.
7. Replace all panels.
Part Number STH042 3/14 45
Bin Removal
1. Disconnect power.
1. Remove all ice from bin.
2. Loosen screws and slide clips to release.
3. Disconnect clamp and remove bin drain.
4. Disconnect touch pad communication cable.
5. Slide bin forward to remove.
NOTE: When reinstalling the bin, insure the bin seal is
in place and is not pinched/folded as it mates to the
cabinet. A water tight seal is required to prevent future
condensation or water leakage from entering the ice
machine base.
LOOSEN SCREWS AND SLIDE CLIPS
DISCONNECT CLAMP AND REMOVE BIN DRAIN
DISCONNECT COMMUNICATION CABLE
46 Part Number STH042 3/14
This Page Intentionally Left Blank
Part Number STH042 3/14 47
Operation
Touch Pad Features
The touch pad offers a series of pressure sensitive
buttons to control ice machine operation and provide
operational status.
ON/OFF
The On/Off Button is used to start and stop ice
making. The blue light indicates whether the ice
machine is in Ice Making (light on) or Off (light off).
On/Off - Blue = Machine On
Off = Machine Is Off
Delay - Blue = Delay Mode On
Off = Delay Mode Is Off
Clean - Yellow = Clean Cycle On
Off = Cleaning is Off
Bin Full - Blue = Bin Is Full
Off = Bin Is Not Full
Service - Red Solid or Flashing =
Needs Service
Off = Doesn’t Need Service
48 Part Number STH042 3/14
DELAY
Pressing the Delay button will start a delay period. The
ice machine will finish the freeze and harvest cycle
and then start the delay period.
• Pressing the button once will start a 4 hour delay
period.
• Pressing the button twice will start a 12 hour delay
period.
• Pressing the button three times will start a 24 hour
delay period.
• Pressing the button four times will cancel the delay
periods.
NOTE: The delay period will be canceled if power is
interrupted to the ice machine. When power is
restored, the ice machine will start an ice making
cycle.
CLEAN
Pressing the Clean button for 3 seconds will start a
clean cycle. After the clean cycle is complete, the ice
machine will automatically start an ice making cycle.
• Pressing the Clean button again within 45seconds
of the clean cycle starting will abort the clean
cycle.
• Pressing the Clean button after 45 seconds into
the Clean cycle will de-energize the On/Off LED
and the ice machine will stop after the Clean cycle
is complete.
Pressing the On/Off button will pause the Clean cycle.
The On/Off light will flash on/off to indicate pause
mode. Pressing the On/Off button again will continue
the Clean cycle from the point of interruption.
Part Number STH042 3/14 49
BIN FULL
The Bin Full light energizes when the bin is full or is
de-energized if the bin is not full.
SERVICE
The service light indicates the machine needs
attention.
• Refer to safety limits if this light is energized.
50 Part Number STH042 3/14
Ice Making Sequence of Operation
NOTE: The On/Off button must be depressed and the
ice damper must be closed before the ice machine will
start.
Water Purge Cycle
The ice machine purges any remaining water from the
water trough down the drain.
Freeze Cycle
Prechill - The refrigeration system chills the evaporator
before water flow over the evaporator starts. The
water inlet valve energizes during the pre-chill and
remains on until the ice thickness float switch is
satisfied.
Freeze - Water flowing across the evaporator freezes
and builds ice on the evaporator. After a sheet of ice
has formed, the Harvest float switch signals the control
board to start a harvest cycle.
Harvest Cycle
Any remaining water is purged down the drain as
refrigerant gas warms the evaporator. When the
evaporator warms, the sheet of cubes slides off the
evaporator and into the storage bin. If all cubes fall
clear of the ice damper the ice machine starts another
freeze cycle.
Full Bin Cycle
If the ice damper is held open by ice cubes the ice
machine shuts off. When the ice damper closes the ice
machine starts a new cycle at the water purge.
Part Number STH042 3/14 51
CONTROL BOARD TIMERS
• The ice machine is locked into the freeze cycle for
6 minutes before a harvest cycle can be initiated.
The freeze time lock in feature is bypassed on the
initial cycle (manual start or after a full bin/safety
limit condition).
If the Harvest float Switch is in the down position
for 10 continuous seconds during the start of a
freeze cycle, a harvest sequence is initiated.
• The maximum freeze time is 60 minutes at which
time the control board automatically initiates a
harvest sequence.
• The maximum harvest time is 3.5 minutes. The
control board automatically initiates a freeze
sequence when these times are exceeded.
• The water fill valve is de-energized 1 minute after
the freeze cycle starts. The control board will
energize the water inlet valve one more time 3
minutes into the freeze cycle.
52 Part Number STH042 3/14
SAFETY LIMITS
Safety limits are stored and indicated by the control
board. The number of cycles required to stop the ice
machine varies for each safety limit.
Safety limits can be reset by pressing the On/Off
button and starting a new ice making cycle.
A safety limit is indicated by a flashing Service Light on
the touch pad.
Safety Limit 1
If the freeze time reaches 60 minutes, the control
board automatically initiates a harvest cycle.
• After 3 consecutive 60 minute cycles control board
light SL#1 along with the touch pad service
(wrench) light will flash on/off at 1 second intervals.
• If 6 consecutive 60-minute freeze cycles occur, the
ice machine stops and the SL#1 light on the
control board and the service (wrench) light on the
touch pad will be on continuously.
Safety Limit 2
If the harvest time reaches 3.5 minutes, the control
board automatically returns the ice machine to the
freeze cycle.
• If three consecutive 3.5 minute harvest cycles
occur the SL#2 light on the control board will flash
on/off at 1 second intervals.
• If 75 consecutive 3.5 minute harvest cycles occur
the wrench light on the touch pad will flash on/off
at 1 second intervals.
• If 100 consecutive 3.5 minute harvest cycles
occur, the ice machine stops and the SL#2 light on
the control board and the service (wrench) light on
the touch pad will be on continuously.
Part Number STH042 3/14 53
Safety Limit 3
If the freeze time reaches 4 minutes and water is not
sensed (float remains down for 10 continuous
seconds) the ice machine stops.
• Safety Limit 3 is bypassed on the initial cycle
(manual start or after a full bin/safety limit
condition). For all subsequent cycles if the freeze
time reaches 4 minutes and water is not sensed,
the ice machine stops and initiates a 30 minute
delay period. Control board lights SL#1 and SL#2
along with the touch pad service (wrench) light will
flash on/off at 1 second intervals.
• The ice machine automatically restarts at the end
of the 30 minute delay period and stops flashing
the control board and service (wrench) lights.
• If 100 consecutive failures occur the ice machine
stops and the touch pad service (wrench) light
remains energized.
54 Part Number STH042 3/14
ENERGIZED PARTS CHART
Self-Contained Ice Machines
ICE MAKING
SEQUENCE OF
OPERATION
Water Pump Harvest
Valve
Water Inlet
Valve
Dump
Valve
Compressor
&
Condenser Fan
Motor*
Harvest
Float Switch
Ice Thickness
Float Switch
Length of
Time
Initial Start-up
1. Water purge
OFF ON OFF ON OFF CLOSED CLOSED 20 seconds
2. Refrigeration
System
Start-up
OFF ON OFF OFF ON CLOSED CLOSED 5 seconds
Freeze Sequence
3. Pre chill
OFF OFF ON OFF ON OPEN CLOSED
120
Seconds
initial cycle
Thereafter
60 seconds
Part Number STH042 3/14 55
* Condenser Fan Motor: The fan motor is wired through a fan cycle pressure control; therefore, it may cycle on and off.
** The water fill valve is de-energized by the control board 1 minute after the freeze cycle starts - The control board will energize the water inlet
valve for 7 seconds one last time, 3 minutes into the freeze cycle, regardless of float position.
4. Freeze
ON OFF ON** OFF ON OPEN THEN
CLOSED
CLOSED THEN
OPEN
Until
Harvest
Float Switch
closes for
10 continual
seconds
Harvest
Sequence
5. Water Purge
OFF ON OFF ON FOR 20
SECONDS
THEN OFF
ON CLOSED CLOSED 20 seconds
6. Harvest
OFF ON OFF OFF ON CLOSED CLOSED
Bin switch
activation
7. Automatic
Shut-off
OFF OFF OFF OFF OFF CLOSED CLOSED
Until bin
switch
re-closes
56 Part Number STH042 3/14
Operational Checks
ICE THICKNESS CHECK
After a harvest cycle, inspect the ice cubes in the ice
storage bin. The ice bridge connects the ice cubes and
must be set to maintain an ice bridge thickness of 1/8"
(3.2 mm). To adjust the thickness of the bridge refer to
ice thickness adjustment.
ICE THICKNESS ADJUSTMENT
The ice thickness can be adjusted to three levels.
1. Pull forward on the bottom of the bracket until
clear of the tab.
2. Slide the bracket over the desired tab and
release.
• The center position is the normal factory setting.
• To increase bridge thickness, raise the water level.
• To decrease bridge thickness, lower the water
level.
Thinner
Bridge
Factory
Default
Setting
Thicker
Bridge
Part Number STH042 3/14 57
Troubleshooting
Control Board Test Mode
NOTE: The ice damper/bin switch can be open or
closed and does not effect the operation of the test
mode.
To enter the test mode press and hold the test button
on the control board for 3 seconds. The control board
test mode performs the following functions for a 2
minute time period:
• Energizes all control board relays
• Energizes all control board lights
• Energizes all touch pad control lights
After 2 minutes the control board will automatically
initiate and complete one ice making cycle, then stop.
Canceling a test cycle:
To cancel a test cycle press the test button a second
time.
Restarting a test cycle:
The test cycle will restart each time the test button is
pressed for a 3 second time period.
OPERATING ICE MACHINE WITH BIN AND TOUCH
PAD REMOVED.
The ice machine is designed to allow diagnostic
procedures to be performed with the bin removed. The
touch pad is attached to the bin and is disconnected
during the removal process. Use the control board test
mode to operate the ice machine without connecting
the touch pad.
58 Part Number STH042 3/14
Diagnosing an Ice Machine
that Will Not Run
1. Verify primary voltage is supplied to ice machine
and the fuse/circuit breaker is closed.
2. Verify control board fuse is okay.
NOTE: If any control board lights are on, the fuse is
okay.
3. Verify the bin switch functions properly. A
defective bin switch can falsely indicate a full bin
of ice.
4. Verify power button functions properly. A defective
power button may keep the ice machine in the
OFF mode. Refer to page 98 touch pad
diagnostics when steps 1-3 test good.
5. Be sure Steps 1 – 4 were followed thoroughly.
Intermittent problems are not usually related to
the control board. Replace control board if touch
pad operation is correct.
! Warning
High (line) voltage is applied to the control board
at all times. Removing the control board fuse or
pressing the power button will not remove the
power supplied to the control board.
Part Number STH042 3/14 59
Ice Machine Does Not Cycle Into Harvest
when Water Loses Contact with the
Harvest Float Switch
NOTE: The ice machine will make a thick or double
slab when a new freeze cycle is started with ice
already present on the evaporator.
Two of the most common scenarios are:
• Power is cycled off/on with ice on the evaporator.
• The ice damper/bin switch is opened/closed in the
harvest cycle before the ice releases.
Remove all ice from the evaporator before starting
diagnostic procedures.
Freeze Time Lock-In Feature
The ice machine control system incorporates a freeze
time lock-in feature. This prevents the ice machine
from short cycling in and out of harvest. The control
board locks the ice machine in the freeze cycle for six
minutes. After six minutes a harvest cycle can be
initiated. To allow the service technician to initiate a
harvest cycle without delay, this feature is not used on
the first cycle after pressing the power button OFF and
back to ON.
Step 1 Disconnect power to the ice machine, remove
the electrical panel to allow viewing of the control
board lights and pull the wire connector for the harvest
float switch through the bulkhead and disconnect.
Attach a jumper wire to the wire terminals connected
to the control board.
Step 2 Bypass the freeze time lock-in feature by
pressing the power button to cycle the ice machine on.
Wait until water flows over the evaporator, then refer to
chart.
Result Correction
10 seconds into the freeze
cycle the ice machine cycles
from freeze to harvest and
the control board harvest
light energizes.
Refer to Float Switch
Diagnostics.
The harvest light stays off
and the ice machine remains
in freeze.
Proceed to Step 3
60 Part Number STH042 3/14
Step 3 Disconnect the harvest float switch wire from
the control board and place a jumper on the control
board harvest float switch terminals. Bypass the freeze
time lock-in feature by pressing the power button to
cycle the ice machine off/on. Wait until water flows
over the evaporator, then refer to chart.
Result Correction
10 seconds into the freeze
cycle the ice machine cycles
from freeze to harvest and
the control board harvest
light energizes.
The ice thickness float
switch wire is causing the
malfunction.
The harvest light comes on,
but the ice machine remains
in the freeze cycle.
The ice machine is in a 6
minute freeze lock - Cycle
on/off and retest.
The harvest light stays off
and the ice machine remains
in freeze.
Replace the control board.
Part Number STH042 3/14 61
Ice Machine Cycles Into Harvest Before
Water loses Contact with the Harvest
Float Switch
Step 1 Disconnect power to the ice machine, remove
the electrical panel to allow viewing of the control
board lights and pull the wire connector for the harvest
float switch through the bulkhead and disconnect.
WIRE CONNECTORS ARE LOCATED BEHIND BULKHEAD
PULL THROUGH GROMMET TO DISCONNECT
ICE THICKNESS FLOAT
SWITCH & BRACKET
HARVEST FLOAT
SWITCH & BRACKET
62 Part Number STH042 3/14
Step 2 Reapply power and press the power button to
cycle the ice machine off/on and bypass the freeze
time lock-in feature. Wait until water flows over the
evaporator, then refer to chart.
Step 3 Disconnect the harvest float switch wire from
the control board and bypass the freeze time lock-in
feature by pressing the power button to cycle the ice
machine off/on. Wait until water flows over the
evaporator, then refer to chart,
Result Correction
The harvest light does not
come on and the ice
machine stays in freeze.
Refer to Float Switch
Diagnostics
The harvest light comes on
but the ice machine stays in
a freeze cycle.
The ice machine is in a 6
minute freeze lock - Cycle
on/off and retest.
10 seconds into the freeze
cycle the ice machine cycles
from freeze to harvest and
the control board harvest
light energizes.
Proceed to Step 3.
Result Correction
The harvest light does not
come on.
The harvest float switch
wire is causing the
malfunction.
The harvest light comes on
but the ice machine stays in
the freeze sequence.
The ice machine is in a 6
minute freeze lock - Cycle
on/off and retest.
10 seconds into the freeze
cycle the ice machine cycles
from freeze to harvest and
the control board harvest
light energizes.
Replace the control board.
Part Number STH042 3/14 63
Ice Production Check
The amount of ice a machine produces directly relates to the
operating water and air temperatures. This means an ice
machine with a 70°F (21°C) ambient temperature and 50°F
(10°C) water produces more ice than the same ice machine
with 90°F (32°C) ambient and 70°F (21°C) water.
1. Determine the ice machine operating conditions:
Air temp entering condenser: ____°
Air temp around ice machine: ____°
Water temp entering sump trough: ____°
2. Refer to the appropriate 24-Hour Ice Production Chart.
Use the operating conditions determined in Step 1 to
find published 24 hr. ice production:____
Times are in minutes.
Example: 1 min., 15 sec. converts to 1.25 min.
(15 seconds ÷ 60 seconds = .25 minutes)
Weights are in pounds.
Example: 2 lb., 6 oz. converts to 2.375 lb.
(6 oz. ÷16 oz. = .375 lb.)
3. Perform an ice production check using the formula
below.
Weighing the ice is the only 100% accurate check.
4. Compare the results of step 3 with step 2. Ice production
is normal when these numbers match closely. If they
match closely, determine if:
Another larger ice machine is required.
Relocating the existing equipment to lower the load
conditions is required.
Contact the local Manitowoc distributor for information on
available options and accessories.
1. _______ + _______ = _______
Freeze Time Harvest Time Total Cycle Time
2. 1440 ÷ _______ = _______
Mins in 24 hrs Total Cycle Time Cycles Per Day
3. _______ x _______ = _______
Weight of One Cycles Per Day Actual 24 Hr
Harvest Production
64 Part Number STH042 3/14
Installation/Visual Inspection Checklist
Ice machine is not level
• Level the ice machine
Condenser is dirty
• Clean the condenser
Water filtration is plugged (if used)
• Install a new water filter
Water drains are not run separately and/or are not
vented
• Run and vent drains according to the Installation
Manual
Part Number STH042 3/14 65
Water System Checklist
A water-related problem often causes the same
symptoms as a refrigeration system component
malfunction.
Example: A water dump valve leaking during the
freeze cycle, a system low on charge, and a starving
TXV have similar symptoms.
Water system problems must be identified and
eliminated prior to replacing refrigeration components.
Water area (evaporator) is dirty
• Clean as needed
Water inlet pressure not between 20 and 80 psig
(1–5 bar, 138–552 kPa)
• Install a water regulator valve or increase the
water pressure
Incoming water temperature is not between 35°F
(1.7°C) and 90°F (32.2°C)
• If too hot, check the hot water line check valves in
other store equipment
Water filtration is plugged (if used)
• Install a new water filter
Vent tube is not installed on water outlet drain
• See Installation Instructions
Hoses, fittings, etc., are leaking water
• Repair/replace as needed
Water valve is stuck open, closed or is leaking
• Clean/replace as needed
Water is spraying out of the sump trough area
• Stop the water spray
Uneven water flow across the evaporator
• Clean the ice machine
Water is freezing behind the evaporator
• Correct the water flow
Plastic extrusions and gaskets are not secured to
the evaporator
• Remount/replace as needed
66 Part Number STH042 3/14
Ice Formation Pattern
Evaporator ice formation pattern analysis is helpful in
ice machine diagnostics.
Analyzing the ice formation pattern alone cannot
diagnose an ice machine malfunction. However, when
this analysis is used along with Manitowoc’s
Refrigeration System Operational Analysis Table, it
can help diagnose an ice machine malfunction.
Examples of Evaporator Tubing Routing
Normal Ice Formation
Ice forms across the entire evaporator surface.
At the beginning of the Freeze cycle, it may appear
that more ice is forming on the inlet of the evaporator
than at the outlet. At the end of the Freeze cycle, ice
formation at the outlet will be close to, or just a bit
thinner than, ice formation at the inlet. The dimples in
the cubes at the outlet of the evaporator may be more
pronounced than those at the inlet. This is normal.
If ice forms uniformly across the evaporator surface,
but does not do so in the proper amount of time, this is
still considered a normal ice fill pattern.
OUTLET
INLET
OUTLET
INLET
U0140
U0190 U0240 U0310
Part Number STH042 3/14 67
Extremely Thin at Evaporator Outlet
There is no ice, or a considerable lack of ice formation
on the outlet of the evaporator.
Examples: No ice at all at the outlet of the evaporator,
but ice forms at the inlet half of the evaporator. Or, the
ice at the outlet of the evaporator reaches the correct
thickness, but the outlet of the evaporator already has
1/2" to 1" of ice formation.
Possible cause: Water loss, low on refrigerant,
starving TXV, hot water supply, faulty float valve, etc.
Extremely Thin at Evaporator Inlet
There is no ice, or a considerable lack of ice formation
at the inlet of the evaporator. Examples: The ice at the
outlet of the evaporator reaches the correct thickness,
but there is no ice formation at all at the inlet of the
evaporator.
Possible cause: Insufficient water flow, flooding TXV,
etc.
Spotty Ice Formation
There are small sections on the evaporator where
there is no ice formation. This could be a single corner,
or a single spot in the middle of the evaporator. This is
generally caused by loss of heat transfer from the
tubing on the backside of the evaporator.
No Ice Formation
The ice machine operates for an extended period, but
there is no ice formation at all on the evaporator.
Possible cause: Water float valve, water pump,
starving expansion valve, low refrigerant charge,
compressor, etc.
68 Part Number STH042 3/14
Safety Limit Feature
In addition to the standard safety controls, your
Manitowoc ice machine features built-in safety limits
that will stop the ice machine if conditions arise which
could cause a major component failure.
Service Light: The service light energizes whenever
a safety limit has been exceeded.
Safety Limit 1
If the freeze time reaches 60 minutes, the control
board automatically initiates a harvest cycle.
• After 3 consecutive 60 minute cycles control board
light SL#1 along with the touch pad service
(wrench) light will flash on/off at 1 second intervals.
• If 6 consecutive 60-minute freeze cycles occur, the
ice machine stops and the SL#1 light on the
control board and the service (wrench) light on the
touch pad will be on continuously.
Safety Limit 2
If the harvest time reaches 3.5 minutes, the control
board automatically returns the ice machine to the
freeze cycle.
• If three consecutive 3.5 minute harvest cycles
occur the SL#2 light on the control board will flash
on/off at 1 second intervals.
• If 75 consecutive 3.5 minute harvest cycles occur
the wrench light on the touch pad will flash on/off
at 1 second intervals.
• If 100 consecutive 3.5 minute harvest cycles
occur, the ice machine stops and the SL#2 light on
the control board and the service (wrench) light on
the touch pad will be on continuously.
Part Number STH042 3/14 69
Safety Limit 3
If the freeze time reaches 4 minutes and water is not
sensed (float remains down for 10 continuous
seconds) the ice machine stops.
• Safety Limit 3 is bypassed on the initial cycle
(manual start or after a full bin/safety limit
condition). For all subsequent cycles if the freeze
time reaches 4 minutes and water is not sensed,
the ice machine stops and initiates a 30 minute
delay period. Control board lights SL#1 and SL#2
along with the touch pad service (wrench) light will
flash on/off at 1 second intervals.
• The ice machine automatically restarts at the end
of the 30 minute delay period and stops flashing
the control board and service (wrench) lights.
• If 100 consecutive failures occur the ice machine
stops and the touch pad service (wrench) light
remains energized.
70 Part Number STH042 3/14
Determining Which Safety Limit Stopped
the
Ice Machine:
When a safety limit condition causes the ice machine
to stop, the safety limit light on the control board
continually flashes on and off.
CONTROL BOARD SAFETY LIMIT LIGHT
OPERATION, BEFORE THE POWER BUTTON HAS
BEEN CYCLED ON/OFF:
Watch the safety limit lights on the control board:
• SL#1 flashes = 3 or more 60 minute cycles
• SL#1 continuously on = 6 consecutive 60 minute
freeze cycles
• SL#2 flashes = 3 consecutive 3.5 minute harvest
cycles
• SL#2 continuously on = 100 consecutive 3.5
minute harvest cycles
• SL#1 & SL#2 flash = SL#3, neither float opened
within 4 minutes of the freeze cycle.
CONTROL BOARD SAFETY LIMIT LIGHT
OPERATION USING THE POWER BUTTON:
1. Press the power button once.
2. Press the power button again to start ice making.
3. Watch the safety limit lights.
• One will flash corresponding to safety limits 1 or 2.
4. Safety limit 3 is indicated by both SL#1 & SL#2
flashing.
After safety limit indication, the ice machine will restart
and run until a safety limit is exceeded again.
Safety Limit Notes
• A continuous run of 100 harvests automatically
erases the safety limit code.
• The control board will store and indicate only one
safety limit – the last one exceeded.
• If the power button is cycled OFF and then ON
prior to reaching the 100-harvest point, the last
safety limit exceeded will be indicated.
Part Number STH042 3/14 71
Safety Limit Checklist
The following checklists are designed to assist the
service technician in analysis. However, because
there are many possible external problems, do not
limit your diagnosis to only the items listed.
Safety Limit #1
Freeze time exceeds 60 minutes for 3 consecutive
freeze cycles.
Possible Cause Checklist
Improper installation
• Refer to “Installation/Visual Inspection Checklist”
on page 64
Water System
• Water Level too high or defective float switch
(water escaping water trough)
• Low water pressure (20 psig min.)
• High water pressure (80 psig max.)
• High water temperature (90°F/32.2°C max.)
• Clogged water distribution tube
• Dirty/defective water inlet valve
• Defective water pump
Electrical System
• Harvest cycle not initiated electrically
• Contactor not energizing
• Compressor electrically non-operational
• Restricted condenser air flow
• High inlet air temperature (110°F/43.3°C max.)
• Condenser discharge air re-circulation
• Dirty condenser fins
• Defective fan cycling control
• Defective fan motor
• Low water pressure (20 psig min.)
• High water temperature (90°F/32.2°C max.)
• Dirty condenser
72 Part Number STH042 3/14
Refrigeration System
• Non-Manitowoc components
• Improper refrigerant charge
• Defective compressor
• TXV starving or flooding (check bulb mounting)
• Non-condensable in refrigeration system
• Plugged or restricted high side refrigerant lines or
component
• Defective harvest valve
Part Number STH042 3/14 73
Safety Limit #2
Harvest time exceeds 3.5 minutes for 100
Consecutive harvest cycles.
Possible Cause Checklist
Improper installation
• Refer to “Installation/Visual Inspection Checklist”
on page 64.
Water System
• Water area (evaporator) dirty
• Dirty/defective water dump valve
• Vent tube not installed on water outlet drain
• Water freezing behind evaporator
• Plastic extrusions and gaskets not securely
mounted to the evaporator
• Low water pressure (20 psig min.)
• Loss of water from sump area
• Clogged water distribution tube
• Dirty/defective water inlet valve
• Defective water pump
Electrical system
• Water inlet valve defective
• Bin switch defective
• Premature harvest
Refrigeration system
• Non-Manitowoc components
• Improper refrigerant charge
• Defective harvest valve
• TXV flooding (check bulb mounting)
• Defective fan cycling control
74 Part Number STH042 3/14
Safety Limit 3
Freeze time reaches 4 minutes and water is not
sensed.
Possible Cause Checklist
Improper installation
• Refer to “Installation/Visual Inspection Checklist”
on page 64.
Water System
• Dirty/defective water dump valve
• Low water float valve dirty or defective
• Vent tube not installed on water outlet drain
• Low water pressure (20 psig min.)
• Dirty defective water filter (when used)
• Loss of water from sump area
• Dirty/defective water inlet valve
Electrical system
• Water inlet valve coil defective
• Low water float valve defective
Part Number STH042 3/14 75
Analyzing Discharge Pressure
1. Determine the ice machine operating conditions:
Air temp. entering condenser ______
Air temp. around ice machine ______
Water temp. entering sump trough ______
2. Refer to “Cycle Times, 24 Hr. Ice Production and
Refrigerant Pressure Charts” on page 121 for ice
machine being checked.
Use the operating conditions determined in step 1 to
find the published normal discharge pressures.
Freeze Cycle ______
Harvest Cycle ______
3. Perform an actual discharge pressure check.
4. Compare the actual discharge pressure (step 3)
with the published discharge pressure (step 2).
The discharge pressure is normal when the actual
pressure falls within the published pressure range for
the ice machine’s operating conditions. It is normal for
the discharge pressure to be higher at the beginning of
the freeze cycle (when load is greatest), then drop
through out the freeze cycle.
Freeze
Cycle PSIG
Harvest
Cycle PSIG
Beginning of
Cycle
__________ __________
Middle of
Cycle
__________ __________
End of
Cycle
__________ __________
76 Part Number STH042 3/14
Discharge Pressure High Checklist
Improper Installation
• Refer to “Installation/Visual Inspection Checklist”
on page 64.
Restricted Condenser Air Flow
• High inlet air temperature
• Condenser discharge air re-circulation
• Dirty condenser fins
• Defective fan cycling control
• Defective fan motor
Improper Refrigerant Charge
• Overcharged
• Non-condensable in system
• Wrong type of refrigerant
Other
• Non-Manitowoc components in system
• High side refrigerant lines/component restricted
(before mid-condenser)
Freeze Cycle Discharge Pressure Low Checklist
Improper Installation
• Refer to “Installation/Visual Inspection Checklist”
on page 64.
Improper Refrigerant Charge
• Undercharged
• Wrong type of refrigerant
Other
• Non-Manitowoc components in system
• High side refrigerant lines/component restricted
(before mid-condenser)
• Defective fan cycle control
NOTE: Do not limit your diagnosis to only the items
listed in the checklists.
Part Number STH042 3/14 77
Analyzing Suction Pressure
The suction pressure gradually drops throughout the
freeze cycle. The actual suction pressure (and drop
rate) changes as the air and water temperature
entering the ice machine changes. These variables
also determine the freeze cycle times.
To analyze and identify the proper suction pressure
drop throughout the freeze cycle, compare the
published suction pressure to the published freeze
cycle time.
NOTE: Analyze discharge pressure before analyzing
suction pressure. High or low discharge pressure may
be causing high or low suction pressure.
78 Part Number STH042 3/14
Procedure
Step
1. Determine the ice machine operating conditions.
Example:
Air temp. entering condenser: 90°F/32.2°C
Air temp. around ice machine: 80°F/26.7°C
Water temp. entering water fill valve: 70°F/21.1°C
2A. Refer to “Cycle Time” and “Operating Pressure” charts
for ice machine model being checked. Using operating
conditions from Step 1, determine published freeze cycle
time and published freeze cycle suction pressure.
Example:
Published freeze cycle time: 14.8 - 15.9 minutes
Published freeze cycle suction pressure: 65 - 26 psig
2B. Compare the published freeze cycle time and
published freeze cycle suction pressure. Develop a chart.
Example:
Published Freeze Cycle Time (minutes)
1247101214
|||||||
65 55 47 39 34 30 26
Published Freeze Cycle Suction Pressure (psig)
In the example, the proper suction pressure should be
approximately 39
psig at 7 minutes; 30 psig at 12
minutes; etc.
3. Perform an actual suction pressure check at the
beginning, middle and end of the freeze cycle. Note the
times at which the readings are taken.
Example:
Manifold gauges were connected to the example ice
machine and suction pressure readings taken as
follows: ________ PSIG
Beginning of Freeze cycle: 79 (at 1 min.)
Middle of freeze cycle: 48 (at 7 min.)
End of freeze cycle: 40 (at 14 min.)
4. Compare the actual freeze cycle suction pressure (Step
3) to the published freeze cycle time and pressure
comparison (Step 2B). Determine if the suction pressure is
high, low or acceptable.
Example:
In this example, the suction pressure is considered high
throughout the freeze cycle. It should have been:
Approximately 65 psig (at 1 minute) – not 79
Approximately 39 psig (at 7 minutes) – not 48
Approximately 26 psig (at 14 minutes) – not 40
Part Number STH042 3/14 79
Suction Pressure High Checklist
Improper Installation
• Refer to “Installation/Visual Inspection Checklist”
on page 64.
Discharge Pressure
• Discharge pressure is too high, and is affecting
suction pressure, refer to
“Discharge Pressure
High Checklist” on page 76.
Improper Refrigerant Charge
• Overcharged
• Wrong type of refrigerant
• Non-condensable in system
Other
• Non-Manitowoc components in system
• Harvest valve leaking
• TXV flooding (check bulb mounting)
• Defective compressor
80 Part Number STH042 3/14
Suction Pressure Low Checklist
Improper Installation
• Refer to “Installation/Visual Inspection Checklist”
on page 64.
Discharge Pressure
• Discharge pressure is too low, and is affecting
suction pressure, refer to “Freeze Cycle Discharge
Pressure Low Checklist”
Improper Refrigerant Charge
• Undercharged
• Wrong type of refrigerant
Other
• Non-Manitowoc components in system
• Improper water supply over evaporator refer to
“Water System Checklist” on page 65.
• Loss of heat transfer from tubing on back side of
evaporator
• Restricted/plugged liquid line drier
• Restricted/plugged tubing in suction side of
refrigeration system
• TXV starving
NOTE: Do not limit your diagnosis to only the items
listed in the checklists.
Part Number STH042 3/14 81
Harvest Valve
General
The harvest valve is an electrically operated valve that
opens when energized, and closes when deenergized.
Normal Operation
The valve is de-energized (closed) during the freeze
cycle and energized (open) during the harvest cycle.
The valve is positioned between the receiver and the
evaporator and performs two functions:
1. Prevents refrigerant from entering the evaporator
during the freeze cycle.
The harvest valve is not used during the freeze
cycle. The harvest valve is de-energized (closed)
preventing refrigerant flow from the receiver into
the evaporator.
2. Allows refrigerant vapor to enter the evaporator in
the harvest cycle.
During the harvest cycle, the harvest valve is
energized (open) allowing refrigerant gas from the
discharge line of the compressor to flow into the
evaporator. The heat is absorbed by the
evaporator and allows release of the ice slab.
Exact pressures vary according to ambient
temperature and ice machine model. Harvest
pressures can be found in the Cycle Time/24 Hour Ice
Production/ Refrigerant Pressure Charts in this book.
82 Part Number STH042 3/14
Harvest Valve Analysis
The valve can fail in two positions:
• Valve will not open in the harvest cycle.
• Valve remains open during the freeze cycle.
VALVE WILL NOT OPEN IN THE HARVEST CYCLE
Although the circuit board has initiated a harvest cycle,
the evaporator temperature remains unchanged from
the freeze cycle.
VALVE REMAINS OPEN IN THE FREEZE CYCLE:
Symptoms of a harvest valve remaining partially open
during the freeze cycle can be similar to symptoms of
an expansion valve, float valve or compressor
problem. Symptoms are dependent on the amount of
leakage in the freeze cycle.
A small amount of leakage will cause increased freeze
times and an ice fill pattern that is “Thin at the Outlet”,
but fills in at the end of the cycle.
As the amount of leakage increases the length of the
freeze cycle increases and the amount of ice at the
outlet of the evaporator decreases.
Refer to the Parts Manual for proper valve application.
If replacement is necessary, use only “original”
Manitowoc replacement parts.
Part Number STH042 3/14 83
Use the following procedure and table to help
determine if a harvest valve is remaining partially open
during the freeze cycle.
1. Wait five minutes into the freeze cycle.
2. Feel the inlet of the harvest valve(s).
3. Feel the compressor discharge line.
4. Compare the temperature of the inlet of the
harvest valves to the temperature of the
compressor discharge line.
Important
Feeling the harvest valve outlet or across the
harvest valve itself will not work for this
comparison.
The harvest valve outlet is on the suction side
(cool refrigerant). It may be cool enough to touch
even if the valve is leaking.
! Warning
The inlet of the harvest valve and the compressor
discharge line could be hot enough to burn your
hand. Just touch them momentarily.
84 Part Number STH042 3/14
5. Record your findings on the table.
Findings Comments
The inlet of the harvest
valve is cool enough to
touch and the compressor
discharge line is hot.
Cool & Hot
This is normal as the
discharge line should
always be too hot to touch
and the harvest valve inlet,
although too hot to touch
during harvest, should be
cool enough to touch after 5
minutes into the freeze
cycle.
The inlet of the harvest
valve is hot and approaches
the temperature of a hot
compressor discharge line.
Hot & Hot
This is an indication
something is wrong, as the
harvest valve inlet did not
cool down during the freeze
cycle. If the compressor
dome is also entirely hot,
the problem is not a harvest
valve leaking, but rather
something causing the
compressor (and the entire
ice machine) to get hot.
Both the inlet of the harvest
valve and the compressor
discharge line are cool
enough to touch.
Cool & Cool
This is an indication
something is wrong, causing
the compressor discharge
line to be cool to the touch.
This is not caused by a
harvest valve leaking.
Part Number STH042 3/14 85
Comparing Evaporator Inlet/Outlet
Temperatures
The temperatures of the suction lines entering and
leaving the evaporator alone cannot diagnose an ice
machine. However, comparing these temperatures
during the freeze cycle, along with using Manitowoc’s
Refrigeration System Operational Analysis Table, can
help diagnose an ice machine malfunction.
The actual temperatures entering and leaving the
evaporator vary by model, and change throughout the
freeze cycle. This makes documenting the “normal”
inlet and outlet temperature readings difficult. The key
to the diagnosis lies in the difference between the two
temperatures five minutes into the freeze cycle. These
temperatures must be within 7°F (4°C) of each other.
Use this procedure to document freeze cycle inlet and
outlet temperatures.
1. Use a quality temperature meter, capable of
taking temperature readings on curved copper
lines.
2. Attach the temperature meter sensing device to
the copper lines entering and leaving the
evaporator.
3. Wait five minutes into the freeze cycle.
4. Record the temperatures below and determine
the difference between them.
5. Use this with other information gathered on the
Refrigeration System Operational Analysis Table
to determine the ice machine malfunction.
Important
Do not simply insert the sensing device under the
insulation. It must be attached to and reading the
actual temperature of the copper line.
___________ ___________ ___________
Inlet
Temperature
Difference must be
within 7°F (4°C) at
5
minutes into the
freeze cycle
Outlet
Temperature
86 Part Number STH042 3/14
Discharge Line Temperature Analysis
GENERAL
Knowing if the discharge line temperature is
increasing, decreasing or remaining constant can be
an important diagnostic tool. Maximum compressor
discharge line temperature on a normally operating ice
machine steadily increases throughout the freeze
cycle. Comparing the temperatures over several
cycles will result in a consistent maximum discharge
line temperature.
Ambient air temperatures affect the maximum
discharge line temperature.
Higher ambient air temperatures at the condenser =
higher discharge line temperatures at the compressor.
Lower ambient air temperatures at the condenser =
lower discharge line temperatures at the compressor.
Regardless of ambient temperature, the freeze cycle
discharge line temperature will be higher than 150°F
(66°C) on a normally operating ice machine.
PROCEDURE
Connect a temperature probe on the compressor
discharge line within 6" (15.2 cm) of the compressor.
Observe the discharge line temperature for the last
three minutes of the freeze cycle and record the
maximum discharge line temperature.
Part Number STH042 3/14 87
Discharge Line Temperature Above 150°F (66°C) at
End of Freeze Cycle:
Ice machines that are operating normally will have
consistent maximum discharge line temperatures
above 150°F (66°C).
Verify the expansion valve sensing bulb is positioned
and secured correctly.
Discharge Line Temperature Below 150°F (66°C) at
End of Freeze Cycle
Ice machines that have a flooding expansion valve will
have a maximum discharge line temperature that
decreases each cycle.
Verify the expansion valve sensing bulb is 100%
insulated and sealed airtight. Condenser air contacting
an incorrectly insulated sensing bulb will cause
overfeeding of the expansion valve.
88 Part Number STH042 3/14
Refrigeration Component Diagnostics
All electrical and water related problems must be
corrected before these charts will work properly. These
tables must be used with charts, checklists and other
references to eliminate refrigeration components not
listed and external items and problems that will cause
good refrigeration components to appear defective.
The tables list four different defects that may affect the
ice machine’s operation.
NOTE: A low-on-charge ice machine and a starving
expansion valve have very similar characteristics and
are listed under the same column.
Part Number STH042 3/14 89
PROCEDURE
Step 1 Complete each item individually in the
“Operational Analysis” column.
Enter check marks (✓) in the boxes.
Each time the actual findings of an item in the
“Operational Analysis” column matches the published
findings on the table, enter a check mark.
Example: Freeze cycle suction pressure is determined
to be low. Enter a check mark in the “low” box.
Perform the procedures and check all information
listed. Each item in this column has supporting
reference material.
While analyzing each item separately, you may find an
“external problem” causing a good refrigerant
component to appear bad. Correct problems as they
are found. If the operational problem is found, it is
not necessary to complete the remaining
procedures.
Step 2 Add the check marks listed under each of the
four columns. Note the column number with the
highest total and proceed to “Final Analysis.”
NOTE: If two columns have matching high numbers, a
procedure was not performed properly and/or
supporting material was not analyzed correctly.
90 Part Number STH042 3/14
FINAL ANALYSIS
The column with the highest number of check marks
identifies the refrigeration problem.
Column 1 – Harvest Valve Leaking
A leaking harvest valve must be replaced.
Column 2 – Low Charge/TXV Starving
Normally, a starving expansion valve only affects the
freeze cycle pressures, not the harvest cycle
pressures. A low refrigerant charge normally affects
both pressures. Verify the ice machine is not low on
charge before replacing an expansion valve.
Add refrigerant charge in 2 oz. increments as a
diagnostic procedure to verify a low charge. (Do not
add more than the total charge of refrigerant). If the
problem is corrected, the ice machine is low on
charge. Find the refrigerant leak.
The ice machine must operate with the nameplate
charge. If the leak cannot be found, proper refrigerant
procedures must still be followed. Change the liquid
line drier, evacuate the system and weigh in the proper
charge.
If the problem is not corrected by adding charge, the
expansion valve is faulty.
Column 3 – TXV Flooding
A loose or improperly mounted expansion valve bulb
causes the expansion valve to flood. Check bulb
mounting, insulation, etc., before changing the valve.
Column 4 – Compressor
Replace the compressor and start components. To
receive warranty credit, the compressor ports must be
properly sealed by crimping and soldering them
closed. Old start components must be returned with
the faulty compressor.
Part Number STH042 3/14 91
Refrigeration Component Diagnostic
Chart
4
Published 24 hour ice production ____________
Calculated (actual) 24 hour ice production ____________
Note: The ice machine is operating properly if the ice fill patterns is normal and ice
production is within 10% of charted capacity.
All installation and water related problems must be corrected
before proceeding with chart.
Ice formation is
normal
-or-
No ice formation
on entire
evaporator
3
Ice formation is
normal
-or-
ice formation is
extremely thin on
the bottom of the
evaporator or
No ice formation
on evaporator
2
Ice formation is
extremely thin on
outlet of
evaporator
-or-
No ice formation
on entire
evaporator
1
Ice formation is
extremely thin on
outlet of evaporator
-or-
No ice formation
on entire
evaporator
Operational
Analysis
Ice Production
Installation and
Water system
Ice Formation
Pattern
92 Part Number STH042 3/14
4
Stops on
safety limit:
1
If discharge pressure is High or Low, refer to freeze cycle high or
low discharge pressure problem checklist to eliminate problems
and/or components not listed on this table before proceeding.
If suction pressure is High or Low refer to freeze cycle high or low
suction pressure problem checklist to eliminate problems and/or
components not listed on this table before proceeding.
Suction
pressure is
High
3
Stops on
safety limit:
1 or 2
Suction
pressure is
High
2
Stops on
safety limit:
1
Suction
pressure is
Low
1
Stops on
safety limit:
1 or 2
Suction
pressure is
High
Operational Analysis
Safety limits
Refer to “Analyzing Safety
Limits” to eliminate all non-
refrigeration problems.
Freeze cycle
Discharge Pressure
_______ _______
_______
1 minute Middle End
Freeze cycle
Suction Pressure
_______ _______
_______
1 minute Middle End
Part Number STH042 3/14 93
4
The harvest valve
inlet is
COOL
and
The compressor
discharge line is
HOT
Discharge line
temp 150°F
(66°C) or higher
at the end of
freeze cycle
Compressor
3
The harvest valve
inlet is
COOL
and
The compressor
discharge line is
COOL
Discharge line
temp less than
150°F (66°C) at
the end of freeze
cycle
TXV Flooding
2
The harvest valve
inlet is
COOL
and
The compressor
discharge line is
HOT
Discharge line
temp 150°F
(66°C) or higher
at the end of
freeze cycle
Low On Charge
-or-
TXV Starving
1
The harvest valve
inlet is
HOT
and
The compressor
discharge line is
HOT
Discharge line
temp 150°F
(66°C) or higher
at the end of
freeze cycle
Harvest Valve
Leaking
Operational Analysis
harvest Valve
Discharge Line Temp.
Record freeze cycle
discharge line temp at the
end of freeze cycle.
Final Analysis
Enter total number of
boxes checked in
each column.
94 Part Number STH042 3/14
This Page Intentionally Left Blank
Part Number STH042 3/14 95
Component Check Procedures
Main Fuse
Function
The control board fuse stops ice machine operation if
electrical components fail causing high amp draw.
Specifications
• The main fuse is 250 Volt, 10 amp.
Check Procedure
1. If the curtain light is on with the ice damper
closed, the fuse is good.
2. Remove the fuse. Check the resistance across
the fuse with an ohmmeter.
! Warning
High (line) voltage is applied to the control board
at all times. Removing the control board fuse or
pressing the power button will not remove the
power supplied to the control board.
! Warning
Disconnect electrical power to the entire ice
machine before proceeding.
Reading Result
Open (OL) Replace fuse
Closed (O) Fuse is good
96 Part Number STH042 3/14
Bin Switch
Function
Bin switch operation is controlled by the movement of
the ice damper. The bin switch has two main functions:
1. Terminating the harvest cycle and returning the
ice machine to the freeze cycle.
This occurs when the bin switch is opened and
closed again within 7 seconds of opening during
the harvest cycle.
2. Automatic ice machine shut-off.
If the storage bin is full at the end of a harvest
cycle, the sheet of cubes fails to clear the ice
damper and holds it down. After the ice damper is
held down for 7 seconds, the ice machine shuts
off.
The ice machine remains off until enough ice is
removed from the storage bin to allow the sheet of
cubes to drop clear of the ice damper. As the ice
damper swings back to the operating position, the
bin switch closes and the ice machine restarts.
Check Procedure
1. Press the power button to OFF.
2. Watch the curtain light on the control board.
3. Move the ice damper upward, toward the
evaporator. The bin switch must close. The
curtain light “on” indicates the bin switch has
closed properly.
4. Move the ice damper away from the evaporator.
The bin switch must open. The curtain light “off”
indicates the bin switch has opened properly.
Important
The ice damper must be up (bin switch closed) to
start ice making.
Part Number STH042 3/14 97
Ohm Test
1. Disconnect the bin switch wires to isolate the bin
switch from the control board.
2. Connect an ohmmeter to the disconnected bin
switch wires.
3. Cycle the bin switch open and closed numerous
times by opening and closing the water curtain.
NOTE: To prevent misdiagnosis:
• Always use the water curtain magnet to cycle the
switch (a larger or smaller magnet will affect switch
operation).
• Watch for consistent readings when the bin switch
is cycled open and closed (bin switch failure could
be erratic).
98 Part Number STH042 3/14
Touch Pad
Function
User interface to select ice making, delay start or
cleaning cycle and provides feedback on ice machine
operation.
Check For Normal Operation
Action Normal Function
Press and hold the control
board test button for 3 seconds
All Touch Pad lights turn on
Press test button All Touch Pad lights turn off
Press power button Power light turns on
With power light energized
press the delay button 4 times
Cycles through 4 hour delay,
12 hour delay, 24 hour delay
and off
Press and hold the power
button for 3 seconds
Power light turns off
Press and hold the clean button
for 3 seconds
Clean light turns on
Press and hold the clean button
for 3 seconds
Clean light turns off
If any switches do not operate correctly, disconnect main
power to the ice machine to reset the control board and
perform a second test. If the second test doesn’t show normal
function, perform the Ohm test to verify the issue is not a
wiring or control board issue.
Part Number STH042 3/14 99
Ohm Test
Disconnect wire from control board and Ohm touch
pad and interconnecting wire to verify correct
operation. Pressing and depressing the touch pad
must open and close the circuit. A switch that
functions correctly will close as the button is pressed
and open as the button is released.
Do not insert electrical probe into end of connector.
This will stretch the connector and cause intermittent
connection issues. All readings must be taken on the
flat exterior of the connector
Selection Wires
On/Off #2 & #7
Delay #3 & #7
Clean #4 & #7
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
Control Board Connector
TOUCH ELECTRICAL
PROBE TO THESE
LOCATIONS ONLY
DO NOT INSERT IN END
OF CONNECTOR
100 Part Number STH042 3/14
Float Switch
Function
Open and close to indicate to the control board the
level of water in the water trough.
Specifications
Normally closed, float operated magnetic reed switch.
The float switch contacts are closed in the down
position. When water raises the float to the up position
the magnet in the float opens the contacts.
Check Procedure
The ice machine uses two float switches.
Ice Thickness Float -Indicates the water level has
been reached.
Harvest Float - Indicates a harvest cycle needs to be
initiated.
Initial testing can be performed by viewing the control
board light(s) while raising and lowering the float. The
corresponding control board light must turn on and off
when the float is raised and lowered.
Harvest Float switch:
A. The light must be on in the down position.
B. The light must be off in the up position.
Ice Thickness Float Switch:
A. The light must be off in the down position.
B. The light must be on in the up position.
If the control board light does not respond to the float
proceed with step 1 below.
1. Disconnect power to the ice machine, pull the wire
connector for the float switch through the
bulkhead and disconnect.
2. Attach an ohm meter lead to each float switch
wire.
3. Place the float in the down position - The float
switch must be closed.
4. Place the float in the up position - The float switch
must be open.
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