Manitowoc Ice K-0170 Service Manual

Undercounter Ice Machines

Technician’s Handbook

This manual is updated as new information and models
are released. Visit our website for the latest manual.
www.kool-aire.com

Part Number STH047 5/16

Safety Notices

Read these precautions to prevent personal injury:

• 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.

• Routine adjustments and maintenance procedures
outlined in this manual are not covered by the
warranty.

• Proper installation, care and maintenance are
essential for maximum performance and trouble-free
operation of your equipment.

• Visit our website www.kool-aire.com for manual
updates, translations, or contact information for
service agents in your area.

• 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.

• This equipment is intended for indoor use only. Do
not install or operate this equipment in outdoor
areas.

• As you work on this 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.

Warning

n

Follow these electrical requirements during
installation of this equipment.

• All field wiring must conform to all applicable
codes of the authority having jurisdiction. It is
the responsibility of the end user to provide the
disconnect means to satisfy local codes. Refer to
rating plate for proper voltage.

• This appliance must be grounded.

• This equipment must be positioned so that
the plug is accessible unless other means for
disconnection from the power supply (e.g., circuit
breaker or disconnect switch) is provided.

• Check all wiring connections, including factory
terminals, before operation. Connections can
become loose during shipment and installation.

Warning

n

Follow these precautions to prevent personal
injury during installation of this equipment:

• Installation must comply with all applicable
equipment fire and health codes with the authority
having jurisdiction.

• To avoid instability the installation area must be
capable of supporting the combined weight of
the equipment and product. Additionally the
equipment must be level side to side and front to
back.

• Ice machines require a deflector when installed on
an ice storage bin. Prior to using a non-OEM ice
storage system with this ice machine, contact the
bin manufacturer to assure their ice deflector is
compatible.

• Remove all removable panels before lifting and
installing and use appropriate safety equipment
during installation and servicing. Two or more
people are required to lift or move this appliance to
prevent tipping and/or injury.

• Do not damage the refrigeration circuit when
installing, maintaining or servicing the unit.

• Connect to a potable water supply only.

• This equipment contains refrigerant charge.

• Installation of the line sets must be performed by
a properly trained and EPA certified refrigeration
technician aware of the dangers of dealing with
refrigerant charged equipment.

Warning

n

Follow these precautions to prevent personal
injury while operating or maintaining this
equipment.

• Legs or casters must be installed and the legs/
casters must be screwed in completely. When
casters are installed the mass of this unit will allow
it to move uncontrolled on an inclined surface.
These units must be tethered/secured to comply
with all applicable codes. Swivel casters must be
mounted on the front and rigid casters must be
mounted on the rear. Lock the front casters after
installation is complete.

• Some 50 Hz models may contain up to 150 grams
of R290 (propane) refrigerant. R290 (propane)
is flammable in concentrations of air between
approximately 2.1% and 9.5% by volume (LEL lower
explosion limit and UEL upper explosion limit). An
ignition source at a temperature higher than 470°C
is needed for a combustion to occur.

• Refer to nameplate to identify the type of
refrigerant in your equipment.

• Only trained and qualified personnel aware of the
dangers are allowed to work on the equipment.

• 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.

• Crush/Pinch Hazard. Keep hands clear of moving
components. Components can move without
warning unless power is disconnected and all
potential energy is removed.

• Moisture collecting on the floor will create a
slippery surface. Clean up any water on the floor
immediately to prevent a slip hazard.

Warning

n

Follow these precautions to prevent personal
injury while operating or maintaining this
equipment.

• Objects placed or dropped in the bin can affect
human health and safety. Locate and remove any
objects immediately.

• Never use sharp objects or tools to remove ice or
frost.

• Do not use mechanical devices or other means to
accelerate the defrosting process.

• When using cleaning fluids or chemicals, rubber
gloves and eye protection (and/or face shield) must
be worn.

DANGER

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, clean or maintain this
appliance without proper supervision.

DANGER

Follow these precautions to prevent personal
injury during use and maintenance of this
equipment:

• It is the responsibility of the equipment owner to
perform a Personal Protective Equipment Hazard
Assessment to ensure adequate protection during
maintenance procedures.

• Do Not Store Or Use Gasoline Or Other Flammable
Vapors Or Liquids In The Vicinity Of This Or Any
Other

• Appliance. Never use flammable oil soaked cloths
or combustible cleaning solutions for cleaning.

• All covers and access panels must be in place and
properly secured when operating this equipment.

• Risk of fire/shock. All minimum clearances must be
maintained. Do not obstruct vents or openings.

• Failure to disconnect power at the main power
supply disconnect could result in serious injury or
death. The power switch DOES NOT disconnect all
incoming power.

• All utility connections and fixtures must be
maintained in accordance with the authority
having jurisdiction.

• Turn off and lockout all utilities (gas, electric,
water) according to approved practices during
maintenance or servicing.

• Units with two power cords must be plugged
into individual branch circuits. During movement,
cleaning or repair it is necessary to unplug both
power cords.

We reserve the right to make product improvements at
any time. Specifications and design are subject to change
without notice.

Table of Contents

General Information

Model Numbers............................... 13

How to Read a Model Number ................ 14

Accessories ...................................14

Bin Caster .................................14

Cleaner and Sanitizer ......................14

Model/Serial Number Location ............... 15

Ice Machine Warranty Information............ 15

Installation

Location of Ice Machine....................... 17

Ice Machine Clearance Requirements......... 18

Ice Machine Heat of Rejection ................ 18

Leveling the Ice Machine......................19

Electrical Requirements....................... 20

Voltage ...................................20

Fuse/Circuit Breaker .......................20

Total Circuit Ampacity ..................... 20

Electrical Specifications....................... 21

Air-cooled Ice Machine .................... 21

Water-cooled Ice Machines ................22

Water Service/Drains .........................23

Water Supply.............................. 23

Water Inlet Lines ..........................23

Drain Connections ........................ 23

Water Supply and Drain Line Sizing/

Connections .............................. 24

Cooling Tower Applications ................25

Component Identification

Evaporator Compartment ....................27

Part Number STH047 5/16 9

Maintenance

Ice Machine Inspection .................... 29

Exterior Cleaning ..........................29

Cleaning the Condenser ...................29

Interior Cleaning and Sanitizing............ 31

Removal from Service/Winterization .........44

Operation

Initial Start-up or Start-up After Automatic

Shut-off ................................... 47

Freeze Sequence ..........................47

Harvest Sequence ......................... 48

Automatic Shut-off ........................48

Energized Parts Chart...................... 49

Operational Checks ...........................51

Troubleshooting

Diagnosing an Ice Machine that Will Not Run..

........................................... 54

Diagnosing Ice Thickness Control Circuitry . 55

Ice Production Check ......................58

Installation and Visual Inspection Checklist. 60

Water System Checklist.................... 61

Ice Formation Pattern......................62

Safety Limit Feature .......................64

Analyzing Discharge Pressure .............71

Analyzing Suction Pressure ................ 73

Harvest Valve.............................. 77

Comparing Evaporator Inlet/Outlet

Temperatures ............................. 81

Discharge Line Temperature Analysis.......82

Refrigeration Component Diagnostic Chart 84

Procedure................................. 85

Final Analysis.............................. 86

Refrigeration Component Diagnostic Chart 87
Ice Quality Is Poor — Cubes are Shallow,

Incomplete or White....................... 90

Freeze Cycle Is Long, Low Ice Production ...91
Ice Machine Runs and No Ice Is Produced...92

10 Part Number STH047 5/16

Component Check Procedures

Main Fuse .....................................93

Bin Switch..................................... 94

Diagnosing Start Components................ 97

Capacitor .................................97

Relay...................................... 97

ON/OFF/WASH Toggle Switch .................98

Ice Thickness Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Ice Thickness Check ......................100

Compressor Electrical Diagnostics...........101

Fan Cycle Control ............................103

High Pressure Cutout (HPCO) Control........104

Filter-Driers ..................................105

Refrigerant Recovery/Evacuation............106

Refrigerant Re-use Policy .................107

Recovery and Recharging Procedures ....109

System Contamination Cleanup .............112

Mild System Contamination Cleanup

Procedure................................114

Severe System Contamination Cleanup

Procedure................................115

Replacing Pressure Controls without

Removing Refrigerant Charge.............117

K270 Condenser Fan Motor Access...........119

Part Number STH047 5/16 11

Component Specifications

Main Fuse ....................................121

Bin Switch....................................121

ON/OFF/WASH Toggle Switch ................121

Fan Control Cycle ............................121

High Pressure Cutout (HPCO) Control........121

Filter-Driers ..................................121

Total System Refrigerant Charge.............122

Charts

Cycle Times, 24 Hr. Ice Production and

Refrigerant Pressure Charts..................123

K170 Self-contained Air-cooled ...........124

K270 Self-contained Air-cooled ...........125

K270 Self-contained Water-cooled ........126

Diagrams

Wiring Diagrams .............................127

K170 / K270 Wiring Diagram ..............128

Electronic Control Boards....................130

K170/K270 Tubing Schematic .............131

12 Part Number STH047 5/16

General Information

Model Numbers

This manual covers the following models:

Self-contained Air-cooled Self-contained Water-cooled

KD0172A N/A
KY0174A N/A
KR0270A KR0271W
KD0272A KD0273W
KY0274A KY0275W

Warning

n

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.

Part Number STH047 5/16 13

How to Read a Model Number

Cube Size

Series

Capacity

Condenser

Type

K D 0172 A

A - Air-cooled

D - Dice
Y - Half-dice

Accessories

Contact your distributor for these optional accessories:

BIN CASTER

Replaces standard legs.

CLEANER AND SANITIZER

Manitowoc Ice Machine Cleaner and Sanitizer are
available in convenient 16 oz. (473 ml) and 1 gal (3.78 l)
bottles. These are the only cleaner and sanitizer approved
for use with Koolaire products.

Cleaner Part Number Sanitizer Part Number

16 oz 94-0456-3 16 oz 94-0565-3
*16 oz 000000084
1 Gallon 4-0580-3 1 Gallon 94-0581-3

2 - Dice, Air-cooled
4 - Half-dice, Air-cooled

14 Part Number STH047 5/16

Model/Serial Number Location

The model and serial numbers are required when
requesting information from your local distributor, service
representative, or Manitowoc KitchenCare®. The model
and serial number are listed on the OWNER WARRANTY
REGISTRATION CARD. They are also listed on the MODEL/
SERIAL NUMBER DECAL affixed to the ice machine.

MODEL/SERIAL
NUMBER PLATE

MODEL/SERIAL
NUMBER PLATE

SV1687G

Model/Serial Number Location

Ice Machine Warranty Information

For warranty information visit:

http://www.koo-aire.com/Service/Warranty

• Warranty Verification

• Warranty Registration

• View and download a copy of the warranty

Part Number STH047 5/16 15

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16 Part Number STH047 5/16

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.

Part Number STH047 5/16 17

Ice Machine Clearance Requirements

Self-contained

Air-cooled

Top/Sides 5" (127 mm)*

Back 5" (127 mm)*

*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

Series

Ice Machine

K170 2200 2600
K270 3800 6000

* B.T.U./Hour
** Because the heat of rejection varies during the ice making

cycle, the figure shown is an average.

Air Conditioning** Peak

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 air­cooled ice machines are installed.

Heat of Rejection*

18 Part Number STH047 5/16

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.

Caution

,

The legs must be screwed in tightly to prevent them
from bending.

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.

NOTE: An optional 2-1/2" (6.35 cm) caster assembly is
available for use in place of the legs on the K170, K210,
and K270. Installation instructions are supplied with the
casters.

THREAD
LEVELING LEG
INTO BASE OF

CABINET

THREAD “FOOT”

IN AS FAR AS

POSSIBLE

SV1606

Leg Installation

Part Number STH047 5/16 19

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).

The 115/1/60 ice machines are factory pre-wired with a 6'
(1.8 m) power cord, and NEMA 5-15P-plug configuration.

The 208-230/1/60 and 230/1/50 ice machines are factory
pre-wired with a power cord only, no plug is supplied.

FUSE/CIRCUIT BREAKER

A separate fuse/circuit breaker must be provided for each
ice machine. Circuit breakers must be H.A.C.R. rated (does
not apply in Canada).

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.

20 Part Number STH047 5/16

Electrical Specifications

AIRCOOLED ICE MACHINE

Ice Machine Voltage Phase

Cycle

K170 115/1/60 15 amp 7.0

208/1/60 15 amp 3.5
230/1/50 15 amp 4.0

K270 115/1/60 15 amp 10.7

208-230/1/60 15 amp 5.2

230/1/50 15 amp 5.2

Warning

n

All wiring must conform to local, state and national
codes.

Warning

n

The ice machine must be grounded in accordance
with national and local electrical code.

Max. Fuse/

Circuit

Breaker

Total

Amps

Part Number STH047 5/16 21

WATERCOOLED ICE MACHINES

Ice Machine Voltage

Phase Cycle

K170 115/1/60 15 amp 6.3

208/1/60 15 amp 3.6
230/1/50 15 amp 4.0

K270 115/1/60 15 amp 9.9

208-230/1/60 15 amp 4.7

230/1/50 15 amp 4.7

Max. Fuse/

Circuit

Breaker

Total

Amps

22 Part Number STH047 5/16

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.

Important

If you are installing a water filter system, refer to
the Installation Instructions supplied with the filter
system for ice making water inlet connections.

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 distributor.

• Install a water shut-off valve for ice making potable
water.

• Insulate water inlet lines to prevent condensation.

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.

• Run separate bin and ice machine drain lines. Insulate
them to prevent condensation.

• Vent the bin and ice machine drain to the
atmosphere.

Part Number STH047 5/16 23

WATER SUPPLY AND DRAIN LINE SIZING/ CONNECTIONS

to Ice Machine

Tubing Size Up

Ice Machine

Water

Water

Fitting

Fitting

Pressure

Temperature

inside diameter

inside diameter

3/8" (9.5 mm) min.

3/8” Female

Pipe Thread

80 psi (5.5 bar) max.

20 psi (1.38 bar) min.

(32.2°C) max.

40°F (4°C) min. 90°F

inside diameter

3/8" (9.5 mm) min.

3/8" (9.5 mm) min.

3/8” Female

3/8” Female

Pipe Thread

Pipe Thread

20 psi (1.38 bar) min.

150 psi (10.3 bar) max.

— —

33°F (0.6°C) min.

90°F (32.2°C) max.

diameter

min. inside

1/2" (12.7 mm)

1/2” Female

Pipe Thread

Location

24 Part Number STH047 5/16

Condenser

Ice Making

Water Inlet

Water Inlet

Bin Drain — —

Condenser

Water Drain

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 STH047 5/16 25

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26 Part Number STH047 5/16

Component Identification

Evaporator Compartment

DISTRIBUTION

TUBE

DAMPER

WATER

TROUGH

FLOAT VALVE

ICE THICKNESS

PROBE

ICE

WATER

PUMP

SV1694A

SIPHON CAP

BIN SWITCH

MAGNET

SV1695A

Evaporator Compartment

Part Number STH047 5/16 27

ON/OFF/WASH

TOGGLE
SWITCH

CONDENSED AIR

FILTER

ON/OFF/WASH

TOGGLE

SWITCH

COMPRESSOR

COMPARTMENT ACCESS

SCREWS

COMPRESSOR

COMPARTMENT

ACCESS SCREWS

SV1686G

K170 Ice Machines

CONDENSED AIR

FILTER

PT1288

K270 Ice Machines

28 Part Number STH047 5/16

Maintenance

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.

CLEANING THE CONDENSER

Warning

n

Disconnect electric power to the ice machine at the
electric service switch before cleaning the condenser.

Caution

,

If you are cleaning the condenser fan blades with
water, cover the fan motor to prevent water damage.

COMB
DOWN

Part Number STH047 5/16 29

CONDENSER

FIN COMB

ONLY

Air-cooled Condenser

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. Follow the steps below.

Warning

n

The condenser fins are sharp. Use care when cleaning
them.

1. The washable aluminum filter on self-contained air­cooled ice machines is designed to catch dust, dirt,
lint and grease. This helps keep the condenser clean.
Clean the filter with a mild soap and water solution.

2. Clean the outside of the condenser with a soft brush
or a vacuum with a brush attachment. Clean from
top to bottom, not side to side. Be careful not to
bend the condenser fins.

3. Shine a flashlight through the condenser to check
for dirt between the fins. If dirt remains:

A. Blow compressed air through the condenser

fins from the inside. Be careful not to bend the
fan blades.

B. Use a commercial condenser coil cleaner. Follow

the directions and cautions supplied with the
cleaner.

4. Straighten any bent condenser fins with a fin comb.

5. Carefully wipe off the fan blades and motor with
a soft cloth. Do not bend the fan blades. If the fan
blades are excessively dirty, wash with warm, soapy
water and rinse thoroughly.

30 Part Number STH047 5/16

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.

Caution

,

Use only Manitowoc Ice Machine Cleaner (part
number 95-0546-3) and Sanitizer (part number 94­0565-3). 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.

Cleaning and Sanitizing Procedure

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.

Warning

n

Wear rubber gloves and safety goggles (and/or
face shield) when handling Ice Machine Cleaner or
Sanitizer.

Ice machine cleaner is used to remove lime scale and
mineral deposits. Ice machine sanitizer disinfects and
removes algae and slime.

Part Number STH047 5/16 31

Step 1 Set the toggle switch to the OFF position after
ice falls from the evaporator at the end of a Harvest cycle.
Or, set the switch to the OFF position and allow the ice to
melt off the evaporator.

Caution

,

Never use anything to force ice from the evaporator.
Damage may result.

Step 2 Remove all ice from the bin.

Step 3 To start a cleaning cycle, move the toggle

switch to the WASH position.

Step 4 Add the proper amount of Ice Machine Cleaner
to the water trough.

Model Amount of Cleaner

K170 2 ounces (60 ml)
K270 2 ounces (60 ml)

Step 5 Wait until the clean cycle is complete
(approximately 22 minutes) then place the toggle switch
in the OFF position, disconnect power and water supplies
to the ice machine.

Warning

n

Disconnect electric power to the ice machine at the
electric switch box before proceeding.

32 Part Number STH047 5/16

Step 6 Remove parts for cleaning.

A. Remove Two Thumbscrews and Water Pump

Cover (When Used).

B. Remove the Vinyl Hose Connecting the

Water Pump and Water Distribution Tube

C. Remove Water Pump

• Disconnect the water pump power cord

• Loosen the screws securing the pump­mounting bracket to the bulkhead

• Lift the pump and bracket assembly off the
mounting screws.

WHEN USED - REMOVE

THUMBSCREWS AND

WATER PUMP COVER

DO NOT SOAK WATER

PUMP MOTOR IN

CLEANER OR SANITIZER

SOLUTION

Water Pump Removal

Part Number STH047 5/16 33

D. Remove the Ice Thickness Probe

• Compress the side of the ice thickness
probe near the top hinge pin and remove it
from the bracket.

ICE

THICKNESS

PROBE

COMPRESS SIDES OF

ICE THICKNESS PROBE

SV1138A

Ice Thickness Probe Removal

NOTE: At this point, the ice thickness probe can easily
be cleaned. If complete removal is desired, follow the
ice thickness probe wire to the bulkhead grommet (exit
point) in the back wall. Pop the bulkhead grommet out
of the back wall by inserting fingernails or a flat object
between the back wall and the grommet and prying
forward. Pull the bulkhead grommet and wire forward
until the connector is accessible, then disconnect the wire
lead from the connector.

Ice Thickness Probe Cleaning

• Mix a solution of ice machine cleaner and water
(2 ounces of cleaner to 16 ounces of water) in a
container.

• Soak the ice thickness probe a minimum of 10
minutes.

Clean all ice thickness probe surfaces and verify the ice
thickness probe cavity is clean. Rinse thoroughly with
clean water, then dry completely. Incomplete rinsing and
drying of the ice thickness probe can cause premature
harvest.

34 Part Number STH047 5/16

E. Remove the Water Distribution Tube

1. LIFT UP

2. SLIDE BACK

3. SLIDE TO RIGHT

DISTRIBUTION

TUBE

3

2

1

THUMBSCREW

THUMBSCREW

SV1630

Water Distribution Tube Removal

• Loosen the two thumbscrews, which secure
the distribution tube.

• Lift the right side of the distribution tube
up off the locating pin, then slide it back
and to the right.

Caution

,

Do not force this removal. Be sure the locating pin is
clear of the hole before sliding the distribution tube
out.

Part Number STH047 5/16 35

Disassembly

• Twist both of the inner tube ends until the tabs line
up with the keyways.

• Pull the inner tube ends outward.

INNER

TUBE

INNER

TUBE

TAB

KEYWAY

SV1211

Water Distribution Tube Disassembly

36 Part Number STH047 5/16

F. Remove the Float Valve

• Turn the splash shield counterclockwise
one or two turns.

FLOAT VALVE

BRACKET

COMPRESSION

FITTING

SHUT-OFF

VALVE

CAP AND FILTER

SPLASH

SHIELD

Float Valve Removal

• Pull the float valve forward and off the
mounting bracket.

• Disconnect the water inlet tube from the
float valve at the compression fitting.

• Remove the cap and filter screen for
cleaning.

SCREEN

FL OAT

SV1695-2

Part Number STH047 5/16 37

G. Remove the Water Trough

• Apply downward pressure on the siphon
tube and remove from the bottom of the
water trough.

• Remove the upper thumbscrew.

• While supporting the water trough remove
the two thumbscrews from beneath the
water trough.

• Remove the water trough from the bin area.

UPPER

THUMBSCREW

SV1689-1

LOWER

THUMBSCREWS

REMOVE

SIPHON

TUBE

SV1689-2

Remove the Ice Damper

38 Part Number STH047 5/16

H. Remove the ice damper

• Grasp ice damper and apply pressure toward the left­hand mounting bracket.

• Apply pressure to the right-hand mounting bracket
with thumb.

• Pull ice damper forward when the right-hand ice
damper pin disengages.

STEP 3

STEP 2

STEP 1

SV1742A

Installation

• Place ice damper pin in left-hand mounting bracket
and apply pressure toward the left-hand mounting
bracket.

• Apply pressure to the right-hand mounting bracket
with thumb.

• Push ice damper toward evaporator until right-hand
damper pin engages.

STEP 2

STEP 1

Part Number STH047 5/16 39

STEP 3

SV1742H

Remove the Bin Door

• Grasp the rear of the bin door and pull bin door
forward approximately 5".

• Slide bin door to the rear while applying upward
pressure (The rear door pins will ride up into the track
slot and slide backward to the stop tab).

• While applying pressure against the bin door pull
down on the rear of each bin door track until the door
pins clear the stop tabs.

• Slide the rear door pins off the end and then below
the door track. Slide bin door forward allowing the
back of the door to lower into the bin. Continue
forward with the bin door until the front pins bottom
out in the track.

• Lift right side of door until the front pins clear the
track, then remove door from bin.

• Remove rollers (4) from all door pins.

STOP TAB

TRACK SLOT

SLIDE DOOR

FORWARD

SV1748

40 Part Number STH047 5/16

Step 7 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.

Solution Type Water Mixed with

Cleaner 1 gal. (4 l) 16 oz (500 ml) cleaner

Step 8 Use 1/2 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 9 While components are soaking, use 1/2 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.

Step 10 Mix a solution of sanitizer and warm water.

Solution Type Water Mixed With

Sanitizer 6 gal. (23 l) 4 oz (120 ml) sanitizer

Part Number STH047 5/16 41

Step 11 Use 1/2 of the sanitizer/water solution to
sanitize all removed components. Use a cloth or sponge
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 12 Use 1/2 of the sanitizer/water solution to
sanitize all foodzone surfaces of the ice machine and
bin. Use a cloth or sponge 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 13 Replace all removed components.

Step 14 Reapply power and water to the ice machine

and place the toggle switch in the WASH position.

Add the proper amount of Ice Machine Sanitizer to the
water trough.

Model Amount of Sanitizer

K170 2.2 ounces (66 ml)
K270 1.9 ounces (57 ml)

Step 15 Wait until the sanitize cycle is complete
(approximately 22 minutes) then place the toggle switch
in the OFF position, disconnect power and water supplies
to the ice machine.

Warning

n

Disconnect electric power to the ice machine at the
electric switch box before proceeding.

Step 16 Repeat step 6 to remove parts for hand
sanitizing.

42 Part Number STH047 5/16

Step 17 Mix a solution of sanitizer and warm water.

Solution Type Water Mixed With

Sanitizer 6 gal. (23 l) 4 oz (120 ml) sanitizer

Step 18 Use 1/2 of the sanitizer/water solution to
sanitize all removed components. Use a cloth or sponge
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 19 Use 1/2 of the sanitizer/water solution to
sanitize all foodzone surfaces of the ice machine and
bin. Use a cloth or sponge 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 20 Replace all removed components.

Step 21 Reapply power and water to the ice machine

and place the toggle switch in the ICE position.

Part Number STH047 5/16 43

Removal from Service/Winterization

General

Special precautions must be taken if the ice machine is
to be removed from service for an extended period of
time or exposed to ambient temperatures of 32°F (0°C) or
below.

Caution

,

If water is allowed to remain in the ice machine in
freezing temperatures, severe damage to some
components could result. Damage of this nature is
not covered by the warranty.

Follow the applicable procedure below.

Self-contained Air-cooled Models

1. Disconnect the electric power at the circuit breaker
or the electric service switch.

2. Turn off the water supply.

3. Remove the water from the water trough.

4. Disconnect and drain the incoming ice-making
water line at the rear of the ice machine.

5. Blow compressed air in both the incoming water and
the drain openings in the rear of the ice machine
until no more water comes out of the inlet water
lines or the drain.

6. Make sure water is not trapped in any of the water
lines, drain lines, distribution tubes, etc.

44 Part Number STH047 5/16

Water-cooled Ice Machines

1. Perform steps 1-6 under “Self-contained Air-cooled
Models” on page 44.

2. Disconnect the incoming water and drain lines from
the water-cooled condenser.

3. Insert a large screwdriver between the bottom
spring coils of the water regulating valve. Pry upward
to open the valve.

SV1624

Pry Open the Water Regulating Valve

4. Hold the valve open and blow compressed air
through the condenser until no water remains.

Part Number STH047 5/16 45

THIS PAGE INTENTIONALLY LEFT BLANK

46 Part Number STH047 5/16

Operation

INITIAL STARTUP OR STARTUP AFTER AUTOMATIC
SHUTOFF

1. Pressure Equalization

Before the compressor starts the harvest valve is
energized for 15 seconds to equalize pressures during the
initial refrigeration system start-up.

2. Refrigeration System Start-up

The compressor starts after the 15-second pressure
equalization, and remains on throughout the entire
Freeze and Harvest Sequences. The harvest valve remains
on for 5 seconds during initial compressor start-up and
then shuts off.

At the same time the compressor starts, the condenser
fan motor (air-cooled models) is supplied with power
throughout the entire Freeze and Harvest Sequences. The
fan motor is wired through a fan cycle pressure control,
therefore it may cycle on and off. (The compressor and
condenser fan motor are wired through the relay. As a
result, any time the relay coil is energized, the compressor
and fan motor are supplied with power.)

FREEZE SEQUENCE

3. Prechill

The compressor is on for 30 seconds prior to water flow to
prechill the evaporator.

4. Freeze

The water pump starts after the 30-second prechill. An
even flow of water is directed across the evaporator and
into each cube cell, where it freezes.

When sufficient ice has formed, the water flow (not the
ice) contacts the ice thickness probe. After approximately
7 seconds of continual water contact, the Harvest
Sequence is initiated. The ice machine cannot initiate a
Harvest Sequence until a 6-minute freeze time has been
surpassed.

Part Number STH047 5/16 47

HARVEST SEQUENCE

5. Harvest

The water pump de-energizes stopping flow over the
evaporator. The rising level of water in the sump trough
diverts water out of the overflow tube, purging excess
minerals from the sump trough. The harvest valve also
opens to divert hot refrigerant gas into the evaporator.

The refrigerant gas warms the evaporator causing the
cubes to slide, as a sheet, off the evaporator and into the
storage bin. The sliding sheet of cubes contacts the ice
damper, opening the bin switch.

The momentary opening and re-closing of the bin switch
terminates the Harvest Sequence and returns the ice
machine to the Freeze Sequence (steps 3 - 4).

AUTOMATIC SHUTOFF

6. Automatic Shut-off

When the storage bin is full at the end of a harvest
sequence, the sheet of cubes fails to clear the ice damper
and will hold it down. After the ice damper is held open
for 7 seconds, the ice machine shuts off. The ice machine
remains off for 3 minutes before it can automatically
restart.

The ice machine remains off until enough ice has been
removed from the storage bin to allow the ice to fall
clear of the damper. As the ice damper swings back to
the operating position, the bin switch re-closes and the
ice machine restarts (steps 1 - 2), provided the 3 minute
delay period is complete.

48 Part Number STH047 5/16

ENERGIZED PARTS CHART

Time1

3B

Compressor

3A

Compressor

3

Relay

2

Harvest Valve

Control Board Relays Relay Length of

Water Pump

probe

Until 7 sec.

Water contact

w/ice thickness

Fan Motor*

Coil

OPERATION

ICE MAKING

SEQUENCE OF

Initial Start-up

1. Water purge off on off off off 15 seconds

2. Refrigeration

System Start-up off on on on on 5 seconds

3. Pre chill off off on on on 30 seconds

Freeze Sequence

4. Freeze on off on on on

* Condenser Fan Motor: The fan motor is wired through a
fancycle pressure control; therefore, it may cycle on and off.

Part Number STH047 5/16 49

Time1

Bin switch

activation

switch

Until bin

re-closes

3B

Fan Motor*

Compressor

3A

Compressor

3

Coil

Relay

2

Harvest Valve

Control Board Relays Relay Length of

Water Pump

Harvest

OPERATION

ICE MAKING

SEQUENCE OF

off on on on on

5. Harvest

Sequence

off off off off off

Shut-off

Automatic

6. Auto Shut-off

50 Part Number STH047 5/16

Operational Checks

Siphon System

To reduce mineral build-up and cleaning frequency, the
water in the sump trough must be purged during each
harvest cycle.

When the water pump de-energizes, the level in the
water trough rises above the standpipe, starting a siphon
action. The siphon action stops when the water level in
the sump trough drops. When the siphon action stops,
the float valve refills the water trough to the correct level.

Follow steps 1 through 6 under water level check to verify
the siphon system functions correctly.

Water Level

Check the water level while the ice machine is in the ice
mode and the water pump is running. The correct water
level is 1/4" (6.3 mm) to 3/8" (9.5 mm) below the top of
the standpipe. A line in the water trough indicates the
correct level.

SET THE WATER LEVEL TO

THE LINE IN THE WATER

TROUGH

SIPHON CAP

SV1689-1

Part Number STH047 5/16 51

Water Level Check

The float valve is factory-set for the proper water level. If
adjustments are necessary:

1. Verify the ice machine is level.

2. Remove the siphon cap from the standpipe.

3. Place the main ON/OFF/WASH toggle switch to the
ON position, and wait until the float valve stops
adding water.

4. Adjust the water level to [1/4" to 3/8" (6.3 to 9.5 mm)
below the standpipe] the line in the water trough:

A. Loosen the two screws on the float valve

bracket.

B. Raise or lower the float valve assembly as

necessary, then tighten the screws.

5. Move the main ON/OFF/WASH toggle switch to the
OFF position. The water level in the trough will rise
above the standpipe and run down the drain.

6. Replace the siphon cap on the standpipe, and verify
water level and siphon action by repeating steps 3
through 5.

Ice Thickness Check

After a harvest cycle, inspect the ice cubes in the ice
storage bin. The ice thickness probe is set to maintain an
ice bridge of 1/8" (3.2 mm). If an adjustment is needed,
follow the steps below.

1. Turn the ice thickness probe adjustment
screw clockwise for a thicker ice bridge, or
counterclockwise for a thinner ice bridge.

52 Part Number STH047 5/16

ADJUSTING

SCREW

1/8" ICE BRIDGE

THICKNESS

SV3113

SV3114

Ice Thickness Adjustment

2. Make sure the ice thickness probe wire and bracket
does not restrict movement of the probe.

Part Number STH047 5/16 53

Troubleshooting

DIAGNOSING AN ICE MACHINE THAT WILL NOT RUN

Warning

n

High (line) voltage is applied to the control board
(terminals #2 and #4) at all times. Removing control
board fuse or moving the toggle switch to OFF will
not remove the power supplied to the control board.

1. Verify primary voltage is supplied to ice machine and
the fuse/circuit breaker is closed.

2. Verify control board fuse is okay.

3. If the bin switch light functions, the fuse is okay.

4. Verify the bin switch functions properly. A defective
bin switch can falsely indicate a full bin of ice.

5. Verify ON/OFF/WASH toggle switch functions
properly. A defective toggle switch may keep the ice
machine in the OFF mode.

6. Verify low DC voltage is properly grounded. Loose
DC wire connections may intermittently stop the ice
machine.

7. Replace the control board.

8. Be sure Steps 1 – 5 were followed thoroughly.
Intermittent problems are not usually related to the
control board.

DIAGNOSING ICE THICKNESS CONTROL CIRCUITRY

Ice Machine Does Not Cycle Into Harvest when Water
Contacts the Ice Thickness Control Probe

Step 1 Bypass the freeze time lock-in feature by

moving the ON/OFF/WASH switch to OFF and back to ON.
Wait until the water starts to flow over the evaporator.

Step 2 Clip the jumper wire to the ice thickness probe
and any cabinet ground.

ICE THICKNESS

PROBE

GROUND

JUMPER WIRE

PROBE

CONNECTION

EVAPORATOR

HARVEST LIGHT

(RED)

BIN SWITCH

LIGHT

(GREEN)

SV1592i

Step 2 Jumper wire connected from probe to ground

Monitoring Harvest Light Correction

The harvest light comes on,
and 6-10 seconds later, ice
machine cycles from freeze to
harvest.
The harvest light comes on but
the ice machine stays in the
freeze sequence.

The ice thickness control
circuitry is functioning
properly. Do not change any
parts.
The ice control circuitry is
functioning properly. The ice
machine is in a six minute
freeze time lock-in. Verify
Step 1 of this procedure was
followed correctly.

The harvest light does not

Proceed to Step 3.

come on.

Part Number STH047 5/16 55

Step 3 Disconnect the ice thickness probe from
the control board terminal. Clip the jumper wire to the
terminal on the control board and any cabinet ground.
Monitor the harvest light.

PROBE

ICE THICKNESS

PROBE

JUMPER WIRE

GROUND

CONNECTION

EVAPORATOR

BIN SWITCH

LIGHT

(GREEN)

HARVEST LIGHT

(RED)

SV1592J

Step 3 Jumper wire connected from control board

terminalto ground

Monitoring Harvest Light Correction

The harvest light comes on,
and 6-10 seconds later, ice

The ice thickness probe is

causing the malfunction.
machine cycles from freeze to
harvest.
The harvest light comes on but
the ice machine stays in the
freeze sequence.

The control circuitry is

functioning properly. The ice

machine is in a six-minute

freeze time lock-in (verify

step 1 of this procedure was

followed correctly).
The harvest light does not
come on.

The control board is causing

the malfunction.

56 Part Number STH047 5/16

Ice Machine Cycles Into Harvest Before Water Contact
with the Ice Thickness Probe

Step 1 Bypass the freeze time lock-in feature by

moving the ON/OFF/WASH switch to OFF and back to ON.
Wait until the water starts to flow over the evaporator,
then monitor the harvest light.

Step 2 Disconnect the ice thickness probe from the
control board terminal.

ICE THICKNESS

PROBE

DISCONNECT

PROBE WIRE

BIN SWITCH

(GREEN)

LIGHT

HARVEST LIGHT

(RED)
SV1592J_2

Step 2 Disconnect probe from control board terminal.

Monitoring Harvest Light Correction

The harvest light stays off and
the ice machine remains in the
freeze sequence.

The ice thickness probe is
causing the malfunction. Verify
that the ice thickness probe is

adjusted correctly.
The harvest light comes on,
and 6-10 seconds later, the ice

The control board is causing

the malfunction.
machine cycles from freeze to
harvest.

Part Number STH047 5/16 57

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 (21.2°C) ambient temperature
and 50°F (10.0°C) water produces more ice than the same
ice machine with 90°F (32.2°C) ambient and 70°F (21.2°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-Hour 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.

1. _________
Freeze Time

2. 1440

_________

Minutes in

24 Hrs.

3. _________

Weight of

One Harvest

+ _________

Harvest

Time

÷ _________

Total Cycle

Time

× _________

Cycles per

Day

= _________

Total Cycle

Time

= _________

Cycles per

Day

= _________

Actual

24-Hour

Production

58 Part Number STH047 5/16

Weighing the ice is the only 100% accurate check.
However, if the ice pattern is normal and the 1/8" (.44 cm)
thickness is maintained, the ice slab weights listed with
the 24-Hour Ice Production Charts may be used.

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 distributor for information on available
options and accessories.

Part Number STH047 5/16 59

INSTALLATION AND 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

60 Part Number STH047 5/16

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 float valve is stuck open or closed

• 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

Part Number STH047 5/16 61

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 the Refrigeration System
Operational Analysis Table, it can help diagnose an ice
machine malfunction.

Any number of problems can cause improper ice
formation.

Example: An ice formation that is “extremely thin at the
outlet” could be caused by a hot water supply, water
leaking out the overflow pipe, a faulty water float valve, a
low refrigerant charge, etc.

OUTLET

OUTLET

INLET

K170 K270

INLET

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.

62 Part Number STH047 5/16

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.

Part Number STH047 5/16 63

SAFETY LIMIT FEATURE

In addition to the standard safety controls, your Koolaire
ice machine features built-in safety limits that will stop
the ice machine if conditions arise which could cause a
major component failure.

Before calling for service, re-start the ice machine using
the following procedure:

1. Move the ON/OFF/WASH switch to OFF and then
back to ON.

2. If the safety limit feature has stopped the ice
machine, it will restart after a short delay. Proceed to
step 4.

3. If the ice machine does not restart, see “Ice machine
does not operate”.

4. Allow the ice machine to run to determine if the
condition is reoccurring.

A. If the ice machine stops again, the condition has

reoccurred. Call for service.

B. If the ice machine continues to run, the

condition has corrected itself. Allow the ice
machine to continue running.

64 Part Number STH047 5/16

Safety Limits

In addition to standard safety controls, the control board
has two built in safety limit controls which protect the ice
machine from major component failures.

Safety Limit #1: If the freeze time reaches 60 minutes,
the control board automatically initiates a harvest cycle. 3
cycles outside the time limit = 1 hour Stand-by Mode.

Safety Limit #2: If the harvest time reaches 3.5 minutes,
the control board automatically returns the ice machine
to the freeze cycle. 3 cycles outside the time limit = Safety
Limit (must be MANUALLY reset).

Safety Limit Stand-by Mode: The first time a safety
limit shut down occurs, the ice machine turns off for
60 minutes (Stand-by Mode). The ice machine will then
automatically restart to see if the problem reoccurs.
During the Stand-by Mode the harvest light will be
flashing continuously and a safety limit indication can be
viewed. If the same safety limit is reached a second time
(the problem has reoccurred), the ice machine will initiate
a safety limit shut down and remain off until it is manually
restarted. During a safety limit shut down the harvest
light will be flashing continuously.

Determining Which Safety Limit Stopped the Ice
Machine: When a safety limit condition causes the

ice machine to stop, the harvest light on the control
board continually flashes on and off. Use the following
procedures to determine which safety limit has stopped
the ice machine.

1. Move the toggle switch to OFF.

2. Move the toggle switch back to ON.

3. Watch the harvest light. It will flash one or two times,
corresponding to safety limits 1 and 2, to indicate
which safety limit stopped the ice machine.

After safety limit indication, the ice machine will restart
and run until a safety limit is exceeded again.

Part Number STH047 5/16 65

Safety Limit Notes

• A safety limit indication is completed before the
water pump starts. Water contacting the ice thickness
probe in the freeze cycle will cause the harvest light
to flash. Do not mistake a harvest light flashing in the
freeze cycle with a safety limit indication.

• 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 toggle switch is moved to the OFF position and
then back to the ON position prior to reaching the
100-harvest point, the last safety limit exceeded will
be indicated.

• If the harvest light did not flash prior to the ice
machine restarting, then the ice machine did not stop
because it exceeded a safety limit.

66 Part Number STH047 5/16

ANALYZING WHY SAFETY LIMITS MAY STOP THE ICE
MACHINE

According to the refrigeration industry, a high percentage
of compressor failure is a result of external causes. These
can include flooding or starving expansion valves, dirty
condensers, water loss to the ice machine, etc. The safety
limits protect the ice machine (primarily the compressor)
from external failures by stopping ice machine operation
before major component damage occurs.

The safety limit system is similar to a high-pressure cutout
control. It stops the ice machine, but does not tell what
is wrong. The service technician must analyze the system
to determine what caused the high-pressure cutout, or a
particular safety limit, to stop the ice machine.

The safety limits are designed to stop the ice machine
prior to major component failures, most often a minor
problem or something external to the ice machine. This
may be difficult to diagnose, as many external problems
occur intermittently.

Example: An ice machine stops intermittently on safety
limit #1 (long freeze times). The problem could be a low
ambient temperature at night, a water pressure drop; the
water is turned off one night a week, etc.

When a high-pressure cutout or a safety limit stops the
ice machine, they are doing what they are supposed
to do. That is, stopping the ice machine before a major
component failure occurs.

Refrigeration and electrical component failures may also
trip a safety limit. Eliminate all electrical components and
external causes first. If it appears that the refrigeration
system is causing the problem, use the Refrigeration
System Operational Analysis Table, along with detailed
charts, checklists, and other references to determine the
cause.

Part Number STH047 5/16 67

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 6 consecutive
freeze cycles.

Possible Cause Checklist

Improper Installation

• Refer to “Installation and Visual Inspection Checklist”
on page 60

Water System

• Water Level set too high (water escaping through
over flow tube)

• 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 float valve

• Defective water pump

Electrical System

• Ice thickness probe out of adjustment

• Harvest cycle not initiated electrically

• Compressor relay not energizing

• Compressor electrically non-operational

• High inlet air temperature (110°F/43.3°C max.)

• Defective fan cycling control

• Defective fan motor

• Dirty condenser

68 Part Number STH047 5/16

Refrigeration System

• Restricted condenser air flow

• Condenser discharge air re-circulation

• Dirty condenser fins

• Non-OEM 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 STH047 5/16 69

Safety Limit #2

Harvest time exceeds 3.5 minutes for 6 Consecutive
harvest cycles.

Possible Cause Checklist

Improper Installation

• Refer to “Installation and Visual Inspection Checklist”
on page 60.

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 float valve

• Defective water pump

Electrical System

• Ice thickness probe out of adjustment

• Ice thickness probe dirty

• Bin switch defective

• Premature harvest

Refrigeration System

• Non-OEM components

• Improper refrigerant charge

• Defective harvest valve

• TXV flooding (check bulb mounting)

• Defective fan cycling control

70 Part Number STH047 5/16

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 123 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.

Freeze Cycle

PSIG

Beginning of

Cycle __________ __________

Middle of

Cycle __________ __________

End of

Cycle __________ __________

Harvest Cycle

PSIG

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.

Part Number STH047 5/16 71

Discharge Pressure High Checklist

Improper Installation

• Refer to “Installation and Visual Inspection Checklist”
on page 60.

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-OEM components in system

• High side refrigerant lines/component

• Restricted (before mid-condenser)

Freeze Cycle Discharge Pressure Low Checklist

Improper Installation

• Refer to “Installation and Visual Inspection Checklist”
on page 60.

Improper Refrigerant Charge

• Undercharged

• Wrong type of refrigerant

Other

• Non-OEM 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.

72 Part Number STH047 5/16

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.

Part Number STH047 5/16 73

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)

1 2 4 7 10 12 14
| | | | | | |
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

74 Part Number STH047 5/16

Suction Pressure High Checklist

Improper Installation

• Refer to “Installation and Visual Inspection Checklist”
on page 60.

Discharge Pressure

• Discharge pressure is too high, and is affecting
suction pressure, refer to “Discharge Pressure High
Checklist” on page 72.

Improper Refrigerant Charge

• Overcharged

• Wrong type of refrigerant

• Non-condensables in system

Other

• Non-OEM components in system

• Harvest valve leaking

• TXV flooding (check bulb mounting)

• Defective compressor

Part Number STH047 5/16 75

Suction Pressure Low Checklist

Improper Installation

• Refer to “Installation and Visual Inspection Checklist”
on page 60.

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-OEM components in system

• Improper water supply over evaporator refer to
“Water System Checklist” on page 61.

• 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.

76 Part Number STH047 5/16

HARVEST VALVE

General

The harvest valve is an electrically operated valve that
opens when energized, and closes when de-energized.

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.

Part Number STH047 5/16 77

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.

Caution

,

Coil must be seated 100% on solenoid to function
correctly. Install coil with a twisting motion to
properly seat.

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” replacement
parts.

78 Part Number STH047 5/16

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.

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.

3. Feel the compressor discharge line.

Warning

n

The inlet of the harvest valve and the compressor
discharge line could be hot enough to burn your
hand. Just touch them momentarily.

4. Compare the temperature of the inlet of the
harvest valve to the temperature of the compressor
discharge line.

Part Number STH047 5/16 79

Findings Comments

The inlet of the harvest valve is

cool enough to touch and the

compressor discharge line is hot.

Cool & Hot

The inlet of the harvest

valve is hot and approaches

the temperature of a hot

compressor discharge line.

Hot & Hot

Both the inlet of the harvest

valve and the compressor

discharge line are cool enough

to touch.

Cool & Cool

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.

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.

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.

5. Record your findings on the table.

80 Part Number STH047 5/16

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 the 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.

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.

3. Wait five minutes into the freeze cycle.

4. Record the temperatures below and determine the
difference between them.

___________ ___________ ___________

Inlet

Temperature

Difference must be within
7°F (4°C) at 5minutes into

the freeze cycle

Outlet

Temperature

5. Use this with other information gathered on the
Refrigeration System Operational Analysis Table to
determine the ice machine malfunction.

Part Number STH047 5/16 81

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.

82 Part Number STH047 5/16

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.

Part Number STH047 5/16 83

REFRIGERATION COMPONENT DIAGNOSTIC CHART

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.

84 Part Number STH047 5/16

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.

Part Number STH047 5/16 85

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.

86 Part Number STH047 5/16

Ice formation is normal

-or-

entire evaporator

No ice formation on

-or-

Ice formation is

evaporator

evaporator

no ice formation on

extremely thin on the

bottom of evaporator

-or-

entire evaporator

No ice formation on

-or-

entire evaporator

No ice formation on the

Calculated (actual) 24 hour ice production_______________

Ice Production Published 24 hour ice production________________

Operational Analysis 1 2 3 4

10% of charted capacity.

NOTE: The ice machine is operating properly if the ice fill pattern is normal and ice production is within

All installation and water related problems must be corrected

Installation and Water

-or-

Ice formation is normal

before proceeding with chart.

thin on top of the

Ice formation extremely

extremely thin on top of

System

Ice Formation Pattern Ice formation is

REFRIGERATION COMPONENT DIAGNOSTIC CHART

Part Number STH047 5/16 87

evaporator

1

High

Stops on safety limit:

Stops on safety limit:

Stops on safety limit:

Stops on safety limit:

1 or 2

1

1 or 2

checklist to eliminate problems and/or components not listed on this table before proceeding.

If discharge pressure is High or Low, refer to freeze cycle high or low discharge pressure problem

Suction pressure is

High

Suction pressure is

Low

Suction pressure is

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

High

Suction pressure is

Safety Limits

Operational Analysis 1 2 3 4

88 Part Number STH047 5/16

Refer to “Analyzing Safety

Limits” to eliminate all non-

Freeze Cycle

refrigeration problems.

DischargePressure

________ ______ ______

1 minute Middle End

into cycle

Freeze Cycle

SuctionPressure

________ ______ ______

1 minute Middle End

and

COOL

inlet is

The harvest valve

and

COOL

inlet is

The harvest valve

The compressor

discharge line is

The compressor

discharge line is

HOT

COOL

Discharge line temp

Discharge line temp

150°F (66°C) or higher

at the end of freeze cycle

TXV Flooding Compressor

less than 150°F (66°C)

at the end of freeze cycle

Low On Charge

Final Analysis

Harvest Valve

-or-

Leaking

Enter total number of boxes

TXV Starving

checked in each column.

and

COOL

inlet is

The harvest valve

and

HOT

inlet is

The harvest valve

Harvest Valve

Operational Analysis 1 2 3 4

Part Number STH047 5/16 89

The compressor

discharge line is

The compressor

discharge line is

HOT

HOT

Discharge line temp

Discharge line temp

Discharge Line Temp.

150°F (66°C) or higher

150°F (66°C) or higher

Record freeze cycle

at the end of freeze cycle

at the end of freeze cycle

end of freeze cycle.

discharge line temp at the

ICE QUALITY IS POOR — CUBES ARE SHALLOW, INCOMPLETE OR WHITE

Ice machine is dirty

• Clean and sanitize the ice machine

Water filtration is poor

• Replace the filter

Water softener is working improperly (if applicable)

• Repair the water softener

Poor incoming water quality

• Contact a qualified company to test the quality of
the incoming water and make appropriate filter
recommendations

Water escaping from sump during freeze cycle

• Check standpipe and drain

• Check for water tracking out of water circuit

90 Part Number STH047 5/16

FREEZE CYCLE IS LONG, LOW ICE PRODUCTION

Water temperature is too high

• Connect to a cold water supply, verify check valves
in faucets and other equipment are functioning
correctly

Dirty Condenser

• Clean condenser

High air temperature entering condenser

• Air temperature must not exceed 120°F (39°C)

Water inlet valve filter screen is dirty

• Remove the water inlet valve and clean the filter
screen

Water inlet valve stuck open or leaking

• Turn off ice machine, if water continues to enter ice
machine, verify water pressure is ok then replace
water inlet valve

Water inlet valve is not working

• Water inlet valve must be replaced

Refrigeration problem

• Refer to refrigeration diagnostics

Water escaping from sump during freeze cycle

• Check standpipe and drain

• Check for water tracking out of water circuit

Part Number STH047 5/16 91

ICE MACHINE RUNS AND NO ICE IS PRODUCED

No water to ice machine

• Correct water supply

Incorrect incoming water pressure

• Water pressure must be 20-80 psi (1.4-5.5 bar)

Excessive mineral buildup

• Clean and sanitize the ice machine

Ambient temperature is too high or low

• Ambient temperature must be between 50°F and
110°F (10°C and 43°C)

Compressor relay inoperable

• No voltage to coil or coil defective

• Defective contacts

Compressor off on overload

• Condenser fan motor defective

• Incorrect flow to water cooled condenser

• Ambient temperature too high

• Condenser blocked

• Faulty start components

92 Part Number STH047 5/16

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.

Warning

n

High (line) voltage is applied to the control board at
all times. Removing the control board fuse or moving
the toggle switch to OFF will not remove the power
supplied to the control board.

Check Procedure

1. If the bin switch light is on with the ice damper
closed, the fuse is good.

Warning

n

Disconnect electrical power to the entire ice machine
before proceeding.

2. Remove the fuse. Check the resistance across the
fuse with an ohmmeter.

Reading Result

Open (OL) Replace fuse
Closed (O) Fuse is good

Part Number STH047 5/16 93

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.

Important

The ice damper must be up (bin switch closed) to
start ice making.

Check Procedure

1. Set the toggle switch to OFF.

2. Watch the bin switch light on the control board.

3. Move the ice damper upward, toward the
evaporator. The bin switch must close. The bin
switch light “on” indicates the bin switch has closed
properly.

4. Move the ice damper away from the evaporator.
The bin switch must open. The bin switch light “off”
indicates the bin switch has opened properly.

94 Part Number STH047 5/16

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).

Part Number STH047 5/16 95

Bin Switch Removal

1. Disconnect power to the ice machine at service
disconnect.

2. Disconnect bin switch wires in control box.

3. Insert a small screwdriver through the hole located
in the top of the bin switch, and depress mounting
tab slightly.

4. While depressing mounting tab roll bin switch to
right to release.

5. Pull wiring into evaporator compartment.

INSERT

SCREWDRIVER AND

DEPRESS TAB

BIN SWITCH

SV1695B

Bin Switch Removal

96 Part Number STH047 5/16

Diagnosing Start Components

If the compressor attempts to start, or hums and trips the
overload protector, check the start components before
replacing the compressor.

CAPACITOR

Visual evidence of capacitor failure can include a bulged
terminal end or a ruptured membrane. Do not assume a
capacitor is good if no visual evidence is present. A good
test is to install a known good substitute capacitor. Use
a capacitor tester when checking a suspect capacitor.
Clip the bleed resistor off the capacitor terminals before
testing.

RELAY

The relay has a set of contacts that connect and
disconnect the start capacitor from the compressor start
winding. The contacts on the relay are normally open.
The relay senses the voltage generated by the start
winding and closes and then opens the contacts as the
compressor motor starts. The contacts remain open until
the compressor is de-energized.

Part Number STH047 5/16 97

ON/OFF/WASH Toggle Switch

Function

The switch is used to place the ice machine in ON, OFF or
WASH mode of operation.

Specifications

Single-pole, double-throw switch. The switch is
connected into a varying low D.C. voltage circuit.

Check Procedure

NOTE: Because of a wide variation in D.C. voltage, it is not
recommended that a voltmeter be used to check toggle
switch operation.

1. Inspect the toggle switch for correct wiring.

2. Isolate the toggle switch by disconnecting all wires
from the switch, or by disconnecting the Molex
connector from the control board.

3. Check across the toggle switch terminals using a
calibrated ohmmeter. Note where the wire numbers
are connected to the switch terminals, or refer to the
wiring diagram to take proper readings.

Switch Setting Terminals Ohm Reading

ON 24-21 Open

24-20 Closed
20-21 Open

WASH 24-20 Open

24-21 Closed
20-21 Open

OFF 24-20 Open

24-21 Open
20-21 Open

Replace the toggle switch if ohm readings do not match
all three-switch settings.

98 Part Number STH047 5/16

Ice Thickness Probe

How the Probe Works

Koolaire’s electronic sensing circuit does not rely on
refrigerant pressure, evaporator temperature, water levels
or timers to produce consistent ice formation.

As ice forms on the evaporator, water (not ice) contacts
the ice thickness probe. After the water completes this
circuit across the probe continuously for 6-10 seconds, a
harvest cycle is initiated.

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. If water contacts the ice thickness
probe during these six minutes, the harvest light will
come on (to indicate that water is in contact with the
probe), but the ice machine will stay in the freeze cycle.
After the six minutes are up, a harvest cycle is initiated.
This is important to remember when performing
diagnostic procedures on the ice thickness control
circuitry.

To allow the service technician to initiate a harvest cycle
without delay, this feature is not used on the first cycle
after moving the toggle switch OFF and back to ON.

Maximum Freeze Time

The control system includes a built-in safety, which will
automatically cycle the ice machine into harvest after
60minutes in the freeze cycle.

Part Number STH047 5/16 99

ICE THICKNESS CHECK

The ice thickness probe is factory-set to maintain the ice
bridge thickness at 1/8" (3.2 mm).

NOTE: Make sure the water curtain is in place when
performing this check. It prevents water from splashing
out of the water trough.

1. Inspect the bridge connecting the cubes. It should
be about 1/8" (3.2 mm) thick.

2. If adjustment is necessary, turn the ice thickness
probe adjustment screw clockwise to increase
bridge thickness, or counterclockwise to decrease
bridge thickness.

NOTE: Turning the adjustment 1/3 of a turn will change
the ice thickness about 1/16" (1.5 mm).

ADJUSTING

SCREW

1/8" ICE BRIDGE

THICKNESS

NOTE:

SV3113

SV3114

Ice Thickness Check

Make sure the ice thickness probe wire and the bracket
do not restrict movement of the probe.

100 Part Number STH047 5/16