Marine
Q 1800
Ice Machine
Service Manual
Thank you for selecting a Manitowoc Ice Machine, the dependability leader in ice making equipment and
related products. With proper installation, care and maintenance, your new Manitowoc Ice Machine will
provide you with many years of reliable and economical performance.
Part Number 80-1211-3
7/00
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Table of Contents
Electrical System
Energized Parts Charts
Self-Contained Water-Cooled Models ...........................................................................................................1
Wiring Diagram Sequence of Operation
Self-Contained Models.....................................................................................................................................2
Wiring Diagrams
Wiring Diagram Legend..................................................................................................................................9
Self-Contained - Q1800 - 1 Phase .................................................................................................................10
Component Specifications and Diagnostics
Main Fuse .......................................................................................................................................................11
Bin Switch.......................................................................................................................................................11
Compressor Electrical Diagnostics...............................................................................................................13
PTCR Diagnostics..........................................................................................................................................14
Ice/Off/Clean Toggle Switch .........................................................................................................................17
Control Board Relays ....................................................................................................................................17
Electronic Control Board..............................................................................................................................18
Ice Thickness Probe (Harvest Initiation)
How the Probe Works ...................................................................................................................................20
Harvest/Safety Limit Light ...........................................................................................................................20
Freeze Time Lock-In Feature .......................................................................................................................20
Maximum Freeze Time..................................................................................................................................20
Diagnosing Ice Thickness Control Circuitry
Ice Machine Does Not Cycle Into Harvest When Water Contacts The Ice Thickness Probe..........21
Ice Machine Cycles Into Harvest Before Water Contact With The Ice Thickness Probe ................22
Water Level Control Circuitry
Diagnosing Freeze Cycle Potable Water Level Control Circuitry ...........................................................23
Water Trough Overfilling During The Freeze Cycle ...........................................................................24
Water Will Not Run Into The Sump Trough During The Freeze Cycle ............................................26
Diagnosing Ice Machine That Will Not Run..........................................................................................27
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Table of Contents
Refrigeration System
Sequence of Operation
Self-Contained Water-Cooled Models .........................................................................................................28
Operational Analysis (Diagnostics)
General............................................................................................................................................................29
Before Beginning Service ..............................................................................................................................30
Ice Production Check ....................................................................................................................................30
Installation/Visual Inspection Checklist ......................................................................................................31
Water System Checklist ................................................................................................................................31
Ice Formation Pattern ...................................................................................................................................32
Safety Limits...................................................................................................................................................34
Hot Gas Valve Temperature Check.............................................................................................................37
Analyzing Discharge Pressure During Freeze or Harvest Cycle
Procedure..................................................................................................................................................38
Freeze Cycle Discharge Pressure High Checklist .................................................................................38
Freeze Cycle Discharge Pressure Low Checklist..................................................................................38
Analyzing Suction Pressure During Freeze Cycle
Procedure..................................................................................................................................................39
Freeze Cycle Suction Pressure High Checklist .....................................................................................40
Freeze Cycle Suction Pressure Low Checklist ......................................................................................40
How to Use the Refrigeration System Operational Analysis Tables.........................................................41
Refrigeration System Operational Analysis Table
Dual TXV..................................................................................................................................................42
Pressure Control Specifications and Diagnostics
High Pressure Cutout (HPCO) Control.......................................................................................................43
Cycle Time/24 Hour Ice Production/Refrigerant Pressure Charts
Q1800 ..............................................................................................................................................................44
Refrigerant Recovery/Evacuating and Recharging
Normal Self-Contained Model Procedures..................................................................................................45
System Contamination Cleanup...................................................................................................................47
Replacing Pressure Controls Without Removing Refrigerant Charge ....................................................49
Filter-Driers....................................................................................................................................................51
Total System Refrigerant Charges...............................................................................................................51
Refrigerant Definitions..................................................................................................................................52
Refrigerant Re-Use Policy.............................................................................................................................53
HFC Refrigerant Questions and Answers...................................................................................................54
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Electrical System
Electrical System
Energized Parts Charts
SELF-CONTAINED WATER-COOLED MODELS
Ice Making
Sequence
Of
Control Board Relays
1
2
3
4
5
5A
Length
Of
Time
Water
Dump
Valve
Water Water Fill Hot Gas
Contactor Compressor
Coil
Operation
Pump
Valve Valve(s)
Start-Up1
On
Off
On
On
On
On
Off
On
Off
On
45 Sec onds
5 Sec onds
1. Water Purge
2. Refrigeration System
Start-Up
Off
Off
Freeze Sequence
May cycle
On/Off
Off
On
Off
Off
Off
Off
On
On
On
On
30 Sec onds
3. Pre-Chill
during first
45 sec.
Until 7 sec .
wa ter c onta c t
with ic e
Freeze
-------------
Cycles On,
then Off 1
more time
thic kness
probe
30 sec .
Off, 15
sec . On
Harvest Sequence
Fa c tory-set a t
45 Sec onds
On
On
On
On
On
5. Water Purge
Bin switc h
a c tiva tion
Until bin switc h
re-c loses
6. Harvest
Off
Off
Off
On
Off
Off
Off
On
Off
On
Off
7. Automatic
Shut-Off
Off
1Initial Start-Up or Start-Up After Automatic Shut-Off
FREEZE SEQUENCE
Harvest Water Purge
The circuit board has an adjustable water purge in
the harvest cycle. This permits a 15, 30 or 45
second purge cycle.
• The ice machine is locked into the freeze cycle
for the first 6 minutes, not allowing the ice
thickness probe to initiate a harvest sequence.
• The maximum freeze time is 60 minutes, at
which time the control board automatically
initiates a harvest sequence (steps 5-6).
Auto Shut-Off
The ice machine remains off for 3 minutes before it
can automatically restart. The ice machine restarts
(steps 1-2) immediately after the delay period, if the
bin switch re-closes prior to 3 minutes.
HARVEST SEQUENCE
The maximum harvest time is 3-1/2 minutes, at
which time the control board automatically
terminates the harvest sequence. If the bin switch is
open, the ice machine will go to automatic shut-off
(step7). If the bin switch is closed, the ice machine
will go to the freeze sequence (steps 3-4).
Safety Timers
The control board has the following non-adjustable
safety timers:
1
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Electrical System
Wiring Diagram Sequence of
Operation
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
L1
(21)
(22)
(55)
TB32
(61)
(60)
TB35
SELF-CONTAINED MODELS
WATER
VALVE
HIGH PRES
CUTOUT
(77)
2
(80)
(81)
HOT GAS
4
1
3
5
Initial Start-Up or Start-Up After
Automatic Shut-Off
SOLENOID
(76)
(75)
TB30
DUMP
SOLENOID
(57)
1. WATER PURGE
(99)
(98)
TB31
TRANS.
TB30
WATER
PUMP
Before the compressor starts, the water
pump and water dump solenoid are
energized for 45 seconds to purge old water
from the ice machine. This ensures that the
ice-making cycle starts with fresh water.
FUSE (7A)
(58)
TB37
(59)
(73)
TERMINATES AT
PIN CONNECTION
(74)
ICE THICKNESS PROBE
TB30
TB30
1C
CONTACTOR
COIL
(56)
1F
1G
WATER LEVEL PROBE
NOT USED
CLEAN LIGHT
WATER LEVEL
LOW D.C.
VOLTAGE
PLUG
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
SAFETY LIMIT CODE LIGHT
The hot gas valve(s) is also energized
during the water purge. In the case of an
initial refrigeration start-up, it stays on for
an additional 5 seconds (50 seconds total).
(64)
(66)
BIN SWITCH
(65)
TOGGLE SWITCH
VIEW FOR WIRING
(68)
(69)
ICE
68
(67)
(66)
INTERNAL WORKING
OFF
66
62
67
VIEW
CLEAN
69
(62)
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
(46)
(50)
TB30
CONTACTOR
CONTACTS
*OVERLOAD
(48)
C
(42)
(45)
TB35
L1
(51)
PTCR
(85)
(86)
(53)
(52)
TB33
TB34
FAN CYCLE CONTROL
TB30
FAN MOTOR
(AIR COOLED ONLY)
RUN CAPACITOR**
SV1646-1
Self-Contained Models
1. Water Purge (45 Sec onds)
Toggle Switch
Bin Switch
IC E
C losed
Control Board Relays
#1
#2
#3
#4
#5
Wa ter Pump
C losed / ON
Open / OFF
C losed / ON
C losed / ON
Open / OFF
OFF
Wa ter Fill Va lve
Hot G a s Solenoid
Wa ter Dump Va lve
C onta c tor C oil
C ompressor
Safety Controls (Whic h c ould stop ic e ma c hine opera tion)
High Pressure C ut-Out
C losed
C losed
Ma in Fuse (On C ontrol Boa rd)
2
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Electrical System
Initial Start-Up Or Start-Up After
Automatic Shut-Off (cont.)
2. REFRIGERATION SYSTEM
START-UP
The compressor starts after the 45-
second water purge, and it remains on
throughout the Freeze and Harvest
cycles.
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
L1
(21)
(22)
(55)
TB32
(61)
(60)
TB35
WATER
VALVE
HIGH PRES
CUTOUT
(77)
2
(80)
(81)
HOT GAS
4
1
3
5
SOLENOID
(76)
(75)
TB30
TB30
DUMP
SOLENOID
(57)
(99)
(98)
TB31
TRANS.
WATER
PUMP
FUSE (7A)
(58)
TB37
(59)
(73)
The water fill valve is energized at the
same time as the compressor. It
remains on until the water level sensor
closes for 3 continuous seconds.
TERMINATES AT
PIN CONNECTION
(74)
ICE THICKNESS PROBE
TB30
TB30
1C
CONTACTOR
COIL
(56)
1F
1G
WATER LEVEL PROBE
NOT USED
CLEAN LIGHT
WATER LEVEL
LOW D.C.
VOLTAGE
PLUG
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
The hot gas valve(s) remains on for
the first 5 seconds of the initial
compressor start-up.
SAFETY LIMIT CODE LIGHT
(64)
(66)
BIN SWITCH
(65)
TOGGLE SWITCH
VIEW FOR WIRING
(68)
(69)
ICE
68
(67)
(66)
INTERNAL WORKING
OFF
66
62
67
VIEW
CLEAN
69
(62)
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
(46)
(50)
TB30
CONTACTOR
CONTACTS
*OVERLOAD
(48)
C
(42)
(45)
TB35
L1
(51)
PTCR
(85)
(86)
(53)
(52)
TB33
TB34
FAN CYCLE CONTROL
TB30
FAN MOTOR
(AIR COOLED ONLY)
RUN CAPACITOR**
SV1646-2
Self-Contained Models
2. Refrigeration System Start-Up (5 Sec onds)
Toggle Switch
Bin Switch
IC E
C losed
Control Board Relays
#1
#2
#3
#4
#5
Wa ter Pump
Open / OFF
C losed / ON
C losed / ON
Open / OFF
C losed / ON
ON
Wa ter Fill Va lve
Hot G a s Solenoid
Wa ter Dump Va lve
C onta c tor C oil
C ompressor
Safety Controls (Whic h c ould stop ic e ma c hine opera tion)
High Pressure C ut-Out
C losed
C losed
Ma in Fuse (On C ontrol Boa rd)
3
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Electrical System
Freeze Sequence
3. PRE-CHILL
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
L1
To pre-chill the evaporator, the compressor runs
for 30 seconds prior to water flow.
(21)
(22)
(55)
TB32
(61)
(60)
TB35
WATER
VALVE
HIGH PRES
CUTOUT
The water fill valve remains on until the water
level sensor closes for three continuous
seconds.
(77)
2
(80)
(81)
HOT GAS
SOLENOID
4
1
3
5
(76)
(75)
TB30
DUMP
SOLENOID
(57)
(99)
(98)
TB31
TRANS.
TB30
WATER
PUMP
FUSE (7A)
(58)
TB37
(59)
(73)
TERMINATES AT
PIN CONNECTION
(74)
ICE THICKNESS PROBE
TB30
TB30
1C
CONTACTOR
COIL
(56)
1F
1G
WATER LEVEL PROBE
NOT USED
CLEAN LIGHT
WATER LEVEL
LOW D.C.
VOLTAGE
PLUG
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
SAFETY LIMIT CODE LIGHT
(64)
(66)
BIN SWITCH
(65)
TOGGLE SWITCH
VIEW FOR WIRING
(68)
(69)
ICE
68
(67)
(66)
INTERNAL WORKING
OFF
66
62
67
VIEW
CLEAN
69
(62)
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
(46)
(50)
TB30
CONTACTOR
CONTACTS
*OVERLOAD
(48)
C
(42)
(45)
TB35
L1
(51)
PTCR
(85)
(86)
(53)
(52)
TB33
TB34
FAN CYCLE CONTROL
TB30
FAN MOTOR
(AIR COOLED ONLY)
RUN CAPACITOR**
Self-Contained Models
3. Pre-Chill (30 Sec onds)
Toggle Switch
Bin Switch
IC E
C losed
Control Board Relays
#1
#2
#3
#4
#5
Wa ter Pump
Open / OFF
Wa ter Fill Va lve
Hot G a s Solenoid
Wa ter Dump Va lve
C onta c tor C oil
C ompressor
C losed / ON
Open / OFF
Open / OFF
C losed / ON
ON
Safety Controls (Whic h c ould stop ic e ma c hine opera tion)
High Pressure C ut-Out
C losed
C losed
Ma in Fuse (On C ontrol Boa rd)
4
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Electrical System
Freeze Sequence (cont.)
4. FREEZE
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
The water pump starts after the 30-
second pre-chill. An even flow of
water is directed across the evaporator
and into each cube cell, where it
freezes.
L1
(21)
(22)
(55)
TB32
(61)
(60)
TB35
WATER
VALVE
HIGH PRES
CUTOUT
(77)
2
(80)
(81)
HOT GAS
4
1
3
5
SOLENOID
(76)
(75)
TB30
TB30
DUMP
SOLENOID
When sufficient ice has formed, the
water flow (not the ice) contacts the
ice thickness probes. After
approximately 7 seconds of continual
contact, a harvest cycle is initiated.
(57)
(99)
(98)
TB31
TRANS.
WATER
PUMP
FUSE (7A)
(58)
TB37
(59)
(73)
TERMINATES AT
PIN CONNECTION
(74)
ICE THICKNESS PROBE
TB30
TB30
1C
CONTACTOR
COIL
(56)
1F
1G
WATER LEVEL PROBE
NOT USED
CLEAN LIGHT
WATER LEVEL
LOW D.C.
VOLTAGE
PLUG
NOTE: The ice machine cannot
initiate a harvest cycle until a 6-
minute freeze lock has expired.
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
SAFETY LIMIT CODE LIGHT
(64)
(66)
BIN SWITCH
(65)
TOGGLE SWITCH
VIEW FOR WIRING
(68)
(69)
ICE
68
(67)
(66)
INTERNAL WORKING
OFF
66
62
67
VIEW
CLEAN
69
(62)
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
(46)
(50)
TB30
CONTACTOR
CONTACTS
*OVERLOAD
(48)
C
(42)
(45)
TB35
L1
(51)
PTCR
Self-Contained Models
(85)
(86)
(53)
(52)
TB33
TB34
FAN CYCLE CONTROL
TB30
FAN MOTOR
(AIR COOLED ONLY)
RUN CAPACITOR**
SV1646-4
4. Freeze (Until 7 Sec onds of Wa ter C onta c t with Ic e Thic kness Probe)
Toggle Switch
Bin Switch
IC E
C losed
Control Board Relays
#1
#2
#3
#4
#5
Wa ter Pump
C losed / ON
Wa ter Fill Va lve
Hot G a s Solenoid
Wa ter Dump Va lve
C onta c tor C oil
C ompressor
C yc les ON then OFF
Open / OFF
Open / OFF
C losed / ON
ON
Safety Controls (Whic h c ould stop ic e ma c hine opera tion)
High Pressure C ut-Out
C losed
C losed
Ma in Fuse (On C ontrol Boa rd)
5
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Electrical System
Harvest Sequence
5. WATER PURGE
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
The water pump continues to run, and
the water dump valve energizes for 45
seconds to purge the water in the sump
trough. The water fill valve energizes
(turns on) and de-energizes (turns off)
strictly by time. The water fill valve
energizes for the last 15 seconds of the
45-second water purge. The water
purge must be at the factory setting of
45 seconds for the fill valve to
L1
(21)
(22)
(55)
TB32
(61)
(60)
TB35
WATER
VALVE
HIGH PRES
CUTOUT
(77)
2
(80)
(81)
HOT GAS
SOLENOID
4
1
3
5
(76)
(75)
TB30
DUMP
SOLENOID
(57)
(99)
(98)
TB31
TRANS.
TB30
WATER
PUMP
FUSE (7A)
(58)
TB37
(59)
(73)
TERMINATES AT
PIN CONNECTION
(74)
ICE THICKNESS PROBE
TB30
TB30
1C
CONTACTOR
COIL
(56)
1F
1G
WATER LEVEL PROBE
NOT USED
CLEAN LIGHT
WATER LEVEL
LOW D.C.
VOLTAGE
PLUG
energize during the last 15 seconds of
the Water Purge. If set at less than 45
seconds, the water fill valve does not
energize during the water purge.
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
SAFETY LIMIT CODE LIGHT
(64)
(66)
BIN SWITCH
(65)
TOGGLE SWITCH
VIEW FOR WIRING
(68)
(69)
ICE
68
(67)
(66)
INTERNAL WORKING
OFF
66
62
67
VIEW
After the 45 second water purge, the
water fill valve, water pump and dump
valve de-energize. (Refer to "Water
Purge Adjustment for details.) The hot
gas valve also opens at the beginning
of the water purge to divert hot
CLEAN
69
(62)
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
(46)
(50)
TB30
CONTACTOR
CONTACTS
*OVERLOAD
(48)
C
(42)
(45)
TB35
L1
(51)
PTCR
(85)
(86)
(53)
(52)
TB33
TB34
refrigerant gas into the evaporator.
FAN CYCLE CONTROL
TB30
FAN MOTOR
(AIR COOLED ONLY)
RUN CAPACITOR**
SV1646-5
Self-Contained Models
5. Water Purge (45 Sec onds)
Toggle Switch
Bin Switch
IC E
C losed
Control Board Relays
#1
#2
#3
#4
#5
Wa ter Pump
C losed / ON
Wa ter Fill Va lve
Hot G a s Solenoid
Wa ter Dump Va lve
C onta c tor C oil
C ompressor
C yc les OFF then ON
C losed / ON
C losed / ON
C losed / ON
ON
Safety Controls (Whic h c ould stop ic e ma c hine opera tion)
High Pressure C ut-Out
C losed
C losed
Ma in Fuse (On C ontrol Boa rd)
6
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Electrical System
Harvest Sequence (cont.)
6. HARVEST
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
The hot gas valve(s) remains open,
allowing refrigerant gas to warm the
evaporator. This causes the cubes to
slide, as a sheet, off the evaporator and
into the storage bin.
L1
(21)
(22)
(55)
TB32
(61)
(60)
TB35
WATER
VALVE
HIGH PRES
CUTOUT
(77)
2
(80)
(81)
HOT GAS
4
1
3
5
SOLENOID
(76)
(75)
TB30
TB30
DUMP
SOLENOID
The sliding sheet of cubes swings the
water curtain out, opening the bin
switch. This momentary opening and
closing of the bin switch terminates
the Harvest Cycle and returns the ice
machine to the Freeze Cycle (steps 3-
4).
(57)
(99)
(98)
TB31
TRANS.
WATER
PUMP
FUSE (7A)
(58)
TB37
(59)
(73)
TERMINATES AT
PIN CONNECTION
(74)
ICE THICKNESS PROBE
TB30
TB30
1C
CONTACTOR
COIL
(56)
1F
1G
WATER LEVEL PROBE
NOT USED
CLEAN LIGHT
WATER LEVEL
LOW D.C.
VOLTAGE
PLUG
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
SAFETY LIMIT CODE LIGHT
(64)
(66)
BIN SWITCH
(65)
TOGGLE SWITCH
VIEW FOR WIRING
(68)
(69)
ICE
68
(67)
(66)
INTERNAL WORKING
OFF
66
62
67
VIEW
CLEAN
69
(62)
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
(46)
(50)
TB30
CONTACTOR
CONTACTS
*OVERLOAD
(48)
C
(42)
(45)
TB35
L1
(51)
PTCR
(85)
(86)
(53)
(52)
TB33
TB34
FAN CYCLE CONTROL
TB30
FAN MOTOR
(AIR COOLED ONLY)
RUN CAPACITOR**
SV1646-6
Self-Contained Models
6. Harvest (Until Bin Switc h Ac tiva tion)
IC E
Toggle Switch
Bin Switch
C losed
Control Board Relays
#1
#2
#3
#4
#5
Wa ter Pump
Open / OFF
Open / OFF
C losed / ON
Open / OFF
C losed / ON
ON
Wa ter Fill Va lve
Hot G a s Solenoid
Wa ter Dump Va lve
C onta c tor C oil
C ompressor
Safety Controls (Whic h c ould stop ic e ma c hine opera tion)
High Pressure C ut-Out
C losed
C losed
Ma in Fuse (On C ontrol Boa rd)
7
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Electrical System
7. Automatic Shut-Off
If the storage bin is full at the end of a
harvest cycle, the sheet of cubes fails
to clear the water curtain and holds it
open. After the water curtain is held
open for 7 seconds, the ice machine
shuts off.
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
L1
(21)
(22)
(55)
TB32
(61)
(60)
TB35
WATER
VALVE
HIGH PRES
CUTOUT
(77)
2
(80)
(81)
HOT GAS
4
1
3
5
SOLENOID
(76)
(75)
TB30
DUMP
SOLENOID
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 water curtain. As
the water curtain swings back to the
operating position, the bin switch
closes and the ice machine restarts
(steps 1-2).
(57)
(99)
(98)
TB31
TRANS.
TB30
WATER
PUMP
FUSE (7A)
(58)
TB37
(59)
(73)
TERMINATES AT
PIN CONNECTION
(74)
ICE THICKNESS PROBE
TB30
TB30
1C
CONTACTOR
COIL
(56)
1F
1G
WATER LEVEL PROBE
NOT USED
CLEAN LIGHT
WATER LEVEL
LOW D.C.
VOLTAGE
PLUG
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
SAFETY LIMIT CODE LIGHT
(64)
(66)
BIN SWITCH
(65)
TOGGLE SWITCH
VIEW FOR WIRING
(68)
(69)
ICE
68
(67)
(66)
INTERNAL WORKING
OFF
66
62
NOTE: The ice machine must remain
off for 3 minutes before it can
automatically restart.
67
VIEW
CLEAN
69
(62)
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
(46)
(50)
TB30
CONTACTOR
CONTACTS
*OVERLOAD
(48)
C
(42)
(45)
TB35
L1
(51)
PTCR
(85)
(86)
(53)
(52)
TB33
TB34
FAN CYCLE CONTROL
TB30
FAN MOTOR
(AIR COOLED ONLY)
RUN CAPACITOR**
SV1646-7
Self-Contained Models
7. Automatic Shut-Off (Until Bin Switc h C loses)
Toggle Switch
Bin Switch
IC E
Open
Control Board Relays
#1
#2
#3
#4
#5
Wa ter Pump
Open / OFF
Wa ter Fill Va lve
Hot G a s Solenoid
Wa ter Dump Va lve
C onta c tor C oil
C ompressor
Open / OFF
Open / OFF
Open / OFF
Open / OFF
OFF
Safety Controls (Whic h c ould stop ic e ma c hine opera tion)
High Pressure C ut-Out
C losed
C losed
Ma in Fuse (On C ontrol Boa rd)
8
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Electrical System
Wiring Diagrams
The following pages contain electrical wiring diagrams. Be sure you are referring to the correct diagram for
the ice machine which you are servicing.
WARNING
Always disconnect power before working on
electrical circuitry.
WIRING DIAGRAM LEGEND
The following symbols are used on all of the wiring diagrams:
*
Internal Compressor Overload
(Some models have external compressor overloads)
TB
( )
Terminal Board Connection
(Terminal board numbers are printed on the actual terminal board)
Wire Number Designation
(The number is marked at each end of the wire)
⎯>>⎯ Multi-Pin Connection
(Electrical Box Side) ⎯>>⎯ (Compressor Compartment Side)
9
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Electrical System
Q1800 - 1 PHASE
CAUTION: DISCONNECT POWER BEFORE
WORKING ON ELECTRICAL CIRCUITRY.
NOTE:
DIAGRAM SHOWN DURING FREEZE CYCLE.
SEE SERIAL PLATE FOR VOLTAGE
L2 (N)
L1
(21)
WATER
(22)
VALVE
TB32
(55)
RH HOT GAS
SOLENOID
TB35
(61)
(60)
(
(88)
HIGH
PRESSURE
CUT-OUT
(87)
(77)
2
4
1
(80)
(81)
LH HOT GAS
SOLENOID
(75)
(99)
(76)
3
5
TB30
TB30
DUMP
SOLENOID
(57)
TB31
(98)
TRANS.
WATER
PUMP
(58)
FUSE (7A)
TB37
(59)
TERMINATES AT
PIN CONNECTION
1C
1F
(73)
(74)
ICE THICKNESS PROBE
WATER LEVEL PROBE
TB30
TB30
CONTACTOR
COIL
(56)
CLEAN LIGHT
LOW D.C.
1G
VOLTAGE
PLUG
AUCS DISPENSE TIME
WATER LEVEL LIGHT
(62)
(63)
BIN SWITCH LIGHT
HARVEST LIGHT/
(64)
SAFETY LIMIT CODE LIGHT
BIN SWITCH
TOGGLE SWITCH
(68)
(65)
VIEW FOR WIRING
68
(67)
(66)
ICE
OFF
(69)
← INTERNAL
WORKING VIEW
66
62
67
69
(66)
CLEAN
(62)
CRANKCASE HEATER
(95)
(94)
TB35
TB30
(49)
(47)
COMPRESSOR
S
RUN CAPACITOR
R
R
R
*OVERLOAD
(50)
(46)
CONTACTOR
CONTACTS
C
CONTACTOR
CONTACTS
(45)
(96)
(42)
(48)
TB30
TB35
L2
L1
PTCR
(44)
SV1652
10
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Electrical System
Component Specifications and Diagnostics
MAIN FUSE
BIN SWITCH
Function
Function
The control board fuse stops ice machine operation
if electrical components fail causing high amp
draw.
Bin switch operation is controlled by movement of
the water curtain. The bin switch has two main
functions:
1. Terminating the harvest cycle and returning the
ice machine to the freeze cycle.
Specifications
The main fuse is 250 Volt, 7 amp.
This occurs when the bin switch is opened and
closed again within 7 seconds during the harvest
cycle.
Check Procedure
WARNING
2. Automatic ice machine shut-off.
High (line) voltage is applied to the control board
(terminals #55 and #56) 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.
If the storage bin is full at the end of a harvest
cycle, the sheet of cubes fails to clear the water
curtain and holds it open. After the water curtain
is held open for 7 seconds, the ice machine
shuts off.
1. If the bin switch light is on with the water
curtain closed, the fuse is good.
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 water curtain. As
the water curtain swings back to the operating
position, the bin switch closes and the ice
machine restarts.
WARNING
Disconnect electrical power to the entire ice
machine before proceeding.
2. Remove the fuse. Check the resistance across
the fuse with an ohm meter.
Important
The water curtain must be ON (bin switch closed)
to start ice making.
Reading
Open (OL)
C losed (O)
Result
Repla c e fuse
Fuse is good
Specifications
The bin switch is a magnetically operated reed
switch. The magnet is attached to the lower right
corner of the water curtain. The switch is attached
to the evaporator mounting bracket.
The bin switch is connected to a varying D.C.
voltage circuit. (Voltage does not remain constant.)
NOTE: Because of a wide variation in D.C. voltage,
it is not recommended that a voltmeter be used to
check bin switch operation.
11
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Electrical System
Check Procedure
Water Curtain Removal Notes
1. Set the toggle switch to OFF.
The water curtain must be on (bin switch closed) to
start ice making. While a freeze cycle is in progress,
the water curtain can be removed and installed at
any time without interfering with the electrical
control sequence.
2. Watch the bin switch light on the control board.
3. Move the water curtain toward the evaporator.
The bin switch must close. The bin switch light
“on” indicates the bin switch has closed
properly.
4. Move the water curtain away from the
evaporator. The bin switch must open. The bin
switch light “off” indicates the bin switch has
opened properly.
If the ice machine goes into harvest sequence while
the water curtain is removed, one of the following
will happen:
• Water curtain remains off
Ohm Test
When the harvest cycle time reaches 3.5
minutes and the bin switch is not closed, the ice
machine stops as though the bin were full.
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. Set the ohmmeter to the 10,000
ohm scale.
• Water curtain is put back on
If the bin switch closes prior to reaching the 3.5
minute point, the ice machine immediately
returns to another freeze sequence prechill.
3. Cycle the bin switch by opening and closing the
water curtain.
4. With the bin switch open: Resistance readings
of more than 30,000 ohms indicate a correctly
operating bin switch.
5. With the bin switch closed: Resistance readings
of less than 70 ohms indicates a correctly
operating bin switch.
Important
Any reading between 70 and 30,000 ohms,
regardless of curtain position, indicates a
defective bin switch
INFINITE
30,000 OHMS
OHMS
SWITCH OPEN
METER
READS
(OL)
GOOD
70 OHMS
SWITCH CLOSED
BAD
0 OHMS
GOOD
Bin Switch Resistance Readings
12
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Electrical System
COMPRESSOR ELECTRICAL
DIAGNOSTICS
The compressor will not start or will trip repeatedly
on overload.
Determine if the Compressor is Seized
Check the amp draw while the compressor is trying
to start.
COMPRESSOR DRAWING LOCKED ROTOR
The two likely causes of this are:
• Defective starting component
Check Resistance (Ohm) Values
NOTE: Compressor windings can have very low
ohm values. Use a properly calibrated meter.
• Mechanically seized compressor
Perform the resistance test after the compressor
cools. The compressor dome should be cool enough
to touch (below 120°F/49°C) to assure that the
overload is closed and the resistance readings will
be accurate.
To determine which you have:
1. Install high and low side gauges.
2. Try to start the compressor.
3. Watch the pressures closely.
A. If the pressures do not move, the compressor
is seized. Replace the compressor.
B. If the pressures move, the compressor is
turning slowly and is not seized. Check the
capacitors and start relay.
SINGLE PHASE COMPRESSORS
1. Disconnect power from the cuber and remove
the wires from the compressor terminals.
2. The resistance values must be within published
guidelines for the compressor. The resistance
values between C and S and between C and R,
when added together, should equal the
resistance value between S and R.
3. If the overload is open, there will be a resistance
reading between S and R, and open readings
between C and S and between C and R. Allow
the compressor to cool, then check the readings
again.
COMPRESSOR DRAWING HIGH AMPS
The continuous amperage draw on start-up should
not be near the maximum fuse size indicated on the
serial tag.
The voltage when the compressor is trying to start
must be within ±10% of the nameplate voltage.
Diagnosing Capacitors
Check Motor Windings to Ground
• If the compressor attempts to start, or hums and
trips the overload protector, check the starting
components before replacing the compressor.
• 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.
Check continuity between all three terminals and
the compressor shell or copper refrigeration line.
Scrape metal surface to get good contact. If
continuity is present, the compressor windings are
grounded and the compressor should be replaced.
• 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.
Diagnosing PTCR’s
See “PTCR Diagnostics” on the next page.
13
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Electrical System
PTCR DIAGNOSTICS
Compressor Start Sequence
PTCR’s provide additional starting torque by
increasing the current in the auxiliary (start)
winding during starting. The PTCR is wired across
the run capacitor (in series with the start winding).
What is a PTCR?
A PTCR (or Positive Temperature Coefficient
Resistor) is made from high-purity, semi-
conducting ceramics.
1. It is important for the refrigerant discharge and
suction pressures to be somewhat equalized
prior to the compressor starting. To assure
equalization of pressures the hot gas valve (and
HPR valve on remotes) will energize for 45
seconds prior to compressor starting. The hot
gas valve (and HPR valve on remotes) remains
on for an additional 5 seconds while the
compressor is starting.
A PTCR is useful because of its resistance versus
temperature characteristic. The PTCR has a low
resistance over a wide (low) temperature range, but
upon reaching a certain higher temperature, its
resistance greatly increases, virtually stopping
current flow. When the source of heat is removed,
the PTCR returns to its initial base resistance.
In severe duty cycles, it can be used to repeatedly
switch (virtually stop) large currents at line
voltages.
2. When starting the compressor, the contactor
closes and the PTCR, which is at a low
resistance value, allows high starting current to
flow in the start winding.
PTCR’s have been used for many years in millions
of HVAC applications. In place of using the
conventional start relay/start capacitor, a simple
PTCR provides the starting torque assistance to
PSC (Permanent Split Capacitor) single-phase
compressors, which can equalize pressures before
starting.
3. The current passing through the PTCR causes it
to rapidly heat up, and after approximately .25-1
second it abruptly “switches” to a very high
resistance, virtually stopping current flow
through it.
4. At this point the motor is up to speed and all
current going through the start winding will now
pass through the run capacitor.
5. The PTCR remains hot and at a high resistance
as long as voltage remains on the circuit.
6. It is important to provide time between
compressor restarts to allow the PTCR to cool
down to near its initial temperature (low
resistance). When the contactor opens to stop
the compressor, the PTCR cools down to its
initial low resistance and is again ready to
provide starting torque assistance. To assure the
PTCR has cooled down, during an automatic
shut-off, the Q model ice machines have a built-
in 3-minute off time before it can restart.
14
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Electrical System
Q-Model Automatic Shut-Off and Restart
When the storage bin is full at the end of a harvest
cycle, the sheet of cubes fails to clear the water
curtain and will hold it open. After the water curtain
is held open for 7 seconds, the ice machine shuts
off. To assure the PTCR has cooled, the ice
machine remains off for 3 minutes before it can
automatically restart.
Troubleshooting PTCR’s
WHY A GOOD PTCR MAY FAIL
TO START THE COMPRESSOR
The PTCR must be cooled before attempting to start
the compressor, otherwise the high starting torque
may not last long enough.
For example, if the PTCR is properly cooled, say
60°F (15.6°C) when the compressor starts, it will
take .25 to 1.0 seconds before its temperature
reaches 260°F (126.6°C), and current flow is
stopped.
The ice machine remains off until enough ice has
been removed from the storage bin to allow the ice
to fall clear of the water curtain. As the water
curtain swings back to operating position, the bin
switch closes and the ice machine restarts, provided
the three-minute delay period is complete.
If the PTCR is still warm, say 160°F (71.1°C) when
the compressor starts, it will take only .125 to .50
seconds before its temperature reaches 260°F
(126.6°C), and current flow is stopped. This
decreased time may be insufficient to start the
compressor.
L1
L2
CONTACTOR
CONTACTS
R
RUN CAPACITOR
C
R
R
S
COMPRESSOR
A good PTCR may be too hot to operate properly at
start-up because:
PTCR
SV1506
• The ice machine’s 3-minute delay has been
overridden. Opening and closing the service
disconnect or cycling the toggle switch from
OFF to ICE will override the delay period.
• The control box temperature is too high.
Though rare, very high air temperatures (intense
sunlight, etc.) can greatly increase the
temperature of the control box and its contents.
This may require a longer off time to allow the
PTCR to cool.
During Start-Up (First .25 - 1.0 Seconds)
L1
L2
CONTACTOR
CONTACTS
R
RUN CAPACITOR
C
R
R
S
COMPRESSOR
• The compressor has short-cycled, or the
compressor overload has opened. Move the
toggle switch to OFF and allow the compressor
and PTCR to cool.
PTCR
SV1507
After Start-Up
(Current Flows Through Run Capacitor)
Continued on next page…
15
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Electrical System
There are other problems that may cause
compressor start-up failure with a good PTCR in a
new, properly wired ice machine.
• The voltage at the compressor during start-up is
too low.
Room
Manitowoc
Cera-Mite
Model
Temperature
Resistance
8-22 Ohms
Part Number Part Number
Q1800
8504913 305C 9
MEASURE OHMS BETWEEN
CENTER TAB AND END TAB
Manitowoc ice machines are rated at ±10% of
nameplate voltage at compressor start-up. (Ex:
An ice machine rated at 208-230 should have a
compressor start-up voltage between 187 and
253 volts.)
LEAVE JUMPER
WIRE IN PLACE
• The compressor discharge and suction pressures
are not matched closely enough or equalized.
SV1541
These two pressures must be somewhat
equalized before attempting to start the
compressor. The hot gas valve (and HPR valve
on remotes) energizes for 45 seconds before the
compressor starts, and remains on 5 seconds
after the compressor starts. Make sure this is
occurring before assuming that the PTCR is
bad.
Manitowoc PTCR 8504913
CHECKING THE PTCR
WARNING
Disconnect electrical power to the entire ice
machine at the building electrical disconnect box
before proceeding.
1. Visually inspect the PTCR. Check for signs of
physical damage.
NOTE: The PTCR case temperature may reach
210°F (100°C) while the compressor is running.
This is normal. Do not change a PTCR just because
it is hot.
2. Wait at least 10 minutes for the PTCR to cool to
room temperature.
3. Remove the PTCR from the ice machine.
4. Measure the resistance of the PTCR as shown
below. If the resistance falls outside of the
acceptable range, replace it.
16
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Electrical System
ICE/OFF/CLEAN TOGGLE SWITCH
Function
CONTROL BOARD RELAYS
Function
The switch is used to place the ice machine in ICE,
OFF or CLEAN mode of operation.
The control board relays energize and de-energize
system components.
Specifications
Specifications
Double-pole, double-throw switch. The switch is
connected into a varying low D.C. voltage circuit.
Relays are not field replaceable. There are five
relays on the control board:
Check Procedure
Relay
#1 Wa ter Pump
#2 Wa ter Inlet Va lve
#3 Hot G a s Va lve
#4 Wa ter Dump Va lve
#5 C onta c tor (Self-C onta ined)
Controls
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 and removing wire #69 from
the toggle switch.
C onta c tor / Liquid Line Solenoid (Remotes)
3. Check across the toggle switch terminals using a
calibrated ohm meter. Note where the wire
numbers are connected to the switch terminals,
or refer to the wiring diagram to take proper
readings.
Switch Setting
Terminals
66-62
67-68
67-69
66-62
67-68
67-69
66-62
67-68
67-69
Ohm Reading
Open
IC E
C losed
Open
C losed
Open
C losed
Open
Open
C LEAN
OFF
Open
4. Replace the toggle switch if ohm readings do
not match all three switch settings.
15
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Electrical System
ELECTRONIC CONTROL BOARD
AC LINE VOLTAGE
20
ELECTRICAL PLUG
(NUMBERS MARKED ON
WIRES)
57
60
61
CLEAN LIGHT
YELLOW
58
55
L1 PRIMARY
POWER SUPPLY
N 115V
L2 208-230V
56
WATER LEVEL
PROBE LIGHT
GREEN
MAIN FUSE (7A)
BIN SWITCH LIGHT
GREEN
AUTOMATIC CLEANING
SYSTEM (AuCS)
ACCESSORY PLUG
HARVEST LIGHT/
SAFETY LIMIT
CODE LIGHT
RED
ICE THICKNESS
PROBE
(3/16” CONNECTION)
1C
WATER LEVEL
PROBE
1F
Q1800 ONLY
1G
67
62
68
65
63
DC LOW VOLTAGE
ELECTRICAL PLUG
(NUMBERS MARKED
ON WIRES)
SV1588
Control Board
18
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Electrical System
General
Inputs
Q-Model control boards use a dual voltage
transformer. This means only one control board is
needed for both 115V and 208-230V use.
The control board, along with inputs, controls all
electrical components, including the ice machine
sequence of operation. Prior to diagnosing, you
must understand how the inputs affect the control
board operation.
Safety Limits
In addition to standard safety controls, such as the
high pressure cut-out, the control board has built-
in safety limits.
Refer to specific component specifications
(inputs), wiring diagrams and ice machine
sequence of operation sections for details.
These safety limits protect the ice machine from
major component failures. For more information,
see “Safety Limits”.
As an example, refer to “Ice Thickness Probe” in
the component specifications section of this
manual for information relating to how the probe
and control board function together.
This section will include items such as:
• How a harvest cycle is initiated
• How the harvest light functions with the probe
• Freeze time lock-in feature
• Maximum freeze time
• Diagnosing ice thickness control circuitry
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Electrical System
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 ICE.
Ice Thickness Probe (Harvest Initiation)
HOW THE PROBE WORKS
Manitowoc’s electronic sensing circuit does not rely
on refrigerant pressure, evaporator temperature,
water levels or timers to produce consistent ice
formation.
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.
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.
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.
SV1729A
Ice Thickness Probe
NOTE: Turning the adjustment 1/3 of a turn will
change the ice thickness about 1/16” (1.5 mm).
HARVEST/SAFETY LIMIT LIGHT
This light’s primary function is to be on as water
contacts the ice thickness probe during the freeze
cycle, and remain on throughout the entire harvest
cycle. The light will flicker as water splashes on the
probes.
ADJUSTING
SCREW
The light’s secondary function is to continuously
flash when the ice machine is shut off on a safety
limit, and to indicate which safety limit shut off the
ice machine.
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.
1/8” (3.2MM)
ICE
THICKNESS
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.
Ice Thickness Check
SV1208
Make sure the ice thickness probe wire and the
bracket do not restrict movement of the probe.
20
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Electrical System
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 ICE/OFF/CLEAN switch to OFF and back to
ICE. Wait until the water starts to flow over the evaporator.
Step 2 Clip the jumper wire leads to the ice thickness probe and any cabinet ground.
ICE THICKNESS PROBE
CLEAN LIGHT
WATER LEVEL LIGHT
GROUND
BIN SWITCH LIGHT
HARVEST/SAFETY LIMIT LIGHT
EVAPORATOR
1C
JUMPER WIRE
SV1588A
SV1592G
Step 2
Step 2 Jumper wire connected from probe to ground
Monitoring of Harvest Light
The ha rvest light c omes on, a nd 6-10 sec onds la ter,
ic e ma c hine c yc les from freeze to ha rvest.
The ha rvest light c omes on but the ic e ma c hine
sta ys in the freeze sequenc e.
Correction
The ic e thic kness c ontrol c irc uitry is func tioning
properly. Do not c ha nge a ny pa rts.
The ic e thic kness c ontrol c irc uitry is func tioning
properly. The ic e ma c hine is in a six-minute freeze
time loc k-in. Verify step 1 of this proc edure wa s
followed c orrec tly.
The ha rvest light does not c ome on.
Proc eed to Step 3, below.
Step 3 Disconnect the ice thickness probe from the control board at terminal 1C. Clip the jumper wire leads
to terminal 1C on the control board and any cabinet ground. Monitor the harvest light.
GROUND
CLEAN LIGHT
ICE THICKNESS PROBE
WATER LEVEL LIGHT
JUMPER WIRE
BIN SWITCH LIGHT
HARVEST/SAFETY LIMIT LIGHT
EVAPORATOR
1C
SV1588G
SV1591G
Step 3
Step 3 Jumper wire connected from control board terminal 1C to ground
Monitoring of Harvest Light
The ha rvest light c omes on, a nd 6-10 sec onds la ter,
ic e ma c hine c yc les from freeze to ha rvest.
The ha rvest light c omes on but the ic e ma c hine
sta ys in the freeze sequenc e.
Correction
The ic e thic kness probe is c a using the ma lfunc tion.
The c ontrol c irc uitry is func tioning properly. The ic e
ma c hine is in a six-minute freeze time loc k-in (verify
step 1 of this proc edure wa s followed c orrec tly).
The c ontrol boa rd is c a using the ma lfunc tion.
The ha rvest light does not c ome on.
21
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Electrical System
Ice Machine Cycles Into Harvest Before Water Contact With The Ice Thickness Probe
Step 1 Disconnect the ice thickness probe from the control board at terminal 1C.
Step 2 Bypass the freeze time lock-in feature by moving the ICE/OFF/CLEAN switch to OFF and back to
ICE. Wait until the water starts to flow over the evaporator, then monitor the harvest light.
CLEAN LIGHT
ICE THICKNESS PROBE
WATER LEVEL LIGHT
BIN SWITCH LIGHT
HARVEST/SAFETY LIMIT LIGHT
EVAPORATOR
1C
SV1591G
SV1588G
Step 2
Step 2 Disconnect probe from control board terminal 1C
Monitoring of Harvest Light
The ha rvest light sta ys off a nd the ic e ma c hine
rema ins in the freeze sequenc e.
Correction
The ic e thic kness probe is c a using the ma lfunc tion.
Verify tha t the Ic e Thic kness probe is a djusted
c orrec tly.
The ha rvest light c omes on, a nd 6-10 sec onds la ter,
the ic e ma c hine c yc les from freeze to ha rvest.
The c ontrol boa rd is c a using the ma lfunc tion.
22
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Electrical System
Water Level Control Circuitry
WATER LEVEL PROBE LIGHT
FREEZE CYCLE CIRCUITRY
The water level probe circuit can be monitored by
watching the water level light. The water level
light is on when water contacts the probe, and off
when no water is in contact with the probe. The
water level light functions any time power is
applied to the ice machine, regardless of toggle
switch position.
Manitowoc’s electronic sensing circuit does not
rely on float switches or timers to maintain
consistent water level control. During the freeze
cycle, the water inlet valve energizes (turns on)
and de-energizes (turns off) in conjunction with
the water level probe located in the water trough.
During the first 45 seconds of the Freeze Cycle:
• The water inlet valve is on when there is no
water in contact with the water level probe.
• The water inlet valve turns off after water
contacts the water level probe for 3 continuous
seconds.
WATER LEVEL
ABOVE HOUSING
WATER
PUMP
WATER LEVEL
PROBE
• The water inlet valve will cycle on and off as
many times as needed to fill the water trough.
After 45 seconds into the Freeze Cycle:
The water inlet valve will cycle on, and then off
one more time to refill the water trough. The water
inlet valve is now off for the duration of the freeze
sequence.
WATER PUMP
IMPELLER HOUSING
PUMP
OUTLET
HARVEST CYCLE CIRCUITRY
The water level probe does not control the water
inlet valve during the harvest cycle. During the
harvest cycle water purge, the water inlet valve
energizes (turns on) and de-energizes (turns off)
strictly by time. The harvest water purge
110°
SV1616
Freeze Cycle Water Level Setting
During the freeze cycle, the water level probe is
set to maintain the proper water level above the
water pump housing. The water level is not
adjustable. If the water level is incorrect, check
the water level probe for damage (probe bent,
etc.). Repair or replace the probe as necessary.
adjustment dial may be set at 15, 30 or 45 seconds.
CONTROL BOARD
HARVEST WATER PURGE
45
ADJUSTMENT
30
15
WATER INLET VALVE SAFETY SHUT-OFF
In the event of a water level probe failure, this
feature limits the water inlet valve to a six-minute
on time. Regardless of the water level probe input,
the control board automatically shuts off the water
inlet valve if it remains on for 6 continuous
minutes. This is important to remember when
performing diagnostic procedures on the water
level control circuitry.
SV1617
NOTE: The water purge must be at the factory
setting of 45 seconds for the water inlet valve to
energize during the last 15 seconds of the Water
Purge. If set at 15 or 30 seconds the water inlet
valve will not energize during the harvest water
purge.
23
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Electrical System
DIAGNOSING FREEZE CYCLE POTABLE WATER LEVEL CONTROL CIRCUITRY
Problem: Water Trough Overfilling During The Freeze Cycle
Step 1 Start a new freeze sequence by moving the ICE/OFF/CLEAN toggle switch to OFF, then back to
ICE.
Important
This restart must be done prior to performing diagnostic procedures. This assures the ice machine is not in
a freeze cycle water inlet valve safety shut-off mode. You must complete the entire diagnostic procedure
with-in 6 minutes of starting.
Step 2 Wait until the freeze cycle starts (approximately 45 seconds, the freeze cycle starts when the
compressor energizes) then connect a jumper from the water level probe to any cabinet ground.
Important
For the test to work properly you must wait until the freeze cycle starts, prior to connecting the jumper
wire. If you restart the test you must disconnect the jumper wire, restart the ice machine, (step 1) and then
reinstall the jumper wire after the compressor starts.
CLEAN LIGHT
YELLOW
GREEN
GREEN
WATER LEVEL LIGHT
BIN SWITCH LIGHT
RED
HARVEST/SAFETY LIMIT LIGHT
1C
1F
1G
JUMPER
GROUND
SV1621G
SV1588
Step 2
Step 2 Jumper wire connected from probe to ground
Is water flowing
into the water
trough?
The Water Inlet
The Water Level
Valve Solenoid
Light is:
Cause
Coil is:
This is norma l opera tion.
Do not c ha nge a ny pa rts.
The wa ter inlet va lve is
c a using the problem.
Proc eed to step 3.
no
on
De-Energized
yes
yes
on
off
De-Energized
Energized
Continued on next page…
24
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Electrical System
Problem: Water Trough Overfilling During The Freeze Cycle (continued)
Step 3 Allow ice machine to run. Disconnect the water level probe from control board terminal 1F, and
connect a jumper wire from terminal 1F to any cabinet ground.
Remember if you are past 6 minutes from starting, the ice machine will go into a freeze cycle water inlet
valve safety shut-off mode, and you will be unable to complete this test. If past 6 minutes you must restart
this test by disconnecting the jumper wire, restarting the ice machine, (step 1) and then reinstalling the
jumper wire to terminal 1F, after the compressor starts.
YELLOW
GREEN
GREEN
CLEAN LIGHT
WATER LEVEL LIGHT
BIN SWITCH LIGHT
RED
HARVEST/SAFETY LIMIT LIGHT
JUMPER
1C
1F
1G
GROUND
SV1588
Step 3
Step 3 Jumper wire connected from control board terminal 1F to ground
Is water flowing
into the water
trough?
The Water Inlet
Valve Solenoid
Coil is:
The Water Level
Cause
Light is:
The wa ter level probe is c a using the problem.
C lea n or repla c e the wa ter level probe.
The c ontrol boa rd is c a using the problem.
The wa ter fill va lve is c a using the problem.
no
on
De-Energized
yes
yes
off
on
Energized
De-Energized
25
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Electrical System
Problem: Water Will Not Run Into The Sump Trough During The Freeze Cycle
Step 1 Verify water is supplied to the ice machine, and then start a new freeze sequence by moving the
ICE/OFF/CLEAN toggle switch to OFF then back to ICE.
Important
This restart must be done prior to performing diagnostic procedures. This assures the ice machine is not in
a freeze cycle water inlet valve safety shut-off mode. You must complete the entire diagnostic procedure
with-in 6 minutes of starting.
Step 2 Wait until the freeze cycle starts (approximately 45 seconds, the freeze cycle starts when the
compressor energizes), and then refer to chart.
Step 2
Step 2 Checking for normal operation
Is water flowing
into the water
trough?
The Water Inlet
Valve Solenoid
Coil is:
The Water Level
Light is:
Cause
yes
off
Energized
Energized
Or
This is Norma l Opera tion don’t c ha nge a ny pa rts
Proc eed to step 3
no
on or off
De-Energized
Step 3 Leave the ice machine run, then disconnect the water level probe from control board terminal 1F.
Important
For the test to work properly you must wait until the freeze cycle starts, prior to disconnecting the water
level probe. If you restart the test you must reconnect the water level probe, restart the ice machine, (step
1) and then disconnect the water level probe after the compressor starts.
CLEAN LIGHT
YELLOW
GREEN
DISCONNECT
WATER LEVEL
PROBE FROM
TERMINAL 1F
WATER LEVEL LIGHT
BIN SWITCH LIGHT
GREEN
RED
HARVEST/SAFETY
LIMIT LIGHT
1C
1F
SV1621G
SV1588
Step 3
Step 3 Disconnect water level probe from control board terminal 1F
Is water flowing
into the water
trough?
The Water Inlet
Valve Solenoid
Coil is:
The Water Level
Cause
Light is:
The wa ter level probe is c a using the problem.
C lea n or repla c e the wa ter level probe.
The wa ter inlet va lve is c a using the problem.
The c ontrol boa rd is c a using the problem.
yes
off
Energized
no
no
off
on or off
Energized
De-Energized
26
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Electrical System
Diagnosing Ice Machine That Will Not Run
WARNING
High (line) voltage is applied to the control board
(terminals #55 and #56) at all times. Removing
control board fuse or moving the toggle switch to
OFF will not remove the power supplied to the
control board.
Step
1
Check
Verify prima ry volta ge supply to ic e
ma c hine.
Notes
Verify tha t the fuse or c irc uit brea ker is c losed.
2
Verify the high-pressure c utout is
The H.P.C .O. is c losed if prima ry power volta ge is present
a t termina ls #55 a nd #56 on the c ontrol boa rd.
If the bin switc h light func tions, the fuse is OK.
c losed.
3
4
5
Verify c ontrol boa rd fuse is OK.
Verify the bin switc h func tions properly. A defec tive bin switc h c a n fa lsely indic a te a full bin of ic e.
Verify IC E/OFF/C LEAN toggle switc h
func tions properly.
A defec tive toggle switc h ma y keep the ic e ma c hine in
the OFF mode.
6
7
Verify low DC volta ge is properly
grounded.
Repla c e the c ontrol boa rd.
Loose DC wire c onnec tions ma y intermittently stop the ic e
ma c hine.
Be sure Steps 1-6 were followed thoroughly. Intermittent
problems a re not usua lly rela ted to the c ontrol boa rd.
27
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Refrigeration System
Refrigeration System
Sequence of Operation
Q1800 REFRIGERATION TUBING SCHEMATICS
EVAPORATOR
HEAT
EXCHANGE
EXPANSION
VALVE
EXPANSION
VALVE
HOT GAS
SOLENOID VALVES
STRAINER
COMPRESSOR
WATER COOLED
CONDENSER
DRIER
SV1512
RECEIVER
Q1800 Self-Contained Water-Cooled Models
28
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Refrigeration System
Operational Analysis (Diagnostics)
3. An ice machine that is low on charge may cause
a good expansion valve to starve. If a service
technician fails to verify the system charge, he
may replace the expansion valve in error.
GENERAL
When analyzing the refrigeration system, it is
important to understand that different refrigeration
component malfunctions may cause very similar
symptoms.
During the replacement procedure, recovery,
evacuation and recharging are performed
correctly. The ice machine now functions
normally. The technician erroneously thinks that
the problem was properly diagnosed and
corrected by replacing the expansion valve.
Also, many external factors can make good
refrigeration components appear bad. These factors
can include improper installation, or water system
malfunctions such as hot incoming water supply or
water loss.
The following two examples illustrate how similar
symptoms can result in a misdiagnosis.
The service technician’s failure to check the ice
machine for a low charge condition resulted in a
misdiagnosis and the needless replacement of a
good expansion valve.
1. An expansion valve bulb that is not securely
fastened to the suction line and/or not insulated
will cause a good expansion valve to flood. If a
service technician fails to check for proper
expansion valve bulb mounting, he may replace
the expansion valve in error.
When analyzing the refrigeration system, use the
Refrigeration System Operational Analysis Table.
This table, along with detailed checklists and
references, will help prevent replacing good
refrigeration components due to external problems.
The ice machine now functions normally. The
technician erroneously thinks that the problem
was properly diagnosed and corrected by
replacing the expansion valve. Actually, the
problem (loose bulb) was corrected when the
technician properly mounted the bulb of the
replacement expansion valve.
The service technician’s failure to check the
expansion valve bulb for proper mounting (an
external check) resulted in a misdiagnosis and
the needless replacement of a good expansion
valve.
29
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Refrigeration System
BEFORE BEGINNING SERVICE
Ice machines may experience operational problems
only during certain times of the day or night. A
machine may function properly while it is being
serviced, but malfunctions later. Information
provided by the user can help the technician start in
the right direction, and may be a determining factor
in the final diagnosis.
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: ______
3. Perform an actual ice production check. Use the
formula below.
1. __________ + __________ =
__________
Ask these questions before beginning service:
Freeze Time
Harvest Time
Total Cycle Time
2.
1440
÷ __________ =
__________
• When does the ice machine malfunction? (night,
day, all the time, only during the freeze cycle,
etc.)
Minutes in 24 Hours
Total Cycle Time
Cycles Per Day
3. __________ x __________ =
__________
Weight of One Harvest
Cycles Per Day
Actual 24 Hour Ice Production
• When do you notice low ice production? (one
day a week, every day, on weekends, etc.)
• Can you describe exactly what the ice machine
seems to be doing?
• Has anyone been working on the ice machine?
• Is anything (such as boxes) usually stored near
or on the ice machine which could obstruct
airflow around the machine?
Important
• 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.)
• Weighing the ice is the only 100% accurate
check. However, if the ice pattern is normal
and the 1/8” thickness is maintained, the ice
slab weights listed with the 24 Hour Ice
Production Charts may be used.
• During “store shutdown,” is the circuit breaker,
water supply or air temperature altered?
• Is there any reason why incoming water
pressure might rise or drop substantially?
ICE PRODUCTION 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 ice machine is required.
The amount of ice a machine produces directly
relates to the operating water and air temperatures.
This means an ice machine in a 70°F (21.2°C) room
with 50°F (10.0°C) water produces more ice than
the same model ice machine in a 90°F (32.2°C)
room with 70°F (21.2°C) water.
• More storage capacity is required.
• Relocating the existing equipment to lower
the load conditions is required.
1. Determine the ice machine operating conditions:
Contact the local Manitowoc distributor for
information on available options and
accessories.
Air Temp. Entering Condenser:
Air Temp. Around Ice Machine:
____°
____°
Water Temp. Entering Sump Trough: ____°
30
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Refrigeration System
INSTALLATION/VISUAL INSPECTION
CHECKLIST
WATER SYSTEM CHECKLIST
A water-related problem often causes the same
symptoms as a refrigeration system component
malfunction.
Possible Problem
Ic e ma c hine is not level
Improper c lea ra nc e
Corrective Action
Level the ic e ma c hine
Reinsta ll a c c ording to
Example: A water dump valve leaking during the
freeze cycle, a system low on charge, and a starving
TXV have similar symptoms.
a round top, sides a nd/or the Insta lla tion Ma nua l
ba c k of ic e ma c hine
Ic e ma c hine is not on a n Reinsta ll a c c ording to
independent elec tric a l
c irc uit
Wa ter filtra tion is
plugged (if used)
the Insta lla tion Ma nua l
Water system problems must be identified and
eliminated prior to replacing refrigeration
components.
Insta ll a new wa ter filter
Possible Problem
Wa ter a rea (eva pora tor)
is dirty
Wa ter inlet pressure not
between 20 a nd 80 psi
Corrective Action
C lea n a s needed
Wa ter dra ins a re not run Run a nd vent dra ins
sepa ra tely a nd/or a re
not vented
a c c ording to the
Insta lla tion Ma nua l
Insta ll a wa ter
regula tor va lve or
inc rea se the wa ter
pressure
Inc oming wa ter
If too hot, c hec k the
tempera ture is not
hot wa ter line c hec k
between 35°F (1.7°C ) a nd va lves in other store
90°F (32.2°C ).
equipment
Wa ter filtra tion is plugged Insta ll a new wa ter
(if used)
filter
Wa ter dump va lve
lea king during the freeze
c yc le
C lea n/repla c e dump
va lve a s needed
Vent tube is not insta lled
on wa ter outlet dra in
Hoses, fittings, etc ., a re
lea king wa ter
Wa ter fill va lve is stuc k
open
See Insta lla tion
Instruc tions
Repa ir/repla c e a s
needed
C lea n/repla c e a s
needed
Wa ter is spra ying out of
the sump trough a rea
Stop the wa ter spra y
Uneven wa ter flow a c ross C lea n the ic e
the eva pora tor
Wa ter is freezing behind
the eva pora tor
ma c hine
C orrec t the wa ter
flow
Pla stic extrusions a nd
ga skets a re not sec ured
to the eva pora tor
Remount/repla c e a s
needed
Wa ter does not flow over C lea n/repla c e wa ter
the eva pora tor (not level probe a s
tric kle) immedia tely a fter needed
the prec hill
31
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Refrigeration System
ICE FORMATION PATTERN
Evaporator ice formation pattern analysis is helpful
in ice machine diagnostics.
2. Extremely Thin at Evaporator Outlet
There is no ice, or a considerable lack of ice
formation on the top of the evaporator (tubing
outlet).
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: No ice at all on the top of the evaporator,
but ice forms on the bottom half of the evaporator.
Or, the ice at the top of the evaporator reaches 1/8”
to initiate a harvest, but the bottom of the
evaporator already has 1/2” to 1” of ice formation.
Improper ice formation can be caused by any
number of problems.
ICE
Example: An ice formation that is “extremely thin
on top” could be caused by a hot water supply, a
dump valve leaking water, a faulty water fill valve,
a low refrigerant charge, etc.
OUTLET
Important
Keep the water curtain in place while checking
the ice formation pattern to ensure no water is
lost.
ICE
1. Normal Ice Formation
Ice forms across the entire evaporator surface.
INLET
At the beginning of the freeze cycle, it may appear
that more ice is forming on the bottom of the
evaporator than on the top. At the end of the freeze
cycle, ice formation on the top will be close to, or
just a bit thinner than, ice formation on the bottom.
The dimples in the cubes at the top of the
SV1576
Extremely Thin Ice Formation
At Evaporator Outlet
evaporator may be more pronounced than those on
the bottom. This is normal.
The ice thickness probe must be set to maintain the
ice bridge thickness at approximately 1/8”. If ice
forms uniformly across the evaporator surface, but
does not reach 1/8” in the proper amount of time,
this is still considered normal.
32
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Refrigeration System
3. Extremely Thin at Evaporator Inlet
There is no ice, or a considerable lack of ice
formation on the bottom of the evaporator (tubing
inlet). Examples: The ice at the top of the
evaporator reaches 1/8” to initiate a harvest, but
there is no ice formation at all on the bottom of the
evaporator.
5. No Ice Formation
The ice machine operates for an extended period,
but there is no ice formation at all on the
evaporator.
Important
The Q1800 model machines have left and right
expansion valves and separate evaporator circuits.
These circuits operate independently from each
other. Therefore, one may operate properly while
the other is malfunctioning.
OUTLET
Example: If the left expansion valve is starving, it
may not affect the ice formation pattern on the
entire right side of the evaporator.
ICE
OUTLET
OUTLET
INLET
SV1575
Extremely Thin Ice Formation at Evaporator
INLET
INLET
Inlet
SV1571
4. Spotty Ice Formation
Q1800 Evaporator Tubing
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.
OUTLET
ICE
INLET
Spotty Ice Formation
SV1577
33
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Refrigeration System
SAFETY LIMITS
Analyzing Why Safety Limits
General
May Stop the Ice Machine
In addition to standard safety controls, such as high
pressure cut-out, the control board has two built in
safety limit controls which protect the ice machine
from major component failures.
According to the refrigeration industry, a high
percentage of compressors fail as 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.
Safety Limit #1: If the freeze time reaches 60
minutes, the control board automatically initiates a
harvest cycle. If three consecutive 60-minute freeze
cycles occur, the ice machine stops.
The safety limit system is similar to a high pressure
cut-out 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 cut-out, or a particular safety limit, to
stop the ice machine.
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 ice machine
stops.
Determining Which Safety Limit
Stopped 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.
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.
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.
1. Move the toggle switch to OFF.
2. Move the toggle switch back to ICE.
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.
When a high pressure cut-out 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.
After safety limit indication, the ice machine will
restart and run until a safety limit is exceeded again.
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 Manitowoc’s Refrigeration System Operational
Analysis Table, along with detailed charts,
checklists, and other references to determine the
cause.
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.
34
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Refrigeration System
Safety Limit #1
Freeze time exceeds 60 minutes for 3 consecutive freeze cycles.
Possible Cause
Improper insta lla tion
Wa ter system
Check/Correct
See “Insta lla tion/Visua l Inspec tion C hec klist” on pa ge 7-10
Low wa ter pressure (20 psi min.)
High wa ter pressure (80 psi ma x.)
High wa ter tempera ture (90°F/32.2°C ma x.)
C logged wa ter distribution tube
Dirty/defec tive wa ter fill va lve
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Dirty/defec tive wa ter dump va lve
Defec tive wa ter pump
Elec tric a l system
Ic e thic kness probe out of a djustment
Ha rvest c yc le not initia ted elec tric a lly
C onta c tor not energizing
C ompressor elec tric a lly non-opera tiona l
Low wa ter pressure (20 psi min.)
High wa ter tempera ture (90°F/32.2°C ma x.)
Dirty c ondenser
Restric ted c ondenser wa ter
flow (wa ter-c ooled models)
Dirty/defec tive wa ter regula ting va lve
Wa ter regula ting va lve out of a djustment
Non-Ma nitowoc c omponents
Refrigera tion system
Improper refrigera nt c ha rge
Defec tive hot ga s va lve
Defec tive c ompressor
TXV sta rving or flooding (c hec k bulb mounting)
Non-c ondensa bles in refrigera tion system
Plugged or restric ted high side refrigera nt lines or c omponent
SAFETY LIMIT NOTES
• Because there are many possible external problems, do not limit your diagnosis to only the items listed in
this chart.
• 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 ICE 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.
35
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Refrigeration System
Safety Limit #2
Harvest time exceeds 3.5 minutes for 3 consecutive harvest cycles.
Possible Cause
Improper insta lla tion
Wa ter system
Check/Correct
See “Insta lla tion/Visua l Inspec tion C hec klist” on pa ge 7-10
Wa ter a rea (eva pora tor) dirty
Dirty/defec tive wa ter dump va lve
Vent tube not insta lled on wa ter outlet dra in
Wa ter freezing behind eva pora tor
Pla stic extrusions a nd ga skets not sec urely mounted to the eva pora tor
Low wa ter pressure (20 psi min.)
Loss of wa ter from sump a rea
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
C logged wa ter distribution tube
Dirty/defec tive wa ter fill va lve
Defec tive wa ter pump
Elec tric a l system
Ic e thic kness probe out of a djustment
Ic e thic kness probe dirty
Bin switc h defec tive
Prema ture ha rvest
Refrigera tion system
Non-Ma nitowoc c omponents
Wa ter regula ting va lve dirty/defec tive
Improper refrigera nt c ha rge
Defec tive hot ga s va lve
TXV flooding (c hec k bulb mounting)
SAFETY LIMIT NOTES
• Because there are many possible external problems, do not limit your diagnosis to only the items listed in
this chart.
• 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 ICE 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.
36
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Refrigeration System
HOT GAS VALVE TEMPERATURE CHECK
3. Feel the compressor discharge line.
General
A hot gas valve requires a critical orifice size. This
meters the amount of hot gas flowing into the
evaporator during the harvest cycle. If the orifice is
even slightly too large or too small, long harvest
cycles will result.
WARNING
The inlet of the hot gas 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 hot
gas valves to the temperature of the compressor
discharge line.
A too-large orifice causes refrigerant to condense to
liquid in the evaporator during the harvest cycle.
This liquid will cause compressor damage. A too-
small orifice does not allow enough hot gas into the
evaporator. This causes low suction pressure, and
insufficient heat for a harvest cycle.
Findings
Comments
The inlet of the
hot ga s va lve is
c ool enough to
touc h a nd the
c ompressor
This is norma l a s the disc ha rge
line should a lwa ys be too hot to
touc h a nd the hot ga s va lve
inlet, a lthough too hot to touc h
during ha rvest, should be c ool
Normally, a defective hot gas valve can be rebuilt.
Refer to the Parts Manual for proper valve
application and rebuild kits. If replacement is
necessary, Use only “original” Manitowoc
replacement parts.
disc ha rge line is enough to touc h a fter 5
hot.
minutes into the freeze c yc le.
This is a n indic a tion something is
wrong, a s the hot ga s va lve
inlet did not c ool down during
The inlet of the
hot ga s va lve is
hot a nd
a pproa c hes the the freeze c yc le. If the
tempera ture of
a hot
Hot Gas Valve Analysis
Symptoms of a hot gas valve remaining partially
open during the freeze cycle can be similar to
symptoms of either an expansion valve or
compressor problem. The best way to diagnose a
hot gas valve is by using Manitowoc’s Ice Machine
Refrigeration System Operational Analysis Table.
c ompressor dome is a lso
entirely hot, the problem is not
a hot ga s va lve lea king, but
ra ther something c a using the
c ompressor (a nd the entire ic e
ma c hine) to get hot.
c ompressor
disc ha rge line.
Both the inlet of This is a n indic a tion something is
Use the following procedure and table to help
determine if a hot gas valve is remaining partially
open during the freeze cycle.
the hot ga s
wrong, c a using the c ompressor
disc ha rge line to be c ool to the
touc h. This is not c a used by a
hot ga s va lve lea king.
va lve a nd the
c ompressor
disc ha rge line
a re c ool enough
to touc h.
1. Wait five minutes into the freeze cycle.
2. Feel the inlet of the hot gas valve(s).
Important
Feeling the hot gas valve outlet or across the hot
gas valve itself will not work for this comparison.
The hot gas valve outlet is on the suction side
(cool refrigerant). It may be cool enough to touch
even if the valve is leaking.
37
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Refrigeration System
ANALYZING DISCHARGE PRESSURE DURING FREEZE OR HARVEST CYCLE
1. Determine the ice machine operating conditions:
3. Perform an actual discharge pressure check.
Air temp. entering c ondenser
Air temp. a round ic e ma c hine
Wa ter temp. entering sump trough
______
______
______
Freeze
C yc le PSIG
Ha rvest
C yc le PSIG
__________
__________
__________
Beginning of C yc le __________
Middle of C yc le
End of C yc le
__________
__________
2. Refer to Operating Pressure Chart for ice
machine being checked.
4. Compare the actual discharge pressure (Step 3)
with the published discharge pressure (Step 2).
Use the operating conditions determined in Step
1 to find the published normal discharge
pressures.
The discharge pressure is normal when the
actual pressure falls within the published
pressure range for the ice machine’s operating
conditions.
Freeze C yc le ______
Ha rvest C yc le ______
Freeze Cycle Discharge Pressure High Checklist
Possible Cause
Improper insta lla tion
Restric ted c ondenser wa ter
flow (wa ter-c ooled models)
Check/Correct
See “Insta lla tion/Visua l Inspec tion C hec klist” on pa ge 7-10
Low wa ter pressure (20 psi min.)
High inlet wa ter tempera ture (90°F/32.2°C ma x.)
Dirty c ondenser
•
•
•
•
•
•
•
•
•
•
•
Dirty/defec tive wa ter regula ting va lve
Wa ter regula ting va lve out of a djustment
Overc ha rged
Improper refrigera nt c ha rge
Other
Non-c ondensibles in system
Wrong type of refrigera nt
Non-Ma nitowoc c omponents in system
High side refrigera nt lines/c omponent restric ted (before mid-
c ondenser)
Freeze Cycle Discharge Pressure Low Checklist
Possible Cause
Improper insta lla tion
Improper refrigera nt c ha rge
Check/Correct
See “Insta lla tion/Visua l Inspec tion C hec klist” on pa ge 7-10
Underc ha rged
•
•
•
•
•
•
Wrong type of refrigera nt
Out of a djustment
Wa ter regula ting va lve
(wa ter-c ooled c ondensers)
Other
Defec tive
Non-Ma nitowoc c omponents in system
NOTE: Do not limit your diagnosis to only the items listed in the checklists.
38
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Refrigeration System
ANALYZING SUCTION PRESSURE DURING FREEZE CYCLE
The suction pressure gradually drops throughout the
freeze cycle. The actual suction pressure (and drop
rate) changes as the air and water temperatures
entering the ice machine change. This affects 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. “Operating Pressure” and “Freeze Cycle
Time” charts can be found later in this section.
NOTE: Analyze discharge pressure before
analyzing suction pressure. High or low discharge
pressure may be causing high or low suction
pressure.
Procedure
Step
1. Determine the ic e ma c hine opera ting
c onditions.
Example Using QR1801WM Model Ice Machine
Air temp. a round ic e ma c hine:
80°F/26.7°C
Wa ter temp. entering wa ter fill va lve:
70°F/21.1°C
2A. Refer to “C yc le Time” a nd “Opera ting
Pressure” c ha rts for ic e ma c hine model
being c hec ked. Using opera ting c onditions
from Step 1, determine published freeze
c yc le time a nd published freeze c yc le
suc tion pressure.
Published freeze c yc le
time:
Published freeze c yc le
suc tion pressure:
9.6-10.6 minutes
40-20 PSIG
Published Freeze C yc le Time (minutes)
1
3
5
7
10
2B. C ompa re the published freeze c yc le time
a nd published freeze c yc le suc tion
pressure. Develop a c ha rt.
40 35
30
25
20
Published Freeze C yc le Suc tion Pressure (psig)
3. Perform a n a c tua l suc tion pressure c hec k
Beginning of freeze c yc le:
59 PSIG a t 1 minute
a t the beginning, middle a nd end of the
freeze c yc le. Note the times a t whic h the
rea dings a re ta ken.
Middle of freeze c yc le:
48 PSIG a t 5 minutes
40 PSIG a t 10 minutes
End of freeze c yc le:
4. C ompa re the a c tua l freeze c yc le suc tion
pressure (Step 3) to the published freeze
c yc le time a nd pressure c ompa rison (Step
2B). Determine if the suc tion pressure is
high, low or a c c epta ble.
Time Into
Freeze C yc le
Published
Pressure
Ac tua l
Pressure
Result
1 minutes
5 minutes
10 minutes
40 PSIG
30 PSIG
20 PSIG
59 PSIG
48 PSIG
40 PSIG
High
High
High
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Refrigeration System
Freeze Cycle Suction Pressure High Checklist
Possible Cause
Improper insta lla tion
Disc ha rge pressure
Check/Correct
•
•
See “Insta lla tion/Visua l Inspec tion C hec klist”
Disc ha rge pressure is too high, a nd is a ffec ting low side (See “Freeze
C yc le Disc ha rge Pressure High C hec klist”)
Overc ha rged
Improper refrigera nt c ha rge
Other
•
•
•
•
•
•
Wrong type of refrigera nt
Non-Ma nitowoc c omponents in system
Hot ga s va lve stuc k open
TXV flooding (c hec k bulb mounting)
Defec tive c ompressor
Freeze Cycle Suction Pressure Low Checklist
Possible Cause
Improper insta lla tion
Disc ha rge pressure
Check/Correct
•
•
See “Insta lla tion/Visua l Inspec tion C hec klist”
Disc ha rge pressure is too low, a nd is a ffec ting low side (See “Freeze
C yc le Disc ha rge Pressure Low C hec klist”)
Underc ha rged
Improper refrigera nt c ha rge
Other
•
•
•
•
•
•
•
•
Wrong type of refrigera nt
Non-Ma nitowoc c omponents in system
Improper wa ter supply over eva pora tor (See “Wa ter System C hec klist”)
Loss of hea t tra nsfer from tubing on ba c k side of eva pora tor
Restric ted/plugged liquid line drier
Restric ted/plugged tubing in suc tion side of refrigera tion system
TXV sta rving
NOTE: Do not limit your diagnosis to only the items listed in the checklists.
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Refrigeration System
HOW TO USE THE REFRIGERATION SYSTEM OPERATIONAL ANALYSIS TABLES
General
Final Analysis
These tables must be used with charts, checklists
and other references to eliminate refrigeration
components not listed on the tables and external
items and problems which can cause good
refrigeration components to appear defective.
The column with the highest number of check
marks identifies the refrigeration problem.
COLUMN 1 - HOT GAS VALVE LEAKING
Normally, a leaking hot gas valve can be repaired
with a rebuild kit instead of changing the entire
valve. Rebuild or replace the valve as required.
The tables list five different defects that may affect
the ice machine’s operation.
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.
NOTE: A low-on-charge ice machine and a starving
expansion valve have very similar characteristics
and are listed under the same column.
NOTE: Before starting, see “Before Beginning
Service" for a few questions to ask when talking to
the ice machine owner.
1. Add refrigerant charge in 2 to 4 oz. increments
as a diagnostic procedure to verify a low charge.
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. Then,
evacuate and weigh in the proper charge.
2. If the problem is not corrected by adding
charge, the expansion valve is faulty.
Procedure
Step 1 Complete the “Operation Analysis” column.
Read down the left “Operational Analysis” column.
Perform all procedures and check all information
listed. Each item in this column has supporting
reference material to help analyze each step.
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.
On dual expansion valve ice machines, change
only the TXV that is starving. If both TXV’s are
starving, they are probably good, and are being
affected by some other malfunction, such as low
charge.
Step 2 Enter check marks in the small 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.
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. On dual expansion valve machines, the
service technician should be able to tell which TXV
is flooding by analyzing ice formation patterns.
Change only the flooding expansion valve.
Example: Freeze cycle suction pressure is
determined to be low. Enter a check mark in the
“low” box.
Step 3 Add the check marks listed under each of
the four columns. Note the column number with the
highest total and proceed to “Final Analysis.”
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.
NOTE: If two columns have matching high
numbers, a procedure was not performed properly
and/or supporting material was not analyzed
correctly.
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Refrigeration System
Q Model Dual Expansion Valve
Refrigeration System Operational Analysis Table
This table must be used with charts, checklists and other references to eliminate refrigeration components not listed on the table
and external items and problems which can cause good refrigeration components to appear defective.
Operational Analysis
(listed below)
Ice Production
1
2
3
4
Published 24 hour ic e produc tion
_____________
C a lc ula ted (a c tua l) ic e produc tion _____________
NOTE:
The ic e ma c hine is opera ting properly if the ic e produc tion
a nd ic e forma tion pa ttern is norma l
Safety limits
Refer to "Ana lyzing
Sa fety Limits" to
Stops on sa fety limit:
1
Stops on sa fety limit:
1
Stops on sa fety limit:
1 or 2
Stops on sa fety limit:
1
elimina te problems
a nd/or c omponents not
listed on this ta ble
Ice Formation Pattern
Left side_______________
_______________________
Ic e forma tion is
extremely thin on top
of one side of
eva pora tor
Ic e forma tion is
extremely thin on top
of one or both sides of
eva pora tor
Ic e forma tion norma l
-or-
Ic e forma tion norma l
-or-
No ic e forma tion on
entire eva pora tor
Ic e forma tion is
extremely thin on
bottom of one side of
eva pora tor
-or-
-or-
Right side______________
_______________________
No ic e forma tion on
one side of
No ic e forma tion on
entire eva pora tor
-or-
eva pora tor
No ic e forma tion on
entire eva pora tor
Wa it 5 minutes into the
freeze c yc le.
C ompa re tempera tures
of compressor discharge
line a nd both hot gas
valve inlets.
One hot ga s va lve
inlet is Hot
Both hot ga s va lve
inlets a re c ool enough
to hold ha nd on
-a nd-
the c ompressor
disc ha rge line is Hot.
Both hot ga s va lve
inlets a re c ool enough
to hold ha nd on
-a nd-
Both hot ga s va lve
inlets a re c ool enough
to hold ha nd on
-a nd-
the c ompressor
disc ha rge line is Hot.
-a nd-
a pproa c hes the
tempera ture of a Hot
c ompressor disc ha rge
line.
the c ompressor
disc ha rge line is c ool
enough
C omp. Disc . ______ °F
Left ga s inlet ______ °F
Right ga s inlet ______ °F
to hold ha nd on.
Freeze cycle
DISCHARGE pressure
_______
_______ _______
Middle End
1 minute
If disc ha rge pressure is High or Low refer to a freeze c yc le high or low disc ha rge pressure problem
c hec klist to elimina te problems a nd/or c omponents not listed on this ta ble before proc eeding.
If suc tion pressure is High or Low refer to a freeze c yc le high or low suc tion pressure problem
c hec klist to elimina te problems a nd/or c omponents not listed on this ta ble before proc eeding.
into c yc le
Freeze cycle
SUCTION pressure
________
Beginning
_______ _______
Middle End
Suc tion pressure is
Suc tion pressure is
Suc tion pressure is
Suc tion pressure is
High
Low
High
High
Miscellaneous
Enter items in proper boxes.
Final Analysis
Enter tota l number of
boxes c hec ked in ea c h
c olumn.
Hot gas valve leaking
Low on charge
-or-
TXV Starving
TXV Flooding
Compressor
MANITOWOC ICE, INC.
2110 South 26th Street P.O. Box 1720 Ma nitowoc , WI 54221-1720
Phone: (920) 682-0161
Servic e Fa x: (920) 683-7585
Web Site - www.ma nitowoc ic e.c om
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Refrigeration System
Pressure Control Specifications and Diagnostics
HIGH PRESSURE CUTOUT
(HPCO) CONTROL
Function
Stops the ice machine if subjected to excessive
high-side pressure.
The HPCO control is normally closed, and opens on
a rise in discharge pressure.
Specifications
Cut-out: 450 psig ±10
Cut-in: Manual or automatic reset
(Must be below 300 psig to reset).
Check Procedure
1. Set ICE/OFF/CLEAN switch to OFF, (Manual
reset HPCO reset if tripped).
2. Connect manifold gauges.
3. Hook voltmeter in parallel across the HPCO,
leaving wires attached.
4. On water-cooled models, close the water service
valve to the water condenser inlet. On self-
contained air-cooled and remote models,
disconnect the fan motor.
5. Set ICE/OFF/CLEAN switch to ICE.
6. No water or air flowing through the condenser
will cause the HPCO control to open because of
excessive pressure. Watch the pressure gauge
and record the cut-out pressure.
WARNING
If discharge pressure exceeds 460 psig and the
HPCO control does not cut out, set
ICE/OFF/CLEAN switch to OFF to stop ice
machine operation.
Replace the HPCO control if it:
• Will not reset (below 300 psig)
• Does not open at the specified cut-out point
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Refrigeration System
Cycle Time/24 Hour Ice Production/Refrigerant Pressure Charts
Q1800 SERIES WATER-COOLED
NOTE: These characteristics may vary depending
on operating conditions.
Cycle Times
Freeze Time + Harvest Time = Cycle Time
Operating Pressures
Air Temp.
Around Ice
Machine
°F/°C
Freeze Cycle
Harvest Cycle
Air Temp.
Around Ice
Machine
°F/°C
70/21.1
80/26.7
90/32.2
100/37.8
1Times in minutes
Freeze Time
Harvest
Time
Discharge
Pressure
PSIG
Suction
Pressure
PSIG
36-20
38-20
40-20
42-22
44-22
46-22
Discharge
Pressure
PSIG
Suction
Pressure
PSIG
Water Temperature °F/°C
50/10.0
8.7-9.6
9.0-9.9
9.1-10.1
9.2-10.1
70/21.1
9.6-10.5
9.6-10.6
9.7-10.7
9.8-10.7
90/32.2
50/10.0
70/21.1
80/26.7
90/32.2
100/37.8
110/43.3
235-245
235-245
235-245
235-250
235-255
235-260
170-190
170-190
170-190
175-190
175-190
175-190
65-80
65-80
65-80
65-80
65-80
65-80
10.8-11.9
10.8-11.9
10.9-12.0
11.1-12.1
1-2.5
1Suction pressure drops gradually throughout the freeze cycle
24 Hour Ice Production
Air Temp.
Water Temperature °F/°C
Around Ice
Machine
°F/°C
50/10.0
70/21.1
90/32.2
70/21.1
80/26.7
90/32.2
100/37.8
1840
1780
1760
1750
1690
1680
1670
1660
1520
1520
1510
1490
1Based on average ice slab weight of 13.0 – 14.12 lb.
2Regular cube derate is 7%
Condenser
Water
Consumption
90/32.2 Air Temperature Around Ice Machine
Water Temperature °F/°C
50/10.0
70/21.1
90/32.2
Gal/24 hours
2000
2670
7750
1Water regulating valve set to maintain 240 PSIG discharge
pressure
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Refrigeration System
Refrigerant Recovery/Evacuation and Recharging
SELF-CONTAINED RECOVERY/EVACUATION
1. Place the toggle switch in the OFF position.
2. Install manifold gauges, charging cylinder/scale,
NORMAL SELF-CONTAINED MODEL
PROCEDURES
Refrigerant Recovery/Evacuation
and recovery unit or two-stage vacuum pump.
Do not purge refrigerant to the atmosphere. Capture
refrigerant using recovery equipment. Follow the
manufacturer’s recommendations.
MANIFOLD SET
OPEN
OPEN
Important
BACKSEATED
BACKSEATED
LOW SIDE
SERVICE
VALVE
HIGH SIDE
SERVICE
VALVE
Manitowoc Ice, Inc. assumes no responsibility for
the use of contaminated refrigerant. Damage
resulting from the use of contaminated refrigerant
is the sole responsibility of the servicing
company.
Important
Replace the liquid line drier before evacuating
and recharging. Use only a Manitowoc (O.E.M.)
liquid line filter drier to prevent voiding the
warranty.
CHARGING
CYLINDER
VACUUM PUMP/
RECOVERY UNIT
OPEN
CONNECTIONS
1. Suction side of the compressor through the
suction service valve.
CLOSED
SV1404A
Recovery/Evacuation Connections
2. Discharge side of the compressor through the
discharge service valve.
3. Open (backseat) the high and low side ice
machine service valves, and open high and low
side on manifold gauges.
4. Perform recovery or evacuation:
A. Recovery: Operate the recovery unit as
directed by the manufacturer’s instructions.
B. Evacuation prior to recharging: Pull the
system down to 250 microns. Then, allow
the pump to run for an additional half hour.
Turn off the pump and perform a standing
vacuum leak check.
NOTE: Check for leaks using a halide or electronic
leak detector after charging the ice machine.
5. Follow the Charging Procedures on the next
page.
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Refrigeration System
Self-Contained Charging Procedures
2. Close the vacuum pump valve, the low side
service valve, and the low side manifold gauge
valve.
3. Open the high side manifold gauge valve, and
backseat the high side service valve.
4. Open the charging cylinder and add the proper
refrigerant charge (shown on nameplate)
through the discharge service valve.
Important
The charge is critical on all Manitowoc ice
machines. Use a scale or a charging cylinder to
ensure the proper charge is installed.
1. Be sure the toggle switch is in the OFF position.
MANIFOLD SET
5. Let the system “settle” for 2 to 3 minutes.
6. Place the toggle switch in the ICE position.
7. Close the high side on the manifold gauge set.
Add any remaining vapor charge through the
suction service valve (if necessary).
OPEN
CLOSED
FRONTSEATED
BACKSEATED
LOW SIDE
SERVICE
VALVE
HIGH SIDE
SERVICE
VALVE
NOTE: Manifold gauges must be removed properly
to ensure that no refrigerant contamination or loss
occurs.
8. Make sure that all of the vapor in the charging
hoses is drawn into the ice machine before
disconnecting the charging hoses.
A. Run the ice machine in freeze cycle.
B. Close the high side service valve at the ice
machine.
CHARGING
CYLINDER
VACUUM PUMP/
RECOVERY UNIT
CLOSED
OPEN
C. Open the low side service valve at the ice
machine.
D. Open the high and low side valves on the
manifold gauge set. Any refrigerant in the
lines will be pulled into the low side of the
system.
SV1404B
Charging Connections
E. Allow the pressures to equalize while the ice
machine is in the freeze cycle.
F. Close the low side service valve at the ice
machine.
Remove the hoses from the ice machine and install
the caps.
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Refrigeration System
SYSTEM CONTAMINATION CLEANUP
General
This section describes the basic requirements for
restoring contaminated systems to reliable service.
If either condition is found, or if contamination is
suspected, use a Total Test Kit from Totaline or a
similar diagnostic tool. These devices sample
refrigerant, eliminating the need to take an oil
sample. Follow the manufacturer’s directions.
Important
Manitowoc Ice, Inc. assumes no responsibility for
the use of contaminated refrigerant. Damage
resulting from the use of contaminated refrigerant
is the sole responsibility of the servicing
company.
If a refrigerant test kit indicates harmful levels of
contamination, or if a test kit is not available,
inspect the compressor oil.
1. Remove the refrigerant charge from the ice
machine.
2. Remove the compressor from the system.
3. Check the odor and appearance of the oil.
4. Inspect open suction and discharge lines at the
compressor for burnout deposits.
Determining Severity Of Contamination
System contamination is generally caused by either
moisture or residue from compressor burnout
entering the refrigeration system.
Inspection of the refrigerant usually provides the
first indication of system contamination. Obvious
moisture or an acrid odor in the refrigerant indicates
contamination.
5. If no signs of contamination are present,
perform an acid oil test.
Check the chart below to determine the type of
cleanup required.
Contamination/Cleanup Chart
Symptoms/Findings
No symptoms or suspic ion of c onta mina tion
Moisture/Air C onta mina tion symptoms
Required Cleanup Procedure
Norma l eva c ua tion/rec ha rging proc edure
•
Refrigera tion system open to a tmosphere for
longer tha n 15 minutes
•
Refrigera tion test kit a nd/or a c id oil test shows
c onta mina tion
Mild c onta mina tion c lea nup proc edure
•
•
Lea k in wa ter-c ooled c ondenser
No burnout deposits in open c ompressor lines
Mild C ompressor Burnout symptoms
•
•
Oil a ppea rs c lea n but smells a c rid
Refrigera tion test kit or a c id oil test shows ha rmful Mild c onta mina tion c lea nup proc edure
a c id c ontent
•
No burnout deposits in open c ompressor lines
Severe C ompressor Burnout symptoms
•
•
Oil is disc olored, a c idic , a nd smells a c rid
Burnout deposits found in the c ompressor a nd
lines, a nd in other c omponents
Severe c onta mina tion c lea nup proc edure
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Refrigeration System
Mild System Contamination Cleanup
Procedure
Severe System Contamination Cleanup
Procedure
1. Replace any failed components.
2. If the compressor is good, change the oil.
3. Replace the liquid line drier.
1. Remove the refrigerant charge.
2. Remove the compressor.
3. Disassemble the hot gas solenoid valve. If
burnout deposits are found inside the valve,
install a rebuild kit, and replace manifold
strainer, and TXV valves.
4. Wipe away any burnout deposits from suction
and discharge lines at compressor.
5. Sweep through the open system with dry
nitrogen.
NOTE: If the contamination is from moisture, use
heat lamps during evacuation. Position them at the
compressor, condenser and evaporator prior to
evacuation. Do not position heat lamps too close
to plastic components, or they may melt or warp.
Important
Dry nitrogen is recommended for this procedure.
This will prevent CFC release.
Important
Refrigerant sweeps are not recommended, as they
release CFC’s into the atmosphere.
4. Follow the normal evacuation procedure,
except replace the evacuation step with the
following:
7. Install a new compressor and new start
components.
8. Install a suction line filter-drier with acid and
moisture removal capability (P/N 89-3028-3).
Place the filter drier as close to the compressor
as possible.
9. Install an access valve at the inlet of the
suction line drier.
10. Install a new liquid line drier.
A. Pull vacuum to 1000 microns. Break the
vacuum with dry nitrogen and sweep the
system. Pressurize to a minimum of 5 psi.
B. Pull vacuum to 500 microns. Break the
vacuum with dry nitrogen and sweep the
system. Pressurize to a minimum of 5 psi.
C. Change the vacuum pump oil.
D. Pull vacuum to 250 microns. Run the
vacuum pump for 1/2 hour on self-
contained models, 1 hour on remotes.
Continued on next page
NOTE: You may perform a standing vacuum test
to make a preliminary leak check. You should use
an electronic leak detector after system charging
to be sure there is no leak.
5. Charge the system with the proper refrigerant
to the nameplate charge.
6. Operate the ice machine.
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Refrigeration System
11. Follow the normal evacuation procedure, except
replace the evacuation step with the following:
REPLACING PRESSURE CONTROLS
WITHOUT REMOVING REFRIGERANT
CHARGE
This procedure reduces repair time and cost. Use it
when any of the following components require
replacement, and the refrigeration system is
operational and leak-free.
• Water regulating valve (water-cooled only)
• High pressure cut-out control
• High side service valve
Important
Dry nitrogen is recommended for this procedure.
This will prevent CFC release.
A. Pull vacuum to 1000 microns. Break the
vacuum with dry nitrogen and sweep the
system. Pressurize to a minimum of 5 psi.
B. Change the vacuum pump oil.
C. Pull vacuum to 500 microns. Break the
vacuum with dry nitrogen and sweep the
system. Pressurize to a minimum of 5 psi.
D. Change the vacuum pump oil.
• Low side service valve
Important
This is a required in-warranty repair procedure.
E. Pull vacuum to 250 microns. Run the
vacuum pump for 1/2 hour on self-contained
models, 1 hour on remotes.
1. Disconnect power to the ice machine.
2. Follow all manufacturer’s instructions supplied
with the pinch-off tool. Position the pinch-off
tool around the tubing as far from the pressure
control as feasible. (See the figure on next
page.) Clamp down on the tubing until the
pinch-off is complete.
NOTE: You may perform a standing vacuum test to
make a preliminary leak check. You should use an
electronic leak detector after system charging to be
sure there is no leak.
12. Charge the system with the proper refrigerant to
the nameplate charge.
13. Operate the ice machine for one hour. Then,
check the pressure drop across the suction line
filter-drier.
WARNING
Do not unsolder a defective component. Cut it out
of the system. Do not remove the pinch-off tool
until the new component is securely in place.
A. If the pressure drop is less than 1 psi, the
filter-drier should be adequate for complete
cleanup.
B. If the pressure drop exceeds 1 psi, change
the suction line filter-drier and the liquid
line drier. Repeat until the pressure drop is
acceptable.
3. Cut the tubing of the defective component with
a small tubing cutter.
4. Solder the replacement component in place.
Allow the solder joint to cool.
5. Remove the pinch-off tool.
6. Re-round the tubing. Position the flattened
tubing in the proper hole in the pinch off tool.
Tighten the wingnuts until the block is tight and
the tubing is rounded. (See the drawing on next
page.)
14. Operate the ice machine for 48-72 hours. Then,
remove the suction line drier and change the
liquid line drier.
15. Follow normal evacuation procedures.
NOTE: The pressure controls will operate normally
once the tubing is re-rounded. Tubing may not re-
round 100%..
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Refrigeration System
FIG. A - “PINCHING OFF” TUBING
TYPICAL PRESSURE
CONTROL SHOWN
“PINCH-OFF” TOOL USED HERE
SEE FIG. A AND FIG. B
FIG. B - RE-ROUNDING TUBING
SV1406
Using Pinch-Off Tool
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Refrigeration System
FILTER-DRIERS
TOTAL SYSTEM REFRIGERANT CHARGES
The filter-driers used on Manitowoc ice machines
are manufactured to Manitowoc specifications.
Important
Refer to the ice machine serial number tag to
verify the system charge.
The difference between Manitowoc driers and off-
the-shelf driers is in filtration. Manitowoc driers
have dirt-retaining filtration, with fiberglass filters
on both the inlet and outlet ends. This is very
important because ice machines have a back-
flushing action which takes place during every
harvest cycle.
Series
Version
Wa ter-C ooled
Charge
46 oz.
Q1800
NOTE: Charged using R-404A refrigerant.
These filter-driers have a very high moisture
removal capability and a good acid removal
capacity.
The size of the filter-drier is important. The
refrigerant charge is critical. Using an improperly
sized filter-drier will cause the ice machine to be
improperly charged with refrigerant.
Important
Driers are covered as a warranty part. The drier
must be replaced any time the system is opened
for repairs.
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Refrigeration System
REFRIGERANT DEFINITIONS
Recover
To remove refrigerant, in any condition, from a
system and store it in an external container, without
necessarily testing or processing it in any way.
Reclaim
To reprocess refrigerant to new product
specifications (see below) by means which may
include distillation. A chemical analysis of the
refrigerant is required after processing to be sure
that product specifications are met. This term
usually implies the use of processes and procedures
available only at a reprocessing or manufacturing
facility.
Recycle
To clean refrigerant for re-use by oil separation and
single or multiple passes through devices, such as
replaceable core filter-driers, which reduce
moisture, acidity and particulate matter. This term
usually applies to procedures implemented at the
field job site or at a local service shop.
Chemical analysis is the key requirement in this
definition. Regardless of the purity levels reached
by a reprocessing method, refrigerant is not
considered “reclaimed” unless it has been
chemically analyzed and meets ARI Standard 700
(latest edition).
New Product Specifications
This means ARI Standard 700 (latest edition).
Chemical analysis is required to assure that this
standard is met.
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Section 7
Refrigeration System
REFRIGERANT RE-USE POLICY
Manitowoc recognizes and supports the need for
proper handling, re-use, and disposal of, CFC and
HCFC refrigerants. Manitowoc service procedures
require recapturing refrigerants, not venting them to
the atmosphere.
3. Recovered or Recycled Refrigerant
• Must be recovered or recycled in accordance
with current local, state and federal laws.
• Must be recovered from and re-used in the
same Manitowoc product. Re-use of
recovered or recycled refrigerant from other
products is not approved.
• Recycling equipment must be certified to
ARI Standard 740 (latest edition) and be
maintained to consistently meet this
standard.
It is not necessary, in or out of warranty, to reduce
or compromise the quality and reliability of your
customers’ products to achieve this.
Important
Manitowoc Ice, Inc. assumes no responsibility for
use of contaminated refrigerant. Damage
resulting from the use of contaminated,
recovered, or recycled refrigerant is the sole
responsibility of the servicing company.
• Recovered refrigerant must come from a
“contaminant-free” system. To decide
whether the system is contaminant free,
consider:
• Type(s) of previous failure(s)
• Whether the system was cleaned,
evacuated and recharged properly
following failure(s)
Manitowoc approves the use of:
1. New Refrigerant
• Must be of original nameplate type.
• Whether the system has been
contaminated by this failure
• Compressor motor burnouts and
improper past service prevent refrigerant
re-use.
2. Reclaimed Refrigerant
• Must be of original nameplate type.
• Must meet ARI Standard 700 (latest edition)
specifications.
• Refer to “System Contamination
Cleanup” to test for contamination.
4. “Substitute” or “Alternative” Refrigerant
• Must use only Manitowoc-approved
alternative refrigerants.
• Must follow Manitowoc-published
conversion procedures.
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Refrigeration System
Section 7
HFC REFRIGERANT QUESTIONS AND ANSWERS
Manitowoc uses R-404A and R-134A HFC
refrigerants with ozone depletion potential (ODP)
factors of zero (0.0). R-404A is used in ice
machines and reach-in freezers and R-134A is
used in reach-in refrigerators.
4. Are there any special procedures required if a
POE system is diagnosed with a refrigerant
leak?
For systems found with positive refrigerant
system pressure, no special procedures are
required.
1. What compressor oil does Manitowoc require
for use with HFC refrigerants?
For systems found without any positive
refrigerant pressure, assume that moisture has
entered the POE oil. After the leak is found
and repaired, the compressor oil must be
changed. The compressor must be removed
and at least 95% of the oil drained from the
suction port of the compressor. Use a
“measuring cup” to replace the old oil with
exactly the same amount of new POE oil, such
as Mobil EAL22A.
Manitowoc products use Polyol Ester (POE)
type compressor oil. It is the lubricant of
choice among compressor manufacturers.
2. What are some of the characteristics of POE
oils?
They are hygroscopic, which means they have
the ability to absorb moisture. POE oils are
100 times more hygroscopic than mineral oils.
Once moisture is absorbed into the oil, it is
difficult to remove, even with heat and
vacuum. POE oils are also excellent solvents,
and tend to “solvent clean” everything inside
the system, depositing material where it is not
wanted.
Remember, care must be taken to prevent
moisture from getting into the refrigeration
system during refrigeration repairs.
5. How do I leak-check a system containing HFC
refrigerant?
Use equipment designed for HFC detection.
Do not use equipment designed for CFC
detection. Consult leak detection equipment
manufacturers for their recommendations.
Also, standard soap bubbles will work with
HFC refrigerants.
3. What do these POE oil characteristics mean to
me?
You must be more exacting in your
procedures. Take utmost care to prevent
moisture from entering the refrigeration
system. Refrigeration systems and
compressors should not be left open to the
atmosphere for more than 15 minutes. Keep oil
containers and compressors capped at all times
to minimize moisture entry. Before removing
the system charge to replace a faulty
component, be sure you have all of the needed
components at the site. Remove new system
component plugs and caps just prior to
brazing. Be prepared to connect a vacuum
pump immediately after brazing.
6. Does Manitowoc use a special liquid line
filter-drier with HFC refrigerants?
Yes. Manitowoc uses an ALCO “UK” series
filter-drier for increased filtration and moisture
removal. During a repair, Manitowoc
recommends installing the drier just before
hooking up a vacuum pump.
Continued on next page...
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Section 7
Refrigeration System
7. Is other special equipment required to service
HFC refrigerants?
8. Do I have to recover HFC refrigerants?
Yes. Like other refrigerants, government
No. Standard refrigeration equipment such as
gauges, hoses, recovery systems, vacuum
pumps, etc., are generally compatible with HFC
refrigerants. Consult your equipment
regulations require recovering HFC refrigerants.
9. Will R-404A or R-134A separate if there is a
leak in the system?
manufacturer for specific recommendations for
converting existing equipment to HFC usage.
Once designated (and calibrated, if needed) for
HFC use, this equipment should be used
specifically with HFC refrigerants only.
No. Like R-502, the degree of separation is too
small to detect.
10. How do I charge a system with HFC
refrigerant?
The same as R-502, Manitowoc recommends
charging only liquid refrigerant into the high
side of the system.
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Refrigeration System
Section 7
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MANITOWOC ICE, INC.
2110 South 26th Street P.O. Box 1720
Ma nitowoc , WI 54221-1720
Phone: (920) 682-0161
Fa x: (920) 683-7585
Web Site - www.ma nitowoc ic e.c om
We reserve the right to ma ke produc t
improvements a t a ny time.
©2000 Ma nitowoc Ic e, Inc .
Spec ific a tions a nd design a re subjec t
to c ha nge without notic e.
Litho in U.S.A.
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