Hoshizaki KML-600MRF, KML-450MAH, KMD-450MWH SERVICE MANUAL

Hoshizaki America, Inc.

Hoshizaki

Modular Crescent Cuber with
"G" Control Board

Models
KMD-460MAH, MWH

“A Superior Degree

of Reliability”

www.hoshizaki.com

KMD-530MAH, MWH, MRH
KML-250MAH, MWH
KML-351MAH, MWH
KML-451MAH, MWH
KML-631MAH, MWH, MRH

SERVICE MANUAL

Number: 73205
Issued: 5-7-2015

WARNING

Only qualied service technicians should install and service the appliance. To
obtain the name and phone number of your local Hoshizaki Certied Service
Representative, visit www.hoshizaki.com. No service should be undertaken until
the technician has thoroughly read this Service Manual. Failure to service and
maintain the appliance in accordance with this manual will adversely affect safety,
performance, component life, and warranty coverage and may result in costly water
damage. Proper installation is the responsibility of the installer. Product failure or
property damage due to improper installation is not covered under warranty.

Should the reader have any questions or concerns which have not been satisfactorily
addressed, please call, send an e-mail message, or write to the Hoshizaki Technical
Support Department for assistance.

Phone: [phone]
Fax: [phone]

E-mail: [e-mail]

HOSHIZAKI AMERICA, INC.
618 Highway 74 South
Peachtree City, GA 30269
Attn: Hoshizaki Technical Support Department

Web Site: www.hoshizaki.com

NOTE: To expedite assistance, all correspondence/communication MUST include the

following information:

• Model Number

• Serial Number

• Complete and detailed explanation of the problem.

2

IMPORTANT

This manual should be read carefully before the appliance is serviced. Read
the warnings and guidelines contained in this manual carefully as they provide
essential information for the continued safe use, service, and maintenance of the
appliance. Retain this manual for any further reference that may be necessary.

CONTENTS

Important Safety Information ................................................................................................. 5

I. Construction and Water/Refrigeration Circuit Diagram ....................................................... 7

A. Construction .................................................................................................................. 7

1. Air-Cooled (MAH) ..................................................................................................... 7

2. Water-Cooled (MWH) .............................................................................................. 8

3. Remote Air-Cooled (MRH) ....................................................................................... 9

B. Water/Refrigeration Circuit Diagram ............................................................................ 10

1. Air-Cooled Models (MAH) ...................................................................................... 10

2. Water-Cooled Models (MWH) .................................................................................11

3. Remote Models (MRH) .......................................................................................... 12

II. Sequence of Operation and Service Diagnosis ............................................................... 13

A. Sequence of Operation Flow Chart ............................................................................. 13

1. "G" Control Board without Harvest Pump Timer Operation .................................... 13

2. "G" Control Board with Harvest Pump Timer Operation ........................................ 14

3. Thermostatic and Mechanical Bin Control Shutdown Operation ........................... 15

B. Service Diagnosis ....................................................................................................... 16

1. "G" Control Board without Harvest Pump Timer Operation Diagnosis ................... 17

2. "G" Control Board with Harvest Pump Timer Operation Diagnosis ........................ 23

C. Control Board Check ................................................................................................... 30

D. Bin Control Check ....................................................................................................... 31

1. Thermostatic Bin Control Check ............................................................................ 31

2. Mechanical Bin Control Check and Cleaning ....................................................... 32

E. Float Switch Check and Cleaning ............................................................................... 34

1. Float Switch Check ................................................................................................ 34

2. Float Switch Cleaning ............................................................................................ 35

F. Thermistor Check ......................................................................................................... 36

G. Diagnostic Tables ........................................................................................................ 37

1. No Ice Production ................................................................................................... 37

2. Freeze-Up .............................................................................................................. 38

3. Low Ice Production ................................................................................................ 39

III. Controls and Adjustments ............................................................................................... 41

A. Control Board Layout ................................................................................................. 42

B. LED Lights and Audible Alarm Safeties ...................................................................... 43

C. Settings and Adjustments ............................................................................................ 44

1. Default Dip Switch Settings .................................................................................... 44

2. Harvest Timer (S4 dip switch 1 & 2) ...................................................................... 45

3. Pump-Out Timer (S4 dip switch 3 & 4) .................................................................. 45

4. Pump-Out Frequency Control (S4 dip switch 5 & 6) .............................................. 46

5. Harvest Pump Timer Operation (S4 dip switch 7) .................................................. 46

6. Factory Use (S4 dip switch 8) ................................................................................ 46

3

7. Freeze Timer (S4 dip switch 9 & 10) ....................................................................... 47

8. Float Switch Selector (S5 dip switch 1) ................................................................. 47

9. Rell Counter (S5 dip switch 2, 3, and 5), Program Selector (4) ............................ 47

D. Switches ...................................................................................................................... 48

1. Control Switch ........................................................................................................ 48

2. Service Switch ....................................................................................................... 48

a) DRAIN .............................................................................................................. 48

b) CIRCULATE ..................................................................................................... 48

c) WASH ............................................................................................................... 48

IV. Refrigeration Circuit and Component Service Information.............................................. 49

A. Refrigeration Circuit Service Information .................................................................... 49

B. Component Service Information .................................................................................. 52

C. Water Regulating Valve Adjustment (water-cooled model) .......................................... 52

V. Maintenance .................................................................................................................... 53

VI. Preparing the Appliance for Periods of Non-Use ............................................................ 54

VII. Disposal ......................................................................................................................... 56

VIII. Technical Information .................................................................................................... 57

A. Specication and Performance Data Sheets ............................................................... 57

1. KMD-460MAH ........................................................................................................ 57

2. KMD-460MWH ...................................................................................................... 58

3. KMD-530MAH ....................................................................................................... 59

4. KMD-530MWH ...................................................................................................... 60

5. KMD-530MRH ....................................................................................................... 61

6. KML-250MAH ........................................................................................................ 62

7. KML-250MWH ........................................................................................................ 63

8. KML-351MAH ........................................................................................................ 64

9. KML-351MWH ....................................................................................................... 65

10. KML-451MAH ........................................................................................................ 66

11. KML-451MWH ........................................................................................................ 67

12. KML-631MAH ........................................................................................................ 68

13. KML-631MWH ....................................................................................................... 69

14. KML-631MRH ........................................................................................................ 70

B. Wiring Diagrams ......................................................................................................... 71

1. Operation with Thermostatic Bin Control and without Harvest Pump Timer .......... 71

a) KML-250M_H, KML-351MWH, KML-451M_H ................................................. 71

b) KML-631MAH, KML-631MWH .......................................................................... 72

c) KML-631MRH ................................................................................................... 73

2. Harvest Pump Timer Operation with Thermostatic or Mechanical Bin Control ......74

a) KML-351MAH, KMD-460M_H, KMD-530M_H ...................................................74

b) KML-631MAH, KML-631MWH .......................................................................... 75

c) KML-631MRH - C-1 to D-0 (No Crankcase Heater Relay) ................................ 76

d) KML-631MRH - D-1 and Later (Crankcase Heater Relay) ................................ 77

4

Important Safety Information

Throughout this manual, notices appear to bring your attention to situations which could
result in death, serious injury, damage to the appliance, or damage to property.

WARNING Indicates a hazardous situation which could result in death or

serious injury.

NOTICE Indicates a situation which could result in damage to the

appliance or property.

IMPORTANT Indicates important information about the use and care of the

appliance.

WARNING

The appliance should be destined only to the use for which it has been expressly
conceived. Any other use should be considered improper and therefore dangerous.
The manufacturer cannot be held responsible for injury or damage resulting from
improper, incorrect, and unreasonable use. Failure to service and maintain the
appliance in accordance with this manual will adversely affect safety, performance,
component life, and warranty coverage and may result in costly water damage.

To reduce the risk of death, electric shock, serious injury, or re, follow basic
precautions including the following:

• Only qualied service technicians should install and service this appliance.

• The appliance must be installed in accordance with applicable national, state, and
local codes and regulations.

• Electrical connection must be hard-wired and must meet national, state, and local
electrical code requirements. Failure to meet these code requirements could result
in death, electric shock, serious injury, re, or damage.

• The icemaker requires an independent power supply of proper capacity. See the
nameplate for electrical specications. Failure to use an independent power supply
of proper capacity can result in a tripped breaker, blown fuses, damage to existing
wiring, or component failure. This could lead to heat generation or re.

• THE ICEMAKER MUST BE GROUNDED. Failure to properly ground the icemaker
could result in death or serious injury.

• Move the control switch to the "OFF" position and turn off the power supply before
servicing. Lockout/Tagout to prevent the power supply from being turned back on
inadvertently.

• To reduce the risk of electric shock, do not touch the control switch or service switch
with damp hands.

• Do not make any alterations to the unit. Alterations could result in electric shock,
injury, re, or damage to the unit.

• The appliance is not intended for use by persons (including children) with reduced
physical, sensory, or mental capabilities, or lack of experience and knowledge,
unless they have been given supervision or instruction concerning use of the
appliance by a person responsible for their safety.

5

WARNING, continued

• Children should be properly supervised around this appliance.

• Do not climb, stand, or hang on the appliance or allow children or animals to do so.
Serious injury could occur or the appliance could be damaged.

• Do not use combustible spray or place volatile or ammable substances near the
appliance. They might catch re.

• Keep the area around the appliance clean. Dirt, dust, or insects in the appliance
could cause harm to individuals or damage to the appliance.

Additional Warning for Remote Models

• THE REMOTE CONDENSER UNIT MUST BE GROUNDED. The power supply and
ground connection to the remote condenser unit are supplied from the icemaker.
Failure to properly ground the remote condenser unit could result in death or
serious injury.

• Move the icemaker control switch to the "OFF" position and turn off the power
supply to the icemaker before servicing the remote condenser unit.
Lockout/Tagout to prevent the power supply from being turned back on
inadvertently.

NOTICE

• Follow the instructions in this manual carefully to reduce the risk of costly water
damage.

• In areas where water damage is a concern, install in a contained area with a oor
drain.

• Install the appliance in a location that stays above freezing. Normal operating
ambient temperature must be within 45°F to 100°F (7°C to 38°C).

• Do not leave the icemaker on during extended periods of non-use, extended
absences, or in sub-freezing temperatures. To properly prepare the icemaker for
these occasions, follow the instructions in "VI. Preparing the Appliance for Periods
of Non-Use."

• Do not place objects on top of the appliance.

• The dispenser unit/ice storage bin is for ice use only. Do not store anything else in
the dispenser unit/ice storage bin.

6

I. Construction and Water/Refrigeration Circuit Diagram

A. Construction

1. Air-Cooled (MAH)

Thermostatic
Expansion Valve

Cleaning Valve

Spray Tubes

Drain Valve

Water Supply Inlet

Inlet Water Valve

Thermostatic
Bin Control

Pump Motor

Control Switch

Service Switch

Float Switch

Thermostatic Bin Control
Bracket & Bulb Holder

Compressor

Control Box

Model Shown: KML-351MAH

Liquid Line Valve

Hot Gas Valve

Condenser

Fan Motor

High-Pressure
Switch

Drier

Model Shown: KMD-460MAH

7

Mechanical Bin Control
and Bracket

2. Water-Cooled (MWH)

Cleaning Valve

Inlet Water Valve

Thermostatic
Bin Control

Pump Motor

Thermostatic
Expansion Valve

Drain Valve

Float Switch

Spray Tubes

Water Supply Inlet

Water Regulating
Valve

Condenser

High-Pressure
Switch

Control Box

Drier

Thermostatic Bin Control
Bracket & Bulb Holder

Compressor

Control Switch

Service Switch

Model Shown: KML-451MAH

Hot Gas Valve

Mechanical Bin Control
and Bracket

8

Model Shown: KMD-460MWH

3. Remote Air-Cooled (MRH)

Cleaning Valve

Inlet Water Valve

Cleaning Valve

Control Switch

Service Switch

Pump Motor

Drain Valve

Spray Tubes

Thermostatic
Expansion Valve

Water Supply Inlet

Hot Gas Valve

Control Box

High-Pressure
Switch

Reciever

Float Switch

Thermostatic Bin Control
Bracket & Bulb Holder

Thermostatic
Bin Control

Compressor

Model Shown: KML-631MRH

Crankcase Heater

Drier

Liquid Line Valve

Mechanical Bin Control
and Bracket

9

Model Shown: KMD-530MRH

B. Water/Refrigeration Circuit Diagram

1. Air-Cooled Models (MAH)

Spray Tubes

Drain

Water Pump

Water Supply Inlet

Inlet Water Valve

Cleaning Valve

Drain Valve

Thermistor

Float Switch

Condenser

Condenser
Fan Motor

Drier

Heat Exchanger

Compressor

High-Pressure
Switch

Hot Gas Valve

Strainer

10

Thermostatic Expansion Valve

2. Water-Cooled Models (MWH)

Water Regulating
Val ve

Spray Tubes

Drain

Water Pump

Condenser

Water Supply Inlet

Inlet Water Valve

Cleaning Valve

Drain Valve

Thermistor

Float Switch

Drier

Heat Exchanger

Compressor

High-Pressure
Switch

Hot Gas Valve

Strainer

11

Thermostatic Expansion Valve

3. Remote Models (MRH)

Condenser

Spray Tubes

Condenser
Fan Motor

Drain Valve

Water Pump

Headmaster

Water Supply Inlet

Inlet Water Valve

Cleaning Valve

Heat Exchanger

Thermistor

High-Pressure
Switch

Drier

Receiver

Liquid Line
Val ve

Hot Gas Valve

Drain

Float Switch

12

Compressor

Thermostatic Expansion Valve

Strainer

II. Sequence of Operation and Service Diagnosis

A. Sequence of Operation Flow Chart

1. "G" Control Board without Harvest Pump Timer Operation

cycles

(S4 dip switch 5 & 6)

2 sec., then energizes

for 10/20 sec.

• Pump motor stops for

(S4 dip switch 3 & 4)

Comp continues

FMR continues

HGV energized

PM de-energizes for 2 sec.,

then DV and PM energize

for 10/20 sec.

FM de-energized

LLV de-energized

• Every 1, 2, 5, or 10

4. Pump-Out Cycle

• Min. freeze time: 5 min.

• Max. freeze time: freeze timer

FS in control

5 min. minimum

(S4 dip switch 9 & 10)

freeze timer in

1 to 3 min. harvest

timer in control

setting

FS opens or

freeze timer

control

FS closed

FS Check

(S4 dip switch 1 & 2)

terminates

Comp continues

FMR continues

Thermistor temperature

reaches 48°F (9°C)

FM energized

LLV energized

(3.9kΩ or less) Harvest

timer starts (1 to 3 min.).

PM energized

HGV de-energized

WV de-energized

FS open

Components Energized when the Control Switch is in the "SERVICE" Position

When in the "SERVICE" position, the control switch supplies power to the service switch and the machine is in service mode.

The service switch has three positions: "DRAIN," "CIRCULATE" and "WASH." See the information below for details of each

function.

Power is supplied to the pump motor and drain valve. This drains the water tank.

Power is supplied to the pump motor only. This can be used to circulate cleaner over the

DRAIN

CIRCULATE

outside surface of the evaporator for extended periods of time.

Power is supplied to the pump motor and wash valve. This is used to circulate cleaner and

sanitizer over both the inside and outside surfaces of the evaporator.

WASH

Thermistor in

• Maximum inlet water valve time: 6 minutes

• Maximum harvest time: 20 minutes

2. Harvest Cycle 3. Freeze Cycle

"G" Control Board without Harvest Pump Timer Operation Flow Chart

Cycle

1. 1-Minute Fill

Cycle

Steps

control

FS closed

Comp energized

FMR energized

HGV energized

WV energized

LLV de-energized

WV Energized

FS open

If FS is open, Comp stops and cycle returns to 1-min. ll.

Legend:

Comp–compressor

DV–drain valve

FM–fan motor

FMR–fan motor-remote

FS–oat switch

HGV–hot gas valve

LLV–liquid line valve

PM–pump motor

WV–inlet water valve

Shutdown and Restart See "II.A.3. Thermostatic and Mechanical Bin Control Shutdown Operation"

FS Check

Startup

13

2. "G" Control Board with Harvest Pump Timer Operation

cycles

(S4 dip switch 5 & 6)

2 sec., then energizes

for 10/20 sec.

4. Pump-Out Cycle

3. Freeze Cycle

• Every 1, 2, 5, or 10

• Min. freeze time: 5 min.

• Max. freeze time: freeze timer setting

(S4 dip switch 9 & 10)

• Pump motor stops for

(S4 dip switch 3 & 4)

FS in control

5-min. minimum

freeze timer in

control

Comp continues

FS opens or

FS closed

FMR continues

HGV energized

freeze timer

terminates

Comp continues

FMR continues

FM energized

PM de-energizes for 2 sec.,

LLV energized

then DV and PM energize

for 10/20 sec.

PM energized

HGV de-energized

FM de-energized

LLV de-energized

FS check

50 sec.

Harvest Pump

Timer

PM energized

WV de-energized

1 to 3-min. harvest timer in

control (S4 dip switch 1 & 2)

Thermistor temperature reaches

Thermistor in

control

• Max. inlet water valve time: 6 min. or the length of

harvest minus 50 sec. (S4 dip switch 7), whichever is shorter.

"G" Control Board with Harvest Pump Timer Operation Sequence Flow Chart

2. Harvest Cycle

1. 1-Minute

• Max. harvest time: 20 min.

Fill Cycle

FS closed

FS check

WV energized

Comp energized

FMR energized

HGV energized

48°F (9°C) (3.9 kΩ or less). Harvest

WV energized

FS open

FS open

timer starts (1 to 3 min.).

Power is supplied to the pump motor and drain valve. This drains the water tank.

Power is supplied to the pump motor only. This can be used to circulate cleaner over the

outside surface of the evaporator for extended periods of time.

Power is supplied to the pump motor and wash valve. This is used to circulate cleaner and

sanitizer over both the inside and outside surfaces of the evaporator.

DRAIN

CIRCULATE

Components Energized when the Control Switch is in the "SERVICE" Position

When in the "SERVICE" position, the control switch supplies power to the service switch and the machine is in service mode.

The service switch has three positions: "DRAIN," "CIRCULATE" and "WASH." See the information below for details of each

function.

If FS is open, Comp stops and cycle returns to 1-min. ll.

WASH

Cycle

Steps

Startup

14

Shutdown and Restart See "II.A.3. Thermostatic and Mechanical Bin Control Shutdown Operation"

Legend:

Comp–compressor

DV–drain valve

FM–fan motor

FMR–fan motor-remote

FS–oat switch

HGV–hot gas valve

LLV–liquid line valve

PM–pump motor

WV–inlet water valve

3. Thermostatic and Mechanical Bin Control Shutdown Operation

Icemaker starts at

"1. 1-Minute Fill Cycle."

3. Ice Level Lowered

2. Icemaker Off

All components

de-energized.

To 1. 1-Minute Fill Cycle

MBC closed

(MBC actuator paddle disengaged)

Green "BC CLOSED" LED on

Yellow "BC OPEN" LED off

Shutdown Operation

To 1. 1-Minute Fill Cycle

Yellow "BC OPEN" LED continues. All

components de-energized.

3. Ice Level Lowered

No ice touching

TBC bulb.

Icemaker starts at

"1. 1-Minute Fill Cycle."

TBC closed

NOTE: "G" control board green "BC CLOSED" LED

on continuously when the K4 jumper is in place.

2. Icemaker Off

All components

de-energized.

Thermostatic Bin Control Shutdown Sequence Flow Chart

1. Bin Full

Within 10 sec.

after ice contacts

TBC bulb, icemaker

shuts down.

TBC open

All components

de-energized

Mechanical Bin Control Shutdown Sequence Flow Chart

freeze cycle if activated at the end of the harvest cycle.

the 5-min. short cycle protection timer terminates.

• Harvest Cycle–At the end of the harvest cycle, or up to 15 sec. into the

• Freeze Cycle–15 sec. after activation if activated at least 15 sec. before

Otherwise, at the end of the next harvest cycle.

MBC open (MBC actuator paddle engaged)

Green "BC CLOSED" LED off

Yellow "BC OPEN" LED on

1. Bin Full

Shutdown Delay:

• Fill Cycle–15 sec. after activation.

Shutdown

Ice contacts TBC bulb

Shutdown

and Restart

TBC Operation

and Restart

Legend:

MBC–mechanical bin control

MBC Operation

TBC–themostatic bin control

15

B. Service Diagnosis

WARNING

• The appliance should be diagnosed and repaired only by qualied service
personnel to reduce the risk of death, electric shock, serious injury, or re.

• Risk of electric shock. Control switch in "OFF" position does not de-energize all
loads Use extreme caution and exercise safe electrical practices.

• Moving parts (e.g., fan blade) can crush and cut. Keep hands clear.

• Before servicing the appliance, move the control switch to the "OFF" position and
turn off the power supply.

• CHOKING HAZARD: Ensure all components, fasteners, and thumbscrews are
securely in place after the appliance is serviced. Make sure that none have fallen
into the dispenser unit/ice storage bin.

• Make sure all food zones in the appliance and dispenser unit/ice storage bin are
clean after service.

The diagnostic procedure is a sequence check that allows you to diagnose the electrical
system and components. Before proceeding, check for correct installation, proper voltage
per nameplate, and adequate water supply. Check CB using the steps in "II.C. Control
Board Check." Check dip switch settings to assure that S4 dip switch 3, 4, 7, 8, 9, 10
and S5 dip switch 1 through 5 are in the factory default position. S4 dip switch 1, 2, 5, 6
are cleaning adjustments and the settings are exible. For factory default settings, see
"III.C.1. Default Dip Switch Settings."

Note: • When checking high voltage (115VAC), always choose a white (W) neutral wire to

establish a good neutral connection.

• When checking voltage from the CB K1 connector (10 pin connector), pull
CBK1connector out slightly to allow room for multimeter test leads contact.

1) Turn off the power supply, then access the control box. Move the control switch to the
"OFF" position. Clear any ice from BC.

2) Check that the 115VAC 10A fuse is good.

16

1. "G" Control Board without Harvest Pump Timer Operation Diagnosis

3) Power On: Turn on the power supply, then move the control switch to the "ICE" position.
A 5-sec. delay occurs. CB red "POWER OK" LED and green "BC CLOSED" LEDturn
on. If yellow "BC OPEN" LED is on (indicating a missing or loose jumper (4A4883G01)),
check that the jumper is securely in place. Move ice away from TBC bulb. If yellow "BC
OPEN" LED stays on, see"II.D.1. Thermostatic Bin Control (TBC) Check."

NOTICE! Do not adjust S4 dip switch 7 out of the factory default position. This dip
switch must be left in the factory default position or the appliance will not operate
correctly.

Note: CB red "POWER" LED remains on unless the 10.5VAC power supply is
interrupted (K2 connector).

a) Power On Diagnosis: If CB red "POWER OK" LED is off, conrm 10A fuse is good.

Check for 115VAC at control switch #2(BR) to neutral (W) then at control switch
#3(P) to neutral (W). If 115VAC is present on #2 (BR) and not on #3(P), replace
control switch. If 115VAC is present on control switch #3 (P), check for 115VAC at
HPS (P) to neutral (W) then HPS (BK) to neutral (W). If115VAC is present at HPS (P)
and not at HPS (BK), HPS is open. See HPS Diagnosis below. If 115VAC is present
at HPS (BK), check for 10.5VAC at CB K2#1 (R) to CB K2 #2 (R). If 10.5VAC is not
present, check CT continuity. Ifopen replace CT.

b) HPS Diagnosis: Check that the condenser coil is not clogged or restricted. Let

refrigeration circuit pressures equalize. If HPS does not reset and pressures are
equalized, replace HPS. If pressures are not equalized, reclaim refrigerant and
diagnose refrigeration circuit restriction. Check that there are no restrictions in the
refrigeration circuit.
Harvest Cycle: HGV, strainer, or check valve.
Freeze Cycle: FM, FMR, TXV, WRV, HM, LLV, strainer, check valve, drier, and
damaged line set or tting. On water-cooled models, conrm WRV opens in freeze
cycle.

Conrm that the location meets installation requirements:

• The appliance is not intended for outdoor use. Normal operating ambient temperature
should be within 45°F to 100°F (7°C to 38°C).

• Allow 6" (15 cm) clearance at rear, sides, and top for proper air circulation and ease of
maintenance and/or service should they be required.

• The appliance should not be located in a corrosive environment.

17

4) 1-Minute Fill Cycle – LED 4 is on. WV energizes. After 1 min., CB checks for a closed
FS. If FS is closed, harvest cycle begins. If harvest cycle begins (Comp, HGV, and FMR
energize), continue to step 5. If FS is open, WV remains energized through additional
1-min. ll cycles until water enters the water tank and FS closes (low water safety
protection during initial start up and at the end of each harvest).
Diagnosis: Check that water enters the water tank. If not, check that the water supply
line shut-off valve is open and screens or external lters are clear. Check for 115VAC
at CB K1 #6(O) to neutral(W). If 115VAC is not present, replace CB. If 115VAC is
present, and WV does not energize, check for 115VAC at WV. If 115VAC is present,
check coil continuity. Ifopen, replace WV. If the water tank lls, but the appliance fails to
start harvest (Comp energized), check for open FS. See "II.E. Float Switch Check and
Cleaning." If FS is closed and CB fails to start the harvest cycle after 1 min., replace
CB.

5) Initial Harvest Cycle – LEDs 1, 4, and 2 are on. WV continues. Comp, FMR, and
HGV energize. CB monitors the warming of the evaporator via the thermistor located
on the suction line. When the thermistor reaches 48°F (9°C), CB reads 3.9 kΩ from the
thermistor and turns harvest termination over to the harvest timer (S4 dip switch 1 & 2).
The harvest timer has settings of 60, 90, 120, and 180sec. Thepump-out timer (S4dip
switch 3 & 4) acts in place of the harvest timer during cycles with a pump-out (S4 dip
switch 5 & 6). WV remains energized during harvest for a maximum of 6min. or the
length of harvest, whichever is shorter.

a) Comp Diagnosis: Check that evaporator is warming. Ifnot, conrm that Comp

energizes. If not, check for 115VAC at CB K1 #1 or #9 (V) to neutral (W). If 115VAC is
not present, check for 115VAC at CB K1 #7 or #10 (BR) to neutral (W). If115VAC is
present at #7 or #10 (BR) and not at #1 or #9 (V), replace CB. If 115VAC is present,
check for 115VAC at CR or MC solenoid. If 115VAC is present, conrm contacts are
closed. If not, replace CR or MC. If CR or MC contacts are closed, check Comp
external protector, Comp start and run capacitors, Comp start relay, and Comp motor
winding.

b) HGV Diagnosis: If Comp is energized and evaporator is not warming, check that

HGV energizes and opens. Check for 115VAC at CB K1 #2 (P) to neutral (W).
If115VAC is not present, replace CB. If 115VAC is present, check for 115VAC at HGV
coil and check HGV coil continuity. Replace as needed.

c) LLV Diagnosis: Conrm that LLV is de-energized and closed (not bypassing).

Ifenergized, replace CB. If de-energized and bypassing, replace LLV.

d) WRV Diagnosis: Conrm WRV is not leaking by.

18

e) Initial Harvest Cycle Termination Diagnosis: When the thermistor reaches

48°F(9°C), CB reads 3.9 kΩ from the thermistor and turns harvest termination over
to the harvest timer (S4 dip switch 1 & 2). Check discharge line temperature. For a
thermistor check, see "II.F.Thermistor Check." If 1-min. ll cycle starts after harvest
timer terminates, check that FS is clean and operating properly, see "II.E. Float
Switch Check and Cleaning." If FS is closed, CB proceeds to the next cycle. Ifnot,
replace CB.

Note: The minimum total time allowed by CB for a complete harvest cycle is 2 min.

Maximum harvest time allowed is 20 min.

NOTICE! On models without harvest pump timer relays, S4dip switch 7 must
remain off. Otherwise, WV de-energizes the last 50seconds of harvest.

6) Freeze Cycle – LED 1 is on. Comp and FMR continue. PM, FM, and LLVenergize.
WV and HGV de-energize. Appliance is held in freeze by a 5-min. short cycle protection
timer. After 5-min. timer terminates and FSopens, freeze cycle terminates.

a) Freeze Cycle Diagnosis: Conrm Comp and FMR continue. Conrm that PM, FM,

and LLV energize. Conrm WRV opens. Next, conrm WV and HGV de-energize.
During the rst 5 min. of freeze, conrm evaporator is cooling. If not, conrm
WV de-energized (not leaking by), HGV de-energized (not bypassing), LLV and
FM energize, TXV and HM operate correctly, WRV opens, Comp is efficient, and
refrigerant charge is correct. See "VIII.A. Specication and Performance Data
Sheets."

b) Comp and FMR Diagnosis: If Comp and FMR de-energize once freeze begins,

check that appliance has not shut off on HPS ("POWER OK" LED off). If so, check
"3)b) HPS Diagnosis." If "POWER OK" LED is on, check for 115VAC at CB K1#1(V)
or #9 (V) to neutral (W). If 115VAC is not present and LED 1 is on, replace CB.
If115VAC is present, check for 115VAC at CR or MC coil. If 115VAC is present, check
CR or MC coil and contact continuity. Replace as needed. If CR or MC is ok, check
Comp external overload, start relay, and start and run capacitors. Next, check Comp
motor winding continuity. If Comp is energized but evaporator is not cooling, check
for an inefficient Comp. See "VIII.A. Specication and Performance Data Sheets."
If Comp is energized but FMR is not, check for 115VAC at the FMR junction box.
If115VAC is not present, check icemaker wiring connections. If 115VAC is present,
check for voltage at condenser unit. If115VAC is not present, check eld wiring
connections. If 115VAC is present, check FMR capacitor, motor winding, and fan
blade for binding.

c) WV and HGV Diagnosis: If WV is energized, check for 115VAC at CB K1 #6 (O) to

neutral (W). If 115VAC is present after PM energizes, replace CB. If 115VAC is not
present, replace WV (bypassing). If HGV did not de-energize, check for 115VAC at
CB K1 #2 (P) to neutral (W). If 115VAC is present after PM energizes, replace CB.
If115VAC is not present, replace HGV (bypassing).

19

d) PM Diagnosis: Conrm water is owing over evaporator from PM and not WV. If PM

de-energizes once freeze begins, check for 115VAC at CB K1 #4 (R) to neutral (W).
If 115VAC is not present, replace CB. If 115VAC is present and PM is de-energized,
check for 115VAC at control switch #5 (Y) to neutral (W). If 115VAC is present at CB
K1 #4 (R) and not at control switch #5 (Y), check control switch continuity between
#5 (Y) and #6 (R). Replace as needed. If 115VAC is present at control switch #5 (Y)
to neutral (W), check PM capacitor and motor winding continuity.

e) FM and LLV Diagnosis: If FM or LLV does not energize, check for 115VAC at CB

K1#3 (BK) to neutral (W). If 115VAC is not present, replace CB. If 115VAC is present:
For FM, check capacitor, motor winding, and blade for binding.
For LLV, check coil voltage and continuity.

f) Refrigerant Pressures, HM, and TXV Diagnosis: If evaporator is still not cooling,

check refrigerant pressures. See "VIII.A. Specication and Performance Data
Sheets." Next, check HM operation. If refrigeration pressures are above HM setpoint
and HMis bypassing, replace HM. Check TXV for proper operation. Remove TXV
bulb and hold it in your hand, refrigerant low-side pressure should rise, place
TXV bulb in ice water, refrigerant low-side pressure should drop. A 10 to 15 pound
pressure swing between warm and cold conditions indicate a good TXV. If a 10 to
15pound swing is not present, replace TXV.

g) WRV Diagnosis: WRV is factory set and generally no adjustment is required.

IfWRV fails to open in freeze, check for proper refrigerant pressures. See "VIII.A.
Specication and Performance Data Sheets." If refrigerant pressures are correct and
WRV does not open, adjust or replace as needed. See "IV.C. Water Regulating Valve
Adjustment (water-cooled model)."

h) Freeze Termination Diagnosis: After 5 min. in freeze, disconnect CB K5 FS

connector. 15 sec. later appliance should switch out of the freeze cycle (15 second
delay after FS opens before terminating the freeze cycle). If appliance remains in
freeze longer than 15 sec. after FS removed, replace CB. If appliance switches with
FS removed but would previously not switch out of freeze with FS connected (long
freeze - 3 beep alarm), see "II.E. Float Switch Check and Cleaning."

Note: Normal freeze cycle will last 20 to 40 min. depending on model and conditions.

Cycle times and pressures should follow performance data provided in this
manual. See "VIII.A. Specication and Performance Data Sheets."

i) Short Freeze Cycle Diagnosis: Conrm water tank lls and overows during 1 min.

ll and harvest cycles. If not, check water supply lters, shut-off valve, WV screen.
Ifwater tank empties before 5 min. timer terminates and freeze cycle is short, check
that DV is not leaking by or energized (water owing down the potable drain). If DV is
leaking by, clean DV, replace as needed. If DV is energized during the freeze cycle,
replace CB. If water tank is full, see "II.E. Float Switch Check and Cleaning" for
erratic operating FS.

20

7) Pump-Out Cycle – LEDs 1, 3, and 2 are on (10/20 second pump-out). Timing of the
rst pump-out is dependent on CB. The rst pump-out is determined by S4 dip switch
5& 6. See the table below.

"G" Control Board Settings 1st Pump-Out

S4 Dip Switch Setting

No. 5 No. 6

OFF OFF Every cycle After 2nd freeze cycle

ON OFF Every 2 cycles After 3rd freeze cycle

OFF ON Every 5 cycles After 6th freeze cycle

ON ON Every 10 cycles After 11th freeze cycle

Pump-Out

Frequency

"G" Control Board

Comp and FMR continue, HGV energizes, LLV and FM de-energize. If S4dip switch 3
&4 are set to 3 off and 4on, LED 4 turns on and WV energizes. PM stops for 2sec.,
then PM and DV energize for 10/20 sec. depending on pump-out timer (S4 dip switch
3 & 4) setting. When the pump-out timer terminates, pump-out is complete. The pump­out frequency control (S4 dip switch 5& 6) is factory set, and generally no adjustment
is required. However, the pump-out frequency control can be set to have a pump-out
occur every cycle, or every 2, 5, or
10 cycles. For details, see "III.C.4. Pump-Out Frequency Control (S4 dip switch 5 & 6)."

Pump-Out Diagnosis: In the freeze cycle before pump-out (see table above),
after5min. of freeze disconnect CB black K5 connector (FS connector) . Check that
PM stops and re-starts and that DV energizes and water is owing down the drain
through DV. If PM does not stop and re-start and DV does not energize, check that CB
LEDs 1,3, and 2 are on. If not, replace CB. IfLEDs1,3, and 2 are on and PM and DV
do not energize, check for 115VAC at CB K1 #5 (DBU) to neutral (W). If 115VAC is not
present, replace CB. If 115VAC is present, check for 115VAC at X10 relay #8 (DBU) to
neutral(W). If 115VAC is present at X10 relay #8 (DBU) to neutral (W):
PM: Check for 115VAC at X10 relay #6 (BR) and X10 relay #4 (Y) to neutral (W).
If 115VAC is present at X10 relay #6 (BR) and not at X10 relay #4 (Y), replace X10relay.
If 115VAC is present at X10 relay #4 (Y), check PM capacitor, motor winding, and
impeller for binding.
DV: Check for 115VAC from X10 relay #5 (DBU) and X10 relay #3 (GY) to neutral (W).
If 115VAC is present at X10 relay #5 (DBU) and not at X10 relay #3(GY), replace
X10relay. If 115VAC is present at X10 relay #3 (GY), check DV solenoid, replace as
needed. Next, conrm that the drain line is not clogged.

Conrm FM and LLV de-energize. If FM or LLV are energized with LEDs 1, 3, and 2 on,
replace CB.

8) Normal Harvest Cycle – Same as the initial harvest cycle. Return to step 5 above.
Note: Appliance continues to cycle until TBC is satised or power is turned off. The

appliance always restarts at the 1-min. ll cycle.

21

9) Shutdown

a) Thermostatic Bin Control (TBC):

When the appliance is running, hold ice in contact with the thermostatic bulb. BC
switch opens within 10 sec., shutting down the appliance. TBC is factory set, and
generally no adjustment is required. However, adjustment may be needed in some
conditions, particularly at higher altitude locations.
Diagnosis: See "II.D.1. Thermostatic Bin Control Check." CB red K4 connector must
have the jumper in place. When the jumper is in place, the green "BC CLOSED"
LED remains on. If the jumper is not in place, yellow "BC OPEN" LED turns on and
the icemaker turns off and remains off until the jumper is replaced in its original
position. IMPORTANT! CB red K4 connector jumper (4A4883G01) must be in

place.

Legend: BC–bin control; CB–control board; Comp–compressor; CR–compressor relay;

DV–drain valve; FM–fan motor; FMR–fan motor-remote; FS–oat switch;
HGV–hot gas valve; HM–headmaster (C.P.R.); HPS–high-pressure switch;
LLV–liquid line valve; MC–magnetic contactor; PM–pump motor;
TBC–thermostatic bin control; TXV–thermostatic expansion valve;
WRV–water regulating valve; WV–inlet water valve

22

2. "G" Control Board with Harvest Pump Timer Operation Diagnosis

3) Power On: Turn on the power supply, then move the control switch to the "ICE" position.
A 5-sec. delay occurs. CB red "POWER OK" LED and green "BC CLOSED" LED turn
on. If yellow "BC OPEN" LED is on (indicating a full bin):
KML-351MAH, KML-631M_H: If yellow "BC OPEN" LED is on (indicating a missing or
loose jumper (4A4883G01)), check that the jumper is securely in place. Move ice away
from TBC bulb. If yellow "BC OPEN" LED stays on, see "II.D.1. Thermostatic Bin Control
(TBC) Check."
KMD-460M_H, KMD-530M_H: Check MBC. Move ice away from MBC actuator paddle.
If yellow "BC OPEN" LED stays on, see"II.D.2. Mechanical Bin Control (MBC) Check
and Cleaning."

NOTICE! Do not adjust S4 dip switch 7 out of the factory default position. This dip

switch must be left in the factory default position or the appliance will
not operate correctly.

Note: CB red "POWER OK" LED remains on unless the 10.5VAC power supply is
interrupted (K2 connector).

a) Power On Diagnosis: If CB red "POWER OK" LED is off, conrm 10A fuse is good.

Check for 115VAC at control switch #2 (BR or BK) to neutral(W) then at control
switch #3(P) to neutral (W). If 115VAC is present on #2 (BR or BK) and not on
#3(P), replace control switch. If 115VAC is present on control switch #3 (P), check for
115VAC at HPS (P) to neutral (W) then HPS (BK) to neutral (W). If115VAC is present
at HPS (P) and not at HPS (BK), HPS is open. See HPS Diagnosis below. If115VAC
is present at HPS (BK), check for 10.5VAC at CB K2#1 (R) to CB K2#2(R).
If10.5VAC is not present, check CT continuity. If open, replace CT.

b) HPS Diagnosis: Check that the condenser coil is not clogged or restricted. Let

refrigeration circuit pressures equalize. If HPS does not reset and pressures are
equalized, replace HPS. If pressures are not equalized, reclaim refrigerant and
diagnose refrigeration circuit restriction. Check that there are no restrictions in the
refrigeration circuit.
Harvest Cycle: HGV, strainer, or check valve.
Freeze Cycle: FM, FMR, TXV, WRV, HM, LLV, strainer, check valve, drier, and
damaged line set or tting. On water-cooled models, conrm WRV opens in freeze
cycle.

Conrm that the location meets installation requirements:

• The appliance is not intended for outdoor use. Normal operating ambient temperature
should be within 45°F to 100°F (7°C to 38°C).

• Allow 6" (15 cm) clearance at rear, sides, and top. KMD-460/530MAH require
12"(30cm) clearance at right side.

• The appliance should not be located in a corrosive environment.

23

4) 1-Min. Fill Cycle – LED 4 is on. WV and X11 relay energize. After 1 min., CB
checks for a closed FS. If FS is closed, the harvest cycle begins (X10, Comp, HGV,
FMRenergize), Continue to step 5a. If FS is open, WV remains energized through
additional 1-min. ll cycles until water enters the water tank and FS closes (low water
safety protection during initial start up and at the end of each harvest). Diagnosis:
Check that water enters the water tank. If not, check that the water supply line shut-off
valve is open and screens or external lters are clear. Check for 115VAC at CB K1 #6
(O) to neutral (W). If 115VAC is not present, replace CB. If 115VAC is present, and WV
does not energize, check for 115VAC at WV. If 115VAC is present, check coil continuity.
Ifopen, replace WV. If the water tank lls, but the appliance fails to start harvest (Comp
energized), check for open FS. See "II.E. Float Switch Check and Cleaning." If FS is
closed and CB fails to start the harvest cycle after 1 min., replace CB.

5a) Initial Harvest Cycle – LEDs 1, 4, and 2 are on. WV and X11 relay continue. Comp,

FMR, HGV, and X10 relay energize. CBmonitors the warming of the evaporator via the
thermistor located on the suction line. When the thermistor reaches 48°F (9°C), CB
reads 3.9 kΩ from the thermistor and turns harvest termination over to the harvest timer
(S4 dip switch 1 & 2). The harvest timer has settings of 60, 90, 120, and 180 sec. The
pump-out timer (S4 dip switch 3 & 4) acts in place of the harvest timer during cycles
with a pump-out (S4 dip switch 5 & 6). WV and X11 relay are energized during harvest
for a maximum of 6 min. or the length of harvest minus 50sec., whichever is shorter.
50sec. before harvest terminates, PM energizes. See step 5b below.

a) Comp Diagnosis: Check that evaporator is warming. Ifnot, conrm that Comp

energizes. If not, check for 115VAC at CB K1 #1 or #9 (V) to neutral (W). If 115VAC
is not present, check for 115VAC at CB K1 #7 or #10 (BR or BK) to neutral (W).
If115VAC is present at #7 or #10 (BR or BK) and not at #1 or #9 (V), replace CB.
If115VAC is present, check for 115VAC at CR solenoid. If 115VAC is present, conrm
contacts are closed. If not, replace CR. If CR contacts are closed, check Comp
external overload, Comp start and run capacitors, Comp start relay, and Comp motor
winding.

b) HGV Diagnosis: If Comp is energized and evaporator is not warming, check that

HGV energizes and opens. Check for 115VAC at CB K1 #2 (P) to neutral (W).
If115VAC is not present, replace CB. If 115VAC is present, check for 115VAC at HGV
coil and check HGV coil continuity. Replace as needed.

c) LLV Diagnosis: Conrm that LLV is de-energized and closed (not bypassing).

Ifenergized, replace CB. If de-energized and bypassing, replace LLV.

d) WRV Diagnosis: Conrm WRV is not leaking by.

24