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Electronic Icemaker
GE Consumer Home Services Training
TECHNICAL SERVICE GUIDE
Pub # 31-9063 8/00
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CAUTION
To avoid personal injury, disconnect power before servicing thisproduct. If electrical power is required for diagnosis or testpurposes, disconnect the power immediately after performing thenecessary checks.
!IMPORTANT SAFETY NOTICE
The information in this service guide is intended for use byindividuals possessing adequate backgrounds of electrical,electronic and mechanical experience. Any attempt to repair amajor appliance may result in personal injury and propertydamage. The manufacturer or seller cannot be responsible for theinterpretation of this information, nor can it assume any liability inconnection with its use.
RECONNECT ALL GROUNDING DEVICES
If grounding wires, screws, straps, clips, nuts, or washers usedto complete a path to ground are removed for service, they mustbe returned to their original position and properly fastened.
GE Consumer Home Services TrainingTechnician Service Guide
Copyright 2000
All rights reserved. This service guide may not be reproduced in whole or in part
in any form without written permission from the General Electric Company.
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POWER LED
MAGNET 1MAGNET 2
The control board contains two sensors(Hall effect sensors), that are similar to anelectronic reed switch. The sensors areactivated by magnets and are used to assistin controlling icemaker operation. One
magnet, attached to the end of the ejectorarm, allows the control board to use magneticsensing to determine if the motor has reachedthe home position. The second magnet,located on the ice sensing arm (feeler arm),lets the control know whether the arm hasreached a fully extended position.
The on-off rocker switch allows the
icemaker to be turned off. When the switchis set to on, a green LED on the right side ofthe cover will light to show power is on. TheLED is also used to indicate certain icemakerfault conditions, such as an open or shortedthermistor, or a harvest cycle longer than 30minutes. When a fault occurs, the LED willblink 1/2 second on, 1/2 second off indefinitelyuntil the icemaker is turned off.
Electronic Icemaker
Beginning in the Spring 2001, a newlydesigned icemaker will be introduced inseveral refrigerators. This service guide willhelp you become familiar with the icemakerand its operation.
The icemaker contains several new andinnovative features. It has an electroniccontrol board, an on-off switch, a seven icecube mold, a lever style feeler arm and athermistor to monitor temperature.
To access thecontrol board andother componentswithin the icemaker,lift and remove theplastic plug at the topof the cover. Removethe Phillips screwholding the cover inplace.
The control board is held in place by threePhillips screws. All wiring is connected to theboard by plug-on terminals.
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FULLY EXTENDED
FEELER ARM
THERMISTOR
SPRING
PHILLIPS
SCREW
Freeze
The Freeze cycle is the period wherethe icemaker is waiting for the cubes to freezesolid. This period of time is based on analgorithm programmed into the electroniccontrol. The control makes these calculations
once per second and takes into account thethermistors current resistance value and therate of resistance change. As a result, freezetimes vary based on refrigerator control settingsand environmental conditions (door openings,room temperature, etc.) but averageapproximately 75 minutes for each drop of 7ice cubes.
Harvest
The Harvest cycle will begin when thefreeze algorithm has been satisfied and the armis in the out or fully extended position. If thearm is in the in position when harvest is tobegin, a delay of 3 minutes will be added oncethe arm moves to the extended position. This3 minute delay allows drawer type ice bucketsto be removed for up to 3 minutes withoutstarting a harvest. The 3 minute delay will beginagain if the arm goes back to the in positionanytime during the delay period. The arm isspring loaded and will go to the out positionunless it is being held in position by an obstaclesuch as an ice cube.
At the start of the harvest cycle, the mold heaterwill be turned on. One second later, the motorwill start. The heater will remain on until themold temperature is above 35.6F (2C) and a
The feeler arm moves horizontally. A fullice bucket will prevent the arm from moving outto the fully extended position, stopping the nextharvest cycle until ice cubes are removed andthe arm is able to swing out completely
The thermistor is mounted in the mold body,directly behind the control housing. Thethermistor provides two functions: to measurethe ice temperature during freezing and forwater level detection during fill.
The normal icemaker sequence is to fill themold with water, wait until the water is frozen,harvest the ice and then repeat the cycle. Toaccomplish this, three cycles are programmedin the electronic control: Freeze, Harvest andWater Fill. The control also contains a Power-On Diagnostic Test mode, a Harvest Fix mode,a Fault mode and a Service Diagnostic Testmode.
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3 TIMES WITHIN 15 SECONDS
Thermistor Diagnostics
During icemaker operation, the controlcontinuously monitors the thermistor resistancevalue. If the thermistor is open or shorted (toohigh or too low in resistance), the icemaker willenter the Fault Mode. When in the fault mode,
the LED will flash at the rate of 1/2 second onand 1/2 second off.A temperature of -40F (-40C) will be
considered too low and a temperature of 176F(80C) is too high for normal operation tocontinue. When out of range, a fault mode willbe entered, yet the thermistor will continue tobe tested. If the reading should later fall withinthe valid range, the fault mode will end and theicemaker will enter the freeze cycle. If the motoris not home, the control will restart the harvestcycle, followed by the freeze cycle, but bypassthe water fill.
Service Diagnostics
During the first 15 seconds that poweris first applied to the icemaker, the ServiceDiagnostic Test mode may be entered. Theservice mode is entered by pushing the feelerarm from the out position to the in positionand back again 3 times and only 3 timeswithin15 seconds.
Note: If the icemaker has already started aharvest cycle and the arm is moving, it may beimpossible to properly move the arm and enterthe service mode without allowing it to resetand powering up again.
The service diagnostic mode consistsof a harvest cycle followed by a water fill. Theharvest cycle is entered immediately, regardlessof icemaker temperature or arm position.
the freeze cycle. If the temperature is still below39.2F (4C) after 15 seconds, the control willassume an insufficient amount of water enteredthe mold. It will then energize the water valveagain for 2.5 seconds, delay for 15 seconds andtest again. After the second fill, if the thermistoris still below 39.2F (4C), a third fill for 2.4seconds will occur. There is a maximum of threefills available, at which point the fill cycle willend and the icemaker will enter the freeze cycle.No diagnostic information will show if 3 fills wereinsufficient to fill the icemaker mold. The tablebelow shows the possible water fill times:
First Fill 5.1 seconds
Second Fill 2.5 seconds
Third Fill 2.4 seconds
The ability of the control to fill up to threetimes can compensate for low water pressurebeing supplied to the icemaker.
Power On Diagnostics
When the icemaker is first connectedto power and if thermistor temperature is 50F(10C) or higher, the control will perform aPower On test before entering the freeze cycle.
The test consists of the following: Turn on the motor until it reaches home thenext time. Turn on the water valve for 1/2 second. Turn on the heater for 1/2 second. Verify that the feeler arm was in the in andthen in the out position. Verify that the motor was not in the homeposition and then in the home position. Verify that the motor does not remain on afterbeing turned off. Proceed to the freeze cycle.
Note: The power on test will only add 1/2 secondof water, which will not overflow the mold witha normal fill, but may cause a small cube whenthe refrigerator is first started.If the temperature is below 50F (10C), thecontrol will power up normally. If in the homeposition, the control will enter the freeze cycle.If the motor is not home, the control will enterthe harvest cycle but bypass water fill to avoidoverfilling the mold.
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While in the harvest cycle in the service mode,the heater will remain on for a minimum of 20seconds. The water fill cycle will initiate thefirst fill (5.1 seconds) without waiting for the moldto prechill. Only one water fill occurs duringthe service mode, whether the thermistor hasreached 39.2F (4C) or not. The icemaker willexit the service diagnostic test on its own andenter the normal freeze cycle.
NOTE: When replacing an icemaker, the PowerOn test will probably occur since the moldtemperature will be above 50F (10C). Whilein the power on test, the Service Diagnostic testcan be initiated and will override the power ontest mode.
MOTOR ONFREEZE
CYCLEPRECHILL
CYCLEO
N
VAL
VE
MOTOR ON3 MINUTES
Waituntil frozen
(minimum 30 minutes)
About10 MINS.Less than
35.6F (2C)
5.1secs.
NORMAL OPERATION(EJECTOR STARTING AT HOME POSITION)
HEATER ON
(usually takes about 60 minutes)
HEATER ONuntil35.6F (2C)(minimum 20 seconds)
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No
Ice
No
LED
LE
D
Flashing
NoF
ill
NoH
arves
t
Ba
dSw
itch
Loose
Lead
Con
tro
lBoa
rdFa
ilure
Therm
istor
Fa
ilure
Ejec
tor
Not
Home
Con
tro
lBoa
rdFa
ilure
Ba
dTherm
istor
Loose
Lead
Wa
ter
Valve
Fa
ilure
Wa
ter
Supp
lyShu
tOff
Buc
ke
tFull
Fee
ler
Arm
Stuc
k
Therm
istor
Fa
ilure
Magne
tFailure
StalledMotor
Con
tro
lBoa
rdFa
ilure
Magne
tFa
ilure
Con
tro
lBoardF
ailure
StalledMo
tor
TCOFa
ilure
Hea
ter
Elemen
t
Fa
ilure
Open
Circu
it
Groun
d
Wrong
Connec
tion
Jammed
Cu
be
Hea
ter
Failure
Mo
tor
Failure
Winding
Fa
ilure
Loose
Lea
d
Loose
/Bro
ken
Gear
Ben
t/Bro
ken
Sha
ft
Therm
istor
Fa
ilure
Con
tro
lBoard
Fa
ilure
Co
ntro
lBoard
Fa
ilure
Improper
Wa
ter
Va
lve
Connec
tion
Wa
ter
Va
lve
Fa
ilure
Th
erm
istor
No
tDe
tec
ting
Fill
Ha
rves
tToo
Early
Wa
ter
Overf
low
ICEMAKER
TROUBLESHOOTING
(dispenser
/icema
kerreverse
d)
(d
ue
toex
treme
lyco
ldinletwa
ter)
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MOTOR L1
TCO VALVE N HEATER
THERMISTOR
TERMINALS
ORANGE
RED
WHITE
ORANGE
BLACK
BROWN
MOV1
C12
C13
C1
C14
LD1
DB1
U2
U1
X1
BLACK
BLACK
115 VOLTS AC. 60HZ
PCB ASSEMBLY THERMISTOR
MOLD BODY
ICEMAKER
MOTOR
HEATER
T.C.O.
RED
BLACK
ORANGE
ORANGE
WHITE
POWER
SWITCH
GROUND
LINE NEUTRAL
WATER
VALVE
GREENWITHYELLOWS
TRIPE
WHITEB
ROWN
O
RANGE
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9. The ability of the control to fill up to 3 times can compensate for ___________?A. Multiple ejectionsB. Service diagnosticsC. Low water pressure
D. Extremely cold freezer
10. When the icemaker is first connected to power and if thermistor temperature is 50F orhigher, the control will perform a _________________ before entering the freeze cycle.A. Harvest fixB. Series of fluctuationsC. Power on testD. Fault test
11. During icemaker operation, the control continuously monitors the thermistors __________?A. ResistanceB. TemperatureC. Mode
D. Diagnostics
12. If the thermistor is open or shorted, the icemaker will enter a ______________?A. Harvest modeB. Period of inactivityC. Fault modeD. Third water fill
13. The diagnostic service mode is entered by pushing the feeler arm from the out position tothe in position and back _______ times during the first 15 seconds after applying power tothe unit.A. 2B. 3C. 4D. 5