Electronic Ice Maker

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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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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

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Electronic Ice Maker