Patent Publication Number: US-2022235991-A1

Title: Ice maker and control

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     FIELD OF THE INVENTION 
     This application relates generally to a refrigeration appliance with an ice maker, and more particularly, to a control algorithm that controls various operations of an ice maker arranged in a fresh food compartment of a refrigerator. 
     BACKGROUND OF THE INVENTION 
     Refrigeration appliances, such as domestic refrigerators, typically have both a fresh food compartment and a freezer compartment or section. The fresh food compartment is where food items such as fruits, vegetables, and beverages are stored and the freezer compartment is where food items that are to be kept in a frozen condition are stored. The refrigerators are provided with a refrigeration system that maintains the fresh food compartment at temperatures above 0° C., such as between 0.25° C. and 4.5° C. and the freezer compartments at temperatures below 0° C., such as between 0° C. and −20° C. 
     The arrangements of the fresh food and freezer compartments with respect to one another in such refrigerators vary. For example, in some cases, the freezer compartment is located above the fresh food compartment and in other cases the freezer compartment is located below the fresh food compartment. Additionally, many refrigerators have their freezer compartments and fresh food compartments arranged in a side-by-side relationship. Whatever arrangement of the freezer compartment and the fresh food compartment is employed, typically, separate access doors are provided for the compartments so that either compartment may be accessed without exposing the other compartment to the ambient air. 
     Refrigerators are often provided with a unit for making ice pieces, commonly referred to as “ice cubes” despite the non-cubical shape of many such ice pieces. These ice making units normally are located in the freezer compartments of the refrigerators and manufacture ice by convection, i.e., by circulating cold air over water in an ice tray to freeze the water into ice cubes. Storage bins (e.g., buckets) for storing the frozen ice pieces are often provided adjacent to the ice making units. The ice pieces can be dispensed from the storage bins through a dispensing port in the refrigerator door that closes the freezer to the ambient air. The dispensing of the ice usually occurs by means of an ice delivery mechanism that extends between the storage bin and the dispensing port in the freezer compartment door. 
     For refrigerators such as the so-called “bottom mount” refrigerator, which includes a freezer compartment disposed vertically beneath a fresh food compartment, the ice maker may be arranged within the freezer compartment or the fresh food compartment. 
     A typical ice-making cycle includes the steps of initialization, freeze, check bail arm, harvest ice cubes, and water fill. An ejector finger pivots relative to the ice tray for removing ice pieces from the ice tray during the ice harvesting process. 
     However, in certain situations, the ejector finger cannot rotate, possibly due to accumulation of ice that causes a blockage in the ice tray. It is desirable to provide a reliable ice maker control to detect and remove ice that may be interfering with the movement of the ejector finger. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with one aspect, there is provided a method for controlling an ice maker having an ice maker heater and a motor that rotates an ejector finger relative to an ice tray in a first direction and in a second direction opposite the first direction to discharge ice from the ice tray. The method includes determining whether an error condition has occurred and, when it is determined that the error condition has occurred, entering a first error mode. The first error mode includes turning on the ice maker heater, turning off the ice maker heater when an ice maker heater error correction time has elapsed or when a temperature of the ice tray is equal to or greater than a first predetermined temperature, and determining whether the ejector finger is at a home position. When the ejector finger is at the home position, the first error mode further includes rotating the motor in the second direction until the ejector finger is not at the home position or for a first predetermined number of steps, whichever occurs first, and then rotating the motor in the first direction until the ejector finger is at the home position. When the ejector finger is not at the home position, the first error mode further includes rotating the motor in the second direction until the ejector finger is at the home position or for a second predetermined number of steps, whichever occurs first. 
     In the method according to the foregoing aspect, the determining whether the error condition has occurred includes determining the error condition has occurred when the ejector finger cannot rotate in one of the first direction or in the second direction. 
     In the method according to the foregoing aspect, the determining whether the ejector finger is at the home position is performed by a sensor configured to detect an angular position of the ejector finger. 
     In the method according to the foregoing aspect, the determining whether the error condition has occurred includes determining the error condition has occurred when the ejector finger is not at the home position at some time during the rotating the motor. 
     In the method according to the foregoing aspect, the method further includes exiting the first error mode when, after rotating the motor in the first direction or in the second direction, the ejector finger is at the home position within a first predetermined time; and entering a second error mode different from the first error mode if the first error mode is not exited after the first predetermined time. 
     In the method according to the foregoing aspect, the second error mode includes turning on the ice maker heater; turning off the ice maker heater when the temperature of the ice tray is equal to or greater than a second predetermined temperature; and determining whether the ejector finger is at the home position. When the ejector finger is not at the home position, the second error mode includes terminating the second error mode and entering the first error mode. When the ejector finger is at the home position, the second error mode includes rotating the motor in the first direction for a third predetermined number of steps. The second error mode further includes determining whether the ejector finger is at the home position. When the ejector finger is at the home position, the second error mode includes terminating the second error mode. When the ejector finger is not at the home position, the second error mode includes rotating the motor in the first direction until the ejector finger is at the home position and terminating the second error mode or, if the ejector finger is not at the home position after rotating the motor for the second predetermined number of steps, waiting for a second predetermined time and after the second predetermined time elapses, entering the first error mode. 
     In the method according to the foregoing aspect, the method further includes counting at least one of an ice maker heater deactivation period of time or a time the icemaker has been making ice; and comparing at least one of the ice maker heater deactivation period of time or the time the icemaker has been making ice to a third predetermined time. When at least one of the ice maker heater deactivation period of time or the time the icemaker has been making ice is equal to or greater than the third predetermined time and when an ice bin is not full of ice, the method further includes turning on the ice maker heater to melt frost built up on the ice tray; monitoring the temperature of the ice tray; comparing the temperature of the ice tray to a third predetermined temperature; and turning off the ice maker heater when the temperature of the ice tray is equal to or greater than the third predetermined temperature. 
     In the method according to the foregoing aspect, the method further includes, after turning off the ice maker heater, filling the ice maker with water. 
     In the method according to the foregoing aspect, the determining whether the error condition has occurred includes determining the error condition has occurred when the ejector finger rotates in the second direction the first predetermined number of steps and the ejector finger is not at the home position. 
     In the method according to the foregoing aspect, the determining whether the error condition has occurred includes determining the error condition has occurred when the ejector finger rotates in the second direction the second predetermined number of steps and the ejector finger is not at the home position. 
     In accordance with another aspect, there is provided a method for controlling an ice maker having an ice bin, a motor configured to rotate an ejector finger relative to an ice tray in a first direction and in a second direction opposite the first direction to discharge ice from the ice tray, and an ice maker heater. The method includes rotating the ejector finger to a home position; when the ejector finger is at the home position: turning on the ice maker heater; turning off the ice maker heater when an ice maker heater harvest time has elapsed or when a temperature of the ice tray is equal to or greater than a first predetermined temperature; and performing a harvest operation. The harvest operation includes: rotating the motor in the second direction until the ejector finger is not at the home position, then rotating the motor in the second direction until the ejector finger is at the home position, and then rotating the motor in the second direction until the ejector finger is not at the home position. When the harvest operation is completed before the motor has rotated a corresponding number of steps, the method further includes rotating the motor in the first direction until the ejector finger is at the home position and when any part of the harvest operation is not completed before the motor has rotated the corresponding number of steps, entering a first error mode; determining at least one of a time that the ice maker heater has been deactivated or a time the icemaker has been making ice; comparing at least one of the time that the ice maker heater has been deactivated or a time the icemaker has been making ice to a predetermined time; turning on the ice maker heater when at least one of the time that the ice maker heater has been deactivated or the time the icemaker has been making ice is equal to or greater than the predetermined time; and when at least one of the time that the ice maker heater has been deactivated or the time the icemaker has been making ice is lower than the predetermined time, filling the ice tray with water. 
     The method according to the foregoing aspect further comprises, after turning off the ice maker heater, filling the ice tray with water. 
     In accordance with another aspect, there is provided an ice maker including an ice tray having an ice mold with an upper surface and a plurality of cavities formed therein for freezing water into ice pieces; a heater attached to a bottom surface of the ice mold; a motor configured to rotate an ejector finger relative to the ice tray in a first direction and in a second direction opposite the first direction to discharge the ice pieces from the ice tray; an ice bin configured to receive and store the ice pieces from the ice tray; and a controller. The controller is programmed to determine whether an error condition has occurred. When it is determined that the error condition has occurred, the controller causes the ice maker to enter a first error mode. The first error mode comprises turning on the heater; turning off the heater when an ice maker heater error correction time has elapsed or when a temperature of the ice tray is equal to or greater than a first predetermined temperature; and determining whether the ejector finger is at a home position. When the ejector finger is at the home position, the first error mode further comprises rotating the motor in the second direction until the ejector finger is not at the home position or for a first predetermined number of steps, whichever occurs first, and then rotating the motor in the first direction until the ejector finger is at the home position. When the ejector finger is not at the home position, the first error mode further comprises rotating the motor in the second direction until the ejector finger is at the home position or for a second predetermined number of steps, whichever occurs first. 
     The ice maker according to the foregoing aspect further comprises a bail arm attached to the ice tray. The bail arm is configured to pivot between an ice sensing position for sensing a level of ice within the ice bin and an ice harvest position. When the ejector finger is at the home position and the bail arm is in the ice harvest position, the controller is further configured to rotate the motor and the ejector finger to harvest the ice pieces and transfer the ice pieces into the ice bin. 
     In the ice maker according to the foregoing aspect, the temperature of the ice tray is monitored by a temperature sensor arranged on the ice tray and operatively connected to the controller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a household French Door Bottom Mount showing doors of the refrigerator in a closed position; 
         FIG. 2  is a front perspective view of the refrigerator of  FIG. 1  showing the doors in an open position and an ice maker in a fresh food compartment; 
         FIG. 3  is a side perspective view of an ice maker with a side wall of a frame of the ice maker removed for clarity; 
         FIG. 4  is a side perspective view of an ice tray assembly for the ice maker of  FIG. 3  illustrating a bail arm in both a first, upper position and a second, lower position; 
         FIG. 5  is an exploded view of the ice tray assembly of  FIG. 4 ; 
         FIG. 6  is top view of the ice tray assembly of  FIG. 4  with a cover of the ice tray assembly removed; 
         FIG. 7  is a section view of the ice tray assembly of  FIG. 4 ; 
         FIG. 8  is a side perspective view of the bail arm of the ice tray assembly of  FIG. 4 ; 
         FIG. 9  is a section view taken along lines  22 - 22  of  FIG. 8 ; 
         FIG. 10  is an end view of the ice tray assembly of  FIG. 4  illustrating the bail arm in both the first, upper position and the second, lower position; 
         FIG. 11  is an exploded view of a gear box of  FIG. 4 ; 
         FIG. 12  is a front perspective view of a gear mechanism assembly of the gear box of  FIG. 4 ; 
         FIG. 13  is a rear perspective view of the gear mechanism assembly of  FIG. 12 ; 
         FIGS. 14A-14D  are front views of the gear box of  FIG. 11  with a cover and an intermediate cover removed, illustrating the gear mechanism assembly in various states of operation for determining a condition of an ice bin; and 
         FIGS. 15A-15D  is a rear view of the gear box of  FIG. 11  with a housing removed, illustrating the gear mechanism assembly in various states of operation for determining a condition of an ice bin. 
         FIG. 16  is a flowchart illustrating the overall control flow of the ice maker; 
         FIG. 17A  is a flowchart illustrating the ice maker&#39;s first error mode; 
         FIG. 17B  is a flowchart illustrating the ice maker&#39;s second error mode; 
         FIG. 18  is a flowchart illustrating the ice maker&#39;s harvest process; and 
         FIG. 19  is a flowchart illustrating the ice maker&#39;s defrost process. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     An apparatus and a method will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments of the disclosure are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 
     Referring now to the drawings,  FIG. 1  shows a refrigeration appliance in the form of a domestic refrigerator, indicated generally at  20 . Although the detailed description that follows concerns a domestic refrigerator  20 , the invention can be embodied by refrigeration appliances other than with a domestic refrigerator  20 . Further, an embodiment is described in detail below, and shown in the figures as a bottom-mount configuration of a refrigerator  20 , including a fresh food compartment  24  disposed vertically above a freezer compartment  22 . However, the refrigerator  20  can have any desired configuration including at least a fresh food compartment  24  and an ice maker  50  (as shown in  FIG. 2 ), such as a top mount refrigerator (freezer disposed above the fresh food compartment), a side-by-side refrigerator (fresh food compartment is laterally next to the freezer compartment), a standalone refrigerator or freezer, etc. 
     One or more doors  26  shown in  FIG. 1  are pivotally coupled to a cabinet  29  of the refrigerator  20  to restrict and grant access to the fresh food compartment  24 . The door  26  can include a single door that spans the entire lateral distance across the entrance to the fresh food compartment  24 , or can include a pair of French-type doors  26  as shown in  FIG. 1  that collectively span the entire lateral distance of the entrance to the fresh food compartment  24  to enclose the fresh food compartment  24 . For the latter configuration, a center flip mullion  31  ( FIG. 2 ) is pivotally coupled to at least one of the doors  26  to establish a surface against which a seal provided to the other one of the doors  26  can seal the entrance to the fresh food compartment  24  at a location between opposing side surfaces  27  ( FIG. 2 ) of the doors  26 . The mullion  31  can be pivotally coupled to the door  26  to pivot between a first orientation that is substantially parallel to a planar surface of the door  26  when the door  26  is closed, and a different orientation when the door  26  is opened. The externally-exposed surface of the center mullion  31  is substantially parallel to the door  26  when the center mullion  31  is in the first orientation, and forms an angle other than parallel relative to the door  26  when the center mullion  31  is in the second orientation. The seal and the externally-exposed surface of the mullion  31  cooperate approximately midway between the lateral sides of the fresh food compartment  24 . 
     Turning back to  FIG. 1 , a dispenser  28  for dispensing at least ice pieces, and optionally water, can be provided on an exterior of one of the doors  26  that restricts access to the fresh food compartment  24 . The dispenser  28  includes a lever, switch, proximity sensor or other device that a user can interact with to cause frozen ice pieces to be dispensed from an ice bin  54  ( FIG. 2 ) of the ice maker  50  disposed within the fresh food compartment  24 . Ice pieces from the ice bin  54  can exit the ice bin  54  through an aperture  62  and be delivered to the dispenser  28  via an ice chute  32  ( FIG. 2 ), which extends at least partially through the door  26  between the dispenser  28  and the ice bin  54 . 
     Referring to  FIG. 1 , the freezer compartment  22  is arranged vertically beneath the fresh food compartment  24 . A drawer assembly (not shown) including one or more freezer baskets (not shown) can be withdrawn from the freezer compartment  22  to grant a user access to food items stored in the freezer compartment  22 . The drawer assembly can be coupled to a freezer door  21  that includes a handle  25 . When a user grasps the handle  25  and pulls the freezer door  21  open, at least one or more of the freezer baskets is caused to be at least partially withdrawn from the freezer compartment  22 . 
     The freezer compartment  22  is used to freeze and/or maintain articles of food stored in the freezer compartment  22  in a frozen condition. For this purpose, the freezer compartment  22  is in thermal communication with a freezer evaporator (not shown) that removes thermal energy from the freezer compartment  22  to maintain the temperature therein at a temperature of 0° C. or less during operation of the refrigerator  20 , preferably between 0° C. and −50° C., more preferably between 0° C. and −30° C. and even more preferably between 0° C. and −20° C. 
     Referring to  FIG. 2 , the refrigerator  20  includes an interior liner  34  that defines the fresh food compartment  24 . The fresh food compartment  24  is located in the upper portion of the refrigerator  20  in this example and serves to minimize spoiling of articles of food stored therein. The fresh food compartment  24  accomplishes this by maintaining the temperature in the fresh food compartment  24  at a cool temperature that is typically above 0° C., so as not to freeze the articles of food in the fresh food compartment  24 . It is contemplated that the cool temperature preferably is between 0° C. and 10° C., more preferably between 0° C. and 5° C. and even more preferably between 0.25° C. and 4.5° C. According to some embodiments, cool air from which thermal energy has been removed by the freezer evaporator  82  can also be blown into the fresh food compartment  24  to maintain the temperature therein greater than 0° C. preferably between 0° C. and 10° C., more preferably between 0° C. and 5° C. and even more preferably between 0.25° C. and 4.5° C. For alternate embodiments, a separate fresh food evaporator (not shown) can optionally be dedicated to separately maintaining the temperature within the fresh food compartment  24  independent of the freezer compartment  22 . According to an embodiment, the temperature in the fresh food compartment  24  can be maintained at a cool temperature within a close tolerance of a range between 0° C. and 4.5° C., including any subranges and any individual temperatures falling with that range. For example, other embodiments can optionally maintain the cool temperature within the fresh food compartment  24  within a reasonably close tolerance of a temperature between 0.25° C. and 4° C. 
     The upper compartment and the lower compartment of the liner  72  are configured such that the air circulated in the upper compartment is maintained separated from the air circulated in the lower compartment. The lower compartment defines the freezer compartment  100  and an adjustable temperature drawer or a Variable Climate Zone (“VCZ”) compartment  150 . In this respect, the air circulated in the fresh food compartment  52  is maintained separated from the air circulated in the VCZ compartment  150  and the freezer compartment  100 . 
     An illustrative embodiment of the ice maker  50  is shown in  FIG. 3 . In general, the ice maker  50  includes a frame or enclosure  52 , an ice bin  54 , an air handler assembly  70  and an ice tray assembly  100 . The ice bin  54  stores ice pieces made by the ice tray assembly  100  and the air handler assembly  70  circulates cooled air to the ice tray assembly  100  and the ice bin  54 . The ice maker  50  is secured within the fresh food compartment  24  using any suitable fastener. The frame  52  is generally rectangular-in-shape for receiving the ice bin  54 . The frame  52  includes insulated walls for thermally isolating the ice maker  50  from the fresh food compartment  24 . A plurality of fasteners (not shown) may be used for securing the frame  52  of the ice maker  50  within the fresh food compartment  24  of the refrigerator  20 . The ice tray assembly  100 , in turn, can be secured to the frame  52 . 
     For clarity, the ice maker  50  in  FIG. 3  is shown with a side wall of the frame  52  removed; normally, the ice maker  50  would be enclosed by insulated walls. The ice bin  54  includes a housing  56  having an open, front end and an open top. A front cover  58  is secured to the front end of the housing  56  to enclose the front end of the housing  56 . When secured together to form the ice bin  54 , the housing  56  and the front cover  58  define an internal cavity  54   a  of the ice bin  54  used to store the ice pieces made by the ice tray assembly  100 . In various other examples, a recess  59  may be formed in a side of the front cover  58  to define a handle that may be used by a user for ease in removing the ice bin  54  from the ice maker  50 . An aperture  62  is formed in a bottom of the front cover  58 . A rotatable auger (not shown) can extend along a length of the ice bin  54 . As the auger rotates, ice pieces in the ice bin  54  are urged ice towards the aperture  62  wherein an ice crusher (not shown) may be disposed. The ice crusher may be provided for crushing the ice pieces conveyed thereto, when a user requests crushed ice. The auger can optionally be automatically activated and rotated by an auger motor assembly (not shown) of the air handler assembly  70 . The aperture  62  can be aligned with the ice chute  32  ( FIG. 2 ) when the door  26  is closed. This alignment allows for the auger to push the frozen ice pieces stored in the ice bin  54  into the ice chute  32  to be dispensed by the dispenser  28 . 
     Referring to  FIG. 4 , an ice tray assembly  500 , in general, includes an ice mold  510 , an ice stripper  540 , an ice ejector  550 , a cover  570 , a bail arm  610 , and a gear box  630 . The gear box  630  includes a plurality of gears for moving various components of an ice maker, such as the ice ejector  550  and the bail arm  610 , for example. The gear box  630  is usually attached to an end of the ice tray assembly  500 . Components of the ice maker illustrated in  FIGS. 4-15D  are described in U.S. Pat. No. 10,539,354 and US publications 2020/0080759 and 2020/0109886, for example, the entire contents of which are incorporated herein by reference. 
     A temperature sensor  520  ( FIG. 5 ), such as a negative temperature coefficient (NTC) thermistor, for example, may be positioned to measure the temperature of the ice tray  510 . For example, the temperature sensor  520  can be positioned between ice mold  510  (i.e., the ice tray  510 ) and the gear box  630 . Other locations or arrangements of the temperature sensor  520  may be suitable for detecting the temperature of the ice tray  510 . 
     The bottom surface  514  of the ice mold  510  may be contoured to receive a heater  126  (shown in  FIG. 7 ). For, example, the bottom surface  514  can include a groove (not shown) that extends about the periphery of the bottom surface  514  for receiving the heater  126  therein. The heater  126  can heat the ice mold  510  to thereby separate congealed ice pieces from the ice mold  510  during an ice harvesting operation. The heater  126  may be an electric resistive heater that may be captured in the groove formed in the bottom surface  514  of the ice mold  510 . The heater  126  can be configured to be in direct or substantially direct contact with the ice mold  510  for increased conductive heat transfer. The heater  126  may be a U-shaped element that extends around a periphery of the bottom surface  514  and has a cylindrical outer surface. The legs of the U-shaped heater  126  may extend along the lateral direction of the ice mold  512 . It is contemplated that the heater  126  may have other shapes, for example, but not limited to, circular, oval, spiral, etc., so long as the heater  126  is disposed in direct or substantially direct contact with the ice mold  510 . 
     The lateral sides  516  of the ice mold  510  can be contoured or sculpted to receive an ice maker evaporator (not shown). For example, the lateral side surfaces  516  may include elongated recess (not shown) that closely matches the outer profile of the ice maker evaporator. 
     Referring to  FIG. 5 , a support  544  is formed at an end of the ice stripper  540  that is received into a recess  532  of the ice mold  510 . A hole  546  extends through a portion of the ice stripper  540  adjacent the support  544 . The hole  546  is dimensioned and positioned to align with a hole  534  of the ice mold  510  when the support  544  is received into the recess  532  of the ice mold  510 . The support  544  is dimensioned to allow the ice ejector  550  to rotate therein. The support  544  can act as a cylindrical bearing for allowing a matching portion of the ice ejector  550  to rotate therein. 
     The ice ejector  550 , in general, is a rod-shaped element having a main body  552  with a plurality of fingers  554  extending from the main body  552 . A first end  556  of the ice ejector  550  is dimensioned to be received into a first opening  631   a  of the gear box  630  to allow the first end  556  to engage an output gear  658  (shown in  FIG. 11 ) inside the gear box  630 , as described in detail below. The first end  556  rotates within the recess  523  in the ice mold  510 . In this respect, the recess  523  in the ice mold  510  and the support  544  in the ice stripper  540  define bearing surfaces for allowing the ice ejector  550  to rotate about its longitudinal axis. 
     Referring to  FIG. 6 , the ice ejector  550  is positioned within the ice mold  510  and the ice stripper  540 . The fingers  554  of the ice ejector  550  are dimensioned and positioned to align with the spaces between the tabs  542  of the ice stripper  540  and the cavities  518  in the ice mold  510 . As the ice ejector  550  rotates about its longitudinal axis that the fingers  554  move through the cavities  518  in the ice mold  510  to force ice pieces (not shown) out of the cavities  518 . 
     The projection  562  is fixed relative to the fingers  554  for allowing a controller  800  ( FIG. 4 ) to ascertain the orientation of the fingers  554  (collectively referred to herein as the “ejector finger”). 
     The controller  800  may be a part of the main control board of the refrigerator control system that controls a plurality of functions commonly associated with a refrigeration appliance, such as the temperature of the refrigeration compartments, activating the compressor and the condenser fan, and the like. Alternatively, the controller  800  may be a separate dedicated controller that is used substantially only for controlling the ice maker operations. For example, the controller  800  may be a separate controller arranged in the gear box  630  ( FIG. 5 ). 
     The controller  800  can be an electronic controller and may include a processor. The controller  800  can include one or more of a microprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), discrete logic circuitry, or the like. The controller  800  can further include at least one timer that keeps track of, or counts, various time intervals described herein. The controller  800  can also include memory and may store program instructions that, when executed by the controller  800 , cause the controller  800  to provide the functionality ascribed to it herein. Specifically, the controller  800  can be programmed to control the operations of the ice maker, the ice maker heater and the defrost heaters, among other refrigerator components, to carry out the control method described below. The memory may store different predetermined numbers of steps of rotation of the stepper motor, as described below. The memory may include one or more volatile, non-volatile, magnetic, optical, or electrical media, such as read-only memory (ROM), random access memory (RAM), electrically-erasable programmable ROM (EEPROM), flash memory, or the like. The controller  800  can further include one or more analog-to-digital (A/D) converters for processing various analog inputs to the controller. 
     The controller  800  can include input/output circuitry for interfacing with the various system components. For example, the controller  800  can receive and interpret temperature signals from various sensors, including but not limited to a Hall sensor  710 , an ice maker temperature sensor, and a temperature sensor  520  (shown in  FIG. 5 ), such as a negative temperature coefficient (NTC) thermistor, for example, that measures the temperature of the ice tray, and is used only during system defrost, for example. The controller  800  can process these signals to control the operation of ice maker, as well as other refrigeration and non-refrigeration components described above based on these signals. Specifically, based on these inputs, the controller  800  can control the status (on/off) of the ice maker and various ice maker modes, such as initialization, freeze, check bail arm, harvest, full-bucket, error modes, and defrost (which may be an ice maker defrost and/or a system defrost). Outputs of the controller  800  can be parameters related to the operation of the gearbox stepper motor, the ice maker defrost heater, the bistable valve (e.g., stepper valve), an air handler fan, the water valve, the auger motor, the ice selector, the compartment portion defrost heater, and the fill-tube heater. 
     Referring back to  FIGS. 4 and 5 , a D-shaped projection  562  can extend from the second end  558  of the ice ejector  550  such that a flat surface of the projection  562  is in a predetermined orientation when the ejector fingers  554  are in a “Home” position. In the “Home” position, the ejector finger  550  is horizontal, facing the ice stripper  540 . 
     The “Home” position of the ejector finger  550  is not a single point or a specific angle, but rather refers to any angular position within a specified rotational range of the ejector finger  550  (e.g., from −23 to +5 degrees). For example, the “Home” position of the ejector finger  550  may be any position within the range from −23 to +5 degrees and any position within a range from 337 to 360 degrees. The remaining areas (outside the range from −23 to +5 degrees and the range from 337 to 360 degrees) can be programmed into the memory of the controller  800  as positions of the ejector finger  550  that are outside the “Home” position. These ranges are only examples, and other ranges may be programmed as the “Home” position and the positions outside the “Home” position of the ejector finger  550 . 
     Referring to  FIG. 5 , a protrusion  612  extends from a distal end of the bail arm  610  and is dimensioned to a second opening  631   b  of the gear box  630 . It is contemplated that the second opening  631   b  may align with an opening  704  in a drive shaft  702  (both shown in  FIGS. 12 and 13 ) for allowing the drive shaft  702  to pivot the bail arm  610 , as described in detail below. 
     Referring to  FIG. 8 , the bail arm  610 , in general, is an L-shaped element having a first leg  614  and a second leg  622 . The bail arm  610  detects the presence and the level of ice stored in the ice bin  54  located next to the ice maker  50  (both shown in  FIGS. 2 and 3 ). The protrusion  612  is disposed at a distal end of the first leg  614  for engaging the gear box  630 . A fastener (not shown) may extend through a hole  616  that extends through the protrusion  612  for securing the bail arm  610  to the gear box  630 . The second leg  622  extends from an opposite end of the first leg  614 . 
     The second leg  622 , in general, has a T-shaped cross-section (see  FIG. 9 ) and includes a base portion  624  and a leg portion  626 . A plurality of spaced-apart ribs  628  are positioned between the base portion  624  and the leg portion  626 . The plurality of spaced-apart ribs  628  may be contoured to be within a rectangular space C defined by the base portion  624  and the leg portion  626  (see  FIG. 9 ). The spaced-apart ribs  628  may be configured to provide structural support to the bail arm  610 . In the embodiment illustrated, the spaced-apart ribs  628  are aligned to be parallel to a pivot axis D (see  FIGS. 4 and 8-9 ) of the bail arm  610 . The pivot axis D is defined by the hole  616 . 
     A distal end of the second leg  622  is angled relative to the remaining portion of the second leg  622  to define an angled pad  629 . It is contemplated that the angled pad  629  may be dimensioned and positioned to engage ice pieces that are disposed in the ice bin  54  ( FIG. 3 ), as described in detail below. 
     Referring to  FIG. 11 , the gear box  630  includes a housing  632 , a cover  642 , an intermediate cover  644  and a gear mechanism assembly  650 . A motor (not shown) and a drive gear (not shown) are disposed in an area  646  of the housing  632 . The drive gear may be attached to an output shaft (not shown) of the motor for transferring rotational movement to the gear mechanism assembly  650 . An intermediate cover  644  is disposed in the housing  632  and defines a chamber for receiving the gear mechanism assembly  650  and enclosing the area  646  wherein the motor (not shown) and the drive gear (not shown) are disposed. 
     During operation of the ice maker, the controller  800  may energize the motor to rotate, which causes the ice ejector  550  ( FIG. 5 ) to rotate about its longitudinal axis. The motor can be a stepper motor, such as a brushless DC electric motor, that divides a full 360-degree rotation into a number of equal rotational steps, for example. At least certain numbers of steps corresponding to different amounts of rotation of the motor can be programmed and saved in the memory of the controller  800  and used to control the operation of the ice maker as described below. For example, a predetermined number of rotational steps of the stepper motor can be programmed into the memory of the controller  800  to correspond to the amount of rotation of the motor that causes the ice ejector  550  to rotate a certain number of degrees around a circle. The degrees of rotation (and corresponding steps) can cause the ejector finger  550  to rotate from a known or assumed position to a desired position, such as the “Home” position range, positions outside the “Home” position, a position detecting the position of the bail arm  610 , etc. Examples of degrees of rotation and corresponding steps in different situations are described below. 
     Referring to  FIGS. 12 and 13 , the gear mechanism assembly  650  includes a first gear  652  that meshes with the drive gear (not shown) attached to the motor (not shown). The first gear  652  drives a first intermediate gear  654 , which in turn drives a second intermediate gear  656 . The second intermediate gear  656  drives an output gear  658 . The output gear  658  includes an opening  658   a  that is dimensioned to align with the first opening  631   a  in the housing  632 . The first end  556  of the ice ejector  550  ( FIG. 5 ) extends through the first opening  631   a  and engages the opening  658   a  of the output gear  658 . 
     Via the first gear  652 , the first and second intermediate gears  654 ,  656  and the output gear  658 , rotation of the motor causes the ice ejector  550  to turn in the desired direction—clockwise (CW) direction (also referred to as “first direction”) or counter-clockwise (CCW) direction (also referred to as “second direction”). 
     The drive gears  652 ,  654 ,  656 , and  658  can continue to move, and the motor can continue to rotate through the steps, regardless whether the ice ejector  550  is blocked and unable to move. In other words, the motor can keep rotating even if the ice ejector  550  is not moving. 
     The gear mechanism assembly  650  also includes a first lever arm  662  that is pivotably attached inside the gear box  630 . The first lever arm  662  includes a first leg  664  extending from a central pivot body  666  of the first lever arm  662 . A pocket  668  is formed in a distal end of the first leg  664 . The pocket  668  is dimensioned to receive a magnetic element (not shown). A protrusion  669  extends from a side of the first leg  664  and is positioned to engage a first cam  659  on one side of the output gear  658 , as described in detail below. 
     A second leg  672  extends from the central pivot body  666  and includes a hook portion  674  configured to attach to a spring (not shown). The spring biases the first lever arm  662  into a first position, shown in  FIGS. 14A, 14C, 15A, 15C . The first lever arm  662  also includes a post  676  ( FIG. 12 ) that engages a pocket  688  formed in a second lever arm  682 , as described in detail below. 
     The second lever arm  682  includes a central pivot body  684  and an arm portion  686  attached to the central pivot body  684 . The pocket  688  is positioned and dimensioned to receive the post  676  of the first lever arm  662 . A receiver  692  is formed at a distal end of the arm portion  686  for engaging a post  706  extending from a drive shaft  702 , as described in detail below. A protrusion  694  extends from one side of the arm portion  686  and is positioned to engage a second cam  671  on a side of the output gear  658  opposite to the first cam  659 . 
     The drive shaft  702  includes an opening  704  that is dimensioned to receive the protrusion  612  on the distal end of the bail arm  610 . The opening  704  is positioned to align with the second opening  631   b  of the gear box  630  ( FIG. 11 ) when the drive shaft  702  is positioned in the housing  632 . The post  706  extending from the drive shaft  702  is dimensioned and positioned to be received into the receiver  692  of the second lever arm  682 . The post  706  is attached to a spring (not shown) that biases the drive shaft  702  to a first rotated position corresponding to the bail arm  610  being in a second lower position B, as described in detail below. 
     During operation of the ice tray assembly  500 , the controller  800  may first actuate the bail arm  610  to determine whether ice needs to be added to the ice bin  54  ( FIG. 3 ). To determine this, the controller  800  may energize the motor (not shown) in the gear box  630  to cause the bail arm  610  to pivot from a first upper position A to the second lower position B, as shown in  FIGS. 4 and 10  about the pivot axis D. If the bail arm  610  contacts ice pieces prior to reaching the second lower position B (e.g., as determined by an increase in the power required to pivot the bail arm  610  or a combination of gears, linkages and sensors for determining when the bail arm  610  contacts ice pieces) the controller  800  may cause the bail arm  610  to be returned to the first upper position A. Accordingly, the controller  800  may then prevent the harvesting of ice pieces from the ice tray assembly  500  to the ice bin  54 . However, if the bail arm  610  reaches the second lower position B without contacting ice pieces, then the controller  800  may cause the ice tray assembly  500  to harvest ice pieces into the ice bin  54  ( FIG. 3 ). According to one aspect, the controller  800  may control the gear box  630  in the following manner to detect whether the ice bin  54  is full or empty. 
     Referring to  FIGS. 14A-14B , the gear box  630  includes a Hall sensor  710  that may be mounted to a printed circuit board (PCB) (not shown) that is disposed in the housing  632 . The Hall sensor  710  detects the position of the bail arm  610  and the position of the ejector finger  550 , as described below. The Hall sensor provides either a HIGH signal or a LOW signal to the control system of the ice maker (e.g., to the controller  800 ). When the ejector finger  550  and the bail arm  610  are in the so called “Home” position and the ice bin is full of ice, the signal from Hall sensor  710  will be LOW. When the ejector finger  550 , the bail arm  610 , and the ice level are in other conditions (e.g., when the ejector finger  550  is outside the “Home” position or the ice bin is empty), the signal from the Hall sensor  710  will be HIGH. 
     Referring to  FIGS. 14A and 15A , the first and second lever arms  662 ,  682  are shown in a first position, as referred to as a “Home” position. In this first position, the spring (not shown) attached to the hook portion  674  of the first lever arm  662  biases the distal end of the first lever arm  662  (which includes the pocket  668  for receiving the magnetic element (not shown)) to a first position adjacent the Hall sensor  710 . When the magnetic element is positioned adjacent the Hall sensor  710 , based on the Hall effect of the generated voltage, the Hall sensor  710  provides a LOW signal as an input to the controller  800 . A LOW input signal from the Hall sensor  710  indicates that the ejector finger  550  is in the “Home” position and the position of the bail arm  610  indicates a full ice bucket. 
     Further, the first lever arm  662  is allowed into the first position because the protrusion  669  on the first lever arm  662  is received into a recess  659   a  ( FIGS. 15B, 15C and 15D ) of the first cam  659  on the output gear  658 . The position of the ejector finger  550  in the recess  659   a  may be programmed into the memory of the controller  800  as the lowest position (e.g., −23 degrees) in the “Home” position range of −23 to 5 degrees. The position of the ejector finger  550  in the protrusion  669  may be programmed into the memory of the controller  800  as the highest position (e.g., −23 degrees) in the “Home” position range of −23 to 5 degrees. 
     The motor rotates the ejector finger  550  until the output from the Hall sensor  710  changes (from LOW to HIGH, and vice versa) or for a predetermined preprogrammed number of steps, whichever comes first. The controller  800  can be programmed to detect that the ejector finger  550  is at the edge of the “Home” area when the output from the Hall sensor  710  changes. If the ejector finger  550  is in the “Home” position and the motor rotates for a predetermined number of steps, the ejector finger  550  will rotate out of the “Home” position, unless there is a problem (e.g., something is blocking the ejector finger  550 ). Likewise, if the ejector finger  550  is outside the “Home” position and the motor rotates for a predetermined number of steps, the ejector finger  550  will rotate to the “Home” position, unless there is a problem (e.g., something is blocking the ejector finger  550 ). 
     The controller  800  can be programmed to monitor and detect the input signal from the Hall sensor  710  at all times. During ice making, water fill, full bucket mode, and at the beginning of “check bail arm” or “harvest” mode, the input signal from the Hall sensor  710  should always be LOW. The input signal from the Hall sensor  710  can change according to the intended movement of the ejector finger  550 . For example, before the stepper motor starts to rotate, the input signal from the Hall sensor  710  should be LOW, and after a certain number of rotating steps, the input signal from the Hall sensor  710  can change to HIGH. If the controller  800  detects a HIGH input signal from the Hall sensor  710  when such input is not intended, the controller  800  will cause the ice maker to enter an error mode, as described below. A timeout can occur when the motor rotates for a predetermined number of steps and there is no change of state of the Hall sensor  710 . 
     In addition, the protrusion  694  on the second lever arm  682  engages the second cam  671  on the output gear  658  such that the second lever arm  682  is in the first position. When in the first position, the second lever arm  682  is pivoted downward (relative to  FIG. 14A ) such that the drive shaft  702  is positioned in a second rotated position that corresponds to the bail arm  610  being in the upper position A ( FIG. 4 ). 
     As the output gear  658  rotates in the counter-clockwise direction (with reference to  FIGS. 14A-14D ) the output gear  658  is eventually positioned such that the protrusion  694  on the second lever arm  682  aligns with a recess  671   a  in the second cam  671 . In this position, the spring (not shown) attached to the post  706  of the second lever arm  682  causes the drive shaft  702  to rotate the bail arm  610  from the first upper position A toward the second lower position B. If the bail arm  610  is able to reach the second lower position B, then the first lever arm  662  and the second lever arm  682  will be positioned as shown in  FIGS. 14B and 15B . In particular, the protrusion  694  on the second lever arm  682  will bottom out in the recess  671   a  so that the second lever arm  682  pivots to a second position. As the second lever arm  682  pivots, the pocket  688  in the second lever arm  682  will engage the post  676  on the first lever arm  662  and cause the first lever arm  662  to pivot to a second position. In the second position, the pocket  668  (and the magnetic element therein) in the first lever arm  662  are positioned away from the Hall sensor  710 . When the magnetic element is positioned away from the Hall sensor  710 , the Hall sensor  710  will send a signal indicative of HIGH to the controller  800 . 
     In contrast, if the bail arm  610  is not able to reach the second lower position B, e.g., it contacts ice pieces in the ice bin  54 , then the protrusion  694  will not bottom-out in the recess  671   a  and the second lever arm  682  will remain in the first position. See  FIGS. 14C and 14B . In this position the pocket  668  (and the magnetic element therein) will remain adjacent the Hall sensor  710  and the Hall sensor  710  will send a signal indicative of LOW to the controller  800 . As illustrated in  FIG. 15C , the protrusion  669  on the first lever arm  662  will be positioned in the recess  659   a  such that the first lever arm  662  will remain in the first position. 
     As the output gear  658  continues to rotate in the counter-clockwise direction (with reference to  FIGS. 14A-14D ), the protrusion  694  of the second lever arm  682  will continue to ride on the second cam  671  and maintain the second lever arm  682  in the first position and the bail arm in the first upper position A. The protrusion  669  on the first lever arm  662  will ride on the first cam  659  and cause the first lever arm  662  to pivot to the second position. In this second position the pocket  668  (and the magnetic element therein) will pivot away from the Hall sensor  710 . When the magnetic element is moved from the Hall sensor  710 , the Hall sensor  710  will send a signal indicative of HIGH to the controller  800 . 
     As described above, as the output gear  658  rotates in the counter-clockwise direction (with reference to  FIGS. 14A-14D ), the signal from the Hall sensor  710  will change between HIGH and LOW based on the position of the ejector finger  550  and based on whether the ice bin  54  is full or less than full. In particular, the sequence of the changes between HIGH and LOW will depend on whether the ejector finger  550  is in the “Home” position and whether the ice bin  54  is full or less than full. The controller  800  can be programmed such that, based on the sequence of changes between HIGH and LOW of the Hall sensor  710 , the controller  800  can determine whether the ejector finger  550  is in the “Home” position and whether the ice bin  54  is full or less than full. 
     If the ice bin  54  is less than full, the ice pieces are harvested from the ice mold  510 . In particular, the motor associated with the gear box  630  may cause the ice ejector  550  to rotate such that the fingers  554  move through the cavities  518 . As the fingers  554  move through the cavities  518 , they force the ice pieces in the cavities  518  out of the ice mold  510 . When viewed from the end of the ice tray assembly  500  opposite the gear box  630  (see  FIG. 10 ), the ice ejector  550  is rotatable in a counter-clockwise direction such that the ice ejector  550  forces the ice pieces into an area above the ice mold  510 . A lower surface of the cover  570  is curved to direct the ice pieces toward the opening  571  between the cover  570  and the ice mold  510 . As the ice ejector  550  continues to rotate, the ice pieces are then ejected from the ice tray assembly  500  into the ice bin  54  ( FIG. 3 ) positioned below the ice tray assembly  500 . 
     Referring to  FIG. 10 , during the ejection of the ice pieces from the ice mold  510 , the bail arm  610  is in the first upper position A. In particular, the first leg  614  is positioned adjacent a side of the gear box  630  and the second leg  622  is positioned underneath the ice mold  510 . The ice mold  510  functions as a shield to prevent the ice pieces from striking the second leg  622  of the bail arm  610  as the ice pieces fall toward the ice bin  54  ( FIG. 3 ). 
     The ice maker control method described below provides different steps to detect and remove ice that may be interfering with the movement of the ejector finger  550 . As a result, the ice maker control method described below ensures a reliable ice maker initialization, two error (e.g., failure) modes, and an ice maker defrost mode, in addition to the water fill, freeze, and harvest operations of the ice maker. 
     For example, as described above, the controller  800  can determine whether the ice ejector  550  is at the “Home” position by receiving a signal from the Hall sensor  710 . Based on the signal received from the Hall sensor  710 , the controller  800  can determine that the ice ejector  550  is not rotating in one of the first direction or in the second direction when the status of the Hall sensor  710  does not change from LOW to HIGH at some time during the rotation of the motor. When it is detected that, although the motor continues to rotate for a predetermined number of steps, the ice ejector  550  is not rotating in one of the first direction or in the second direction, the controller  800  can determine that an error condition (e.g., a timeout) has occurred because the ejector finger  550  has either not left the “Home” position or has not reached the “Home” position. The controller  800  can then issue commands to various components of the ice maker to remedy the error condition, as described below. 
     Referring to  FIG. 16 , when the ice maker is first turned ON (“Power ON”) and when the input signal from the Hall sensor  710  is LOW (e.g., indicating that the ejector finger  550  is in the “Home” position), the controller  800  causes the ice maker to enter an ice maker initialization mode. During initialization, the motor rotates the ejector finger  550  and the Hall sensor  710  seeks two Hall sensor HIGH signal boundaries to verify whether the ejector finger  550  is within the range of the “Home” position. Then, the motor rotates the ejector finger  550  until the ejector finger  550  is in the “Home” position (i.e., the ejector finger  550  is horizontal, facing the ice stripper  540 ). When it is detected that, although the motor continues to rotate, the Hall sensor  710  cannot verify the two Hall sensor HIGH signal boundaries indicating that the ejector finger  550  is within the range of the “Home” position (e.g., failed verification), the controller  800  can determine that an error condition has occurred. 
     After the ejector finger  550  reaches the “Home” position, the controller  800  causes the ice maker to enter a “Freeze” mode. During the “Freeze” mode, the compressor of the refrigerator is turned on and the air handler fan circulates cold air over the water in the ice tray  510  ( FIGS. 4 and 5 ) to freeze the water into ice cubes (the ice maker makes ice). 
     During the “Full Bucket” mode, the ice bin is full of ice. The controller  800  stops the ice making process and cycles the air handler fan on and off to maintain the temperature of the ice tray at a predetermined temperature. 
     If any of the “HOME” verification steps fails or if the controller  800  determines that the motor rotates in one of the first direction or in the second direction for a predetermined number of steps (such as the first or second predetermined number of steps described below), but there is no change in the status of the Hall sensor  710  (from LOW to HIGH, and vice versa), the controller  800  determines that an error condition has occurred and causes the ice maker to enter an error mode, such as the first error mode (ERROR 1), for example, as described below. 
     In other words, the controller  800  determines that an error condition has occurred and causes the ice maker to enter the first error mode (ERROR 1) when there is a timeout (e.g., there is no change in the status of the Hall sensor  710  during rotation of the motor for a predetermined number of steps) or when any verification fails. Specifically, the controller  800  checks whether the input signal from the Hall sensor  710  is HIGH or LOW, whether the input signal from the Hall sensor  710  is HIGH or LOW for a certain number of steps relative to the “Home” position of the ice ejector  550 , and whether the ice bucket is full. 
     If the Hall sensor  710  is not LOW (e.g., if the Hall sensor  710  is HIGH, indicating that the ejector finger  550  is not in the “Home” position), the controller  800  causes the ice maker to enter an initialization failure recovery mode. During the initialization failure recovery mode, the motor rotates the ejector finger  550  in the CCW direction until the Hall sensor  710  is LOW. If the status of the Hall sensor  710  does not change from HIGH to LOW during the rotation of the motor for the second predetermined number of steps, the controller  800  causes the ice maker to enter the first error mode (ERROR 1). 
     If the status of the Hall sensor  710  changes from HIGH to LOW during the rotation of the motor for the second predetermined number of steps, the controller  800  causes the ice maker to re-enter the ice maker initialization mode. 
     If the controller  800  determines that, during rotation of the motor, the ice ejector  550  is not rotating in one of the first direction or in the second direction, the controller  800  can cause the ice maker to enter a first error mode (shown as “ERROR 1” in  FIGS. 16, 17A -B, and  21 ). 
     As described above, in certain situations, the motor rotates for a predetermined number of steps, but the controller  800  detects that there is no change of state of the Hall sensor  710 , which indicates that the ejector finger  550  cannot rotate either in the counter-clockwise (CCW) direction or in the clockwise (CW) direction during the rotation of the motor, possibly due to blockage in the ice tray. In this situation, the controller  800  causes the ice maker to enter a first error mode (ERROR 1). 
     Referring to  FIG. 17A , during the first error mode (ERROR 1), the controller  800  turns on the ice maker heater  126  (shown in  FIG. 7 ) to melt any ice blockage that might be interfering with the rotation of the ejector finger  550 . The controller  800  turns off the ice maker heater  126  when a predetermined ice maker heater error correction time has elapsed or when the ice tray temperature is equal to or greater than a first predetermined temperature (e.g., 2° C., for example). The predetermined ice maker heater error correction time may be a predetermined period of time that would be sufficient to at least partially melt ice in the ice tray  510  that may be interfering with the movement of the ejector finger  550 . The controller  800  then checks whether the ejector finger  550  is at the “Home” position (i.e., the Hall sensor  710  is LOW). If the Hall sensor  710  is LOW (path “Yes” in  FIG. 17A ), the motor rotates in the second direction or in the counter-clockwise (CCW) direction until the ejector finger  550  is not at the “Home” position (i.e., the Hall sensor  710  is HIGH) or for a first predetermined number of steps, whichever occurs first. The first predetermined number of steps may be programmed in the memory of the controller  800  as a sufficient number of rotational steps of the motor that would allow the ejector finger  550  to leave the “Home” position at some point during rotation of the motor when the starting position of the ejector finger is within the “Home” position, for example 28 degrees (when the “Home” position has a range of 28 degrees). Then, the motor rotates slightly back in the first direction or in the clockwise (CW) direction until the ejector finger  550  is at the “Home” position (the Hall sensor  710  is LOW). 
     An error condition can occur when the motor rotates for a first predetermined number of steps, and there is no change of the status of the Hall sensor  710 . For example, in the first error mode (ERROR 1), if the motor rotates in the counter-clockwise (CCW) direction for the first predetermined number of steps and the status of the Hall sensor  710  does not change from LOW to HIGH, the controller  800  will detect an error condition, which can indicate that the ejector finger  550  has not left the “Home” position and that the rotation of the ejector finger  550  may be blocked due to ice accumulation in the ice tray  500 , for example. Likewise, if the motor rotates slightly back in the first direction or in the clockwise (CW) direction and the status of the Hall sensor  710  does not change to LOW within a predetermined number of steps, the controller  800  will detect an error condition, which can indicate that the ejector finger  550  has not reached the “Home” position and that the rotation of the ejector finger  550  may be blocked due to ice accumulation in the ice tray  500 , for example. When detecting any timeout (e.g., there is no change in the status of the Hall sensor  710  during rotation of the motor for a predetermined number of steps), the controller  800  causes the ice maker to restart the first error mode (ERROR 1), and the steps illustrated in  FIG. 17A  are repeated from the beginning. 
     If, after rotating the motor in the first direction or in the second direction, the ejector finger  550  is at the “Home” position within a first predetermined time (e.g., 30 minutes, for example) from the start of the first error mode (ERROR 1), the controller  800  causes the ice maker to exit the first error mode (ERROR 1) and resume normal operations (e.g., initialization, freeze, check bail arm, harvest, etc.). 
     If the ejector finger is not at the “Home” position (i.e., the Hall sensor  710  is not LOW, but is HIGH) (path “No” in  FIG. 17A ), the motor rotates in the second direction or in the counter-clockwise (CCW) direction until the ejector finger is at the “Home” position (i.e., the Hall sensor  710  is LOW) or for a second predetermined number of steps, whichever occurs first. The second predetermined number of steps may be programmed in the memory of the controller  800  as a sufficient number of rotational steps of the motor that would allow the ejector finger  550  to enter the “Home” position at some point during rotation of the motor assuming a starting position of the ejector finger is outside the “Home” position, for example 332 degrees (when the “Home” position has a range of 28 degrees). If the Hall sensor  710  is LOW without timeout, the controller  800  causes the ice maker to enter an ice maker initialization mode. 
     During the first error mode (ERROR 1), the controller  800  checks whether the first predetermined time (e.g., 30 minutes, for example) from the start of the first error mode (ERROR 1) has elapsed. If the first predetermined time (30 minutes, for example) from the start of the first error mode (ERROR 1) has elapsed and the Hall sensor has not shown expected operation, the controller  800  causes the ice maker to enter a second error mode (ERROR 2) that is different from the first error mode (ERROR 1). In other words, if the status of the Hall sensor  710  does not change (which indicates that the ejector finger  550  cannot rotate either in the counter-clockwise (CCW) direction or in the clockwise (CW) direction during the rotation of the motor) after operating in the first error mode (ERROR 1) for the first predetermined time (e.g., 30 minutes), the controller  800  causes the ice maker to enter a second error mode (ERROR 2) that is different from the first error mode (ERROR 1). 
       FIG. 17B  illustrates the second error mode (ERROR 2) of the ice maker. The second error mode starts if the first error mode (ERROR 1) cannot recover the ice maker for 30 minutes. During the second error mode, the controller  800  turns on the ice maker heater  126 . The controller  800  turns off the ice maker heater  126  when the ice tray temperature is equal to or greater than a second predetermined temperature (e.g., 2° C. or 5° C., for example). The controller  800  then checks whether the ejector finger  550  is at the “Home” position (i.e., the Hall sensor  710  is LOW). 
     If the ejector finger is not at the “Home” position (i.e., the Hall sensor  710  is not LOW, but is HIGH) (path “No” in  FIG. 17B ), the controller  800  terminates the second error mode (ERROR 2) and causes the ice maker to enter the first error mode (ERROR 1). 
     If the ejector finger  550  is at the “Home” position (i.e., the Hall sensor  710  is LOW) (path “Yes” in  FIG. 17B ), the motor rotates in the first direction or in the clockwise (CW) direction for a third predetermined number of steps. The third predetermined number of steps may be programmed in the memory of the controller  800  as a sufficient number of rotational steps of the motor that would allow the ejector finger  550  to leave the “Home” position and drive the bail arm to check the ice level assuming a starting position of the ejector finger is inside the “Home” position, for example 53 degrees (when the “Home” position and “Full Bucket” position are within 53 degrees of each other). Then, the controller  800  checks again whether the ejector finger  550  is at the “Home” position (i.e., the Hall sensor  710  is LOW). 
     If the ejector finger is at the “Home” position (i.e., the Hall sensor  710  is LOW) (second path “Yes” to the right in  FIG. 17B ), the controller  800  terminates the second error mode (ERROR 2) and causes the ice maker to enter an ice maker initialization mode. If during the ice maker initialization mode, the status of the Hall sensor  710  does not change (which indicates that the ejector finger  550  cannot rotate either in the counter-clockwise (CCW) direction or in the clockwise (CW) direction during the rotation of the motor), the controller  800  terminates the ice maker initialization mode and causes the ice maker to enter the first error mode (ERROR 1). 
     If the ejector finger  550  is not at the “Home” position (i.e., the Hall sensor  710  is not LOW, but is HIGH) (second path “No” to the right in  FIG. 17B ), the motor rotates in the first direction or in the clockwise (CW) direction until the ejector finger  550  is at the “Home” position (i.e., the Hall sensor  710  is LOW) and the controller  800  terminates the second error mode (ERROR 2), or if the ejector finger  550  is not at the “Home” position after rotating the motor for the second predetermined number of steps, the controller  800  waits for a second predetermined time (e.g., 4 hours, for example) and after the second predetermined time elapses, causes the ice maker to enter the first error mode (ERROR 1). 
     As illustrated in  FIG. 18 , in the ice maker harvest mode, the motor can rotate the ejector finger  550  so that the ejector finger  550  leaves the “Home” position, rotates one revolution, and then returns to the “Home” position. The controller  800  checks whether the ejector finger  550  is at the “Home” position (i.e., the Hall sensor  710  is LOW) and whether the bail arm  610  is in the ice harvest position. 
     If the ejector finger  550  is at the “Home” position (path “Yes” in  FIG. 18 ), the controller  800  turns ON the ice maker heater  126 . The controller  800  turns off the ice maker heater  126  when an ice maker heater harvest time has elapsed or when the ice tray temperature is equal to or greater than a first predetermined temperature (e.g., −1° C., for example). The ice maker heater harvest time may be a predetermined period of time that would allow congealed ice pieces to separate from the ice mold  102  during the ice harvesting operation. The controller  800  then causes the ice maker to enter a harvest mode and perform a harvest operation. 
     The harvest operation includes rotating the motor in the second direction or in the counter-clockwise (CCW) direction to leave the “Home” position or until the ejector finger  550  is not at the “Home” position (i.e., the Hall sensor  710  is HIGH), rotating the motor in the second direction or in the counter-clockwise (CCW) direction until the ejector finger  550  is at the “Home” position (i.e., the Hall sensor  710  is LOW), and then again rotating the motor in the second direction or in the counter-clockwise (CCW) direction until the ejector finger  550  is not at the “Home” position (i.e., the Hall sensor  710  is HIGH). 
     When the harvest operation is completed before the motor has rotated a corresponding number of steps, the motor rotates in the first direction or in the clockwise (CW) direction until the ejector finger  550  is at the “Home” position. When any part of the harvest operation is not completed before the motor has rotated the corresponding number of steps, the controller  800  causes the ice maker to enter the first error mode (ERROR 1). 
     The controller  800  then determines either a time during which the ice maker heater has been deactivated (e.g., by checking an ice maker defrost timer) or a time during which the icemaker has been making ice (the time the ice maker has been in freeze mode—Freeze ON time). The controller  800  compares either the time that the ice maker heater has been deactivated or the time during which the icemaker has been making ice to a third predetermined time. If either the time that the ice maker heater has been deactivated or the time during which the icemaker has been making ice is equal to or greater than the third predetermined time, the controller  800  turns on the ice maker heater and causes the ice maker to enter an ice maker defrost mode. The third predetermined time can be one fixed time period (e.g., 12 hours or any other time period in a particular cycle). For example, when the ice maker heater has been deactivated for a continuous period of 12 hours, for example, the controller  800  can cause the ice maker to enter an ice maker defrost mode after the next harvest mode, but before the “Water Fill” mode. Similarly, when the ice maker has been in a freeze mode (e.g., making ice) for a continuous period of 12 hours, for example, the controller  800  can cause the ice maker to enter an ice maker defrost mode after the next harvest mode, but before the “Water Fill” mode. Alternatively, the third predetermined time can be a combination of time periods of different events in a particular cycle. For example, when the ice maker has been in a freeze mode (e.g., making ice) for a continuous period of 10 hours, for example, the controller  800  can cause the ice maker to enter a “Full Bucket” mode (the ice bin is full of ice). When the ice maker has been in a “Full Bucket” mode for a continuous period of 5 hours, for example, the controller  800  can cause the ice maker to enter the freeze mode, once again. When the ice maker has been in the freeze mode for an additional continuous period of 2 hours, for example, (so that the ice maker has been in the freeze mode for a cumulative period of 12 hours, the controller  800  can cause the ice maker to enter an ice maker defrost mode after the next harvest mode, but before the “Water Fill” mode. 
     If the time that the ice maker heater has been deactivated is lower than the predetermined time, the controller  800  causes the ice maker to enter a “Water Fill” mode and fill the ice tray with water. 
     As illustrated in  FIG. 18 , the ice maker defrost mode starts after the harvest mode and when an ice maker defrost timer reaches the third predetermined time. During the ice maker defrost mode ( FIG. 19 ), the controller  800  activates only the ice maker heater  126  to melt frost built up on the ice tray. The controller  800  turns off the ice maker heater  126  when the temperature of the ice tray reaches a predetermined defrost temperature (e.g., 1.7° C.) (also referred to as a “third predetermined temperature”). The ice maker defrost mode runs independently from the defrosting of the ice maker evaporator or the entire refrigeration system defrost. 
     The invention has been described with reference to the example embodiments described above. Modifications and alterations will occur to others upon a reading and understanding of this specification. Example embodiments incorporating one or more aspects of the invention are intended to include all such modifications and alterations insofar as they come within the scope of the appended claims and their equivalents.