Icemaker control system

Abstract

A control system for an icemaker utilizes a control scheme in which various operating conditions of the icemaker are monitored sand the icemaker is shut down if a fault condition is sensed. In response to detection of the fault condition, steps are taken to actively remove the fault. Restarting of the icemaker is then attempted if sensors indicate that normal continued operation should be possible. The operating conditions sensed include the temperature of refrigerant at an outlet from a condenser, the rate at which a water pan fills with water while water is delivered to it for subsequent delivery to and over an evaporator to freeze the water into ice on the evaporator. and the time required to harvest ice from the evaporator.

1 . A control system for an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan, means for delivering water to said water pan and a pump for delivering water from said water pan to and across said evaporator to freeze the water into ice on said evaporator for subsequent harvesting of the ice, said control system comprising: 
 means responsive to the temperature of refrigerant at an outlet from said condenser being greater than a predetermined high temperature to interrupt operation of said icemaker;    means responsive to a level of water in said water pan that is less than a selected high level and to delivery of water to said water pan at a rate less than a predetermined rate to inhibit operation of said compressor;    and means responsive during an ice harvesting cycle of said icemaker to a failure to complete harvesting of ice from said evaporator within a selected period of time to interrupt operation of said icemaker.    
   
   
       2 . A control system as in  claim 1 , wherein said means responsive to the temperature of refrigerant at said condenser outlet is responsive to the temperature being greater than said predetermined high temperature for a selected time to interrupt operation of said icemaker.  
   
   
       3 . A control system as in  claim 1 , wherein said means responsive to the temperature of refrigerant at said condenser outlet includes timer means responsive to the temperature being greater than said predetermined high temperature to begin timing a selected period of time, means for resetting said timer means upon occurrence of a the temperature being no greater than said predetermined high temperature, and means responsive to timing out of said timer means at the end said selected time period to interrupt operation of said icemaker.  
   
   
       4 . A control system as in  claim 3 , wherein said means responsive to the temperature of refrigerant at said condenser outlet further includes means, operative following interruption of operation of said icemaker upon timing out of said timer means at the end of said selected time period, for enabling continued operation of said icemaker upon the temperature of refrigerant at said condenser outlet decreasing to a predetermined low temperature.  
   
   
       5 . A control system as in  claim 4 , wherein said means responsive to the temperature of refrigerant at said condenser outlet further includes counter means for storing a count of the number of times said timer means times out by reaches the end of said selected time period, means responsive to said stored count being less than a selected number for enabling operation of said icemaker upon the temperature of refrigerant at said condenser outlet decreasing to said predetermined low temperature, and means responsive to said stored count reaching said selected number for interrupting operation of said icemaker and generating a signal that manual intervention is required to enable continued operation of said icemaker.  
   
   
       6 . A control system as in  claim 1 , including means for sensing the level of water in said water pan, and means responsive to the sensed level of water being at said selected high level to prevent delivery of water to said water pan and to enable operation of said icemaker, and responsive to the sensed level of water being less than a selected low level for inhibiting operation of said icemaker and for generating an indication that manual intervention is required to enable continued operation of said icemaker.  
   
   
       7 . A control system as in  claim 6 , including means for sensing, upon delivery of water to said water pan, the rate of filling of said water pan with water, and means responsive to the sensed water fill rate being at least equal to a selected rate and to the sensed water level being intermediate said selected low and high levels for enabling operation of said compressor while the sensed water level is less than said selected high level, and for interrupting delivery of water to said water pan and enabling operation of said icemaker when the sensed water level reaches said selected high level.  
   
   
       8 . A control system as in  claim 7 , wherein said means for sensing the rate of filling of said water pan water includes means responsive to changes in the sensed level of water in the water pan with respect to time to determine the rate of filling.  
   
   
       9 . A control system as in  claim 1 , including means for delivering hot refrigerant from said condenser to said evaporator to heat said evaporator to cause release of ice formed on said evaporator in order to harvest the ice, and wherein said means responsive to a failure to complete harvesting of ice from said evaporator within said selected period of time includes timer means responsive to delivery of hot refrigerant to said evaporator to beg timing said selected time period, means for sensing release of ice from said evaporator, and means responsive to said sensing means sensing release of ice from said evaporator before said timer means reaches the end of said selected time period to enable continued operation of said icemaker.  
   
   
       10 . A control system as in  claim 9 , wherein said means responsive to a failure to complete harvesting of ice from said evaporator within said selected time period includes means responsive to failure of said sensing means to sense release of ice from said evaporator before said timer means times out at the end of said selected time period to disable operation of said compressor.  
   
   
       11 . A control system as in  claim 10 , wherein said means responsive to failure to complete harvesting of ice from said evaporator within said selected time period includes means for delivering water to said water pan and for operating said pump to flow the water from the water pan over said evaporator to warm and release ice remaining on said evaporator, and for then enabling operation of said icemaker.  
   
   
       12 . A control system as in  claim 9 , including counter means for storing a count of the number of failures of said sensing means to sense release of ice from said evaporator before said tier means times out at the end of said selected time period, and means responsive to said counter means stored count being equal to a selected count to interrupt operation of said icemaker and to generate a signal indicating that manual intervention is required to enable continued operation of said icemaker.  
   
   
       13 . A control system for an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan, means for delivering water to said water pan and a pump for delivering water from said water pan to and across said evaporator to freeze the water into ice on said evaporator for subsequent harvesting, said control system comprising: 
 means for sensing the temperature of refrigerant at an outlet from said condenser;    and means responsive to said sensed refrigerant temperature being no greater than a predetermined high temperature or greater than said predetermined high temperature for less than a selected period of time for enabling continued operation of said icemaker.    
   
   
       14 . A control system as in  claim 13 , including timer means responsive to said sensed refrigerant temperature being greater than said predetermined high temperature to begin timing said selected time period; means for resetting said timer means in response to sensing a refrigerant temperature no greater than said predetermined high temperature before said timer means times out at the end of said selected time period; means responsive to said timer means timing out at the end of said selected time period to interrupt operation of said icemaker; and means responsive to said sensing means sensing a subsequent decrease in refrigerant temperature to a predetermined low temperature to enable continued operation of said icemaker.  
   
   
       15 . A control system as in  claim 13 , including counter means responsive to each occurrence of said timer means timing out at the end of said selected time period to advance by one a count stored therein; and means responsive to said counter means reaching a selected stored count to inhibit operation of said icemaker and to generate a signal indicating that manual intervention is required to enable continued operation of said icemaker.  
   
   
       16 . A control system for an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan for being filled with water, means for delivering water to said water pan, and a pump for delivering water from said water pan to and across said evaporator to freeze the water into ice on said evaporator for subsequent harvesting of the ice, said control system comprising: 
 means for operating said compressor to deliver cold refrigerant to said evaporator;    means for sensing the level of water in said water pan;    means responsive to a selected maximum level of water in said water pan to enable operation of said icemaker;    means responsive to less than said selected maximum level of water in said water pan to initiate delivery of water to said water pan;    means for sensing the rate of filling of said water pan with water during delivery of water;    means responsive to said sensed water fill rate being at least equal to a selected rate to continue operation of said compressor;    and means responsive to said water level sensing means sensing said selected maximum level of water in said water pan to interrupt delivery of water and enable operation of said icemaker.    
   
   
       17 . A control system as in  claim 16 , including means responsive to said sensed water fill rate being less than said selected rate to interrupt operation of said compressor until said water level sensing means senses said selected maximum level of water in said water pan, and for then enabling operation of said compressor and said icemaker.  
   
   
       18 . A control system as in  claim 16 , including means responsive to said water level sensing means sensing a selected minimum level of water in said water pan to inhibit operation of said compressor and icemaker and to generate a signal indicating that manual intervention is required to enable continued operation of said icemaker.  
   
   
       19 . A control system for an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan for being filled with water, means for delivering water to said water pan, and a pump for delivering water from said water pan to and across said evaporator to freeze the water into ice on said evaporator for subsequent harvesting of the ice, said control system comprising: 
 means for delivering hot refrigerant from said condenser to said evaporator to heat said evaporator to release ice formed on said evaporator in order to harvest the ice;    timer means responsive to delivery of hot refrigerant to said evaporator to begin timing a selected period of time;    means for sensing release of ice from said evaporator;    means responsive to sensing release of ice from said evaporator before said timer means times out at the end of said selected time period for enabling continued operation of said icemaker;    means responsive to a failure to sense release of ice from said evaporator before said timer means times out at the end of said selected time period for turning off said compressor, causing delivery of water to said water pan, operating said pump to flow water across said evaporator to release ice remaining said evaporator, and then enabling continued operation of said icemaker.    
   
   
       20 . A control system as in  claim 19 , said control system including a water pump timer for controlling the time for which said pump is operated to flow water from said water pan over said evaporator to warm and release ice from said evaporator before continued operation of said icemaker is enabled.  
   
   
       21 . A control system as in  claim 19 , including counter means for storing a count of the number of failures to sense release of ice from said evaporator before said timer means times out at the end of said selected time period, and means responsive to said counter means stored count equaling a selected count to inhibit further operation of said icemaker and to generate a signal indicating that manual intervention is required to enable continued operation of said icemaker.  
   
   
       22 . A method of controlling an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan, a supply line for delivering water to the water pan and a pump for delivering water from the water pan to and across the evaporator to freeze the water into ice on the evaporator for subsequent harvesting of the ice, said method comprising the steps of: 
 controlling the temperature of refrigerant at an outlet from the condenser to be no greater than a predetermined high temperature by sensing the temperature of refrigerant at the condenser outlet and, in response to the sensed temperature being greater than a predetermined high temperature, interrupting operation of the icemaker;    ensuring the availability of sufficient water in the water pan for delivery to the evaporator during an ice freezing cycle by delivering water to the water pan while sensing both the level of water in the water pan and the rate at which the water pan is being filled with water and, in response to a sensed level of water in the water pan that is less than a selected high level and to a sensed water fill rate that less than a selected rate, inhibiting operation of the compressor; and    after water has been frozen into ice on the evaporator, monitoring completion of a cycle of harvesting ice from the evaporator upon delivery of hot refrigerant from the condenser to the evaporator to warm the evaporator to release the ice from its bond to the evaporator, by sensing release of the ice from the evaporator and, if release of the ice from the evaporator is not sensed within a selected period of time, interrupting operation of the icemaker.    
   
   
       23 . A method as in  claim 22 , wherein controlling the temperature of refrigerant at the condenser outlet includes the step of measuring the time for which the sensed refrigerant temperature is greater than the predetermined high temperature, said interrupting step being responsive to the sensed temperature being continuously greater than the predetermined high temperature for a selected time to interrupt operation of the icemaker.  
   
   
       24 . A method as in  claim 23 , wherein controlling the temperature of refrigerant at the condenser outlet includes the further steps, following performance of said interrupting step, of sensing a decrease in the temperature of refrigerant at the condenser outlet to a predetermined low temperature and, in response thereto, enabling continued operation of the icemaker.  
   
   
       25 . A method as in  claim 24 , wherein controlling the temperature of refrigerant at the condenser outlet includes the further steps of storing a count of the number of times said icemaker operation interrupting step is performed and, upon the stored count equaling a selected number, interrupting operation of the icemaker and generating a signal indicating that manual intervention is required to enable continued operation of the icemaker.  
   
   
       26 . A method as in  claim 22 , wherein ensuring the availability of sufficient water in the water pan for delivery to the evaporator during an ice freezing cycle includes the steps, performed in response to said sensing step sensing that the level of water in the water pan is at a selected high level, of interrupting delivery of water to the water pan, and enabling operation of the icemaker, as well as the steps, performed in response to said sensing step sensing that the level of water in the water pan is less than a selected low level, of inhibiting operation of the icemaker and generating an indication that manual intervention is required.  
   
   
       27 . A method as in  claim 22 , wherein ensuring the availability of sufficient water in the water pan for delivery to the evaporator during an ice freezing cycle includes the further steps, performed in response to said sensing step sensing that the rate at which the water pan is being filled with water is at least the selected rate and that the level of water in the water pan is intermediate a selected low level and the selected high level, of enabling operation of the compressor and continuing to deliver water to the water pan, and interrupting delivery of water to the water pan and enabling operation of the icemaker when the sensed water level reaches the selected high level.  
   
   
       28 . A method as in  claim 22 , wherein monitoring completion of a cycle of harvesting ice from the evaporator includes the further steps, in response to a failure to sense release of the ice from the evaporator within the selected time period, of delivering water to the water pan, operating the pump to flow the water from the water pan over the evaporator to warm and release ice remaining on the evaporator, and then enabling operation of the icemaker.  
   
   
       29 . A method as in  claim 28 , wherein monitoring completion of a cycle of harvesting ice from the evaporator includes the further steps of storing a count of the number of times failures to sense release of the ice from the evaporator within the selected time period during ice harvesting and, in response to the stored count reaching a selected count, interrupting operation of the icemaker and generating an indication that manual intervention is required to enable continued operation of the icemaker.  
   
   
       29 . A method of controlling an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan, a supply line for delivering water to the water pan and a pump for delivering water from the water pan to and across the evaporator to freeze the water into ice on the evaporator for subsequent harvesting, said method comprising the steps of: 
 sensing the temperature of refrigerant at an outlet from the condenser; and    enabling operation of the icemaker in response to a sensed temperature of refrigerant that is no greater than a predetermined high temperature or that is greater than the predetermined high temperature for less than a selected time.    
   
   
       30 . A method as in  claim 29 , including the further steps of: 
 interrupting operation of the icemaker in response to a sensed refrigerant temperature that is greater than the predetermined high temperature continuously for a selected time; and    enabling continued operation of the icemaker, following performance of said interrupting step, in response to a sensed decrease in refrigerant temperature to a predetermined low temperature.    
   
   
       31 . A method as in  claim 29 , including the further steps of: 
 storing a count of each occurrence of a sensed refrigerant temperature that is greater than the predetermined high temperature continuously for the selected time; and    in response to the stored count reaching a selected count, inhibiting operation of the icemaker and generating an indication that manual intervention is required to enable continued operation of the icemaker.    
   
   
       32 . A method of controlling an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan, a supply line for delivering water to the water pan and a pump for delivering water from the water pan to and across the evaporator to freeze the water into ice on the evaporator for subsequent harvesting of the ice on the evaporator, said method comprising the steps of: 
 operating the compressor to deliver cold refrigerant to the evaporator;    sensing the level of water in the water pan;    enabling operation of the icemaker in response to a sensed maximum level of water in the water pan;    delivering water to the water pan in response to a sensing less than the maximum level of water in the water pan;    sensing the rate of filling of the water pan with water during deliver of water to the water pan;    continuing operation of the compressor in response to the sensed water fill rate being at least equal to a selected water fill rate; and    interrupting delivery of water to the water pan and enabling operation of the icemaker in response to sensing the maximum level of water in the water pan.    
   
   
       32 . A method as in  claim 32 , including the further steps of; 
 interrupting operation of the compressor upon the sensed water fill rate being less than the selected fill rate while continuing to deliver water to the water pan; and    enabling operation of the icemaker upon the sensed level of water in the water pan reaching the selected maximum level.    
   
   
       34 . A method as in  claim 32 , including the steps of inhibiting operation of the icemaker and, in response to sensing a selected minimum level of water in the ice pan, generating an indication that manual intervention is required to enable continued operation of the icemaker.  
   
   
       35 . A method of controlling an icemaker of a type having a compressor for delivering refrigerant to and though a condenser to an evaporator, a water pan, a supply line for delivering water to the water pan and a pump for delivering water from the water pan to and across the evaporator to freeze the water into ice on the evaporator for subsequent harvesting of the ice on the evaporator, said method comprising the steps, at the end of an icemaking cycle when water has been frozen into ice on the evaporator, of: 
 delivering hot refrigerant from the condenser to the evaporator to heat the evaporator to release the ice from the evaporator;    sensing release of the ice from the evaporator;    enabling continued operation of the icemaker in response to sensing release of the ice from the evaporator within less than a selected time following delivery of hot refrigerant to the evaporator; and    in response to failing to sense release of the ice from the evaporator within the selected time, performing the steps of turning off the compressor, delivering water to the water pan, operating the pump to flow water from the water pan to and across the evaporator to warm and release ice remaining on the evaporator, and then enabling operation of the icemaker.    
   
   
       36 . A method as in  claim 35 , wherein the step of flowing water across the evaporator to release ice from the evaporator flows the water across the evaporator for a selected time.  
   
   
       37 . A method as in  claim 35 , including the steps of storing a count of the number of failures to sense release of the ice from the evaporator within the selected time following delivery of hot refrigerant to the evaporator and inhibiting further operation of the icemaker and, in response the stored count reaching a selected count, generating an indication that manual intervention is required to enable continued operation of the icemaker.