Diswashing appliance and method of operation

Abstract

A dishwashing appliance and method of operation are provided herein. The dishwashing appliance may include a heater operable to heat a tub of the dishwashing appliance. The method may include directing water into the tub, activating the heater by supplying electrical power to the heater, and adjusting the electrical power to the heater. Adjusting the electrical power may include detecting a temperature change within the tub, determining when the temperature change meets a predetermined criterion, and delivering a wattage output from the heater when the predetermined criterion is met.

What is claimed is: 
     
         1 . A method of controlling a dishwashing appliance, the dishwashing appliance comprising a heater operable to heat a tub of the dishwashing appliance, the method comprising:
 directing water into the tub;   activating the heater by supplying electrical power to the heater; and   adjusting the electrical power to the heater, comprising:
 detecting a temperature change within the tub, 
 determining when the temperature change meets a predetermined criterion, and 
 delivering a wattage output from the heater when the predetermined criterion is met. 
   
     
     
         2 . The method of  claim 1 , wherein detecting the temperature change within the tub comprises measuring a rate of temperature increase over a predetermined period of time. 
     
     
         3 . The method of  claim 2 , wherein measuring the rate of temperature increase over the predetermined period of time comprises monitoring a temperature of water flowing through a sump portion of the dishwashing appliance. 
     
     
         4 . The method of  claim 1 , further comprising initiating a wash cycle of the dishwashing appliance, wherein adjusting the electrical power to the heater occurs during the wash cycle. 
     
     
         5 . The method of  claim 1 , further comprising initiating a dry cycle of the dishwashing appliance, wherein adjusting the electrical power to the heater occurs during the dry cycle. 
     
     
         6 . The method of  claim 1 , wherein the predetermined criterion is a target temperature change, and wherein determining when the temperature change meets the predetermined criterion comprises determining that the detected temperature change meets the target temperature change. 
     
     
         7 . The method of  claim 6 , wherein delivering the wattage output from the heater comprises:
 increasing the wattage output when the detected temperature change is less than the target temperature change; and   decreasing the wattage output when the detected temperature change is greater than the target temperature change.   
     
     
         8 . The method of  claim 7 , wherein increasing the wattage output comprises increasing power to the heater according to a preset wattage value, and wherein decreasing the wattage output comprises decreasing power to the heater according to a preset wattage value. 
     
     
         9 . The method of  claim 6 , further comprising repeatedly adjusting the electrical power to the heater according to a predetermined pattern. 
     
     
         10 . The method of  claim 1 , further comprising
 initiating a wash cycle of the dishwashing appliance; and   initiating a dry cycle of the dishwashing appliance;   wherein adjusting the electrical power to the heater occurs during the wash cycle, wherein the delivered wattage output is a high wattage output, and wherein the dry cycle includes initiating a low wattage output from the heater.   
     
     
         11 . A dishwashing appliance comprising:
 a tub defining a wash chamber;   a rack assembly disposed within the wash chamber of the tub, the rack assembly configured for supporting articles for washing within the wash chamber of the tub;   a resistive heating element in thermal communication with the tub, the resistive heating element being operable to heat the wash chamber; and   a controller operably connected to the resistive heating element, the controller being configured to initiate adjusting the electrical power to the resistive heater, adjusting the electrical power comprising:
 detecting a temperature change within the tub, 
 determining when the temperature change meets a predetermined criterion, and 
 delivering a wattage output from the heater when the predetermined criterion is met. 
   
     
     
         12 . The dishwashing appliance of  claim 11 , wherein detecting the temperature change within the tub comprises measuring a rate of temperature increase over a predetermined period of time. 
     
     
         13 . The dishwashing appliance of  claim 12 , wherein measuring the rate of temperature increase over the predetermined period of time comprises monitoring a temperature of water flowing through a sump portion of the dishwashing appliance. 
     
     
         14 . The dishwashing appliance of  claim 11 , wherein the controller is further configured to initiate a wash cycle, and wherein adjusting the electrical power to the heater occurs during the wash cycle. 
     
     
         15 . The dishwashing appliance of  claim 11 , wherein the controller is further configured to initiate a wash cycle, wherein adjusting the electrical power to the heater occurs during the dry cycle. 
     
     
         16 . The dishwashing appliance of  claim 11 , wherein the predetermined criterion is a target temperature change, and wherein determining when the temperature change meets the predetermined criterion comprises determining that the detected temperature change meets the target temperature change. 
     
     
         17 . The dishwashing appliance of  claim 16 , wherein delivering the wattage output from the heater comprises:
 increasing the wattage output when the detected temperature change is less than the target temperature change, and   decreasing the wattage output when the detected temperature change is greater than the target temperature change.   
     
     
         18 . The dishwashing appliance of  claim 17 , wherein increasing the wattage output comprises increasing power to the heater according to a preset wattage value, and wherein decreasing the wattage output comprises decreasing power to the heater according to a preset wattage value. 
     
     
         19 . The dishwashing appliance of  claim 11 , wherein the controller is further configured to initiate repeatedly adjusting the electrical power to the heater according to a predetermined pattern. 
     
     
         20 . The dishwashing appliance of  claim 11 , wherein the controller is further configured to:
 initiate a wash cycle of the dishwashing appliance, and   initiate a dry cycle of the dishwashing appliance,   wherein adjusting the electrical power to the heater occurs during the wash cycle, wherein the delivered wattage output is a high wattage output, and wherein the dry cycle includes initiating a low wattage output from the heater.