Washing machine and control method thereof

Abstract

A washing machine having a boiling washing course function to perform washing by heating water to increase a washing effect, and a control method thereof. In the washing machine and control method, it is possible to increase a washing effect by heating water for a predetermined time according to the temperature of the initially supplied water, draining the water if the temperature of the heated water is less than the set temperature, and maintaining the amount of the initially supplied water without draining the water if the temperature of the water is equal to or greater than the set temperature. Further, by allowing the water to reach the target temperature of a high temperature within a predetermined washing time while maintaining the amount of the initially supplied water, it is possible to maintain a washing effect due to a washing temperature thereof.

What is claimed is: 
     
         1 . A control method of a washing machine including a tub to accommodate water and a heater installed inside the tub to heat the water, the method comprising:
 determining whether a currently washing course is a boiling washing course;   supplying water into the tub if the currently washing course is the boiling washing course;   performing primary heating washing to heat the supplied water for a predetermined time;   detecting a temperature of the primarily heated water; and   controlling a level of water in the tub for secondary heating washing according to the detected temperature of the water,   wherein the controlling the water level comprises varying the level of water in the tub according to the temperature of the primarily heated water.   
     
     
         2 . The control method according to  claim 1 , wherein the controlling the water level comprises:
 comparing the temperature of the primarily heated water with a set temperature; and   maintaining a current water level without draining the primarily heated water if the temperature of the primarily heated water is greater than the set temperature.   
     
     
         3 . The control method according to  claim 2 , wherein if the temperature of the primarily heated water is equal to or less than the set temperature, the primarily heated water is drained to lower the water level. 
     
     
         4 . The control method according to  claim 3 , wherein the supplying the water into the tub comprises supplying water up to a predetermined water level for the boiling washing course. 
     
     
         5 . The control method according to  claim 4 , wherein the supplied water is cold water or hot water. 
     
     
         6 . The control method according to  claim 4 , wherein the performing the primary heating washing comprises:
 detecting a temperature of the water supplied into the tub;   determining a primary heating time according to the detected temperature of the water; and   driving the heater according to the determined primary heating time.   
     
     
         7 . The control method according to  claim 4 , wherein the draining the water comprises draining the water down to a water level lower by one level than the predetermined water level. 
     
     
         8 . The control method according to  claim 4 , further comprising performing secondary heating washing to heat the primarily heated water up to a target temperature after controlling the water level. 
     
     
         9 . The control method according to  claim 8 , wherein the set temperature is a temperature of the water supplied up to the predetermined water level, which may reach the target temperature within a secondary heating time. 
     
     
         10 . The control method according to  claim 9 , wherein the set temperature is about 45° C. 
     
     
         11 . The control method according to  claim 9 , wherein the target temperature is equal to or greater than 70° C. which may provide a boiling effect. 
     
     
         12 . The control method according to  claim 8 , further comprising performing washing for a set time after the secondary heating washing. 
     
     
         13 . The control method according to  claim 12 , further comprising performing a cooling process by supplying cold water after performing the washing. 
     
     
         14 . The control method according to  claim 8 , further comprising performing a washing and cooling process by supplying cold water after performing the secondary heating washing. 
     
     
         15 . A control method of a washing machine including a tub to accommodate water and a heater installed inside the tub to heat the water, the method comprising:
 determining whether a currently washing course is a boiling washing course;   supplying water into the tub if the currently washing course is the boiling washing course;   detecting a temperature of the supplied water;   determining a primary heating time according to the detected temperature of the water;   performing primary heating washing by driving the heater according to the determined primary heating time; and   controlling a level of water in the tub for secondary heating washing according to the detected temperature of the water,   wherein the controlling the water level comprises varying the level of water in the tub according to the temperature of the supplied water.   
     
     
         16 . The control method according to  claim 15 , wherein the controlling the water level comprises:
 comparing the temperature of the supplied water with a set temperature; and   maintaining a current water level without draining the primarily heated water if the temperature of the supplied water is greater than the set temperature.   
     
     
         17 . The control method according to  claim 15 , wherein the controlling the water level comprises:
 comparing the temperature of the supplied water with a set temperature; and   lowering the water level by draining the primarily heated water if the temperature of the supplied water is equal to or less than the set temperature.   
     
     
         18 . The control method according to  claim 15 , further comprising, after controlling the water level, performing secondary heating washing to heat the primarily heated water up to a target temperature. 
     
     
         19 . A washing machine comprising:
 a tub to accommodate water;   a heater installed inside the tub to heat the water;   an input unit through which a boiling washing course is selected;   a control unit to, if the boiling washing course is selected, perform primary heating washing for a predetermined time after supplying water into the tub, detect a temperature of the primarily heated water, and control a level of water in the tub for secondary heating washing,   wherein the control unit varies the level of water in the tub according to the temperature of the primarily heated water.   
     
     
         20 . The washing machine according to  claim 19 , wherein the control unit compares the temperature of the supplied water with a set temperature, and maintains a current water level without draining the primarily heated water if the temperature of the supplied water is greater than the set temperature. 
     
     
         21 . The washing machine according to  claim 19 , wherein the control unit compares the temperature of the supplied water with a set temperature, and lowers the water level by draining the primarily heated water if the temperature of the supplied water is equal to or less than the set temperature. 
     
     
         22 . The washing machine according to  claim 19 , wherein the control unit determines a primary heating time by detecting a temperature of the water supplied into the tub, and performs primary heating washing by driving the heater according to the determined primary heating time. 
     
     
         23 . The washing machine according to  claim 19 , wherein after controlling the water level, the control unit performs secondary heating washing to heat the primarily heated water up to a target temperature. 
     
     
         24 . The washing machine according to  claim 23 , wherein the control unit additionally performs washing for a set time after the secondary heating washing. 
     
     
         25 . The washing machine according to  claim 24 , wherein the control unit performs a cooling process by supplying cold water after the washing. 
     
     
         26 . The washing machine according to  claim 23 , wherein the control unit performs a washing and cooling process by supplying cold water after the secondary heating washing. 
     
     
         27 . A washing machine comprising:
 a tub to accommodate water;   a heater installed inside the tub to heat the water;   an input unit through which a boiling washing course is selected;   a control unit to, if the boiling washing course is selected, supply water into the tub, detect a temperature of the supplied water, perform primary heating washing to drive the heater for a primary heating time determined according to the detected temperature of the water, and control a level of water in the tub for secondary heating washing according to the detected temperature of the water,   wherein the control unit varies the level of water in the tub according to the temperature of the supplied water.   
     
     
         28 . The washing machine according to  claim 27 , wherein the control unit compares the temperature of the supplied water with a set temperature, and maintains a current water level without draining the primarily heated water if the temperature of the supplied water is greater than the set temperature. 
     
     
         29 . The washing machine according to  claim 27 , wherein the control unit compares the temperature of the supplied water with a set temperature, and lowers the water level by draining the primarily heated water if the temperature of the supplied water is equal to or less than the set temperature.