PROLONGED OPERATION HEATER PROTECTION IN AN APPLIANCE
An appliance and method for non-thermal heater protection during prolonged operation of the appliance is provided. A time limit determination apparatus may prevent prolonged operation heater protection that prevents significant damage to the appliance.
1 . A dishwasher appliance, comprising:
a tub that defines a chamber for receipt of articles for cleaning;
a heater for producing heat in said tub;
a timer for measuring a duration said heater is activated (T ACTIVATE ), wherein said timer includes a timer switch;
a controller in communication with said heater, wherein said controller:
regulates operation of the dishwasher,
controls said heater based on a selected operation; and
a time limit determination apparatus that determines when said heater exceeds a predetermined maximum time limit (T MAX ), wherein said heater is deactivated when the duration said heater is activated exceeds the predetermined maximum time limit (T INT >T MAX ).
2 . The dishwasher appliance as in claim 1 , wherein said controller initiates the timer upon initial activation of said heater.
3 . The dishwasher appliance as in claim 2 , wherein said controller resets the timer to zero when said heater is deactivated during the operation of the dishwasher.
4 . The dishwasher appliance as in claim 1 , wherein said heater is deactivated by opening a heater relay or the timer switch when it is determined that the timer measurement exceeds the predetermined time limit.
5 . The dishwasher appliance as in claim 4 , wherein the timer switch is in series or parallel with said heater.
6 . The dishwasher appliance as in claim 1 , further comprising a power outage manager that reactivates said heater and said timer after power is interrupted during heater activation.
7 . The dishwasher appliance as in claim 1 , wherein said controller reactivates said heater after a predetermined time period (T RESET ) when deactivating said heater has occurred.
8 . The dishwasher appliance as in claim 4 , wherein said controller closes the heater relay or the timer switch after a predetermined time period (T RESET ) when deactivating said heater has occurred.
9 . The dishwasher appliance as in claim 1 , wherein said time limit determination apparatus is said timer.
10 . The dishwasher appliance, as in claim 1 , wherein said time limit determination apparatus is said controller.
11 . A method for preventing prolonged heater operation in an appliance, the method comprising the steps of:
regulating operation of the appliance by a controller;
controlling a heater based on a selected operation;
initiating a timer for measuring a duration the heater is activated during the selected operation (T INT );
determining whether the heater exceeds a predetermined maximum time limit (T MAX ); and
deactivating the heater when the duration the heater is activated exceeds the predetermined maximum time limit (T INT >T MAX ).
12 . The method of claim 11 , wherein said initiating the timer step begins upon initial activation of the heater.
13 . The method of claim 11 , further comprising the step of resetting the timer to zero when the heater is deactivated during the operation of the washer.
14 . The method of claim 13 , further comprising a step of reinitiating the timer for measuring the duration the heater is activated during a subsequent operation.
15 . The method of claim 11 , wherein during said deactivating the heater step a heater relay or timer switch is opened.
16 . The method of claim 11 , further comprising a step of reactivating the heater after a predetermined time period (T RESET ) when deactivating said heater has occurred.
17 . The method of claim 11 , wherein the appliance is selected from at least one of a dishwasher, a washer, a dryer, a microwave, a cooking range, and a refrigerator.
18 . The method of claim 11 , wherein the steps of controlling the heater, initiating the timer, determining whether the heater exceeds a predetermined maximum time limit and deactivating the heater are performed by the controller.
19 . The method of claim 11 , wherein the steps of initiating the timer, determining whether the heater exceeds a predetermined maximum time limit and deactivating the heater are performed by timer switch circuitry.
20 . The method of claim 11 , further comprising a step of managing a power outage when power is interrupted during heater activation.