Water heater and method of operating the same
First Claim
1. A method of heating water stored in a water tank of a storage-type water heater comprisinga first electric-resistance heating element comprising a thermal surface disposed within an inner surface of the tank at a first location, a second electric-resistance heating element comprising a thermal surface disposed within the inner surface of the tank at a second location disposed vertically above the first location, and first and second temperature sensors associated with the first and second heating elements, respectively, a third temperature sensor coupled to the tank at a third location disposed vertically between the first and second locations, the method comprising:
- sensing a first temperature with the first temperature sensor;
sensing a second temperature with the second temperature sensor;
preventing power to the second heating element and controllably providing power to the first heating element if the first temperature is below a first set point, the second temperature is above a second set point, and zero or more other conditions exist;
preventing power to the first heating element and controllably providing power to the second heating element if the second temperature is below a second set point and zero or more other conditions exist;
preventing power to the first and second heating elements if the first and second temperatures are above the first and second set points, respectively, and zero or more other conditions exist; and
wherein the acts of preventing power to the second heating element and controllably providing power to the first heating element and preventing power to the first heating element and controllably providing power to the second heating element occur during normal operation, and wherein the method further comprises sensing a third temperature with the third temperature sensor;
ceasing normal operation if the third temperature is below a third set point and zero or more other conditions exist; and
entering boost operation if the third temperature is below a third set point and zero or more other conditions exist.
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Accused Products
Abstract
A storage-type water heater and method of operating the storage-type water heater. The water heater includes a water tank for storing water, at least one heating element to heat the stored water, a jacket surrounding at least a portion of the tank, and a control system for controlling the water heater. In one construction of the water heater, the water heater includes two heating elements, and the control system includes three temperature sensors and two moisture sensors. The control system can also include circuitry for detecting errors and change operation of the water based on a detected error.
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Citations
48 Claims
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1. A method of heating water stored in a water tank of a storage-type water heater comprising
a first electric-resistance heating element comprising a thermal surface disposed within an inner surface of the tank at a first location, a second electric-resistance heating element comprising a thermal surface disposed within the inner surface of the tank at a second location disposed vertically above the first location, and first and second temperature sensors associated with the first and second heating elements, respectively, a third temperature sensor coupled to the tank at a third location disposed vertically between the first and second locations, the method comprising: -
sensing a first temperature with the first temperature sensor;
sensing a second temperature with the second temperature sensor;
preventing power to the second heating element and controllably providing power to the first heating element if the first temperature is below a first set point, the second temperature is above a second set point, and zero or more other conditions exist;
preventing power to the first heating element and controllably providing power to the second heating element if the second temperature is below a second set point and zero or more other conditions exist;
preventing power to the first and second heating elements if the first and second temperatures are above the first and second set points, respectively, and zero or more other conditions exist; and
wherein the acts of preventing power to the second heating element and controllably providing power to the first heating element and preventing power to the first heating element and controllably providing power to the second heating element occur during normal operation, and wherein the method further comprises sensing a third temperature with the third temperature sensor;
ceasing normal operation if the third temperature is below a third set point and zero or more other conditions exist; and
entering boost operation if the third temperature is below a third set point and zero or more other conditions exist. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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9. A method of controlling a storage-type water heater comprising
a water tank comprising an inner surface a first electric-resistance heating element comprising a thermal surface disposed within the inner surface at a first location, a second electric-resistance heating element comprising a thermal surface disposed within the inner surface at a second location, and a control system to operate the first and second heating elements, wherein the control system comprises a current sensor associated with the first heating element, the method comprising: -
controllably providing power to the first and second heating elements to heat water stored in the water tank;
detecting the failure of one of the first and second heating elements;
if detecting the failure of one of the first and second heating elements and zero or more other conditions exist, preventing power to the failed heating element; and
controllably providing power to the non-failed heating element to heat water stored in the water tank;
wherein the act of controllably providing power to the first and second heating elements comprises controllably providing power to the first heating element;
wherein the method further comprises sensing first and second currents with the current sensor, the second current sensed after the first current; and
wherein the act of detecting the failure comprises calculating first and second resistance values with the first and second currents, respectively, calculating a resistance rate change with the first and second resistance values, comparing the resistance rate change to a threshold resistance rate change, the threshold resistance rate change indicating scale buildup, and determining a failure for the first heating element if scale buildup occurs and zero or more other conditions exist. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method of controlling a storage-type water heater comprising
a water tank comprising an inner surface a first electric-resistance heating element comprising a thermal surface disposed within the inner surface at a first location, a second electric-resistance heating element comprising a thermal surface disposed within the inner surface at a second location, and a control system to operate the first and second heating elements, wherein the control system comprises a first temperature sensor associated with the first heating element, the method comprising: -
controllably providing power to the first and second heating elements to heat water stored in the water tank;
detecting the failure of one of the first and second heating elements;
if detecting the failure of one of the first and second heating elements and zero or more other conditions exist, preventing power to the failed heating element; and
controllably providing power to the non-failed heating element to heat water stored in the water tank;
wherein the act of controllably providing power to the first and second heating elements comprises controllably providing power to the first heating element;
wherein the method further comprises sensing first and second temperatures with the first temperature sensor, the second temperature sensed after the first temperature, and wherein the act of detecting the failure comprises calculating a temperature rise with the first and second temperatures, comparing the temperature rise to a threshold temperature rise, the threshold temperature rise indicating scale buildup, and determining a failure for the first heating element if scale buildup occurs and zero or more other conditions exist. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48)
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Specification