WATER HEATING SYSTEMS AND METHODS
A water heating system has a controller that is electronically actuated. In this regard, the controller controls an activation state of at least one heating element by providing an electrical control signal to a relay. In one embodiment, the controller has an emergency shut-off apparatus that is mechanically actuated. Further various features can be optionally implemented to help heat related problems plaguing many conventional water heater controllers that are electronically actuated.
This application claims priority to U.S. Provisional Application No. 60/786,326, entitled “Water Heating System and Method,” and filed on Mar. 27, 2006, which is incorporated herein by reference. This application also claims priority to U.S. Provisional Application No. 60/908,132, entitled “Water Heating Systems and Methods,” and filed on Mar. 26, 2007, which is incorporated herein by reference.
RELATED ARTFor many decades, water heater controllers have been mechanically actuated. In this regard, at least one temperature sensitive switch is typically mounted on a side of a water tank. Thermal stresses within the switch fluctuate as the temperature of the water within the tank changes. If the temperature of water within a region in close proximity to the switch falls below a threshold, referred to as a “lower set point,” mechanical forces caused by thermal stresses in the switch actuate a mechanical component of the switch thereby allowing electrical current to flow to a heating element within the tank. Thus, the heating element begins to heat the water in the tank. Once the temperature of the water rises above a threshold, referred to as an “upper set point,” mechanical forces caused by the thermal stresses actuate the mechanical component of the switch yet again thereby stopping current from flowing to the heating element. Thus, the heating element stops heating the water in the tank. Accordingly, the temperature of the water is kept within a desired range.
Recently, attempts have been made to migrate from mechanically actuated controllers to electronically actuated controllers. In this regard, rather than relying on a temperature sensitive switch that is actuated by mechanical force resulting from thermal stress, a temperature sensor, such as a thermistor, is used to measure water temperature and provide data indicative of the measured temperature. Electronic circuitry, which may include software as well as hardware, then analyzes the temperature data to determine when a heating element is to be activated. Although a relay, which is typically an electro-mechanical component, can be used to control whether current flows to the heating element and, therefore, whether the heating element is activated, the state of the relay and, therefore, the activation state of the heating element are controlled via an electrical signal rather than mechanical force induced by thermal stresses. In this sense, the controller and, in particular, the switch (e.g., relay) used to activate and deactivate the heating element are “electronically actuated.”
Electronically actuated controllers enable water heating systems to be controlled via more complex algorithms. For example, it is possible for the controller to analyze a usage history of the water heating system and to automatically establish the set points based on time of day and the usage history. Thus, the set points can be set higher during expected periods of relative high use, and the set points can be set lower during expected periods of relative low use, thereby increasing the efficiency of the water heating system.
However, several problems have been encountered in the design and development of electronically actuated controllers, and many of the problems are heat related. In this regard, the temperature of the water in a water heating system is usually set significantly higher than 100 degrees Fahrenheit (F) and, in some cases, higher than 150 degrees F. Further, the electronics within an electronically actuated controller produce additional heat within the controller. Indeed, the relays used to control the activation states of the heating elements typically carry 20 to 30 Amperes (A) of a 120 or 240 Volt (V) alternating current (AC) signal and can, therefore, generate significant heat. Moreover, the temperatures within the controller can reach levels that affect the reliability of the controller's electronics.
In addition, as described above, an electronically actuated controller typically uses temperature data from a temperature sensor, such as a thermistor. For ease of installation and to help reduce manufacturing costs, it would be desirable for such a temperature sensor to be integral or embedded with the other electronics of the controller. However, the heat from the other electronics can affect the temperature readings of the temperature sensor, thereby affecting the reliability of the temperature measurements, if the temperature sensor is in close proximity to the other electronics.
To alleviate some of the heat related problems, the size of the controller can be increased. However, increasing the size of the controller is generally undesirable for several reasons, including increasing costs. In this regard, it is generally desirable for an electronically actuated controller to be similar in size to conventional, mechanically actuated controllers so that conventional water tanks do not need to be redesigned. Indeed, if an electronically actuated controller is about the same size as a conventional, mechanically actuated controller, then a conventional water tank that currently has a mechanically actuated controller can be retrofitted with an electronically actuated controller at a relatively low cost. Further, water tank manufacturers already have assembly lines in place that may need to be changed, at a relatively high cost, if the design of the water tank is changed to accommodate a larger controller that is electronically actuated.
Moreover, it is generally desirable for the size of an electronically actuated controller to be minimized and, in particular, to be at a size similar to or less than the size of conventional controllers that are mechanically actuated, but such a goal can be difficult to realize without a significant impact to reliability in view of the heat related problems described above.
BRIEF DESCRIPTION OF THE DRAWINGSThe disclosure can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Furthermore, like reference numerals designate corresponding parts throughout the several views
The upper heating element 55 is mounted to an upper portion of the tank 53 above the lower heating element 56, which is mounted to a lower portion of the tank 53. However, other numbers and arrangements of heating elements are possible in other embodiments. Also mounted to a side of the tank 53 in
Cold water is drawn into the tank 53 via a pipe 63 coupled to a water source 65. Operating under the direction and control of the controller 52, the heating elements 55 and 56 heat the water within the tank 53, and heated water is drawn out of the tank via pipe 67. Various techniques may be used to control the heating provided by the elements 55 and 56. In one exemplary embodiment, the controller 52 has an embedded temperature sensor (e.g., a thermistor), although such a sensor 66 (
In addition, the sensor holding apparatus 59 has an embedded temperature sensor (e.g., a thermistor), although such a sensor 68 (
The electrical components of the controller 52 are preferably housed within and covered by a housing 84. The housing 84 has holes respectively corresponding with the wires 75-79 to enable the wires to be electrically connected to electrical components within the housing 84. For example, as shown by
In one exemplary embodiment, the housing 84 comprises two sections 85 and 83 that can be removed separately. In this regard, section 83 can be removed from section 85. Therefore, the section 83 can be removed from the controller 52 without removing section 85. Alternatively, both sections 83 and 85 can be removed from the controller 52 with or without removing section 83 from section 85. In other embodiments, other numbers of housing sections are possible.
As shown by
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The walls of the hole 104 are preferably threaded. Further, the hole 105 is aligned with the hole 86 (
The housing 84 has a hollow peg 116 (
Note that, when the wires 75-79 are secured to the interfaces 95-99 as described herein, the ends of wires 75-79 shown in
To ensure that no portions of the wire ends inserted into the housing 84 are exposed, the housing holes through which the wire ends are inserted are preferably dimensioned large enough such that the respective wire and its coating fit through the hole. For example, hole 86 (
As shown by
Note that the control logic 125, when implemented in software, can be stored and transported on any computer-readable medium. A “computer-readable medium” can be any means that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution apparatus. The computer readable-medium can be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor apparatus or propagation medium.
Referring to
In one embodiment, the wires 131 may be coupled to an additional controller (not shown), a display device, or other device for performing various functions regarding the control of the system 50. Exemplary devices that may be coupled to the wires 131 or otherwise coupled to the controller 52 are described in U.S. patent application (attorney docket number 321904-1150), entitled “Modular Control System and Method for Water Heaters,” and filed on Mar. 27, 2007, which is incorporated herein by reference.
In one exemplary embodiment, the wires 75 and 76 are coupled to a power source (not shown) and provide electrical power to the controller 52. This power is not only used to power various components, such as the instruction executing apparatus used to execute the instructions of the control logic 125, but is also used to selectively power and, therefore, activate the heating elements 55 and 56. Note that the controller 52 may have a transformer (not shown in
The interface 95 secured to the wire 75 is electrically coupled to the interface 98 through a relay 144 and a mechanical switch 143 of an emergency shut-off apparatus 152, which will be described in more detail hereafter. The interface 95 is also electrically coupled to the interface 99 through a relay 145 and switch 143. If the switch 143 is in a closed state, then the voltage of the wire 75 is applied to the relays 144 and 145. If the switch 143 is in an open state, then the interfaces 98 and 99 are electrically isolated from the wire 75 by the switch 143.
In addition, the interface 96 secured to the wire 76 is electrically coupled to the interface 97 through a mechanical switch 146 of the emergency shut-off apparatus 152. If the switch 146 is in a closed state, then the voltage of the wire 76 is applied to the interface 97. If the switch 146 is in an open state, then the interface 97 is electrically isolated from the wire 76 by the switch 146.
The apparatus 152 is configured to detect when a temperature of the water within the tank 53 has exceeded a predefined threshold indicating that the water temperature is reaching an unsafe range and/or indicating that the water heating system 50 may have a malfunction. In response to such a detection, the apparatus 152 disables at least the heating elements 55 and 56 until the apparatus 152 later receives a manual input indicating that operation of the heating elements 55 and 56 is to be restarted. In one embodiment, the apparatus 152 disables the heating elements 55 and 56 by placing the switches 143 and 146 in open states such that the interfaces 97-99 are electrically isolated from interfaces 95 and 96 and, therefore, from wires 75 and 76 coupled to the power source (not shown). When the apparatus 152 receives a manual input from a user indicating that operation of the heating elements 55 and 56 is to be restarted, the apparatus 152 transitions each of the switches 143 and 146 from an open state to a closed state, provided that the temperature detected by the apparatus 152 has fallen to a normal range below the predefined threshold.
Various safety standards require that the operation of the components for shutting off power to the heating elements 55 and 56 in an emergency to be separate from the operation of the components used to control the heating elements 55 and 56 in normal operation. To comply with such requirements, the operation of the components of the emergency shut-off apparatus 152 is preferably separate from and independent of the operation of the control logic 125.
Further, the emergency shut-off apparatus 152 may be implemented in hardware, software, or a combination thereof. In the embodiment depicted by
In other embodiments, the emergency shut-off apparatus 152 may be electronically actuated, and portions of the apparatus 152 may be implemented in software, if desired. In this regard, rather having a temperature sensitive element that moves due to thermal stresses, the apparatus 152 may be configured to sense a temperature and provide electrical signals for controlling relays (not shown in
In addition, in one embodiment, the switches 143 and 146 are also coupled to a transformer that transforms the power from the interfaces 95 and 96 into a form suitable for powering various components of the controller 52, such as the control logic 125. Thus, in an emergency shut-off condition, power is cut-off to the control logic 125 as well as the heating elements 55 and 56. Indeed, if desired, the apparatus 152 may cut power to all electrically-powered components of the controller 52.
The wire 77 is electrically coupled to the upper and lower heating elements 55 and 56 (
The wire 78 is electrically coupled to the upper heating element 55. If the control logic 125 determines that the upper heating element 55 is to be activated, the control logic 125 places the relay 144 into a closed state. In this regard, the control logic 125 transmits, to the relay 144, an electrical control signal for transitioning the relay 144 to a closed state. In such case, the voltage of the wire 75 is applied, through the switch 143 and relay 144, to the wire 78 and, therefore, the upper heating element 55 thereby activating the upper heating element 55, assuming that the apparatus 152 has not placed the switch 143 in an open state. If the control logic 125, however, determines that the upper heating element 55 is to be deactivated, the control logic 125 places the relay 144 into an open state. Accordingly, the wire 75 is electrically isolated from the wire 78 and, therefore, the upper heating element 55 thereby deactivating the upper heating element 55. In this regard, the heating element 55 is preferably activated only when electrically coupled to both wires 75 and 76 via the controller 52 and, therefore, receiving power from the power source (not shown) connected to these wires 75 and 76.
The wire 79 is electrically coupled to the lower heating element 56. If the control logic 125 determines that the lower heating element 56 is to be activated, the control logic 125 places the relay 145 into a closed state. In this regard, the control logic 125 transmits, to the relay 145, an electrical control signal for transitioning the relay 145 to a closed state. In such case, the voltage of the wire 75 is applied, through the switch 143 and relay 145, to the wire 79 and, therefore, the lower heating element 56 thereby activating the lower heating element 56, assuming that the apparatus 152 has not placed the switch 143 into an open state. If the control logic 125, however, determines that the lower heating element 56 is to be deactivated, the control logic 125 places the relay 145 in an open state. Accordingly, the wire 75 is electrically isolated from the wire 79 and, therefore, the lower heating element 56 thereby deactivating the lower heating element 56. In this regard, the heating element 56 is preferably activated only when electrically coupled to both wires 75 and 76 via the controller 52 and, therefore, receiving power from the power source (not shown) connected to these wires 75 and 76.
As shown by
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Moreover, a bracket 221 identical to the bracket 211 described above may be used to mount the sensor holding apparatus 59 to the tank 53.
As shown by
Between the PCB 305 and the base 166, which has been removed from
The sensor 66 can be electrically coupled to the PCB 305 via one or more wires extending through and/or over the strip 317 so that the sensor 66 can be electrically coupled to the control logic 125 via conductive connections on the PCB 305. When the base 166 is attached to the housing 84, the sensor 66 is preferably in contact with the base 166 to increase the sensor's sensitivity with respect to temperature changes in the base 166. A segment 318 of adhesive material may adhere the strip 317 to the base 166 to ensure that the strip 317 does not move relative to the base 166 and, therefore, that the sensor 66 remains in contact with the base 166. Moreover, during operation, the base 166 contacts a side of the tank 53, which is heated by the water within the tank 53, and the temperatures sensed by the sensor 66 are indicative of the water temperature within the tank 53.
In the embodiment shown by
The terminal block 95 is electrically coupled to the emergency shut-off apparatus 152 via conductive connections 565 and 566, which are joined and pressed together by a conductive rivet 569 passing through both connections 565 and 566. Similarly, the terminal block 96 is electrically coupled to the emergency shut-off apparatus 152 via conductive connections 555 and 556, which are joined and pressed together by a conductive rivet 559 passing through both connections 555 and 556.
As shown by
To connect the wire 75 to the terminal block 95, the wire 75 is inserted through the hole 574 such that the wire 75 is positioned between the connection end 571 and a floor 577 formed by the conductive terminal block 95, as shown by
Once the wire 75 is inserted into the hole 574 of the terminal block 95, the screw 121 is then rotated such that it is in contact with the end 571 and presses the end 571 against the wire 75 thereby decreasing contact resistance for the electrical current that is to flow between the wire 75 and the connection end 571. Generally, the tighter that the screw 121 is screwed against the connection end 571, the greater is the force that presses the connection end 571 against the wire 75 thereby decreasing contact resistance.
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In one exemplary embodiment, the housing 84 forms guides that can help with assembly of the controller 52 during manufacture. For example,
The current-carrying components, such as terminal blocks 95-99 and connections 565, 566, 555, 556, as well as conductive connections on the PCB 305, can be composed of any conductive material, such as copper, bronze, brass, gold, etc. In one exemplary embodiment, each such current-carrying component is composed of a metallic alloy, such as K88(C18080), which is a copper alloy having better stress relaxation properties relative to many other materials typically used for conductive connections. Moreover, heat can be an important issue, particularly when the controller 52 is sized to a small enough scale such that it can fit, as a drop-in replacement, for conventional mechanical controllers that are mounted via the brackets shown in
In one exemplary embodiment, as depicted by
If desired, the control logic 125, based on temperature data indicative of the temperatures sensed by the sensor 701, compensates the temperature data received from the sensor 66 in an effort to determine a more accurate temperature reading for comparison to the upper and/or lower set point of the upper heating element 55. For example, depending on the readings by the sensor 701, the control logic 125 may try to determine the extent to which heat from the apparatus 152, transformer 667, and/or relays 144 and/or 145 has affected a temperature reading from the sensor 66. The control logic 125 may then adjust the reading from the sensor 66 to account for the heating effects of the apparatus 152, transformer 667, and/or relays 144 and/or 145.
There are various methodologies that may be employed to compensate the temperature data from sensor 66 based on readings from the sensor 701. For example, in one embodiment, the controller 52 is tested for many different conditions to empirically determine the effect of the heat from at least one high temperature component to the reading from sensor 66. For example, during operation of the controller 52 or similar controller, readings from the temperature sensor 66 may be recorded by the control logic 125 or a test instrument that may be connected to the temperature sensor 66 for the purpose of conducting a test. Further, an additional temperature sensor (not shown), referred to a “test sensor” is coupled to the tank 53, and the temperature readings from the test sensor are simultaneously recorded with those from the sensor 66. Since the test sensor is not embedded in the controller 52, heat from the high temperature components of the controller 52 should not have a pronounced effect on the readings by the test sensor.
Moreover, the recorded readings of the test sensor and the temperature sensor 66 may then be analyzed to determine how heat from the high temperature components affected the readings of the temperature sensor 66. In this regard, it may be assumed that any difference between two simultaneous readings by the test sensor and the temperature sensor 66 is attributable to heat from the high temperature components. Thus, a determination can be made as to how the temperature readings of the temperature sensor 66, under various conditions, should be adjusted to account for heat from the high temperature components. The control logic 125 may then be configured to adjust the temperature readings from the sensor 66 accordingly.
Note that the adjustment applied to the readings from the sensor 66 may take into account other factors in addition to the readings from the temperature sensor 701. For example, the length of time that one or more heating elements 55 or 56 have been activated may be a factor. As a mere example, based on the test results, it may be determined that a reading from the temperature sensor 66 is usually about a particular number (e.g., two) degrees F. higher than a simultaneous reading from the test sensor when either element 55 or 56 has been activated for longer than a particular number (e.g., ninety) seconds if the reading from sensor 701 is above a particular temperature threshold (e.g., 150 F). In such an example, the control logic 125, during normal operation, may be configured to subtract two degrees F. from the temperature reading from the sensor 66 if the reading from the sensor 701 is above the temperature threshold and if either heating element 55 or 56 has been activated for longer than ninety seconds. It should be noted that the values and factors described in the foregoing example have been presented for illustrative purposes, and it should be apparent to one of ordinary skill in the art that other values and factors may be employed in other examples. Further, other techniques for testing the controller 52 and/or using the test results to compensate the temperature readings from the sensor 52 are possible. In addition, the temperature readings from the sensor 66 can be adjusted in different ways to compensate for the heat from one or more of the high temperature components based on at least one reading from the sensor 701.
In one exemplary embodiment, as depicted by
By configuring a water heater controller, as described herein, many of the heat related problems that plague electronically actuated controllers can be alleviated. In this regard, the exemplary designs of the electrical interfaces described above help to ensure reliable electrical connections with relatively low contact resistance, thereby helping to reduce temperatures within the controller. Temperatures can also be reduced by using a metallic alloy for the current-carrying components. Such metallic alloy preferably has good electrical conductivity and sufficient mechanical strength at high temperature to resist stress relaxation, which could otherwise lead to higher contact resistance over time as the controller operates in a high temperature environment. Further, an emergency shut-off apparatus that is mechanically actuated, such as the one described in U.S. patent application Ser. No. 11/105,889, is likely to produce less heat as compared to one that is electronically actuated. Such a lower heat producing emergency shut-off apparatus can be used while at the same time allowing the heating elements to be electronically actuated during normal operation.
In addition, using a mechanically actuated emergency shut-off apparatus has an additional safety benefit in that the control of the emergency shut-off apparatus is separate from the control of the relays that are controlled based on comparisons of temperature readings to set points during normal operation. Indeed, applicable Underwriters Laboratories, Inc. (UL) standards in the United States require the control of the emergency shut-off apparatus be independent of the control of the switches that are used to activate and deactivate the heating elements during normal operation. To meet such UL requirement using an electronically actuated emergency shut-off apparatus would likely require additional circuitry that would produce at least some additional heat, as well as possibly increase the cost and overall size requirements of the controller to at least some extent.
Further, the temperature sensor is located at an end of the controller away from several components that produce a relatively high amount of heat, such as the emergency shut-off apparatus and the switches (e.g., relays) that control the activation states of the heating elements. In addition, the temperature sensor is located on a side of the PCB opposite to the foregoing components, helping to shield the temperature sensor from the heat produced by such components. Further, the temperature sensor is mounted on a separate strip of thermally insulating material to further shield the temperature sensor.
Moreover, by configuring a water heater controller in accordance with the exemplary embodiments of the present disclosure, the size of the water heater controller can be kept relatively small, such as similar to or smaller than the sizes of conventional water heater controllers that are mechanically actuated, yet exhibit a relatively high degree of reliability and ease of use. Further, such a water heater controller can be manufactured and installed at a relatively low cost.
Claims
1. A water heater controller, comprising:
- a relay for controlling an activation state of a heating element;
- an emergency shut-off apparatus for disabling the heating element if a temperature exceeds a threshold, the emergency shut-off apparatus having a temperature sensitive element that mechanically actuates based on the temperature, the emergency shut-off apparatus having a mechanical switch that is coupled to the relay, wherein actuation of the temperature sensitive element changes a state of the switch; and
- logic configured to receive temperature data indicative of a temperature sensed by a temperature sensor, the logic further configured to control a state of the relay based on the temperature data.
2. The water heater controller of claim 1, wherein the logic is configured to perform a comparison between the temperature data and a threshold value, wherein the logic is configured to transmit an electronic signal to the relay based on the comparison, and wherein the relay transitions from an open state to a closed state in response to the electronic signal thereby activating the heating element.
3. The water heater controller of claim 1, wherein the logic is configured to perform a comparison between the temperature data and a threshold value, wherein the logic is configured to transmit an electrical signal to the relay based on the comparison, and wherein the relay transitions from a closed state to an open state in response to the electronic signal thereby deactivating the heating element.
4. The water heater controller of claim 1, wherein the emergency shut-off apparatus, upon disabling the heating element, is configured to ensure that the heating element remains disabled until at least the emergency shut-off apparatus receives a user input.
5. The water heater controller of claim 1, wherein the temperature sensitive element comprises a bimetallic disc.
6. The water heater controller of claim 1, further comprising an electrically conductive connection coupled to the emergency shut-off apparatus, the connection composed of a metallic alloy having an International Annealed Copper Standard (IACS) of greater than 80%, a stress relaxation temperature greater than 105 degrees Celsius, and a yield stress greater than 50 kilo-pounds per square inch (ksi).
7. The water heater controller of claim 1, further comprising:
- a thermally conductive base;
- a housing coupled to the base, the housing composed of electrically insulating material;
- the temperature sensor, wherein the temperature sensor contacts the base.
8. The water heater controller of claim 7, wherein the relay is mounted on a first side of a printed circuit board (PCB), and wherein the temperature sensor is positioned on a second side of the PCB that is opposite to the first side.
9. The water heater controller of claim 7, wherein the temperature sensor is mounted on an element composed of thermally insulating material and is electrically coupled to the PCB.
10. The water heater controller of claim 1, further comprising an interface for electrically connecting an electrically conductive wire to an electrically conductive connection, the interface having a hole for receiving the wire.
11. The water heater controller of claim 10, wherein the connection is coupled to the emergency shut-off apparatus.
12. The water heater controller of claim 10, wherein the connection is coupled to the relay.
13. The water heater controller of claim 10, wherein the connection has at least one rib for guiding the wire as the wire is being inserted into the first hole.
14. The water heater controller of claim 10, further comprising a housing covering the logic, the housing having a hole, wherein the wire has a coating composed of insulating material, and wherein a portion of the coating passes through the hole of the housing.
15. The water heater controller of claim 14, wherein at least a portion of a wall of the housing contacts the coating, the portion defining the hole of the housing.
16. The water heater controller of claim 14, wherein the interface is composed of a metallic alloy having an International Annealed Copper Standard (IACS) of greater than 80%, a stress relaxation temperature greater than 105 degrees Celsius, and a yield stress greater than 50 kilo-pounds per square inch (ksi).
17. The water heater controller of claim 10, further comprising:
- a thermally conductive base;
- a housing coupled to the base, the housing composed of an electrically insulating material;
- the temperature sensor,
- wherein the temperature sensor contacts the base.
18. The water heater controller of claim 17, wherein the relay is mounted on a first side of a printed circuit board (PCB), and wherein the temperature sensor is positioned on a second side of the PCB that is opposite to the first side.
19. The water heater controller of claim 18, wherein the temperature sensor is mounted on an element composed of thermally insulating material and electrically coupled to the PCB.
20. A water heating system, comprising:
- a tank;
- a heating element mounted on the tank; and
- a controller mounted on the tank, the controller comprising: an emergency shut-off apparatus that is mechanically actuated, the emergency shut-off apparatus coupled to the heating element and having a temperature sensitive element that mechanically actuates due to thermal stresses such that the heating element is disabled if the temperature exceeds a threshold; a relay coupled to the heating element; and logic configured to receive temperature data indicative of a temperature sensed by a temperature sensor, the logic further configured to control a state of the relay based on the temperature data.
21. The system of claim 20, wherein the controller further comprises:
- a thermally conductive base;
- a housing coupled to the base, the housing composed of electrically insulating material;
- the temperature sensor,
- wherein the temperature sensor contacts the base.
22. The system of claim 21, wherein the relay is mounted on a first side of a printed circuit board (PCB), and wherein the temperature sensor is positioned on a second side of the PCB that is opposite to the first side.
23. The system of claim 20, further comprising an electrically conductive wire, wherein the controller further comprises:
- an electrically conductive connection; and
- an interface having a hole, the connection extending through the hole.
24. The system of claim 23, further comprising a housing covering the logic, the housing having a hole, wherein the wire has a coating composed of insulating material, and wherein a portion of the coating passes through the hole of the housing.
25. The system of claim 23, wherein the connection is composed of a metallic alloy having an International Annealed Copper Standard (IACS) of greater than 80%, a stress relaxation temperature greater than 105 degrees Celsius, and a yield stress greater than 50 kilo-pounds per square inch (ksi).
26. The system of claim 23, wherein the connection has at least one rib for guiding the wire as the wire is being inserted into the first hole.
27. A water heater controller, comprising:
- an electromechanical switching means for controlling an activation state of the heating element;
- means for disabling a heating element if a temperature exceeds a threshold, the disabling means having a mechanical switching means coupled to the relay and having a temperature sensing means that mechanically actuates based on the temperature, wherein actuation of the temperature sensing means changes a state of the mechanical switching means; and
- means for receiving temperature data indicative of a temperature sensed by a temperature sensor, and for controlling a state of the relay based on the temperature data.
28. A method for controlling a water heating system having a tank and a heating element mounted on the tank, comprising the steps of:
- disabling the heating element if a temperature exceeds a threshold, the disabling step comprising the step of mechanically actuating a temperature sensitive element based on the temperature;
- sensing a temperature;
- transmitting temperature data indicative of the sensed temperature; and
- controlling an operational state of the heating element based on the temperature data, the controlling step comprising the step of electrically actuating a relay based on the temperature data.
29. The method of claim 28, wherein the disabling step comprises the step of ensuring that the heating element remains disabled until a user input is received.
Type: Application
Filed: Mar 27, 2007
Publication Date: Oct 25, 2007
Inventors: Wade Patterson (Huntsville, AL), Terry Phillips (Meridianville, AL)
Application Number: 11/692,117
International Classification: F24H 9/20 (20060101);