SYSTEMS AND METHODS FOR CONTROLLING A WATER HEATER

• US 20090101085A1
• Filed: 12/12/2008
• Published: 04/23/2009
• Est. Priority Date: 02/07/2005
• Status: Active Grant

• Current Assignee: Copeland Comfort Control LP (Emerson Electric Company)
• Original Assignee: Emerson Electric Company
• Inventors: Evans, Edward B., Vogel, G. Scott, Arensmeier, Jeffrey N., Donnelly, Donald E., Haefner, John S.
• Granted Patent: US 8,176,881 B2
• Time in Patent Office: Days
• US Class Current: 122/14.220
• CPC Class Codes: F23M 2900/11021 Means for avoiding accidental fires in rooms where the combustion device is located
• CPC Class Codes: F23N 2225/10 stack temperature
• CPC Class Codes: F23N 2231/20 Warning devices
• CPC Class Codes: F23N 5/242 using electronic means
• CPC Class Codes: F24H 15/174 Supplying heated water with desired temperature or desired range of temperature
• CPC Class Codes: F24H 15/184 Preventing harm to users from exposure to heated water, e.g. scalding
• CPC Class Codes: F24H 15/225 at different heights of the tank
• CPC Class Codes: F24H 15/235 Temperature of exhaust gases
• CPC Class Codes: F24H 15/242 Pressure
• CPC Class Codes: F24H 15/281 Input from user
• CPC Class Codes: F24H 15/31 of valves having only one inlet port and one outlet port, e.g. flow rate regulating valves
• CPC Class Codes: F24H 15/36 of burners
• CPC Class Codes: F24H 15/395 Information to users, e.g. alarms
• CPC Class Codes: F24H 15/421 using pre-stored data
• CPC Class Codes: F24H 15/464 using local wireless communication
• CPC Class Codes: F24H 15/486 using timers
• CPC Class Codes: F24H 9/2035 using fluid fuel
• CPC Class Codes: H04Q 2209/40 using a wireless architecture
• CPC Class Codes: H04Q 2209/823 where the data is sent when the measured values exceed a threshold, e.g. sending an alarm
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A control for a water heater is provided that comprises a pressure switch for sensing a predetermined level of airflow sufficient for maintaining proper burner operation, and a temperature sensing means for sensing the temperature of the water in the tank. The control further comprises a processor for controlling the operation of the burner to maintain the water temperature above a predetermined value. When the processor receives a signal from the pressure switch or temperature switch indicating a malfunction, the processor shuts down the burner and subsequently attempts to restart the burner. The processor will lock-out further burner operation after a predetermined number of consecutive shut downs occurs, and will communicate any malfunction information to a remote display device.

Claims

1. A control system for a gas-fired water heater having a burner for heating water within a tank of the water heater, the control system comprising:

a lower sensor disposed on a lower portion of the water heater for sensing the temperature of water in a lower portion of the tank;

an upper sensor disposed on an upper portion of the water heater for sensing the temperature of water in an upper portion of the tank;

a water heater controller in communication with the lower sensor and upper sensor for controlling burner operation to heat the water in the water heater to a desired set-point temperature, the water heater controller having a processor that receives a desired set-point temperature and sensed temperatures of both the upper and lower sensors, wherein the processor calculates a value representing the portion of water in the tank that is at the desired set-point temperature, based in part on a first temperature differential equal to the set-point temperature less the upper sensor temperature, and a second temperature differential equal to the set-point temperature less the lower sensor temperature;

a transceiver means for wirelessly transmitting signals including said value representing the portion of water in the tank at the desired set-point temperature;

a user interface having a transceiver means for wirelessly receiving signals, and a display device including a plurality of selectively-illuminated segmented portions arranged in a linear array, wherein the display device selectively illuminates a number of the segmented portions corresponding to said value, to thereby provide a visual depiction representing the portion of the water physically contained within the tank that is at the desired set-point temperature.

2. The control system of claim 1 wherein the water heater controller is mounted on the water heater, and the user interface is mounted in a location remote from the water heater.

3. The control system of claim 2 wherein the calculated value is equal to a maximum value, less an offset that is calculated based in part on the average of both the first differential temperature divided by a differential variable, and the second differential temperature divided by a differential variable.

4. The control system of claim 1 wherein the calculated value is equal to a maximum number, less an offset that is calculated as the average of a first differential temperature value, which is equal to the set-point temperature less the upper sensor temperature, divided by a differential variable, and the second differential temperature, which is equal to equal to the set-point temperature less the upper sensor temperature divided by a differential variable, divided by a differential variable.

5. The control system of claim 2 wherein the maximum number is an integer value of at least 4.

6. The control system of claim 2 wherein the differential variable is a value of at least 10.

7. The control system of claim 6 where the differential variable is a variable that is subtracted from the user'"'"'s set-point temperature for determining an activation temperature at which the water heater controller initiates heating operation to heat the water in the tank up to the desired set-point temperature.

8. The control system of claim 2 wherein the value representing the portion of water within the tank that is at the desired set-point temperature is calculated based on the function defined as:

V=N_maximum−

[(T_setpoint−

T_{upper sensor})/T_differential+(T_setpoint−

T_{lower sensor})/T_differential]/2

9. The control system of claim 8 wherein the calculated value for (T_{set point}−

T_{upper sensor})/T_differential may be limited to a maximum value, and the calculated value for (T_{set point}−

T_{lower sensor})/T_differential may be limited to a maximum value, such that the calculation [(T_setpoint−

T_{upper sensor})/T_differential+(T_setpoint−

T_{lower sensor})/T_differential]/2 does not result in an offset greater than the maximum number N_maximum.

10. The control system of claim 9 wherein the maximum number is an integer value of at least 4.

11. The control system of claim 9 wherein the differential variable is a value of at least 10.

12. A control system for a gas-fired water heater appliance having a burner for heating water within a water-holding tank of the appliance, the control system comprising:

a lower sensor disposed on a lower portion of the water heater for sensing the temperature of water in the lower portion of the tank;

an upper sensor disposed on an upper portion of the water heater for sensing the temperature of water in the upper portion of the tank;

a water heater controller in communication with the lower sensor and upper sensor for controlling burner operation to heat the water in the water heater appliance to a desired set-point temperature, the water heater controller having a processor that receives a user-selected set-point temperature, and the sensed temperature from both the upper and lower sensor, wherein the processor transforms the temperature data by calculation of a value representing the portion of water within the tank that is at the desired set-point temperature, wherein the calculated value is equal to a maximum number, less an offset that is calculated as the average of a first differential temperature value, which is equal to the set-point temperature less the upper sensor temperature, divided by a differential variable, and the second differential temperature, which is equal to the set-point temperature less the upper sensor temperature divided by a differential variable, divided by a differential variable; and

a transceiver means for wirelessly transmitting signals, the transceiver means transmitting a signal including said value representing the portion of water within the tank at the desired set-point temperature; and

a user interface having a transceiver means for wirelessly receiving signals, and a display device including a plurality of selectively illuminated segmented portions thereon, wherein the display device selectively illuminates a number of segmented portions that corresponds to said value, to thereby provide a visual depiction that represents the specific portion of the water physically contained within the tank that is at the desired set-point temperature.

13. The control system of claim 12 wherein the value representing the portion of water within the tank that is at the desired set-point temperature is calculated based on the function defined as:

V=N_maximum−

[(T_setpoint−

T_{upper sensor})/T_differential+(T_setpoint−

T_{lower sensor})/T_differential]/2

14. The control system of claim 13 wherein the calculation for (T_{set point}−

T_{upper sensor})/T_differential may be limited to a maximum value, and the calculation for (T_{set point}−

T_{lower sensor})/T_differential may be limited to a maximum value, such that the calculation [(T_setpoint−

T_{upper sensor})/T_differential+(T_setpoint−

T_{lower sensor})/T_differential]/2 does not result in an offset greater than the maximum number N_maximum.

15. The control system of claim 14 wherein the maximum number N_maximum is an integer value of at least 4.

16. The control system of claim 14 wherein the differential variable T_differential is a value of at least 10.

17. A control system for a gas-fired water heater appliance having a burner for heating water within a water-holding tank of the appliance, the control system comprising:

a lower sensor disposed on a lower portion of the water heater for sensing the temperature of water in the lower portion of the tank;

an upper sensor disposed on an upper portion of the water heater for sensing the temperature of water in the upper portion of the tank;

a water heater controller mounted on the water heater that is in communication with the lower sensor and upper sensor for controlling burner operation to heat the water in the water heater appliance to a desired set-point temperature, the water heater controller having a processor that receives a user-selected set-point temperature, and the sensed temperature from both the upper and lower sensor, wherein the processor transforms the temperature differential data by calculation of a value representing the portion of water within the tank that is at the desired set-point temperature, said value being calculated based on the function defined as;

V=N_maximum−

[(T_setpoint−

T_{upper sensor})/T_differential+(T_setpoint−

T_{lower sensor})/T_differential]/2

a transceiver means for wirelessly transmitting signals, the transceiver means transmitting a signal including said value representing the portion of water within the tank at the desired set-point temperature; and

a user interface mounted in a location remote from the water heater, having a transceiver means for wirelessly receiving signals, and a display device including a plurality of selectively illuminated segmented portions that define a linear array thereon, wherein the display device selectively illuminates a number of segmented portions that corresponds to said value, to thereby provide a visual depiction that represents the specific portion of the water physically contained within the tank that is at the desired set-point temperature.

18. The control system of claim 17 wherein the calculated value representing the portion of water in the tank at the desired set-point temperature is at the maximum number N_maximum when the water temperature sensed by both the upper and lower sensors is equal to or greater than the set point temperature.

19. The control system of claim 17 wherein the calculation for (T_{set point}−

T_{upper sensor})/T_differential may be limited to a maximum value, and the calculation for (T_{set point}−

T_{lower sensor})/T_differential may be limited to a maximum value, such that the calculation [(T_setpoint−

T_{upper sensor})/T_differential+(T_setpoint−

T_{lower sensor})/T_differential]/2 does not result in an offset greater than the maximum number N_maximum.

20. The control system of claim 17 wherein the maximum number N_maximum corresponds to the number of selectively illuminated segmented portions, which represents 100 percent of the water contained within the tank of the water heater.

21. The control system of claim 17, wherein the maximum number N_maximum is an integer value of at least 4, and the differential variable is a value of at least 10.