Water heater with dry tank or sediment detection feature

• US 20070295286A1
• Filed: 06/27/2006
• Published: 12/27/2007
• Est. Priority Date: 06/27/2006
• Status: Active Grant

• Current Assignee: Copeland Comfort Control LP (Emerson Electric Company)
• Original Assignee: Emerson Electric Company
• Inventors: Donnelly, Donald E., Arensmeier, Jeffrey N., Ray, Herbert G.
• Granted Patent: US 7,434,544 B2
• Time in Patent Office: Days
• US Class Current: 122/14.1
• 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 15/20 characterised by control inputs
• CPC Class Codes: F24H 15/225 at different heights of the tank
• 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 9/0042 Cleaning arrangements
• CPC Class Codes: F24H 9/2035 using fluid fuel

Abstract

One or more embodiments of a controller for controlling a fuel-fired water heater are provided that are able to detect a high rate of temperature change condition in the water heater tank. The fuel fired water heater appliance having a water storage vessel comprises a surface mount sensor disposed on the outer surface of the storage vessel near the bottom of the vessel, for sensing the temperature of the vessel. The controller monitors the rate of change of the temperature sensed by the surface mount sensor during a heating cycle, and discontinues operation of the water heater appliance upon detecting an increase in the rate of temperature change that is indicative of an undesirable level of sediment build-up in the water storage vessel.

Claims

1. A controller for controlling the operation of a fuel fired water heater appliance having a water storage vessel and a fuel fired heating apparatus located below the water storage vessel, the controller comprising:

a surface mount sensor disposed on the outer surface of the storage vessel near the bottom of the vessel, for sensing the temperature of the vessel; and

a controller that monitors the rate of change of the temperature sensed by the surface mount sensor during a heating cycle, and discontinues operation of the water heater appliance upon detecting a rate of temperature increase that is indicative of an undesirable level of sediment build-up in the water storage vessel.

2. The controller of claim 1, wherein the rate of temperature increase is in the range of about 20 degrees Fahrenheit to about 35 degrees Fahrenheit.

3. The controller of claim 1, wherein the controller provide a fault signal to alert a user of the water heater of the undesirable level of sediment build-up in the water storage vessel.

4. A controller for a water heater appliance having a fuel-fired heating apparatus, the controller comprising:

a sensor disposed on the outer surface of the storage vessel near the bottom of the vessel, for providing a signal indicative of the temperature of the bottom of the storage vessel; and

a processor that periodically reads the temperature signal from the sensor and determines at least one rate of temperature change of the vessel temperature during a cycle of heating apparatus operation, and discontinues operation of the heating apparatus when the controller detects a rate of temperature change that exceeds a predetermined rate of change that is indicative of an undesirable level of sediment build-up in the water storage vessel.

5. The controller of claim 4, wherein the processor is further capable of providing a fault signal to alert a user of the water heater of the undesirable level of sediment build-up in the water storage vessel.

6. A controller for a water heater appliance having a fuel-fired heating apparatus, the controller comprising:

a sensor disposed on the outer surface of the storage vessel near the bottom of the vessel, for providing a signal indicative of the temperature of the bottom of the storage vessel; and

a processor configured to periodically read the temperature signal from the sensor during a period of heating operation and to determine at least one sensed rate of temperature change during a heating cycle, wherein the processor uses the sensed rate of temperature change during one or more periods of heating operation over a predetermined length of time to determine a baseline rate of temperature change, and the processor provides a fault signal indicating an undesirable level of sediment build-up in the storage vessel when the sensed rate of temperature change during a heating cycle is more than a predetermined amount above the base line rate of temperature change.

7. The controller of claim 6 wherein the processor further discontinues operation when the sensed rate of temperature change exceeds the predetermined amount.

8. The controller of claim 7 wherein the predetermined amount is a value of about 20 degrees Fahrenheit to about 35 degrees Fahrenheit.

9. The controller of claim 7 wherein the predetermined amount is a percentage of the baseline rate of temperature change.

10. The controller of claim 6 wherein the processor provides a fault signal indicating the occurrence of a dry tank condition in the storage vessel when the sensed rate of temperature change during a period of heating operation that is greater than a third predetermined rate of temperature change that is indicative of a dry tank condition.

11. The controller of claim 9 wherein the processor further discontinues operation when the sensed rate of temperature change exceeds the third predetermined amount indicative of a dry tank condition.

12. A controller for a water heater appliance having a fuel-fired heating apparatus, the controller comprising:

a sensor disposed on the outer surface of the storage vessel near the bottom of the vessel, for providing a signal indicative of the temperature of the bottom of the storage vessel; and

a processor configured to periodically read the temperature signal from the sensor at given time intervals during a period of heating operation to determine at least one representative sensed rate of temperature change during the heating period, wherein the processor uses the representative rate of temperature change during one or more periods of heating operation over a predetermined length of time to determine a baseline rate of temperature change, and the processor provides a warning signal alerting a user of the water heater that the water heater has an undesirable level of sediment build-up in the storage vessel when the sensed rate of temperature change during a period of heating operation is more than a first predetermined amount above the base line rate of temperature change, and the processor provides a fault signal indicating an unsafe level of sediment build-up in the storage vessel when the sensed rate of temperature change during a period of heating operation is more than a second predetermined amount above the base line rate of temperature change.

13. The controller of claim 12 wherein the processor further discontinues operation when a sensed rate of temperature change during a period of heating operation exceeds the second predetermined amount.

14. The controller of claim 13 wherein the predetermined amount is a value of about 20 degrees Fahrenheit to about 35 degrees Fahrenheit.

15. The controller of claim 13 wherein the predetermined amount is a percentage of the baseline rate of temperature change.

16. The controller of claim 15 wherein the predetermined amount is about 120 percent of the baseline rate of temperature change.

17. The controller of claim 12 wherein the processor provides a fault signal indicating the occurrence of a dry tank condition in the storage vessel when the sensed rate of temperature change during a period of heating operation that is greater than a third predetermined rate of temperature change that is indicative of a dry tank condition.

18. The controller of claim 16 wherein the processor further discontinues operation when the sensed rate of temperature change exceeds the third predetermined amount indicative of a dry tank condition.

19. The controller of claim 17 wherein the predetermined amount is about 200 percent of the baseline rate of temperature change.

20. A fuel-fired water heater appliance comprising the controller of claim 12.