GAS PRESSURE CONTROL FOR WARM AIR FURNACES

• US 20080124667A1
• Filed: 10/18/2006
• Published: 05/29/2008
• Est. Priority Date: 10/18/2006
• Status: Abandoned Application

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Schultz, Michael W.
• Application Number:
  US11/550,619
• Publication Number:
  US 20080124667A1
• Time in Patent Office: Days
• US Class Current: 431/18
• CPC Class Codes: F23N 1/022 using electronic means
• CPC Class Codes: F23N 2005/181 using detectors sensitive to rate of flow of air
• CPC Class Codes: F23N 2233/04 with variable speed
• CPC Class Codes: F23N 2241/02 Space-heating
• CPC Class Codes: F23N 5/10 using thermocouples
• CPC Class Codes: F23N 5/203 using electronic means

Abstract

Systems, methods, and controllers for controlling gas-fired appliances such as warm air furnaces are disclosed. An illustrative furnace system can include a burner unit in communication with a combustion air flow conduit and heat exchanger, a variable speed inducer fan or blower adapted to provide a flow of combustion air to the burner unit, a furnace controller and motor speed control unit adapted to regulate the speed of the inducer fan or blower, and a pneumatically modulated gas valve adapted to variably output gas pressure to the burner unit based at least in part on the combustion air flow.

Claims

1. A furnace system, comprising:

a burner unit in communication with a combustion air flow conduit and a heat exchanger;

a variable speed inducer fan or blower adapted to provide combustion air flow to the burner unit;

a furnace controller and a motor speed control unit adapted to regulate the speed of the fan or blower; and

a pneumatically modulated gas valve adapted to variably output gas pressure to the burner unit based at least in part on the combustion air flow.

2. The system of claim 1, wherein the burner unit includes a gas manifold and a burner box.

3. The system of claim 1, wherein the furnace controller is in communication with one or more thermostat units.

4. The system of claim 1, wherein the motor speed control unit is an integral part of the furnace controller.

5. The system of claim 1, wherein the motor speed control unit is a separate component from the furnace controller.

6. The system of claim 1, wherein the gas valve is pneumatically driven via one or more pressure signals received at one or more locations within the combustion air flow conduit.

7. The system of claim 6, wherein said one or more pressure signals includes:

a first pneumatic signal received from a first conduit in fluid communication with the input side of the heat exchanger; and

a second pneumatic signal received from a second conduit in fluid communication with the output side of the heat exchanger.

8. The system of claim 7, further comprising a pneumatic amplifier coupled to the gas valve, the pneumatic amplifier adapted to amplify a differential pressure control signal fed to the gas valve based at least in part on said first and second pneumatic signals.

9. The system of claim 1, further comprising a sensor or switch for sensing the rotational speed of the inducer fan or blower.

10. The system of claim 1, further comprising a circuit for measuring the voltage and/or current within the inducer fan or blower.

11. The system of claim 1, wherein the furnace system comprises a warm air furnace system.

12. A controller for regulating a gas-fired appliance, the gas-fired appliance including a burner unit, a heat exchanger, a gas valve, and a multi or variable speed fan or blower adapted to produce a combustion air flow to the burner unit, the controller comprising:

a processor adapted to compute the temperature of the combustion air flow at the burner unit; and

a motor speed control unit adapted to regulate the speed of the fan or blower based at least in part on the computed temperature of the combustion air flow.

13. The controller of claim 12, wherein the controller is adapted to receive thermostat signals from one or more thermostats.

14. The controller of claim 12, wherein the controller is adapted to receive a speed signal from the fan or blower.

15. The controller of claim 12, wherein the controller is adapted to receive a voltage or current signal from the fan or blower.

16. A method of controlling a gas-fired appliance including a burner unit, a heat exchanger, a gas valve, a multi or variable speed inducer fan or blower adapted to produce a combustion air flow to the burner unit, and a heated air blower adapted to provide heated air to one or more warm air ducts, the method comprising the steps of:

receiving a heat request signal and activating the fan or blower to provide a combustion air flow to the burner unit;

activating the gas valve to provide fuel to the burner unit and igniting the air/fuel mixture within the burner unit;

adjusting the speed of the inducer fan and/or heated air blower based at least in part on heat demand signals received from one or more thermostats;

sensing or measuring the mass air flow of the inducer fan and/or heated air blower and calculating the supply air temperature fed to the warm air ducts; and

adjusting the speed of the inducer fan or blower to modulate the gas pressure outputted by the gas valve.

17. The method of claim 16, further comprising the step of sensing the presence of a flame within the burner unit after said step of igniting the burner unit.

18. The method of claim 16, wherein said step of sensing or measuring the speed of the inducer fan or blower is accomplished via a sensor or switch.

19. The method of claim 16, wherein said step of sensing or measuring the speed of the inducer fan or blower is accomplished by measuring the voltage and/or current of the inducer fan or blower.

20. The method of claim 16, wherein said step of adjusting the speed of the inducer fan or blower based on heat demand signals received from one or more thermostats is accomplished with a motor speed control unit.