Adaptive forced warm air furnace using analog temperature and pressure sensors

• US 5,307,990 A
• Filed: 11/09/1992
• Issued: 05/03/1994
• Est. Priority Date: 11/09/1992
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Torborg, Ralph H., Adams, Wilmer L.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/973,793
• Time in Patent Office: 540 Days
• Field of Search: 236/49.3, 236/11, 236/37
• US Class Current: 236/11
• CPC Class Codes: F24H 15/208 Temperature of the air after heating
• CPC Class Codes: F24H 15/242 Pressure
• 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 15/35 Control of the speed of fans
• CPC Class Codes: F24H 15/36 of burners
• CPC Class Codes: F24H 15/421 using pre-stored data
• CPC Class Codes: F24H 9/2085 using fluid fuel

Abstract

Furnace control for a forced air furnace utilized in multi-zone heating. The forced air furnace is made up of return ducts, a heat exchanger, warm air ducts, a circulation blower, and a burner. The forced air furnace receives heating requests from external control means wherein the furnace provides heat to a zone or multiple zones to be heated. The control for the furnace comprises a temperature sensor for sensing the temperature of the heat exchanger, a regulator for regulating the burner to hold the temperature at the heat exchanger constant during the on cycle of the furnace, a pressure sensor for measuring the pressure in the heat exchanger and a controller for controlling the circulation blower in order to maintain a constant pressure within the heat exchanger.

Claims

1. A method for regulating circulation blower setpoints to maintain constant pressure in a forced air zoned heating system the forced air furnace having return ducts, a heat exchanger, warm air ducts, a circulation blower, and a burner, comprising the steps of:

receiving a heating request from an external controller;

energizing the burner in the furnace to heat the heat exchanger;

sensing the temperature of the heat exchanger;

energizing the circulation blower when the heat exchanger reaches a first predetermined temperature;

regulating the burner to maintain a second predetermined temperature, said second predetermined temperature being higher than said first predetermined temperature;

sensing the pressure in the heat exchanger;

regulating the circulation blower at a circulation setpoint to maintain a constant pressure in the heat exchanger;

de-energizing the burner when said heating request is satisfied; and

de-energizing the circulation blower when said heat exchanger cools to said first predetermined temperature.

2. A method for regulating circulation blower setpoints to maintain constant pressure in a forced air zoned heating system the forced air furnace having return ducts, a heat exchanger, warm air ducts, a circulation blower, and a burner, comprising the steps of:

receiving a heating request from an external controller;

energizing the burner in the furnace to heat the heat exchanger;

energizing the circulation blower;

sensing the pressure in the heat exchanger;

regulating the circulation blower at a circulation setpoint to maintain a constant pressure in the heat exchanger;

measuring the time required to satisfy said heating request;

increasing the circulation blower setpoint to maintain a second constant pressure if said time required to satisfy said heating request increases;

decreasing the circulation blower setpoint to maintain a third constant pressure if said time required to satisfy said heating request decreases; and

de-energizing the burner and the circulation blower when said heating request is satisfied.

3. The method for regulating circulation blower setpoints of claim 2 further comprising the steps of:

sensing the temperature of the heat exchanger;

energizing the circulation blower when the heat exchanger reaches a first predetermined temperature;

regulating the burner to maintain a second predetermined temperature, said second predetermined temperature being higher than said first predetermined;

de-energizing the burner when said heating request is satisfied;

de-energizing the circulation blower when said heat exchanger cools to said first predetermined temperature.

4. A method for regulating circulation blower setpoints to maintain constant pressure in a forced air zoned heating system the forced air furnace having return ducts, a heat exchanger, warm air ducts, a circulation blower, and a burner, comprising the steps of:

receiving a heating request from an external controller;

energizing the burner in the furnace to heat the heat exchanger;

energizing the circulation blower;

sensing the pressure in the heat exchanger;

regulating the circulation blower at a circulation setpoint to maintain a constant pressure in the heat exchanger;

measuring cycle "on " time of said furnace;

increasing said circulation blower setpoint to maintain a second constant pressure if said "on " time increases;

decreasing said circulation blower setpoint to maintain a third constant pressure if said "on " time decreases;

de-energizing the burner and the circulation blower when said heating request is satisfied.

5. The method for regulating circulation blower setpoints of claim 4 further comprising the steps of:

sensing the temperature of the heat exchanger;

energizing the circulation blower when the air temperature in the heat exchanger reaches a first predetermined temperature;

regulating the burner to maintain a second predetermined temperature, said second predetermined temperature being higher than said first predetermined;

de-energizing the burner when said heating request is satisfied;

de-energizing the circulation blower when said heat exchanger cools to said first predetermined temperature.

6. A furnace control for a forced air control heating system for multi-zone heating, the forced air furnace having return ducts, a heat exchanger, warm air ducts, a circulation blower, and a burner, the forced air furnace receiving the heating requests for external control means, wherein said furnace provides heat to at least one zone to be heated, the burner heating the heat exchanger, the circulation blower forcing air from the return ducts through the heat exchanger and out the warm air duct to the zone to be heated, said furnace control comprising:

temperature sensor for sensing the temperature of the heat exchanger;

regulation means for regulating the burner, said temperature sensor providing a signal representative of the air temperature in the heat exchanger to said regulation means, said regulation means regulating the burner such that said heat exchanger is held to a constant temperature after reaching a preset temperature during the external controller request for heat;

a pressure sensor for measuring the pressure in the heat exchanger;

a controller for controlling the circulation blower, said pressure sensing means providing a signal representative of said pressure in the heat exchanger to said controller, said controller regulating the circulation blower wherein said pressure in the heat exchanger is held constant; and

wherein said controller further comprises timing means, wherein said furnace satisfies said request for heat in a period of time, wherein said timing means times said period of time, said controller increasing said pressure if said period of time is greater than a first predetermined time.

7. The furnace control of claim 6 wherein said controller decreases said pressure if said period of time is less than a second predetermined time.