Furnace control system

• US 4,842,044 A
• Filed: 12/28/1987
• Issued: 06/27/1989
• Est. Priority Date: 12/28/1987
• Status: Expired due to Fees

• Current Assignee: Haven Energy Limited
• Original Assignee: Haven Energy Limited
• Inventors: Ness, William A., Flanders, Staunton O.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/138,310
• Time in Patent Office: 547 Days
• Field of Search: 236/11, 236/46 R, 62/158, 62/231, 165/12, 165/26
• US Class Current: 165/244
• CPC Class Codes: G05D 23/1909 whose output amplitude can only take two discrete values
• CPC Class Codes: G05D 23/275 with sensing element expanding, contracting, or fusing in response to changes of temperature

Abstract

A control system for a combined heating and cooling system connected to the control circuitry therefor, for energizing a fan or other fluid circulating device to circulate fluid and effect thermal transfer of energy therefrom to the spaces being heated in response to energization of the heating and cooling system, and for deenergizing said circulating means a selected time interval after deenergization of said heating and cooling system to effect extraction of thermal energy from the circulating fluid, said control system being operative in the absence of electrical energy or other malfunction to energize fluid circulating device.

Claims

1. In a combined heating and cooling system of the type which is selectively energized to heat and cool a building space by transferring thermal energy to a fluid and by energizing fluid circulating means to circulate the fluid through the building space, a control system comprising:

switching means normally connected to effect energization of said fluid circulating means;

switching control means energizable in response to deenergization of said heating and cooling system for operating said switching means to inhibit energization of said fluid circulating means;

said switching control means being deenergized for operating said switching means to effect substantially immediate energization of the fluid circulating means in response to energization of said heating and cooling system; and

circuit means responsive to the deenergization of said heating and cooling system for energizing said switching control means a selected time interval after deenergization of said heating and cooling system to operate said switching means and deenergize said fluid circulating means.

2. A control system as claimed in claim 1, wherein:

said circuit means is responsive to the energization of said heating and cooling system for effecting deenergization of said switching control means.

3. A control system as claimed in claim 1, wherein:

the combined heating and cooling system includes electrically operated system control means connected to an electrical power source and operable to effect energization of the heating and cooling system; and

wherein;

said circuit means is connected to said power source through said electrically operated system control means for normally effecting energization of said switching control means to operate said switching means and inhibit energization of said fluid circulating means, said circuit means being responsive to energization of said electrically operated system control means for effecting deenergization of said switching control means to effect said energization of said fluid circulating means.

4. A control system as claimed in claim 3, wherein said circuit means is operable in response to disconnection thereof from said electrical power source for effecting deenergization of said switching control means to effect said energization of said fluid circulating means.

5. A control system as claimed in claim 3, wherein said electrically operated system control means comprises heating system control means for effecting energization of the heating and cooling system to heat the fluid to be circulated, and cooling system control means for effecting energization of the heating and cooling system to cool the fluid to be circulated;

and wherein;

said circuit means is connected to said power source through both said electrically operated heating system control means and said electrically operated cooling system control means and is responsive to energization of either of said electrically operated system control means for effecting deenergization of said switching control means and said resultant energization of said fluid circulating means.

6. A control system as claimed in claim 5, wherein said circuit means includes timing means and first normally closed timing switch means connecting said timing means to said electrically operated heating system control-means.

7. A control system as claimed in claim 6, wherein said circuit means further includes second normally closed timing control switch means connected to said electrically operated cooling system control means for normally maintaining said first timing switch means closed in response to deenergization of said electrically operated cooling system control means, and for opening said first timing switch means in response to energization of said electrically operated cooling system control means for effecting deenergization of said switching control means and the resulting energization of said fluid circulating means.

8. In a heating system of the type which has a control circuit that is operable to energize the heating systems to heat a building space by the system heating a fluid to be circulated through the building space by fluid circulating means in response to closure of a thermomtatic switch located in the building space when the temperature in the space drops to a first selected value and in which said control circuit is operable to deenergize the system in response to opening of said thermostatic switch when the temperature is the space rises to a second selected value, a control system comprising;

switching means normally connecting said circulating means to said control circuit to effect energization of said fluid circulating means when power is applied to the control circuit;

switching control means energizable in response to operation of the control circuit to deenergize said heating system for operating said switching means to disconnect said fluid circulating means from said control circuit to inhibit energization thereof;

said switching control means being deenergized in response to energization of said heating system to operate said switching means to connect said fluid circulating means to said control circuit; and

additional circuit means responsive to the deenergization of said heating system for energizing said switching control means a selected time interval after deenergization of said heating system to operate said switching means and disconnect said fluid circulating means from said control circuit.

9. A control system as claimed in claim 8, wherein:

said heating system control circuit includes electrically operated heating control means connected to an electrical power source through said thermostatic switch, said heating control means operable to effect energization of the heating system in response to closure of said thermostatic switch; and

wherein;

said additional circuit means is connected to said power source through said electrically operated heating control means for normally effecting energization of said switching control means to operate said switching means and inhibit energization of said fluid circulating means.

10. A control system as claimed in claim 8, wherein:

said additional circuit means is responsive to energization of said electrically operated heating control means to effect deenergization of said switching control means and operation of said switching means to connect said fluid circulating means to said control circuit means and effect energization of said fluid circulating means.

11. A control system as claimed in claim 8, wherein said additional circuit means is operable in response to disconnection thereof from said control circuit for effecting deenergization of said switching control means to effect said energization of said fluid circulating means.