CA1179416A - Energy saving override blower control for forced air systems - Google Patents

Abstract

Abstract of the Disclosure A blower override system and control for forced air systems such as heat or cooling systems in which and override relay starts the blower to circulate the warmed or cooled air when the heating or cooling element turned on. When the heating or cooling is turned off, the blower is there-upon allowed to continue by the override unit to function for a timed interval by a time delay relay. The unit is in a control box and ready to attach to existing control structures for forced air systems.

Description

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The present invention is directed to a blower override system and control for forced air heating systems wherein a relay, activated by the ignition and supply function of fuel to the burner as, for example, tripped by a thermostat, starts the blower and extends performance of the blower until the burner is turned off and then, via a time delay, continues the blower function for a selected time period. The same unit is operable with air conditioning blower units with equivalent savings.
No interference with regular controls is re~uired and the regular controls serve as a fail-safe back up. The regular controls alone trip the blower at a preset temperature level in the plenum or at the thermostat and results in substantial heat loss to the stack, both before and after the heat cycle. The re~ular controls stop the plenum blower with the stopping of the burner. The present invention is directed to a device which starts the blower at the onset of heat and continues the blower operation for a ti~e interval after the burner is turned off.
Bac~round of the Invention In modern furnaces of the forced air heating type (oil, gas, electric, hot water, and steam), it is usual for the controls to initiate the burner or heater function and thereafter, upon achieving a thermal set condition, for example in the plenum or heat ducts, to -then initiate the blower runction. The heat cycle continues until the house thermostats reach the upper set point and the cont~ols stop the hot air blower and the heat source or furnace. Actuall~v, heat is increasing in the plenum over ambient air conditions substantially at the instant of application of the heat source as, for example, from combustion in the furnace and the heat ~ cr~ ~
, .16 is reslduallv retained in the plenum or heat exchangers after the furnace is turned off and until the heat surfaces reach ambient temperatures.
Regular controls do not treat the situation at start-up by starting the warm air blower and do not treat the situation, as in the present invention, to strip the residual heat after furnace shutdown. Without the present invention, substantial loss of available heat occurs directly up the chimney and as a consequence causes sucking of combustion air into the house or area heated upon commencement of combustion and before commencement of the plenum blower.
Investigations conducted to determine the amount of heat saving have been extraordinarily encouraging and when the contribution of the present invention is compared against regular controls r the forced air heating systems in which the present invention has been utiliæecl have demonstrated substantial savings of heat and consequent economy to the users.
As applied to gas furnaces, the electric consumption held level and a gas savings of about 27,000 cubic feet resulted in a heating season. Maximum savings is realiæed when the - increase in unit costs of gas and oil are contemplated.
This is also true because the gradual heat rise at the start of the cycle and the relatively high thermal residuals at shutdown are utilized. The system is applicable to gas ; fired, oil fired, and electric warm air furnaces as well and on the basis of these findings it is possible to anticipate a fuel savings of between about seven to thirty percent over the experiences of regular controls of varying sophistication. These accomplishments re~uire no physical alteration of e~isting forced air heating plants and with the present invention is achieved by simple addition to e~isting controls.

- 2 -cr/i~) Prior Art Dis-tinguished In 1~77 the United States Letters Patent 4,013,219 issued to James Jacobson and in that struccure a thermostat was modified to include a timer. This device was a manually actuatable timer and its objective was an override for all controls which, then, required manual reset.
The United ~tates Letters Patent 4,0~0,663 to Ulrich Bonne, e-t al is directed to a fan control functioning on the basis of a heat differential between plenum and the return air temperature.
None of the known devices provide an automatic blower control system capable of preventing heat loss at th~e ends of a heating cycle in forced air systems.
While both prior art systems of control seek to achieve an energv savings, they at-tack the prohlem of juggling -the thermal input based upon selected operating optimums or in accord with manual selection of applications of heat.
Neither propose a simple and automatic system and control applicable to all forced air systems and where the regular controls may remain in-tact and perform their regular function.
Accordingly, the principal object of the present invention is to provide an energy conserving device attachable to existing furnace or heating system controls of the forced air type which automatically function.
Another object is to teach energy savers of the control of energy loss via the blower and permitting the blower to start on introduction of combustion gases or heat source to the surfaces over which the blower operates.
Other objects, including simplicity, ease of repair and rèpeti-tive accuracy, will be apparent as the application proceeds.

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9~:~L6 In accordance with the present invention there is provided an energy conserving control for a thermal source which is connected in parallel around existing thermostatic controls and which acts on the blower circuit.
The control comprises an electric blower activating circuit connected to the blower and activating the blower upon initiation of the thermal source. There is also a relay connected in parallel to the thermal source and starts the blower at initiation o~ the heat source. Finally, a selec-tively adjustable time delay is connected to the blower circuit upon discontinuance of the thermal source.
In general, the present invention is an override control for forced air heating and air conditioning systems and which exercises control over the - 3a -cr~

~7~ 16 air blower which delivers warm or cool air. The greatest saving of energy is in the heating field, but energy saving is apparent in air conditioning cycles as well. The control and system comprises an electric activating circuit which s-tarts the blower when the heat media (as a burner) or cooling media (as a compressor or thermal source) is activated. The activating circuit, as applied to forced warm air, is in parallel with an override relay so that upon actuation of the activating circuit by normal controls, the override relay is activated and starts a warm air blower. A time delay relay which acts upon the override relay is connected for actuation upon cessation of flow of heat media source and provides an adjustable time interyal in prevention of deactivation of the activating relay after disco,ntinuance of the heat or thermal source., This keeps th,e blo~er working for the timed interval and therea~fter tke ti,me delay relay deactivates the blower from moving warmed air. While applicable to forced cold air systems, the structure and control can be appreciated easiest where the heat media source is considered as a burner. Then the system is an override control for forced air and in control of a warm air blower having an electric thermal control circuit. An activating circuit initiated by the starting of the burner is provided.
An override relay is connected in parallel to the burner circuit and this is activated when the burner circuit is activated and starts a warm air blower in the forced air system. A time delay element acts upon the override relay in adjustable timed interval in prevention of deac-tivation of the rela~ after discontinuing the burner performance.
The time delay deactiva-tes the warm air blower upon completion of the timed interval after discontinuance of the thermal source.

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While heat installations are referred to, the devices and system of the present invention are equally useful in distribu-ting cold, as from an air conditioner device, so that the blower is started with the compressor or cold thermal source flow and continues for a timed interval beyond cessation of movement of the cooling media~
In the Drawinys Figure 1 is a schematic block diagram of an override control in a conventional gas or oil fired furnace and functions wi-th regular controls to achieve the fuel saving result of the present invention.
Figure 2 is a perspective view of the control of the present invention in a simple circuit box.
Figure 3 is a front elevation view of the embodiment of the invention seen in Figure 2.
Figure 4 is a top plan view of the structure of Figure 3.
SpeciEic Description Referring with first particularity to the Figure 1, there is schematically shown the location of the energy saving overrlde blower control system 11 and it is shown connected to an air conditioning cooling system 12 and to a heating system 130 The arrangement is characteristic - of combining heat and air conditioning installations using common controls. The compressor 14 may be regarded as the source of cooling -thermal energy. The coolant media 15 as, for example, ammonia, brine or other coolant compounds pass from the compressor 14 and into the coolant coils 16 with ultimate return to the compressor 14~ A coolant blower or fan 17 forces air over the coil 16 and into the space such as a dwelling where the cool air drops the temperature and returns to the fan or blower 17 for recirculation. The cooling ~-r - 5 -~ cr/,~

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thermostat 1~ is a part of the regular controls 19 signalling within appropriate opera-ting range the energization of the compressor 14. At its lower set point, the cooling thermostat shuts off the compressor 14 and with it the fan or blower 17. Usin~ regular controls 19, the fan 17 is initiated when the compressor turns on and runs until the thermal condition 20 achieves a set point. Using ordinary or regular controls 19, the cooling system does not commence circulation until the set point is achieved. In the heating system 13 served by the regular controls 19, the thermostat 21 (heat) signals the demand for heat and the heat source, such as burner 22 (gas, oil, electricity), is started in the furnace 23 as by combustion and the exhaust combustion gases travel from the stack and out of the house or heated enclosure. Air in support of the combustion enters the burner 22 from ambient or ou-tside air. The heat generated by the combustion in furnace 23 is exchanged to air ~ia the exchange surfaces of the ~lenum 25. when the plenum 25 reaches a selected heat set point, the blower or fan 26 is started which pumps the warmed air into the house or heated enclosure. The starting condition using regular controls 19 is the thermal set point established in the plenum 25O Using the regular controls 19, the function of the heating and the cooling are as described until the energy saving override blower control 11 for forced air systems with time delay is superimposed. The override blower control 11 with time delay re~ay is activated when the therrnal source, such as compressor 14 or burner 22, is star-ted and this starts the blowers or fans 17 and 26 in accord with the commencement of the regular controls 19 as by the heating thermostat 21 or the cooling thermostat 18 responding to the set conditions in the home or enclosure. The blowers 17 or 26 continue to run until the time delay relay in the cr~

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o~erride control 11 adds its timed in-terval of performance (usually selected between two and five minutes) after the compressor 14 or burner 22 is stopped. This strips the residual heat or cold and distributes it in the house or enclosure beyond the shutdown called for by the thermostats 18 and 21. An evener thermal condition is brought about and the energy which would otherwise waste to an external environment is utilized and the interval between burner activations is extended.
The override control 11 is better understood by examining its simple construction as set out in the Figure 2.
The entire control 11 is enclosed in a simple control box 30. The box 30 is a metal Underwriter approved enclosure with a hinged cover 31 and with knock-out windows on all sides to suit varied installation situations. A channel shaped chassis platform 32 is slidably positioned in the box 30 in whatever position is convenient since the box 30 is rectan~ular and of a depth equal to -the depth of the platform 32 allowing inversion o~ the box 30 to shift the hinged cover to left or right openings. Eight colored leads extend from the box 30 and are color coded to their end uses ~or ease of field installation. The leads (Figure 4) are connected to the control elements as will be appreciated as the description proceeds~
Centrally connected to the chassis platform 32 is an 11 pin octal socket 33 coded 6 x 156 and rated at 10 amps and 300 volts alternating current. It is Underwriter Laboratory Listed as E40944. The socket 33 provides the 11 pin octal receptacle for plug-in enclosed (off delay~ double pole, double throw relay 34 of the adjustable delay type adjustable between 2 and 3Q0 seconds (5 minutes) coded 6 x 155 and bearing Underwriter Laboratory Listing E40944.

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Flanking t~e time ~elay relay 34 are the oYerride relays 35 and 36. These are single pole do~ble throw type relays and are coded 5 x 334and 15 x 835,respectively, at 13 amps and relay 35 operates at 24 volts for control of a gas valve or for a 24 volt air çonditioning relay and bears Underwriter Laboratory Listing E35623G. Relay 36 operates at 120 volts alternating curren~ and is for a 1lO volt alterna,ting current ~as power burner and oil relays~ The relay 36 also ~ears the Underwriter Laboratory Listing E56730. These r~lays 35 and 36 are regarded as the override relays and serve to start the fans or blowers 17 and 26 when t~e regular controls start the air conditioning or burner units, respectively.
While both 24 volt and 120 volt override relays are provided, a selection will have to be made according to what the actuating circuit providesO
~ dentical 11 pin sQc~etS 35a and 35b pro~ide tke socket mountin~ means ,for the plug-in relays 35 and 36~
respectively. The sockets 35a and 35b are coded 5 x 853 rated at 10 amperes and 300 ~olts alt,ernatin~g current and, ?0 bear Underwriter ~aboratory ~isti~ E409~4~
In th,e compa,ct arrangement, s~own, as where a heating and air condition,ing unit are bo~t,~ ser~ed by the same override blowe~ control unit 11~ t,he tim,e delay re,la~ 34 i,s in the mounting socket 33 and the socket 33 is sec~ed firmly to the ckassis 32. The flanking sockets 3Sa and 35b are generally in adjacent aligned rela~ion to t~e socket 33 and are secured to the c~assis 32~
In Figure 3 the override blower control is in~icated as secured in place in -the control box 30, as viewed upon opening t~e box.
sy reference to Figure 4, factory wiring as between the units 34 and 35 and 36 is ins-talled as indicated and these ~; cr/,`

leads in heavy ~ine are preferably fixed at the factary in avoidance of tampering. ~'hese leads interrelate the relays 35 and 36 to the time delay relay 34 so that the time delay relay assures that the blowers 17 and 26 will function at start of the compressor 14 or burner 22 and will continue that functioning until the timed interval of the relay 24 is complete.
In the Fi~ure 4 the leads are shown (as colox coded) extending from the rear of the platform 32 a,nd fxom the interlocked pin socket receptacles 35a and 35b and the central tirne delay relay mounting socket 34~ As will be appreciated, the override relays 35 and 36 are easily removed and ~eplaced for servicing and the time delay element 34 is also ea,sily removed and replaced as necessaryi. The wiring remains intact and the interval timing is imposed on th,e ~owers afte~ the thermal source (hea,ter or air conditioner) has been stopped~
After the timed interval, the b~owers a~e sh~u,t down bu~ the heat has been stri~pe~ an~ delivered to the living space to avoid heat loss up the ckimney and the cold has been normalized by supplying the residual sooling to the served space in the home or use premi~es at a substant,ial savings of - energy~
In Figure 4 the ove,rride blower control 11 is indicated as applied to a furnace a,nd an, air con~iti~on,in~ unit in control over bhe blowers of each. When control is sought only over one o-E -the uni-ts, then only one relay need be used.
The time delay relay 34 is connected to a so~rce of powe,r serving the furnace and/or the air conditioner and including the blowers therefor. In bo-th, the distribution blowers come on whei~ the burner and/or compressor s-tarts. Then, when the thermal set points have been achieved, the blowers stop with cessation of heating or cooling. At that poin-t, the time delay cr/', relay 3~ connected to power ahead of the furnace 23 or air conditioner 12 acts upon the relays 35 and 36 and holding the function of the blowers.
By reference to Figure 4, the brown wires or leads connecting the relays 34, 35 and 36 are factory installed and, as shown, both the heating unit relay and the air condition relay are provided. If only override control over the air conditioner or heating is required, then one of the relays 35 and 36 may be eliminated.
The two red wires are useable cross the burner or gas valve relay 36 if a gas valve relay is used in the heating circuit or otherwise to the burner ignition if oil or electric heat are used. It is, of course, necessary to determine if the voltage is 110 volts or 24 volts.
The two blue wires are across the air conditioning relay 35~
The two yellow wires or leads are to the terminals across the blower control in the regular controls 19.
The lead colored black is attached to the hot line oE the furnace or thermal system served and the white wire is to the ground of the furnace or thermal system served. Thus coded, field installation is vastly simplified and adapts the override control 11 to myriad control circuits as found in heat~ng and air conditioning installation. Basically the override control 11 is wired in parallel.
Where plural speed blower or fan operation is desired, it will be appreciated that additional override controls 11 may be required Eor each opera-tional level.
Noteworthy is the point that the structure of the present invention, once installed, is adjustable via the time delay relay to a selected operating period after cessation of the -thermal source by reason of the selected holdover period cr/~

~. ~7~16 in the time delay relay 34. The optimum time selected should be that period of time where the thermal residual.s are fully delivered to the dwelling space or.use space. Energy saving economies are obvious since the thermal residuals are used rather than exhausted to external atmosphere~
No changes are required in the existing control wiring~
Having thus described my invention and one operative embodiment thereof, those skilled in the art will appreciate changes, modifications and irnprovements therein and such changes, modifications and improvements are intended to be embodied herein limited only by the scope of my hereinafter appended claims. As will be appreciated, the electrical components thus described may be substituted for by suitable electronLc or solid state equivalents without depar-ture from the spirit of the present invention and such modification is contemplated in my hereinafter appended claims.

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Claims (2)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An energy conserving control for a thermal source which is connected in parallel around existing thermostatic controls and which acts on the blower circuit comprising:
an electric blower activating circuit connected to said blower and activating said blower upon initiation of said thermal source;
a relay connected in parallel to said thermal source and to said blower and starting said blower at initiation of said heat source; and a selectively adjustable time delay connected to said blower circuit upon discontinuance of said thermal source.

2. An energy conserving control which is connected in parallel around existing thermostatic controls for a thermal source and which acts on the blower circuit comprising:
an electric blower activating circuit connected to said blower and activating said blower upon initiation of said thermal source by said existing controls;
a relay connected in said blower activating circuit in parallel to said thermal source and to said blower and starting said blower at initiation of said thermal source; and a selectively adjustable time delay element connected to said blower circuit upon discontinuance of said thermal source whereby said blower is permitted to continue to operate for the selected time period and thereafter stopping said blower and restoring said existing thermostatic controls for recycling.