US1981479A - Oil burner control - Google Patents

Description

Nov. 20, 1934. E. J. TE PAS- OIL BURNER CONTROL 3 Sheets-Sheet 1 Filed April 15, 1929 Flu .4

Nov. 20, 1934. E. J. TE PAS OIL BURNER CONTROL Filed April 15, 1929 3 Sheets-Sheet 2 INVENTOR M Nov. 20, 1934. E. J. TE PAS OIL BURNER CONTROL Filed April 15, 1929 3 Sheets-Sheet 5 INVENTOR Patented Nov. 20, 1934 011. BURNER CONTROL Edmund J. Te Pas, Lakewood, Ohio, assignor to The Patrol Valve Company, Cleveland, Ohio, a

corporation of Ohio Application April 15, 1929, Serial No. 355,234 1 Claim. (Cl. 158-28) This invention relates to oil burner controls and more particularly to the application to oil burners of safety controls ofthe type disclosed in my copending application Serial No. 271,802 which 5 matured into Patent No. 1,842,331.

One of the principal objections to the use of oil burners is found in the possibility of explosions which are apt to occur in burners of this type, particularly when they are'automatically controlled. Ordinances have been enacted in several districts of the United States to reduce some of the hazards attendant with the operation of oil burners. The most important of these legislative enactments is that which requires the use of a constantly burning gas pilot for the ignition of the oil burner. v

A large number of automatically controlled oil burners are equipped with electric ignition in which an electric spark ignites either the oil, or an auxiliary gas flame, which in turn ignites the oil. It is apparent that in the event of failure of some of the electrical apparatus forming part of the ignition device the oil burner might be started and no means provided for its ignition.

This was one of the objections which the constantly burning gas pilot was supposed to overcome. The use of a gas pilot is not however entirely safe, as it is quite possible and frequently happens that the flame of the gas pilot becomes extinguished for various reasons, such as, drafty conditions in the appliance, changes in gas pressure or stoppage of the pilot regulating valve and for other causes.

One of the objects of this invention is to provide an oil burner control which uses an auxiliary and a constantly burning gas pilot burner for the ignition of the oil and which is inoperative in case of the extinguishment of the pilot burner.

Another object of this invention is to provide a safety control for oil burners which uses an auxiliary gas burner for the ignition of theoil burner.

Another object of this invention is to provide an itself upon failure and resumption of the electric current supply.

- upon failure of the oil supply.

Another object of this invention is to provide an improved electro-thermostatic gas valve and switch for the control and'ignition of an oil burner.

Another object of my invention is to provide an improved thermostatic switch to control the operation of an auxiliary ignition gas burner and an oil burner.

A further object of this invention is to provide an oil burner control having an improved thermostatic switching mechanism under control of the oil burner and an associated thermostatic gas valve and switch to control the operation of the oil burner and the oil'burner ignition means.

Stated in general terms my improved oil burner control consists of a suitable room thermostat or thermostatic switch that is connected in series with a low voltage circuit. The thermostatic switch controls a solenoid, the energizing current of which is under the further control of a second thermostatic switch that is directly responsive to the heat produced by the oil burner. The solenoid controls the operation of a thermostatic gas valve that directly controls an ignition'flame for the oil burner. The oil burner motor is controlled in part by an electric switch associated with the thermostatic gas valve referred to above and by an independent thermostatic switch under direct control of the heat produced by the oil burner. An electric valve in series with the oil burner motor circuit controls the oil supply.

A gas pilot burner is positioned in front of and exteriorly of the appliance where it is accessible and where it is not affected by the draft conditions within the appliance. In the event of the extinguishment of the constantly burning gas pilot the system is inoperative and it is necessary to relight the pilot before either the ignition burner or the oil burner can be started. At the instant .of starting of the oil burner a large gas flame is provided by an auxiliary gas burner to ignite the oil, insuring the quick and safe ignition of the oil burner without the danger of minor explosions which are apt to occur when a small pilot flame is used and which is apt 'to cause delayed ignition of the oil. Shortly after the ignition of the oil burner the heat of its flame is utilized to cause the enlarged flame of the auxiliary gas burner to be extinguished.

If it should occur that the oil supply be interrupted the oil burner will be automatically stopped and then re-started. In the event of failure of the electrical supply for a short interval of time the oil burner is automatically stopped and upon resumption of the electrical current supply the ignition gas flame is started before the oil burner motor is brought into operation.

These and other objects and advantages will be made apparent in the following detailed description of thedevice and the scope of the invention will be particularly pointed out in the appended claim. Referring to the drawings forming a part of this specification:

Figure 1 is a front elevational view'of the combined thermostatic valve and switch that forms a part of the oil burner control.

Figure 2 is a section taken on line 2-2 Figure 1.

Figure 3 is a section taken thru the center of the gas valve used in connection with the device shown in Figure 1.

Figure 4 is a side elevational view showing the switching mechanism in open valve position.

Figure 5 is a section taken on line 5-5 of Figure 6, showing the construction of the thermostatic switch that is used in the stack or flue of the appliance.

Figure 6 is a front elevational view of the thermostatic switch shown in section in Figure 5.

Figure '7 is a view similar to Figure 6 with the upper mercury switch removed to show the mechanical elements located behind the switch and also to show the switch in a position opposite to that of Figure 6.

Figure 8 is a wiring diagram of the electrical circuits 'of my improved control. a

The general arrangement of the elements of my improved control are shown in their assembled relation in Figure 1, in which the numeral 1 represents a boiler. The general arrangement of the elements of my improved control will be understood from the wiring diagram-Figure 8. An

oil control valve 3 controls the supply of oil to I the oil burner in the boiler, the oil being properly mixed and injected by the motor 17. A further solenoid '7 controls the gasvalv'e. It will be seen that these solenoidsare on separate circuits, one a high voltage circuit and the other a low voltage, the latter being stepped down from the.

former by means of the transformer 11. Four control switches are provided, all thermostatically operated, for producing the cycle of operation that will be disclosed hereafter. These switches include a gas valve switch 6, a ,room temperatu e switch 12 a stack temperature switch 14 and a boiler riser switch 13. The oil burner is ignited by means of an auxiliary blue flame gas burner, the air and gas mixing tube of which is indicated by 4. The ignition burner 4 is ignited by means of a constantly burning gas a pilot burner 5 which islocated in lighting proximity to the nozzle .18 of'the burner 4.

The pilot'burner 5 cooperates in the control and operation of a combined thermostatic gas valve and electric switch 6. This unit is under control of a suitable electric solenoid 7, which is in turn under control of a room thermostat or temperature responsive switch 12. The room thermostat circuit is a low voltage circuit, the

higher voltage supply current being reduced by means 'of transformer 11.

A suitable thermostatic switching mechanism under control of the liquid being heated in the let ports 30 that lead boiler is provided at 13. This device is located I the temperature of the flue gases or heated prod--' ucts of combustion from the oil burner.

Considering the elements of the device just A second thermodescribed there is an oil fired. boiler which is' adapted to maintain a constant temperature in the space in which the thermostat 12 is located The thermostat 12 under certain .pre-det'ermined temperature conditions closes an electrical circuit energizing the solenoid .7. The operation of the solenoid '7 indirectly controls the auxiliary gas ignition burner 4 and the oil burner motor 17. The oil burner motor circuit is under control of two independent thermostatic switches, one of which 13, is under control of the water tempera-' ture of the boiler and the other of which 14, is under control of the temperature of the flue gases in the stack. The motor circuit is operated under the full line voltage of the source of electrical current supply.

The oil supply to the oil burner is under control of a suitable electric valve 3 that is connecte'din series in the circuit of the oil burner motor 17,

so that the oil supply is automatically opened 4 is provided by way of the reducing nozzle 18 which is located adjacent to and in lighting prox-. imity to the constantly burning gas pilot 5. The

thermostatic valve 6 that islocated in the gas supply line 9.

The combined thermostatic switch and gas valve is shown in detail inFigures 1, 2, 3 and 4.'

This device is directly under control of the solee gas supply or the nozzle 18 is controlled by the noid actuator 7 which consists of an energizing coil surrounding an armature connected to the rod 25. Certain of these parts are not illustrated in detail as their construction is well known. The rod 25 is provided with a weight 26 so that when the supply of electrical current to the solenoid 7 is interrupted the armature and the rod 25 will drop and assume the position shown I Figure 3. v

The gas supply to the combined valve and switch 6 is by way of the conduit 9 that is in communication with the inlet opening of the valve body 20. The constantly burning pilot burner 5 is supplied with gas by way of a conduit 10 that is connected to the gas supply line 9 at a point ahead of the valve body 20.

The valve body 20 is. provided with a cap or housing 22 which is connected to an'extending portion of one union nut 21. a sleeve valve consisting of a pin 23 which extends beyond the housing 22 and which'..at its opposite end is formed with a cylindrical sleeve that terminates in a valve seat 33. The interior of the sleeve is in communication with a passageway 31 which in turn communicates with the outto the space inclosed by the housing 22.

side of the valve by means of the Within this housing is provided.

' of the bore 31 and ports to the outlet opening 29 of the cap 22. Gas from the opening 29 is conducted to the burner 39 by way of the conduit 29'. A control valve 39' is provided in this conduit to regulate the maximum height of the flame at the burner 39.

Considering the elements just described it is apparent that when the solenoid 7 is energized by an electrical current its armature and associated rod 25 will be raised. The lower end ofthe rod 25 is pivotally connected to a crank 24 that is journaled in a bracket 24' carried on' the end of the housing 22. With the preceding elements in their raised position one arm o fthe crank 24 is withdrawn from engagement with the pin 23. The sleeve valve 33, of which the pin 23 forms an integral part, is moved to its open position by the spring 32 the relatively light force of which ordinarily is not sufficient to overcome the, forceof the burner 39 to the strip 41.

The strip 41 warps upon heating and its free end shifts to the right as viewed in Figure 1. The

free end of the strip is pivotally connected to an adjustable link 42 which is in turn pivotally connected to an oscillating lever 43. The lever '43 at its upper end engages a resilient lever 44. These two levers 43 and 44 when moved past the point.

where they are in alignment tend to assume an right by the thermostatic strip 41, thef'levers 43 and 44 upon passing their dead center or aligned extreme position, either to one side or theother of their vertical position.

By this arrangement a simpleand effective snap actionis provided. When shifted to the position shift with a snap action to their extreme right hand position under influence of the .re: silient member 44 and the tension which is built up in the strip 41 during the first half; of this movement. The tension of the resilient member 44 may be regulated by means of an adjusting screw 45 when it is desired to change the operating characteristics of the device.

The lever 43 is provided with an aperture 43' i which encompasses a spool 46. The spool 46 'is adjustably carriedfon the rod 36 which termihates in a valve head 34. v The valve; head 34 co:

operates with a valve seat 35fwhich is formed in the valve body 20 to control the gas supplied to the burner 4. Leakage of gas from the 'valve' body 20' is prevented by means of a flexible dia'- phragm 37 carried by the-valve 'stem' 36 that is at its outer periphery secured to the valve body 20 by a bearing cap 38-.

When the gas valve is opened by static strip 41 the port 35 is uncovered, supplying gas .to the nozzle 18' byway of the conduit 18";-

Gas issuing from the'nozzl'e 1'8 is ignited by the constantly burning pilot-5 and projects along ignition flame into the combustion cha'mberof the boiler 1. This flame crosses the path "of the.

atomized oil' that isthrown' iromthe nozzle 19 the thermo of the oil burner. It is to be noted that when gas is supplied to the ignition burner 4, the mercury switch 50 is tilted to the right as in Figure 4 closing-the electrical circuitto the oil burner and the oil supply valve 3.

In the action just described a large gas flame is provided within the boiler by the burner 4, the oil supply is turned on by the valve 3, the motor is started by the tilting of the switch tube motor '50 and a mixture of atomized oil is thrown from thenozzle 19 into the flame of the gas burner 4. The oil is practically instantly ignited and the oil burner is now in operation. Upon the opening or uncovering of the gas port 35 of the valve body 20, the opening 33 of the sleeve valve is closed by the valve head 34 covering this opening cutting off the supply of gas to the burner 39.

Extinguishment of the burner 39- permits the thermostatic strip to cool and in a short time the valve. head 34 is withdrawn 'from engagement with the opening 33 by reason of the shifting of the strip 41 and the action of the spring 32 which causes the valve head 34 to follow the movement switch 50 in theposition shown by Figure 4 which they assumed-upon shifting from the position shown in Figure 1.

The mercury tube switch 50 is clamped to a I mounting 49 thatiis c'arried by a bracket 52 pivotallysupported by the lever 43. The supporting device -or mounting 49 is .unbalanced and weighted on one end so that normally its right hand end as viewed in Figure 3, tends to drop .down. .Thefree movement of tube 50 and its carrier 49 with respect to the lever 43 is regulated by means of the adjusting screws 48 and 51 which arecarried on a bracket 47 that is rigidly secured to the lever.43. The purpose of this arrangement is to permit the. switch 50 to be automatically and independently shifted by either the thermostatic strip 41- and associated mechanism ,or by the lever 27 which-is'connected to the rod 25 that is." under control of the solenoid 7. The

lever'27 is slidably mountedina suitable opening formed inthe housing 28 and can only effect the operation oi the switch 50 when it is tilted-to the right as shown in Figure 6. The screws 48 and 51 are provided'to .facilitate the adjustment of the switch 50 and 'to compensate for changes function ismerely. that'of limiting stops for the movement 'of. the switch carrier-49about its pivotal support 52.

' 'The lead wires. from the mercuryswitch 50 are connected to binding posts53; 54, and 55 that are insulated fromfthe switch and valve mechanism.- A second and independent ;thermo--.

static switching" mechanism 14 cooperating withthe switch 50, iscarriedin the stack 1 mm, conducts theheated gares andproductsof combustion from the boiler.- This-latter device is provided with a helical coil 53 made up of thermostaticmetalwhich'may be similar to that used f nected to theendf of a rotatable rod 59 by means is providedwith 'acam 61 that is. rigidly and ad'- justa'bly. secliie'glthereon. The cam 61- 'engages a lpair iof,rolleflis "741which are carried on' the free en'dsiof :;1. 'p'air of levers '72. Thelevers' 72 are made in the adjustment of the lever 43. Their the cam is thereby accelerated. The purpose of thecam and associated mechanism is to provide a snapaction forthe shifting of the mercury switch tubes 63' and 64. c

The tubes 63 and 6.4 are carried upon a bracket 1 .79 thatis in turn carried by a member rotatablymounted'u'pon the rod 59. The snap action movement of the rod 59 and cam 61 is transmitted to the switch tubes 63 and 64-by means of shifting member 66 that is rigidly secured to therod '59; Thismember 66 is providedwith a pin 68 which engages a slot in the link 67; The link 67 is rotatably carried by thescrew '70 which is re.- ceived in the housing 56- of the thermostatic switch 14:. a

\The link fi'l-"is'slotted for reception of a second pin that is rigidly secured to the switch carrier '79.} By thisgarra-ngement of the aforesaid parts when the rod '59turns ineither one direc-- tion or the. other its movementis transmitted to the switches 6.3" and 164 bymeansof' the-pins 68 and 69and th -1ink 67;} In this manner the switchesiffcan-beswung. to the positions shown 4 inFigures 6 and '7 witha snap action.

"plana'tion of theiei tcircuits usedi in {th This shifting of the swit hes'isj accomplished by the'hea'ting (of the helical strip 58; Whenthe strip 581isfii -a"relatively cold condition, as "for example 200? or less the switch {tubes will ,be in a position Ish" him-Figure 6. -Upon starting of the oilburnen-the heated products of combustion cause" t h,e co il 5.8"t0 unwindand in doing so rotate the'rod' 59' iii-a counter-clockwise direction.

- Whenthe'high points ofl'thehamfil have engaged 'the ro1lers-f'74'the1 switchin mechanism is shifted.

to the position shown F gure 7-. This changes the electrical circuits cbntrolled by the switches. Therunctionter the switches-63 and 64 will-ibe described .-pre sently. 'inf'connection with the exica-leircuit-f r Referringitoflth iringidi'agr'am, Figure 8, it is to be notedthathth re aretw separateelectrical ltage circ'uit may be 110 plantgf The highvoltage ply line from'fth v.

' mes-8 91 r circuit comprising he 55,76; '18,a d,.a 1;isse to operate the-motqr 1?; of the oil-burner, andthe splenoidvalve 8,015 the oil supplyli'nefand isconn'e'cted'in series with the 7 0- t ,ply system are-indicated bywires 87 and8 8; Thethe" risrtat-the boilerfand n the combined the mostatic. gasf'val ve '6.

The line vc1t'ag'eo f the electric current when '11-O volts is used' is reducedby means of a 'transformer-e11, to -from '12 to 15 volts; :The low vol-tf. age ci'rcuit 'indicated byffihe lines' 90, 80,175 77-,

84, 85,- and 86"includes'theithermost'atic switch 14 in the stack of, thboilerpth roomthe'rmostat 12jand-thajs'olenoid -'7 which operates the switch andjvalve 6-. .'-1he feed wires of the 'electrical.'suptransformer '11 is connected across-this; circuit.

' .The lowzvoltage lines leadin'g fromjthe trans-" former, are indicated by 'ithef leadwiijesw and-80.

; The lead' wiref90 is connected in seriesthe coil I.

control. 'One of "these cir-v cuits willfliere afte be called thehighvoltagev circuit The {hi'ghvolts oiz-whatever Rage-is provided'at thes'up of the solenoid 7, from the solenoid 7 a wire 84 connects with the room thermostat 12. Wire 84 is connected to the thermostatic element 93 of the room thermostat 12 and is adapted to complete a circuit with the lead wire 85 or the wire 86 depending upon the temperature of the thermostatic element 93 and the setting of the room thermostat 12.

-The full line position of the several switches indicated in Figure 8 illustrates their normal position when the oil burner is in operation and the thermostat 12 is calling for more heat. When the room thermostat 12 has reached the predetermined temperature for which it is set, the element 93 shifts, closing a circuit between the wires 84 and 85 and when the thermostat is be low the temperature for which it is set the circuit is by way of the wires 84 and 86. The wires 85 and 86 are connected to the'lead wires 75 and 77 respectively of the mercury tube switch 63. The switch tubes 63, 64 and 50 are provided with 4 leads wires each, the inner lead wires of which are connected to each other as illustrated providing a three wire outlet from the switches.

When the temperature of the room reaches the desired point the thermostatic strip 93 of the room thermostat 12 completes or closes a circuit between the wires 84: and 85. The solenoid '7 is then energized, the lever 25 is lifted and asupply of gas is admitted to the burner 39 in the mannerpreviously described. Heat from the burner 39 acting onthe strip 41 causes the shifting of the thermostatic switch 50 to the dotted line position of' Figure 8 and the opening of the gas valve controlling the burner 4.

Upon the shifting or the switch 50 the electrical circuit of the oil burner motor 17 and its oil supply valve 3 is disconnected whereupon the oil supply is cut off and the oil burner motorisstopped. The controlelements remain in this position until the thermostatic element 58 of the thermo- 'stat 14, which isresponsive to the heat of the flue circuit is broken and the armature and associated parts of the solenoid 7 assume the position shown in Figure 1,.tipping the tube 50 preventing the motor circuit from being closed due to the shift.-

ing of the switch 64. Whenthe solenoid 7 is deenergized; the crank 24 engages the pin 23 closing the, gas supply' to the-burner 39 and the ignition burner 4 and shifting the operating parts of the' mechanism to the position shown in Figure 1'. I

The device is now in'the off position and will come sufliciently-cooled to close the circuit .b-

. v I V a tween the wires 84. and 86. thermostatic- switches 14, 13 and..5-0.1ocatedin the stack an Referring now -to the low voltage circuit, as suming that. the room thermostat12 has cooled sfuificientlylso that contact .will be made as indibated by the full line position of 93 and a circuit completed between the'lead wires 84.and 86. "The low voltage current from the transformer 11 then 'remain so until the room thermostat 12 has bepasses thru the solenoid '7 and the. room thermostat'12 by-way'of the- lead wires 84 and 86 and then through the thermostaticgswitch tube 63 by way of the lead wires- 77 and 80. 'At the time of this operation thethermostatic switch M is in an un-heated condition occupying the dotted line position and indicating. that :the oil burner is. not in operation.

- The closing of the low voltage circuit energizes the solenoid 'tcausing-the lifting of its armature the crank arm 24 is moved out of contact with the pin 23.

Disengagement of the pin 23 permits a supply of gas to be admitted to the burner 39 in the manner previously described. This gas is then ignited from the pilot 5. The thermostatic strip 41 is then heated and after ashort interval of time opens the valve controlling the gas supply to the auxiliary burner 4 and at the same time tips switch 50,1placing the oil burner motor in operation. The oil from the burner is thrown in the path of the flame from the gas burner 4 and is thereby ignited.

' The electrical circuit thru the oil burner motor is now byway of the main feed wires 87 and I 88 thru the oil burner motor 17 and thence by way of lead wire ,91 to the solenoid oil valve 3.

From the oil valve 3 the electrical current is conducted by way of the wire 92 thru the closed thermostatic switch 89 which is located in-the riser of the boiler and thence thru the lead wires 54 and 53 which are connected in the right hand side of the switch tube 50; The lead wire 53 from the switch 50 is connected to' the right hand side of the switch 64 by the lead wires 76 and 81; the

short time theswitch tubes 63 and 64 are'shifted to the full'line position shown in Figure 8. This ,shifting of switches 64 and 63 opens the low voltagecircuit de-ehergizing the solenoid '7 allowing the armaturefof this; solenoid and'the associated elements to assume theposition shown in Figure 1.

Q It willbe notedthat at the instant the low." voltage circuit is opened the thermostatic switch 50 is' tipped'to-the'fposition shown in Figure 1 by means of the rocking; lever 2'? that is connect ed to the rod 25 {of the solenoid '7. The high voltage circuit thru .the oil burner motor was momentarily disconnected.v This interruption of the oil burner circuit is howe ver of very short duration.

and not sufliciently long to permit the oil burner motor to; stop turning or t'opermit its flame to become extinguis'hedz With the elements'in this position the oil burner motor circuit is now by way of the lead Wire 55 instead of 53.

Upon :the jde-energizingof the solenoid 7, the

lever-"24 engages' the pin 23 urging the open end 1 of the sleeve valve-whichforms a part of this pin to -engage-theiiyalvehead 34. ,This 'cuts oif,

the supplyiof g'as 'tothe burner 39-and causes. the

thermostatic st'rlpaitffto cool.- Ordinar-i ly the. strip 41; -when-this operation. takesplac'e, is not urging the 'val've'head' 34" to its open-position very stron ly and the weight, of the armature of the solenoid. as well asthe weiglit 26in rod,.25 are suificiently great to'shift the 'valve head 34; to its closedposition or the positionshownin Figure 3, This operation however.- is not necessaryfor with the parts in the position just stated, extinguishment. of the burner'39 causes the. strip 41 to cool and in this manner shiftthe'operating; parts of-the .valve to thepositionshown in Figures 1 and 3. The boiler and its control are now in the 011'? or operating position and the ignition burner 4' is extinguished. This condition will be maintained as long as the temperature surrounding the" room thermostat .12 does not exceed the' temperature for which it is set 1f a vapor or-steam boiler is used the stat 131.can be replaced by a pressure actuated switch'and the control will operate in the same.

One of the importantfeatures of this control is that the constantly burning pilot light is located in front of and outside of the boiler in a very accessible'position. It may be easily lighted and regulated, and is not subject to the draft conditions within the boiler.

By use of an auxiliary gas burner such as 4, l

to light the oil burner it is possible to provide a very large flame for this purpose as this flame operates only a few minutes at a time and does not use any great quantity of gas in fact With the combination of these two burners the gas consumption is actually less than it would be if a single constantly burning pilot burner was used to ignite the oil burner, for in the latter case itcurrent supply interruption is but momentary, the

heated interior of the appliance will ordinarily ignite the oil burner upon its re-starting and in the event that such ignition does nottake place, the stack thermostat will in a very short time open themotor circuit and thus stop the operation of the oil burner.

"Momentary failure of the oil supply, sufficien-t to cause extinguishment of the oil burner, can not lead to hazardous condition with my improved control as the stack thermostat will quickly cool and open the oil burner motor circuit in the event that the heated interior of the appliance does not practically immediately re-ignite the oil burner.

- Failure of the gas supply or 'extingui'shment of thepilot burner when the oil burner is not opcrating renders the appliance wholly inoperative as the presence of the .pilot flame is necessary for most of the steps of the operation 'of my im proved control.

The thermostat 13 is provided as an added" safety feature, and upon failure of the appliance thermo- Y manner .as.before except that pressure instead,

of temperature is usedto actuate theswitch 13.

. The same elem'entsl haveshown could be read-'- Q v ily applied to a hot air furnace using an oil burner. The only change necessary would be that of locating the thermostat'13 in-o'ne of-the .'.hot air ducts leading from the furnace.

My improved control is susceptible to various shown. 4 r Furthermore, it is to be understood that the particular ;forms of apparatus shown anddescribed; and the particular procedure set'forth, are presented for purposes'of explanation and il-v lustration and that various modifications of. said apparatus and procedurecan be made 'without departing from my invention as defined in th appended claim.

I claim:--

In a control system for electrically operated oil burners for steam, vapor and hot water heating appliances, in combination,- sources of oil and gas supply, a high voltage circuit including in series connection an electric motor, an electric fuel oil valve, an electric switch responsive to the physical conditions of the water in the appliance, an electric switch mechanism responsive to the temperature of the flue gases of the appliance, and a gas flame actuated thermostatic switch mechanism, and a low voltage circuit including in series connection a remote thermostatic switch

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