Sept. 10, 1946. ‘ E. P. NEWMANl ' `BURNER CONTROL. - 2,407,433 ^ Filed‘Juney 15, 1944 ' l 2 Sheets-Sheet 1 .95 /A/L/t'A/roe: Emo R Mew/VAN, Err-0 R ME /6 . Sept. 10, 1946.` .- E. P. NEWMAN 2,407,438 l BURNER CONTROLv Filed June 15,- 1944 ' 96) 2 sheets-shéet 2 2,407,438 Patented Sept. 10, 1946 UNITED STATES PATENT OFFICE . 2,407,438 BURNER CONTROL Eric P. Newman, Clayton, Mo., assig'nor to Auto matic Control Corporation, St. Louis, Mo., a corporation of Delaware Application June 15, 1944, serial No. 540,372 11 claims. (o1. 15s-_1171) v Z 1 II,’ a pilot burner I2, an igniter I3, and afname The present invention relates to a control, and switch I4. ~In addition, it comprises a relay actu particularly a control for burners andthe like. Y ated'main Vvalve mechanism I5, and a relayv actu ated pilot valve mechanism I6, and a transformer »It comprises vbroadly a main fuel'valve in a main fuel line, a pilot fuel valve in a pilot fuel line, and an igniter, all under control of some I1. ' » e Y j .The main burner is fed from a fuel line 20, external control such as a space or room thermo which leads tothe main valve mechanism I5, and stat, with suitable switches and connections to operate the burners safely.' An object of the invention is to provide a c'òn trol' wherein, in response to external demand for heat, the pilot name is ignited, andgin response to a substantial and rapid change in heat at the pilot, the main fuel line is opened. More particu thence by a line 2I to the burner I I. A pilot line 22 is >connected into the main line 25 ahead oi-the main valve mechanism I5, the'line22 leading to the pilot valve mechanism I6, and'thence by a line 23 to the pilot burner I2. '_ - y. ‘ " ~ The main valve mechanism I5 includes a valve to ignite a main burner and’also as the actuating member 25 operating againsta valve seat 26 >in terposed between the fuel lines 20 and 2I. The valve is actuated by a'magnetic coil >2l, which, means for a flame switch which controls the main when energized, opens the valve. larly, an object is to provide a control wherein the pilot acts in a dual capacity of being a means ' » The pilot valve mechanism I6 comprises ra ball type valve element 30 adapted to seat upon a seat A further object of the invention is to'provide a> control wherein a failure of the flame switch 20 3|, toward whichvit is urged by a spring 32. The seat V3| is disposed between the lines 22 and 23. to open or a short-circuitingof the flame switch The valve is actuated by a pin 33 extending up at the time of av call for heat will result in a lock valve actuating circuit. ` Y beneath the valveseat. ‘ A flexible diaphragm 34, out of both main and pilot fuel valves, ` » A further object is to provide a control system for a fuel burning system which is entirely auto supported on thevalve housing and` secured in 25 sealing relation tothe pin 33, seals >the pin to matic from one winter season to the next, which wastes no pilot gas when heat is not needed, and which is small and can be installed 'at avery reasonable cost. Another 'object is a control Which'will operate 30 regardless of changes invambient temperature in the furnacebefore, during, or after fuel com bustion. i f prevent leakage of gas around’it. The pinj33 is, in turn, attached to an ¿armature 35, operated by a magnetic coil 36, the latter elements, together with a coil 66, forming 'a relay generally desig nated31. ~‘ « - ' ' " AThe flame îactuated switch I4 is preferablyA of the rate of change type; An illustrativev form of it comprises archannel-shaped supporting mem... A further object is to provide a control system ' ber 4l), having V.flanges 4I ~thereon,’by means of operable with either alternating or direct current. which it maybe securedproperly to the burner. This channel-shaped member 40 embraces and Further objects of the invention include the provision of` a control wherein a momentary break of the pilot valve .relay circuit, such as vby the walking of or manual vibration of the room ther mostat or a momentary power failure`,`wi1l cause a complete recycling to prevent escape of un burned fuel through the main Valve. supports the >pilot burner I2. The member 40 likewise has secured thereto an inner member 43 formed of metal of substantially the same coefli- . cient of expansion as the outer member 40, the two members being secured together at’44 by over lapping ears >spot-.welded together and secured ' Fig. -1l is a vdiagrammatic View of ' one type of at 45 by` similar ears on the member 40 that> over.. the control employing arbucking coilzprinciple lie` wings 45 extending towards the sides of the therein; pilot burner >in the lateral limits'of the member ` Y , ' Fig. 2 is a rdiagrammatic `view of a modification of' Fig. 1; » ` 43. _ A tongue 4l projects from the lower'part of the member 43 toward the pilot burner to form a ‘ -, Fig. 3 is a modification' thereof wherein a re shield. ^ ’ ' Y ` n K ` The ‘member 4I),Y at its upper end, holds an actu sistance combination is used; > _Fig.'4 is a view of the‘ñame-switch preferably 50 ating blade 48 that’ extends downwardly tothe used herein; and . ' Y bottom part of the member 40, where it has 'an l Fig. 5 is a section on the line 5-5 of Fig. 4. insulated actuating button 43`that may be moved Referring to Fig. l, the mechanism includes over to close the switch blade -5IlV against fthe broadly an external control, here shown as a room thermostat I Il. It includes also `a main burner 55 switch blade 5I. » n This ñame actuated switch is adapted to receive 2,407,438 3 4 the pilot flame against the member 43, confined extends from the other end of the coil 36 to between the wings 46, the other transformer lead 13. When flame is applied thereto, the member 43 expands rapidly, increas ing in length between the spot-welds 44 and 45. The outer member 46, within the corresponding length between the welds 44 and 45, receives heat only indirectly from the pilot name,v primarily by From the line 1_6, there also leads a line 8B into the switch 65. From this switch, a line 8i leads into the coil 21, operating the valve 25 and the switch 6I. From the coil 21, the line 83 conduction through the small welded ears. tact 5I of the flame switch. The contact 50 thereof is connected by a line 9E! to the trans former lead 19. Thus the foregoing main valve operating circuit is directly across the secondary of the transformer in parallel with the room As a result, the length between the welds of the outer member 40 expands less rapidly than the corre sponding part of the inner member and does not attain the temperature of the inner member so long as heat is applied to the inner member in leads to a line 84. The line 34 leads to the con thermostat previously mentioned, but subject the relatively unlimited quantity represented by the pilot flame. Consequently, both will expand, to controlby the room thermostat through the switch 65. An additional circuit is provided in parallel but the inner will always be longer when the pilot with the coil 21 in the last described circuit. It flame is applied to it. Conversely, when the.> pilot comprises a line 93 connected to the lead 10, flame is extinguished, the two members rapidly leading to a bucking coil 66, from which a line 94 equalize in temperature and assume their relative 20 leads into the line 84. starting positions. A lower Voltage line 95 leads from an inner Thus, upon rapid temperature change applied point of the secondary of the transformer to the to the inner member, as when the pilot flame switch 64. From this switch, a line 36 leads to comes on, the inner member 43 will expand ra the igniter i3. From the igniter, a line 91 leads pidly relative to the outer, and warp the upper to the switch 6I, from which a line 98 connects end of the device outwardly. As the blade 48 into the return lead 19 of the transformer. is rigidly secured to the upper part of the outer member 46, the lower end of this blade, through Operation the button 49, will act to close the contacts 5U The manual switch 12 is closed during any and 5I. And when the pilot flame goes off, the two members willv rapidly equalize in tempera 30 period in which the system is to be used. The limit switch >16 will normally be closed. At the ture, and when the temperature differential is start, the room thermostat switch 14 is open, below the operating differential, the switchwill the burner II and pilot I2 are off, the flame reopen. 1 ,Y switch I4 is open, the switch 6I is closed, and It will be seen that changes in ambient tem perature will not change the position assumed by . the switches 64 and 65 are open. When the room thermostat Ill closes its switch this switch in response to the condition of the 14 a circuit from the lead 'I3 of the transformer pilot flame, because ambient conditions expand is closed through the line 1 I, the room thermostat or contract the distance between the welds on II) and its switch 14, the line 11, the main coil 36 both inner and outer members in a similar amount. Although the changes in ambient tem 40 of the pilot valve I6, the line 18, the lead 19, back into the transformer. Thereupon the coil 36, perature affect the amount of the differential in being energized, lifts its armature, causing the temperature to a small degree, they do not affect rod 33 to lift the ball valve 3€! from its seat and the existence of a substantial differential of a admit gas from the supply line» 20 through the quantity to operate the switch. Hence the de vice operates in response strictly to pilot ñame 45 pilot line 22', past the valve, and by the line 23 to the pilot burner I2. conditions, Vregardless of the starting tempera ' Energizing the coil 36 also closes the switches tures of the two members 4B and 43 resulting 64 and 65. The closing of the switch 64 closes from any changes in ambient temperature, and a circuit from the inner tapped line 95 of the regardless of'changes in ambient temperature during main burner operation. 50 transformer through the aforesaid switch 64, the line 96, to the igniter i3, and thence by the line 91 The foregoing switch is in principle the same through the now closed switch 6I, by the line S8 as that disclosed in the patent of James A. Rod~ to the return lead 1S to the transformer. The gers, 2,392,065, issued January l, 1946. igniter I3 will then glow and ignite the pilot ñame A relay switch 6I is provided for joint opera 55 Vof the pilot burner I2. This flame will then act tion with the main valve 25 by thecoil 21. upon the flame switch i4, expanding the inner The coil 35 operates through the armature 35, member 43 relative to the outer member 46, and switches 64 and 65, these switches being for pur warping the blade 43 to close the contacts 50 poses to be described. The coil 36 also has as sociated therewith a `bucking coil 66 wound to and 5I. This latter will occur only if the pilot flame ignites and remains ignited. The closure oppose the magnetic pull of the main coil 36, but 60 of these two contacts after such ignition of the of lower power. pilot burner completes a circuit through the The connections are as follows: From the other switch. 65r of the coil 36 as follows: From transformer I-1, a lead 10 is joined with a line the transformer lead 1U, aline 86 leads through 1I, that leads through a manual switch 12, to a 65 the switch 65, and by a line 8l into the coil 21 line 13, connected into the room thermostat I0. of the main valve I5, and thence by a line 83 to When this thermostat cools to a predetermined the line 84 through the flame switch I4', and by temperature, it closes a switch 14l connecting the the line 96 back to the return lead 'I9 of the line 15 to the line 13. The line 15 leads to a transformer. limit switch 16, which comprises one of the fa 70 Energizing of the coil 21 causes it to lift its miliar thermal devices for opening the circuit armature, opening _the valve 25 to admit fuel when the heat transfer medium does not remove to the main burner Il, which is ignited by the heat suñiciently rapidly to keep the furnace at a pilot burner I2. The coil 21 also opens the safe temperature. From the limit switch 16, the switch 6I' to break the circuit to the igniter I3 line 11 leads to the relay coil 36. The line 18 75 and to deenergize the same. 2,407,438 c coil-66 isener'gized‘a's follows: The lead' 10, the lineV 93, the bucking coil 66, 'the'line 94, tothe line 84, and thence through the flame switch and> back -to the transformer. a 6 igniter I3, and, Ain short, to produce a complete recycling from the starting condition. i Also when the name switch closes, the bucking K Were- it not fory the coil 66 or its equivalent, an instantaneous failure ofthe principal circuits, re sulting in at least momentary closing ofthe , The bucking coil is of insufficient strength to f overcome the holding valves, might be accompanied by a failure of flame force of the main coil 36, 'but is of sumcient force at Zboth burners followed by an immediate re-` opening of both valves with lthe igniter I3 in an open circuit. Thus, when the power fails, the When thus started, the burner II will operate 10 armature 35 drops outand the switches 64 and 65 open. Resumption of power before the switch for a running period. The pilot burner will like I4 cools, and without the coil 66 in operation, wise Vburn during this period. Thereafter, when would close the switch 65, open the valve 25 and the room thermostat I0 is 'heated by the heat break the igniter circuit at 6 I. Thereafter, when from the burner, it will break the contacts of the the contacts'50 and 5IÍ open upon the cooling of 1 switch 14, which will open the circuit through the switch I 4, the coil 21 is deenergized, the valve the relay coil 36. The pilot valve will close in-` 25 isA closed and the igniter I3 is madeA operative stantly under "the influence of the'spring 32, and by the vclosing of the switch 6I. The igniter cir the switches 64 and ,'65 will open. Opening of cuit'is thus completed after a substantial amount the .switchY 64 gives an additional break to the to prevent the main coil from moving its arma ture. „ ~ ; ` 1 , of unburned gas had been delivered by the main Y « circuit t'o the igniter, which, during the running , of the switch 65 breaks the circuit to the main burner to the furnace, which action could easily causev an explosion even though the main burner valve :coil 2l, so that the main valve 25 imme had been shut off before the ignition carne on. period, is aiready open at the switch 6 I; Opening If the' pilot isf extinguishedfduring operation, and is notv relit by the main burner llame, this will normally result in opening of the"contacts 56 and 5l of the flame switch, followed immedi time, since it is now open at the switch 64. With ately by closing of the main valve 26 and closing both the main and the pilot valve closed, the of the switch 6I, so that the igniter I3 may again main and pilot burners Il and I2 stop operating, and the ñame switch I4 cools. With the type of 30 be put in the circuit for re-ignition. If fuel pressure falls substantially, the pilot flame will flame> switch shown, and which is preferred, this not Ygenerate sufficient heat to maintainV the openingof the contacts 50 and'5l will occur with diately closes, and the switch 6Iv also recloses. However, as noted, the closure of the switch 6I does not close the circuit to the igniter'at this switch I4 closed, and the main valve 25 will close in a few seconds after the pilot burner goes out, due to the opening ofthe circuit to the coil 2'I. ' as this control responds immediately to an abrupt change of temperature on the inner member 43, 35 If there is a failure of the igniter or of pilot ignition at the start o-f a cycle, the main burner valve 25 will not open and theescaped gas will be only in the limited volume running through regardless of the ambient temperature applying equally to both members. -` « , > As noted, the bucking coil 66 opposes the main , the pilotline.4 coil 36, but is of insufficient power to'cause a re If the room thermostat remains, closed, either lease of the armature.V -Since itis of sufficient power to prevent the armature from being pulled in when both coils are energized, any instanta neous break of the principal circuits, such as by by failure or otherwise, so that the burner attains an excessive temperature, the limit switch 'I6 will be 'opened inV conventional Ffashion. This will bre'alïthe-circuit to the coil 36, resulting in clo vibration of the room thermostat ‘contacts or an instantaneous power failure either of which are `-, sure of the ~main and pilot Valves, which will re main in circuit until the contacts 50 and 5I are of insufficient duration to vpermit the" flame opened. Thereafter the control will be required switch contacts to open, will, nevertheless, result to recycle completely upon any reclosure of the » in aY complete recycling of the control. This oc limit switch. curs because any such ,action deenergizes the ¿If the flame switch I4 failsin hot position, the main coil 3B and its armature falls out.` If this _.3 .control will operate to complete the cycle started, break of the circuit of the main coil 36 occurs by jiggling of the thermostat, the coil 66 will remain in circuit and will act to open the switches 64~ and 65 and close the pilot valve`30. If, however, the main coil 36 is deenergized because lof a momen tary power failure,§the, armaturewill fall, and but afterï the `cycle ends a new one cannot be' ' instituted because the bucking coil 66'is energized whenever the contacts 50 and 5I are closed. _ Obviously, too, if the flame switch fails in open position, the main burner valve can never open. These two failures are controlled inthe forego ing manner, regardless of an additional failure upon restoration of power the coils 36 and 66 willV become simultaneously energized providingY the contacts 50 and 5I remain closed. Insuch case, the coil 66 is energized at the same time the coil 36 becomes reenergized, and, although the alge braio sum of the forces produced by the opposed coils will hold the armature 35 up once it is raised, this force is not ygreat enough 'to pull the armature up from its lower position. ' ' > Thus, with the armatureofthe coil 36 down, the pilot valve is closed and the circuit to the mainv valve coil 2'I is broken through the switch 65. Therefore, the main valve closes upon such instantaneous circuit failure, and it is prevented from reopeninguntilthe switch »I4 coolsand'th'e “bucking” effect of the coil 66 is destroyed by the opening -of the contacts 50 and 5I, whereupon the coil 36 is effective again to close the 'switches 64 and 65,’toopen the pilot vvalve 30, to 'start the of the room thermostat. Ul) ' ' MOdifi'CatiO'n 0f Fig. 2 ` VIn Fig. 2 is shown a modification wherein'the valvesare operated byseparate coils fromtheir associated switches. Each switch coil is Icon nected in parallel with its related valve coil. ' The mainI switch relay (31a) coils are shown at 36a and 66a, the coil 66a Ibeing wound oppo sitely from the _coil 36a. These coils operate the switches 64 and 65, as before, and an additional switch63. The pilot valve ycoil is at 3617,'. con nected in parallel with the coil 36a, but dependent upon the newly added switch 63 controlled by the @ou sea. The main valve switch coil is at 21a, and the iïiain valve operating coil it at 2lb.` These two 2,407,438 7 8 coils are directly in parallel for simultaneous energization, whereby‘the valve 26 and the switch Si; will .he openedA simultaneously. mostat. The line from the resistor RI' into the coil 3621s designated 11o. From the line 11o, a line 1165' leads through a resistor R2 to the line 84. >It will be seen that: the transformer leads 10, When the room thermostat l0 closes, the same IS; and 95 remain as before, as do the leads 84 E@ to the name switch. The line 11 from the thermostat lil branches into a line 11a leading tothe coil 35a, and into a line 11b leading to the coil 35o, by way of a switch 63. circuit from the line 10 through the line 1l, the room thermostat l0, the line 11, the resistor Rl, the line 11o, the coil 36, the line 18 and the line 19' is effected. This closes the switches 64' and 55 as heretofore. When the switch 64 closes, the ' When the room thermostat I 0 closes', `current 10 igniter i3 is energized because the switch 6|, hows from the transformer lead 'lll through the line 1l, the thermostat l0 and the line 11. In this modification, the line 11 branches into a line 11o and a line 11b. The current flows through the line 11a, and thence through the coi-l 36a, whence it íiows by a line 18av to the other trans former leadv 13. Thus the coil 36a is put in cir cuit as soon as the roomV thermostatV closes, in the same manner as before. It then closes the three switches 63, S4, and 55. When the switch 63 is operated by the main valve coil' 21, is closed. The pilot valve 30 is open and the pilot flame ignites, whereupon the flame switch I4 closes the contacts 5i) and 5f. This closes the circuit from the line 1G through the line 80, the switch 65, the line 8i, the coil 21, the line 83, the line 84, the switch I4, the line 90, and the lead 19, whereupon the main valve 21 is opened and the switch 6I is also opened to cut the igniter I3 out. Thus the out out of the igniter and the opening of the main valve are, as before, dependent upon the exist closed, it closes a circuit from the line 11 through a line 11b to the coil 36h, and thence back to the ence of a pilot name. transformer lead 19. This puts the coil 36h for At the same time this last circuit is closed, operating the pilot valve’3llv in parallel with the the parallel circuit from the line 11o, through coil 35a but under control of the switch 63 of the 25 the line HB5 and the resistor R2, is closed by way latter coil. of the line 84, the switch I4 and the line 9i). The When the switch 64~ closes, it establishes the resistor R2 introduces a circuit drawing current ignition circuit through the line 95 as ibefore, and in parallel with the coil 36. This current in the line 91 and the closed switch 8|, and the line creases the voltage drop across the resistor R! 98: back to the transformer lead 19. As the coil 30 (which resistor may comprise in whole or in part '21aV is then out of circuit, as was the fcoil 21 at a the inherent resistance in the circuit). The in corresponding time in the4 other illustration, the creased voltage drop across the resistor Rl re igniter will become operative. Thus the pilot duces the voltage available to the coil 35, so that burner may lbecome ignited. its current drop and its magnetic pull is low When the switch 65 closes, the line 8l is con 35 ered. The reduction in magnetic pull is insuffi nected'with the transformer lead 10, and this line cient to cause the coil to drop its switches open, through its connections Bla and 8lb leads to the but is sufficient to preventl the coil from pulling two coils 21a‘and 21h, and thence by the two the switches from an open position. leads 83o and 83h. These two parallel leads In this circuit, it will be seen that the same merge in the line 83, which is connected with the 4.0 results as in Fig. l' attain, except that the paral lines 94 and St as before. Thus the two Icoils 21a lel voltage reducing circuit Vis open whenever and 2lb are directly in parallel and operate in the room thermostat opens. It acts to prevent unison whenever the switch 55 is closed and the the main Valve from returning to open position name switch also is closed, the two operating in upon break in current through the coil 35 until the same mannerfas the single coil 21 in the " the llame safety switch I4 has cooled. earlier illustration. l It will be understood that the control may be The bucking coil 66a is connected directly employed with other controlling elements, such across the transformer leads and through the as diaphragm valves, in which case the-partic flame switch as before. Its operation is the same ular Valves illustrated become relay or pilot valves as before, but the third switch 63 is employed so controlling the bleed lines of the familiar di that when the bucking coil is effective it not only aphragm type valves. breaks the circuits through the switches 64 and. For use with D; C., the system may beY modi G5, controlling the main valve and igniter, but fied', as by employing voltage dividers of conven also is eiîective through the switch B3 to open the tional types, in which case, the bucking coil has circuit to the pilot valve coil 36h and insure clos the advantage of opposing the lifting of the ar ing of that valve. mature, as well as diminishing the force of the It will further ‘be evident that the choice of main coil. one or two coils, either for the pilot valve control In some installations, it may be desirable to or for the main Valve control, does not affect the use a separate transformer for the igniter in overall operation of the mechanism where the stead of a center» tap on the main transformer. connections are made as shown in Figs. 1 and 2. In such case the primary of the second trans Sometimes, for mechanical reasons such as effi formerv could be energized in parallel iwith the ciency of manufacture or the desire for separat circuit including the coil 21 and flame ‘switch ing the switch operation or control from the valve i4, and the primary circuit would include- the operation or controls, it may be desirable to use switch 6|. Obviously this would eliminate one separate coils to actuate one or more of the valves switch 64 of the relay 31, as the voltage into the and switches. ' switch '6| and the primary would be the same Modification of Fig. 3 as that through the switch 65, permitting inter connection of the circuits. ' What is claimedr is: In Fig. 3, there is shown a control that accom 70 1. In a control for use with a main burner, a plishes the same objective but uses a resistor in stead of the bucking coil 66. In this arrange pilot burner, and a main control device includ ment, the parts are the same except for this sub ing a power element, electrical means operat stitution. It comprises the introduction of a ñrst edy through the main control to supply fuel to resistor Rl in the line 11 leading from the ther 7 the main burner, a flame-responsive> switch op anos-188 î 9. ' 10 6. In a control for Vuse with a main burner, a erated by >combustion at ,the pilot burner, and pilot burner, and a main control device including means controlled by vsaid flame-responsive switch a relay and coil, a flame-responsive switch oper ated upon existence of combustion at the pilot ` for reducing the power of said element to'render .the same effective to hold said control device in a burner, pilot fuel supply means operated by said closed position once,- this position is attained, but maincontrol device, flrstineans responsive to op ineffective to move ksaid device from an opento eration of said relay to effect ignition of the pilot burnery said means including mechanism concur rently ’operated to control actuation of the main pilot burner, Vand a main control device, a flame responsive switch operated upon existence oi" 10 burner, said mechanism ,being also dependent upon operation of the pilot llame switch, and combustion at the pilotburner, an electrical fuel safety means operated upon closing ofthe pilot supply means energizable to operate the main flame switch Vto render said relay incapable of burner, means `responsive to operation of the shifting said first means from an inoperativepto main control device to cause operation of the a closed position. c - 2. In a control for use with a main burner, a pilot burner, means »operated in response to op 15 an operative position when the ñame switch is in a closed position, said ñrst means comprising a eration of the pilot flame switch to energize the switch device and said safety means comprising-a main burner fuel supply means, and means op bucking coil producting a magnetic force in op erated in response to operation of the pilot vilaine position to that of the relay coil. switch to prevent reoperation of the main burner 7. In a control for use with a main burner, a fuel supply Vmeans when the llame-responsive 20 pilot burner, and a main control device includ switch is in operative position. . ing a relay, a name-responsive switch operated 3. In a control for use with a `main burner, a Yupon existence of combustion at the pilot burner, pilot burner, andîa k‘main control device, a ñamc pilot fuel supply means operated by said main responsive switch operated upon existence of combustion at the pilot burner, ñrst means re 25 control device, first means responsive to opera tion of said relay to effect ignition of the pilot sponsive to operation of the main control de burner, said means including mechanism con vice to effect operation of the pilot burner, said currently operated to control actuation of the means including mechanism concurrently oper main burner, said mechanism being also depend ated to control actuation of the main burner, said mechanism being also dependent upon op 30 ent upon operation of the pilot fiame switch, and safety means operated upon closing of the pilot eration of the flame-responsive switch, and safety flame switch to render said relay incapable of means operated upon closing of the pilot flame shifting said flrst means from an inoperative to switch to render the first means incapable of shifting from inoperative to operative position an operative position when the flame switch is in when the iiame switch is in operative position. a closed position, said first means comprising a, relay switching device and said safety meansin 4. In a control for use with a main burner, a cluding a current reducing device to lower the current through a coil of said relay. Vpilot burner, and a main control device having a power element, a name-responsive switch op 8. In a control -for use with a main burner, a erated upon existence of combustion at the pilot> burner, pilot fuel supply means operated by said 40 pilot burner, and a main control device including main control device, first means responsive to op- f a relay, a name-responsive switch operated upon eration of the main control device to effect igni tion of the pilot burner, said means including mechanism concurrently operated to control ac tuation of the main burner, said mechanism being also dependent upon operation of the pilot name switch, and safety means operated upon closing of the pilot flame switch to render the iirst existence of combustion at the pilot burner, pilot fuel supply means operated by said main control device iirst means responsive to operation of said relay to effect ignition of the pilot burner, said means including mechanism concurrently oper ated to control actuation of the main burner, said mechanism being also dependent upon op eration of the pilot flame switch, and safety means operated upon closing of the pilot ilame switch to render said relay incapable of shifting means incapable of shifting from inoperative to operative position when the iiame switch is in , closed position, said safety means comprising a power reducing means adapted to reduce the power of said element below that required to op said ñrst means from an inoperative to an op erate the iirst means from an open to a closed erative position when the flame switch is in a closed position, said first means comprising a position, but not less than that required to hold switching device and said safety means including the first means in a closed position once this po sition is attained. 5. In s, control for use with a main burner, a relay. pilot burner, and a main control device including a relay, a, flame-responsive switch operated upon existence of combustion at the pilot burner, pilot fuel supply means operated 4by said main control device, ñrst means responsive to operation of said relay to effect ignition of the pilot burner, said means including mechanism concurrently oper ated to control actuation ofthe main burner, said mechanism being also dependent upon op- eration of the pilot llame switch, and safety means operated upon closing of the pilot name switch to render said relay incapable of shifting said ñrst means from an inoperative to an operative posi tion when the flame switch is closed, said first a resistance to reduce the current through the . 9. In a control for use with a main burner, a pilot burner, a pilot igniter and a main control GO device, a ñrst means .to admit fuel to the pilot burner »upon operation of the main control device, said means being also adapted to operate the ' pilot igniter, second means including a device operated to actuating position upon existence of combustion at the pilot burner and .the ñrst means to admit fuel to «the main burner, said ~ second means being also adapted to render the igniterinoper-ative, said combustion device being operable in response to combustion or combustion 70 failure at the pilot regardless `of ambient tem perature variations, and said device, upon failure of pilot combustion, being adapted to render .the second means inoperative. means comprising a/switch device, and said safety 10. In a control for use with a main burner, a means comprising an relectrical device to reduce the magnetic p_ull of said relay. 75 pilot burner, a pilot igniter and a main control 1i l2 device, first means to Yadmit fuel to the pilot burner upon operation of the main control de vice, said means being also adapted to operate the pilot igniter, second means including a device operated -to actuating position> upon existence of combustion at the pilot burner and the ñrst »coil capable of actuating said device "to burner means to admit fuel to the main burner, said second means being also Aadapted to render the to said position, the main coil being adapted to be energized and to operate the actuated device to provide burner operation when the space ther mosta-t demands heat, a combustion-responsive switch movable to a combustion-indicating .posi tion when combustion exists at the burner, the bucking coil being connected with the combus tion-responsive switch to be energized When the igniter inoperative, said combustion device being operable in response to combustion or combustion failure at the pilot regardless of ambient tem perature variations, and said device, upon failure of pilot combustion, being adapted to render the second means inoperative, means to effect shut operating' position, and a buckingrcoil'operatively vassociated with the ïmain coil and adapted, when both coils are energized, to reduce the power of the relay to a value suii‘icient to holdthe device in operating position, but incapable of pulling it off of the lmain burner fuel supply means upon \ ,l same moves into combustion-indicating position current break in itscircuit, and means to `prevent reoperation of the Ymain burner fuel supply means until the pilot -flame device has returned to in operative position. v «11. In a control devicefor "use with a burner or the like, under control of a room thermostat, the 4combination of a relay having an actuated device for controlling operation of the burner, a main in response to existence of combustion at the burner, whereby when said thermostat demands heat and the combustion-responsive switch is in combustion-indicating rposition the relay can hold the actuated device., but cannot pull the same to operating position. ERIC P. NEWMAN.