flame safeguard control phần 4 pps

_N.O. lr.\.H D.N.c. 18l , lr.l- MO' "" >NO -@- (ILL. HONEYWELL FLAME SAFEGUARD PRIMARY CONTROLS The Flame safeguard Primary Control. is the heart of the: bu!'flll' control ~. It lrans/ales inputs 1rom the flame delector, controller, and limits into sequenced con- trol 01 the burner molor, ignilion, pilot, and main fuel valve. Primary ",ontrolfunclions are summarized in Fig 1. PRIMARY CONTROL FUNCTIONS INPUTS OUTPUTS lIMIT~ CONTROLLER "G PRIMART CONTROt IGNmON aUINER MOTOR \ PILOT VALVE A U FLAME ~S~'G~N~'~'-1L J~M~'~>N,,-,"~'~V~'I~SI,-+ FIG. 1-FUNCTIONS OF A PRIMARY CONTROL The complete Flame Sareguard Primary Control per- forms 3 pdr :1pIJ fI rlcttc:ni. First, it sequences the operation-start, run, and!hul· down -ot the burner syslem. A timer may be added 10 the primary conlrollo add a liming Capability 10 the sequenc- ing function o1lhe device, and in this case the primary con- trol is known as a programmer. 8ec:oncl the primary control supervises the presence at a flame, cutting off the fU9J Sl.Wly if flame is nol present. lNrd. the pl'lmary conlrol checks lise" against l Im8fe failure. Typically, the conlrol performs e -sa1e start" check, or cheCks for a f1ame-simulaling failure before startup. II such a condition is present, the burner cannol start. In ad:::lilion, most primaries also check the cootinUily of their safety switch circuitry. The ulllmate in self-check- ing ability is the Honeywell Dynamic Salt Check syslem which checks its internal circuitry about 1 to 4 Umes each second during operation. R7023 FLAME DETECTOR RELAY The simplest devJce in the FS~ famityof electronic con- of flame safegJ8rd syslems. It Is used most COiTVT'lOl'1Jy In trol relays is the R7023. This control is oot a primary con- flame safeQUard 8J:fjllcations - trol. It does nol have any SEQJencing or programming ability. Its relay pulls in when flame is sensed, and dt(l:lS out on loss 01 flame, so it musl be used with other equip- ment It a complete flame safegJ8td 8J:fjlicalion is 10 be made. The R7023 is available In 2 mooels: the R7lJ238 and the R7023C. The B mOdal has an electronic circuIt for use with rectification type flame detectors. The C version of the R7023 is for use wilh the ultraviolet "Mlnipeeper- detec- tors-CT027A, C703SA, or CT044A. TheSe small compacl UV tLbes offer the advantage 01 lower cosl sensing. The 8 mcdel has dCllble pole-<:b.ble throw output switching ca- pability; and the C version haS single JXlIe-<:b.ble throw output switChing. Inlemal schematics 01 the 8 and C med- els are shown In Figs. 2 and 3- It a control does not perform aU at these functions, il is not a complete primary control. An example at such a con- Irol is the R7023, to be covered next. The R7lJ23 only haS the ability to supervise a flame. It Ism deSigned to se- quence burner operation, fa provj~ a safe start cheCk, or to have safely switch capability. Because the R7023 is so basic In Its daSl~, It can be used as a basic building block in desl(J\!nQ various I'y?9S 107 1. as a replacemenl for R7lJ23 controls alreactJ in service. R70238 FLAME DETECTOR RELAY lOAD ,.,. "'-'" flAM!: ,.,. ~y :::: Jill ~ ,. LOAD_N.O. LOAD_N,C. '0' COM COMMON u-+ 'G ILKTIONIC OT)POWEI U(TlFY N(TWOU: SUPPLY HAMl ,,-+ 100. ' oto 0 (70 12A,(, FIG.2 SIMPLIFIED SCHEMATIC DlAGRAM OF AN R7023B. 71-97558-1 , .,' 2. 10 ack:I_ electron~ detection capability 10 a bUrner control system. The R7023 can also be ~ on many non-1Iame safe- guard applications where it Is necessary to provide a switChing functIOn as a resull 01 a SiQl1al from a flame de- tector. In such cases, the flame delec:tor doeS nol sense R70ue FLAME DETECTOR RELAY ~ , (1) • flAME 0 nLAr , BLUI IlIC110HI( II WHITE Wf'WOII. • , 10AD-N.0. LOAD·N.t. tOMMON '0 tl017A, tl0UA, u-+ IHOT)~OWU O. iU'~l1" t1044A ,,-+ RAME DmClOI FIG. 3- SIMPLIFIED SCHEMATIC DIAGRAM OF AN R7023C. flame, but monitOl'"s some other pl"ocess or related func- tion. For e)(8IT1'Ie, an R7023C could be usect wllh a UV de- lector and a UV source to control a conveyor bell with a prOCkJct being prOCkJced running along the belt. A UV source on one sIde of the conveyor and a detector on the other side of the conveyor would Jceep the relay de-ener- gized as long as the products are present on the bell. It lhe products were missing, the UV deteclor would sense Ihe UV source and pullin the flame relay, possibly selling off an alarm or shutllng down the conveyor belt and prevent- ing any continued matfunctiOn In lhe process. This system would have the advantage ovar a normal pholosensilive system In lhat it would no! be affected by arrtlienl room light and could be selectively sighted. Some other possi- ble applications are - - automatic Ii~t control, - automatic OOor ~r ~nterrupting UV beam trig- gers OOorl, or - counting Items on a conveyor bell (pull in 01 relay trig- gers counler). REMEMBER - The R7023 0:Jes not perform a safe slart checking function suCh as is found in other flame safe- guard controls. The R7023 merely pulls in or drops out in response to the presenCE! or absenCE! of flame. There is no buill-in protection against malfunction, R485 PRIMARY CONTROL The R48S aci:is 10 the basic; alTplifier and relay of the R7023 some SElQJ8nclng ability and a safe start check. The R485 is tor use on flame saf9QJ3.rd applications where manual or semiautomatic control Is to be used. ~ manual system is one In which lhe burner is purged, start.ed, iglited, SElQJ8nced, modulated, and slopped manually. A semiautomatic system Is one in which lhe burner Is started and .Ignited ~11y; purged, sa- cpenCed, and modulated automatIcally; and stopped manually. wllh certain steps and conditions SLP81Vised by safety Interlocks.) The S445A START-8TQP Station or other manual conlroller Is normally used with the R48S. The R485 ~ Incorporate a sefe stan check, which will no! allow the cor1trolto start Ihe burner if the flame de- tec:tor senses a 118tTl8 al startup. This can be d.Je 10 an ac- tual flame j)(eset'l! within Ihe combustion charrtler, a f1BlT1Et"6imulallng con'lxmanl failure, or ant other condi- tion simulating a flame. In any of lhese cases, the control will nol peoni! a burner slart. A schemallc of the R485B. Inclucing typical external ccnneclions, Is ShOwn In FIg. 4. Nole that the R485 has 2 relays, desl~led 1K and 21<. Relay 2K Is (he flame relay; II Is activated thrlJl Vl the solid slale elec:tronlc network (flame sig.al 8IT1'llfier) when lhe flame detector senses a flame. Relay 1t< Is the load relay in this case. Other more complex controls may have relays perlotming addilional 59qJenclng functions. Here Is the S8CfJ8nCE! 01 q:l8ralion of the R485B. When the q:l8rator closes the master switch, terminal 1 Is p0w- ered. If the name relay contact 2K1ls closed, lermlnal 8 Is 108 powered. (If a flame-simulaling failure is present, 2K wlU already be pulled in; 2Kl will be qJEln, terminal 8 cannot be energized, end the burner cannot be started. This is the safe start Check.) The alarm (leoninal 3) will also be ener- gized (Ihrou~ contact 1t(1) when the master switCh is closed. It may be desirable to add a ¢St alarm silencing switch (as shown in Fig. 4) 10 pr9Yenl an alarm unW the system is started, R4851 WITH TYPICAL EXTERNAL COIIECTIOIS _. - FIG. 4_ SIMPLIFIED SCHEMATIC DIAGRAM OF AN R485B. When the operator pushes and holds in the START but- ton on the S4<lSA. power is fed from terminal 8 through the START switch to the 19l1llon. It also goes from terminal 8 (througr. t~ internat Jumper of the S445A, the STOP switch. the high limit. and the Jurrper from terminal 6 to ler· minal 4) to the burner molor and pilot valve. The pilot should iglite. Power is also fed to the 1K relay coil Oermi- nal 6). Relay 1K pulls In. Contact 1 K1 opens, dEHnergiz- lng Ihealarm (lermlnal3J. Contact 1K2 closes, bypassing the safe start contact (2K1), and 1 K3 closes. When lhe pilot Ignites and the flame Is detected. the flame relay 2K pulls in. Contact 2K2 closes, bypassing the START switch; the operatOl' can now release lhe START bullon. Contact 2K3 closes, energlzlrlQ terminal 7 through contact 1 K3. The main valve(s) should open and the main burner shoUld ignite. The system Is now in the • run" con- dition with the main burner tirirlQ. If!he fJame goes out. the flame relay 2K dropsout. C0n- tacts 2K2 and 2K3 open, d9-energizing terminals 5, 6, 4, and 7. The burner motor, pilot valvoe, and main valve(s) are de-enerQized. Relay 1K drops out and contact 1K1 closes. energizing the alarm (terminal 3). The R485 does not tecy- cle on flame failure. For normal shutCbwn, the q:>erator pushes the STOP bulton on the S445A, removing power from tennlnals 6, 4, and 7. Relay 1K, the burner molOt, the pllOI valve, and the main vatve(s) are de-energlzed. The burner Is shut 00wn. In summary-lhe R7023 conslsls sifT1)ly of a flame de- tection network and a relay. When name Is detected, lhe relay (SPDT or DPDT) pullS in. When flame is 001 dBtecled the relay drops out. The relay has 00 buill·in safety fea- tures. The R485 adds a load telay to the R7023-andwlth It lhe ability to per10rm a sale start check and burnar 56" (J./Elnclng on manual or semiautomaUc start systems. The following sections will cover, In detail, the appllca· lion and operation o1lhe RA890, R4795 and Rn95 pri- mary controls. The RA890 controls use the same baSic hardware as the R485, but add severallnwrtant features. The R4795 also uses the same basic hardware, but ac:k1!; additional features not available on the RA89O. The RT795 improves on the R4795 and is Honeywell's most cOl'Jl)l8te and \lersalile primary control. RAS9D PRIMARY CONTROLS The RA890 is the largest volume flame safeguard de- vice currently manufactured by Honeywell. Three different medals, all solid state. are avaiJable-RA890F, G and H. The RAB90F is pictured beJow. The RA890F Is a solid state version or an older model (RA890E). It is for use with rectification type 'lame detec- tors-llame rods. rectifying photocells, and C7012A or C Purple Peeper Ultraviolet Flame Detectors. The RAB90G Is for use with the C7027A, C7035A, or C7044A Minlpeeper Ultraviolet Flame Detectors. The RAB90H has DynamiC Selt Check circuilry whiCh provides a continuous check for possible COl'f1X)l'l6l1t fait· ute. It directly repla,c85 the RA890E and F for most appJi. RU90F 'RIMARY CONTROL WITH QUO SUBBASE 0:270 SUB6Alif • F\.Ulf s.o.Fn'l' .j I LOAO RU,.A'I' Illtl RllAY (2KJ DIlle,", ~~ ENC\.OUD Run IIIlII ~ :; '/ . Il' FLAME CURRENT TEST JACK ARC ~A~ PRDTECTDR ___ C<J\I~R SOliD HATE CIRCUITS lllU~~RhO FIG. 5-COMPONEHTS OF THE RA890F. cations, and mounts on the same Q270A 51 tbase Recfifying flame rods are recc:mmended. The operaling sequence 01 aU the RA890's Includes a pilot flame-eslablishing peliod-a period of time after startup clrrlng which the pilot flame must be ignited and detected or salety shutdown will occur. If safety shu!c;t)wn occutS, switch contacts in the RA890 open and shut oown the burner. M operator mUSI manually reset the switch before the burner can restart. This safety shutCbwn funcllon Is per10rmed in the RA890 by a safety switch. which is a current-heated resls- lance wire wrapped around a bimetal. The switch is cali- brated so that if it heals for a specific length of time, the bimetal warps to Cfl8r'1 a set of contacts. On each RA890 start. the safety switch begins heating altM same time the pilot ard 19lilian are energized. If the pilot fails to Iglile, 01' is not detected within the safety switch timing, the switch locks out The safety switCh fimlrlQ Is, therefore. the same as the pilot flarne-establishing period for all RA890's. OPERATION OF THE RA890F The followIng flQlJres show the q:>eratlon of the RA890F Primary Control under both normal and abnormal c0n- ditions. EtlergiZed circuits are shaded to aid the explanation. Fig. 6 shows the internal schematic 1m the RAB90F in the stancbt JX)Srtion with the disconnect switch and all lim· its Closed, and the controller q:>en. The RAB90F may be used With a low 01' a line vollage controller. If a line voIlage controller is used, as indicated by the dashed line. termi· nals T-T must be JUrJ1:lered. Assuming the use 01 a low voltage coolroller. the transformer and electronic network are energized (shaded circuit In Fig. 6). If a line voltage controller were used, there would be no power at terminal 6, and the transformer and electronic nelwork wootd not be energized. 109 71-97558-1 • • The slard:Iy perlod is the only time during which the 0p- eratIon using a line voltage controller differs trom the op- erallon using a low VOltage controller. After the conlroller clO68S, the 'OPBrf:ltion Is the same for either type. There- fore, both controllers will be shown energized on the rest of the figures. Keep in minc:lthat a Jumper replaces the low voIlaga c;ontroUer If a line voltage controller Is used. The hook~ shown Is tor a.gas system. The operaling seQ.JBl"lce fo(the RA890 wher;'used on oil is lhe same, bur the hookt.P IS r;hanged as shown In Fig. 7. The R890F contrails pOwered only at terminal 6 (unlike the RA890E or' G, which are pbwered at both termInals 6 anc:f 11. II l6 not necessary to continually power the solid state electronic network of the RA890F since lhere Is no hbe W81r1"l1.4l perkx:l required on start. Nole lhat on IImll acllon, or ~lng of the tine vollage controller, all power 10 ttl:! RA89d ls Intern.pted 118'OF 'AS SYSTEM· STAIDlY .ow ~ VOLTMI~ _. n~ , ~ ,~ , • - 110 M~"""11 ALVll. .~ • 1M""''' MllT0 ".,D • -, , • L l • u nn ,g ,- TO fLAMl PlTteTOIl - ••• • FIG. 6-RA890F IN tHE STANDBY POSITION. 2NC·STAQE Oil VALVE (1' USEOI 1A8'O HOOKUP FOI OIL SYSTEIIS IIIUflNEfI MOTOR _., IGNITION 151T-STAQf OIL VALVE The wire pllot link ~ on the schemalic Is used 10 adapt the control for continuous pilot applications. Its lJS8 will be covered In detail later. The test ~ck, also In lhe flame deleC1ion circuit, Is Included to provIde a means for making direct measurement of the flame signal currenl. On a call for heat the controller closes anc:llhe 1K relay coil Is pOWered through a thermlslor, which delays ilS pull- in a few seconds. The fulctlon of this delay Is to provide lime for the con· trollo delermlne whether the 2K relay Is pulled In (low volt· age controller) or pulls -In on start (when lhe Intemal transformer and electronic netwonc are powered by the clOSIng of lhe contact of a line vOllage contrOller). It relay 2K Is pulled In, tnc:licatlng the presence of a flame (or a cClll- ditm slmulallng a flame), contact 2K3 will open and pre- vent pull-in of the 1K relay. The SlartL4J cperatton cannot continue untillhe flame goes out or unUithe ftame-slmulat- ing ccnjjtion Is corrected. The thermistor delay of lhe load relay pull-in is normally 3 to 5 seconds, but II may be somewhat longer or shorter In the presence of extreme afl'ijjenl temPeratures. A few In- stallations may be encounlered where Ihe load relay must pull in almost Il'T\ITMKsialelY. A spectal fast-thermistor model of the R.A890F with a delay at only 1 second is available for lhese installalions. When lhe 1K relay pulls in: - 1K4 closes and shorts the thermistor out of the cIrculI. - 1K3 closes to start healing the safety switch heater. It also eslablishes a parallet circuil whIch will hold In re- lay 1K when lhe heater Is de-energized by the cpen· Ing of2K3. - 1K1 closes to power lhe pilot valve (gas), or burner molor and firsl-stage oil valve, from terminal 3, and the i "ltlon (through closed contact 2K1) trom termi· na14. - 1 K2 closes with no Immediale effect unless a conlfnl.J' ous pilot is U5ElCl and the pllollink Is removed, In this case, the pull·ln of 1K powers the flame detection circuit. When the fleme delector senses the presence of the pi· lot (gas) or main (oil) flame, a small recti1ied currenl flows SAFE START (HI(I( = =-=:" _-_ LhU:r;l~4- '" • .A'" I'} .ow w.,., , 2U~ VOLTAGI _. a.1it- '" • IGHITIOfII t <!> n. MIlITDIl , ~, OT ~ , " '" U ,~ .Il> ~ACI< " ~.I< u~~~0 ,.,";;(.! ~ TO "LAMl OlTKTOIl ••• 1'== CDH"ICT • <, '.~ .wITCH " " TIMII ___ DI DILAn ",u If< I D~\ " ""5[0 POWIIl .,,~ ". FIG. 7- EXTERNAL CONNECTIONS FOR AN OIL FIG. 8- RA890F OPERATION ON A CALL FOR SYSTEM. HEAT. 110 in the flame detection circuit. This small signal Is amplified by the electronic network and acti ates flame relay 2K. When relay 2K pulls In: - 2t<1 cpens 10 cut off lermlnal 4, ll7'itlon. - 21<2 closes to power lerminal 5, main gas a/ve(s} or second stage 011 val e as appliCable. _ 2K3 opens to stop the healing O1lhe safety switch heater. ,'The. syStem Is now In Ihe -run" condition and Will re- main ir:'llhis condil.ion unlll the controller Is sallsfied, un- less lImi.1 j!ctlon, flame failure, or power failure causes Ihe system to shut dOwn. If the flame fails during • run~ (or it for some other rea- son a satisfactory signal Is not maintained in the flame de- tecllon circuit), the 2K relay drops out 10 CUi ott the main a1ve(s) and relurn il7'itlon. 1A890F CALL FOR HEAT-Ill PULLS .1 "~-:::." t.n'.' :=:.::. '" I@ In II<3"~ , M ,~ "" M 1111 OlTAGE '" CON_ TIIO~ (b~l~ , '" '""111- • -I III M"TOII '.' =. • a TlU 'III JIoCIi L.i:1ii 2K NOTeD 'Il.'f(~ ~ uno LINK I~ ~. .• - "J;; CO_.CT -,. " " '" l fnY ."'m:M HU~ ,. on "'lOT D llI_mON IIO_.IU ~. FIG.9 RA890,F OPERATION WHEN RELAY 1K PULLS IN. I~ F TO flAM. OI'TICTOII • 1A890F FLAME DETECTED -BURIER RUIS ,," "'OlT"'GE CON_ T"OulII t, TO , oor OnlCToll '''FnY IWITCH OI·INlllGWlO n " • l co 011 "' 0 _. IU"lT IO.ITION " CI.rT on - .= - C_ICY I ITC!'I " " ,~ • l'NK "'~ r """ FIG, 10- RA890F OPERATION WHILE THE MAIN BURNER IS FIRING ("RUN" PERIOD). Systems like the RA890Fwhich relurn Iglition on flame failure are called ·re-Iight- or -Iglitlon return- tallrolS. Some codes require thai conlrols which retum igIillon do 50 wilhin 1 second after flame fallure, and modelS ha lng less lhan 1 second flame response time musl be u:sed In these installations. Contact 2K3 c/OSElS lhe safety swilch heater circuit It the flame is nol f&eStablished in safety switch liming (15 or 30 seconds), safety shulcbwn occurs, The same figure lHustrates what t\aR:l9nS II' the burner fails to light on start. The safely swilch hearer tallinues to heal. with pllof and ignition energized, untll the safety switch ~ar~ open. PILOT/IGNITION SEQUENCE Figure 12 shows onty the line oltage porticn of the RAB90F. a.o.nT"l Iwm:H tol n_o " __ CI.rT OFF. __ •• InI_ FIG. 11- RA890F OPERATION IF THE BURNER FLAME GOES OUT. RA890F L1IE VOLTAGE CIRCUIT lIMIT{SI ,,-+ ,., ~ II 2:f!) - ti:;<9 4> J2' _ FIG, 12- RA890F TERMINALS FOR PILOT/IGNIR nON SEQUENCE. 111 71-97558-1 An; time relay 1K pulls ln, terminal 3 wlJi be powered. If 1K IS In and 2K IS out, lermlnal 4 will also be powered. Pull In of 2K cuts off power to 4 and powera 5. So far we have ~ldeted only the ~ where lQ1i- lion IS ec:nleCted 10 terminal 4, or lnlem ded looll1en, In- terrtpled 1Q1llion means thai Ig'lltlon IS out off dJring the -run- period. The RA890F may also be I.lSEld wllh Intermll- lenl jgnjtjon, or with Ignition on wl:len the main burner is fir- Ing {"run"·per,loc:lf simply by"connecllng the iQ1ltlon transformer to larminal 3. l'hiS Is more common on direct spark igiled oil burners. The RA890F normally provides intermittent pilot- - a pUot which Is automatically Iir;tlted each lime there Is a call for heat and which burns dJrlng the entrre pe- riod that the main burner is firing (-run- period). The RA890may .QQ1 be connected for inlerrupted plio! (lSlless using exlema,! circullry)-a pilol which is cut off sometime before the burner reaches Its -run- period. It may, however, be I.lSEld with a conllnuous pilot-a pilot which burns withoul tUrTll:Dwn IhrOlJl;1lOul the entire time the bumar Is In service, whet.her the main burner is Mng or noI. CONTINUOUS PilOT SYSTEMS The hookup for a conUnuous pilot gas system is the same as shown in Fig. 6 excepl thai the connections 10 ter- minals :3 and 4 are not made, and the RA890F pilollink is Clipped out. Nole In the schematic that removing the pilot link puis the delector In series with contacl 1 K2. 11'1 this . case, the detection system IS lnterr~ed when relay '1 K is out. When 1K j.XJlls In on a call for heat, lhe pilot will be de- tecled, if il is prBS9l1t, and the main valve(s) can open. The safe slan check is losl on conlinuous pilol systems. A safe slart check can be acXied 10 I;OllUnuous pilot sys- tams by using an additional relay. A standard switching re- lay could be used to perfonT! this function on old RA890E Installation&. Because of laster relay Pun~ln speed, a spe- cial hOOln.p uSing an R482F relay wilM thermistor delayed pull-,ln musl be used for the RA890F. This hookup is nol teChnically a continuous pllot syslem, bul instead is a melhod of providing plio! flame dJring the burner-offcyCle. The pilot flame i~ actually cut off and then re-igniled on each burner start. Pilolflame Is Sl4'8rvised ooring the off cyele. During the off cyCle, !he RA890F Is powered continu- ously through contact 3K1; RA890 relay 1K ispulled in, the pilot valve Is ~ered, and relay 2K is pUlled in as long as the pilot is proved. On e call for heal by the controller, the thermistor in series wllh the R482F relay coil is powered. This delays relay p Ill-ln Slightly. Conlact 3K1 drops out long enough before 3K2 p IUS In to permitlhe RA890F re- lay 1K to drop out, stnJlling off the pilot. When 1K drq:lS out, Ihe 1K2 contacl opens In the flame delecllon circuit and relay 2K also drops out. The RA890F is now in the nor· mal SlardJy IXlSllion (Fig. 6). When contact 31<2 In lhe R4B2F closes 10 repowar the RAB90F, the pilot is rS'lgnited on a normal start - atter lhe safe start check. RA8iO CUTOFF SYSTEMS In applicalions where it is undesirable for the RA890 to relurn lQ1ilion on name failure, an external cutoff circuit must be used wllh the ~,F, or G. (The RAB90H in- corporates cutoff.) The j.XJrp:lSe of the cutoff hookup Is to prevent reCYCling of the syslem on flame failure. Whe.n us- ing this hookup, flame failure wlll be followed by safety shUldoW'n, requiring thattha RAB90 be manually resel ba- 10re a restart can be made. Culoff systems may be de- SiQ1ed SO thai igUlion only, or iQ11tion and pilot valve, will be CUI off on flame failure. One hundred percent gas shut- off, Including pilot, is rEq.Jired for LP gas. The cutoff system uses a switching relay with ~ ping coolacts (contaclS make before break) to transfer control of the lQ1ition arxl pilot to terminal 5 of the RA890. Power to terminal 5, which controls the main valve(s), Is Interrupled direclly by a dropout of the flame relay, 2K. On a call for heal, terminal 3 is powered when lhe load relay 1K pulls in and ,K1 closes. The burner motor, 11 used, slarts. The pilot valve arxl Ignition ere powered via lhe following circuit-control twmiOftI 3 to relay terminal 5 10 relay lerminal 4 (thrt:VOt1lhe normally closed contacts) to relay tenninal 6 ~hrlXJ\tllhe JU!l1'9rj 10 Ihe pllol valve and iQ11tlon. When lhe flame Is established, the flame relay 2K pulls in arxl 2K2 closes Control lelTTlinal 5 is powered causing the main valve Is) to open an:! pulling power on relay termi- na18. This causes the R482D Relay 10 p IlI in (lermlnaI8, 10 7, to 1 through lhe jumpers). When the relay pulls In, relay tEllrminal 3 is po'N6l"ed from relay terminal 5 10 hold in lhe relay; relay lelTTlinal 6 is powered from relay terminal 8 to power the pilot valve and ig"lilion. lithe burner flame g:l9S out, relay contact 2K2 in the RA890 wlU open, f8l"TlO'ling power from RAB90 terminal 5 and from R482D terminals 8 arxl6. The main valve(s) and pilot valve will close and Ihe ig"lition will be cut off. As the '" 2F ,n USIIIG THE THII· ~. r1t, ~l: RA890F TO MISlO( b MOIIITOR PILOT DURIIIG THE , • , • OFF CYCLE L L1MITISI U (1<011-+ r'" ,J f- VOlU.GI ,.,lIN CONUOUU V,llVI15) 90F • • @ ~ IGNI'ION <D '" TO FL,lMf OUICIO. ~ ., + ON CALL FOI HIAI UI OPllf1lrrOI, .U CLOUI O INIUIlT 0""" Ilf1l1lUPItNG POWtl TO II<I n'll! FIG. 13- RABiOF HOOKUP FOR CONTINUOUS PilOT WITH SAFE START CHECK ON CAll FOR HEAT. ~ ~ ~- I ',' R482D contact between terminals 4 and 5 is A)W open. the ignition and pilot valve cannol be energized again unlillhe R4a2D relay drops out. This can occur only atter the RA890 load relay 1K drops out upon safety shutdown. The safety switch in the RAB90 will heal and safety shutoown will occur In about 15 or 30 seconds ldePending on the model). The RA890 must be manually resel to resume operation. OPERATION OF TWE RA890G OperalLon of the RA890G is very similar 10 that of the RAB9OF, which we have covered in detail. The RA890G is designed 10 be used with the C7027 A. C7035A, or C7044A Minipeeper Ultraviolet Flame Detectors only. Note in the fallowing figure that the RA890G has 2 transfonners. The low voltage relay logic circuit is pow- ered by TFI1 from lerminal 6, and the electronic ~Utler nelwori( is powered by TR2 from terminal 1. (In an earlier IGIIITIOII CUTOFF STSTEM R~nll RU y Itarting . '£;'IT';~:I~" , • '" '" 5 -!E.1"'~ (E.Z"'@'- .! RA890E, (j)\. ~ " C:O,,,nC:UD _.' TO ~'Olo n,. 0. DR o. " " . M IN I- V"'~V.!.I ~,= F,G~ ~ ~ = T , ~ , FIG. 14- STARTING CiRCUIT FOR CUTOFF SYSTEM. IGIIITIOII CUTOFF SYSTEM R"ZD RELAy ,,~, running .~ I'~:"~':' , . ~ • ", '0' • (1_1"'. E.2"''@'- I , iF RA890E, ~ ~ FIG \ 2 ' ~ ""'=~ - -~ _." TI I" ~ , I. CONNlc:TlO " " TO U o. T". ~" n O~ o. FIG. 15-RUNNING CIRCUIT FOR CUTOFF SYSTEM. 113 model, 1 Iransformer powered bolh circuits from terminal 1. However, a line voilage controller could not be used be- cause lhe load relay 1K would not dtop ouI when power was removed from lerminal 6, and safety shutdown would occur when the conlrolLer cpened.) The safe start check differs from thai of the RA890F in that It Inc0rJXIrates safety shutdown. The electronic net- work remains powered as long as the disconnect switch Is closed. regardless at the type of controller usecl. A flame Indication (causecl by an actual flame or by a flame-slmu- talJng condition) during the -ofT- pericd or at startup will pull in relay 2K. Contact 2K3 will open. preventing load re- lay 1K from pulling in, and contact 2K4 will close. It a low Voltage coni roller is used, the safety switch heater will be- gin heating as soon as 2K pulls In. " a line voltage control- ler is used. heating won', start until there is a call for heat and the controller closes. safelY shuloown will occur about 15 seconds after heating starts. During normal operation, on a call for heal the control- ler closes and relay 1K pulls in. When 1K pulls in - -1K1 closes to power the pilot valve from terminal 3 and the ignition from terminal 4. The pilot ignites. (On an oil system, the burner motor and first stage oil valve are powered from terminal 3; see Fig. 7.) -1K2 closes to bypass the thermistor. -1K3 closes to establish a holding circuit tor relay lK: and to establish a heating circuit tor the safety switch haater through 2K3, 1K2, and 1K3. - 1 K4 opens to prevent the safety switch haater from heating through 2K4 when the flame relay 2K pulls in. When the pilol flame (or firSI-fitage oil flame) is de- tected, the flame relay 2K pullS in. When 2K pulls in - - 2K1 c:pens to de-energi:ze terminal 4 and cut off the ignition. - 2K2 closes to energize the main valve(s) (or second- stage oil valve} from terminalS. The main burner lights. - 21<3 opens; !he safety swilch heater stops healing. RA890G -STAIIDBY POSITIOII llU HI TI~ 211 "'LAM. IlnAYJ Til' TO 'LAMI OETEcrD~ • WHITI Lf-~~_ l ~ , FIG. 16-RA890G IN THE STANDBY POSITION. 71·97558·1 I ',' - 2K4 closes with no effect. As previously described, It provides a heating circuit for the safety switch healer WrIng lhe safe stert check. The sysIem Is now In the ~runft condllionwlth the main burner firing. The -run- period wilt continue unIi1lhe call for heal is satisfied 0( until the limlls open. In either case, the load relay 1K will drop out. When 1K drops out - - lK1 will open, cle-enQ(gizing the pllol valve or fjrsl- slaga oil alVQ (IermTnal 3) and the main valve(s) 0( second-staoa oil valve (terminal 5). The bumer flame will go oul. - 1K2 and 11<3 will open and 1K4 will close, resetting the rtA890G fO( the next cycle. \'Vhen the burner flame goes out, relay 2K will drop out The 2K cOnla~ts will be reset tor (he next cycle. tr a limit opei,s,'sa1aly shutdown wlll not occur. \'Vhen normal conditions are restored and the limil(s) closes, the S)'Stem will restart and operete normally. It the flame goes out wring the ,-run- period, relay 2K will drop out When relay 2K CSl'ops out - 2K1 closes to power terminal 4 and ft return Ignltion. - (It -return Ig1llion" Is undesirable, the external cutoff circuit shown in flg. 14 can be used.) - 2K2 opens to de-energize the main valve(sj or sec- ond-stage oil valve (lerminal 5). - 2KJ closes to provide a t16aUng clrcult tor the safety switch heater through 2K3. 1K2, and lK3. -11 a flame Is not re-established and detected within about 15 seconds. sa1ely shutdown will occur. w If a flame is re-established, the operation will conlinue normally. IlltIe wrner 'fails to liglt, operation wlJl be similar and salely shutdown will also occur. Uke the RA890f. safely shutdown requires manual reselling to restart (he system. 114 RA890H SELF-CHECKING PRIMARY CONTROL This control provides a higher level of safely than the RA890F or G. Dynamic Self Check circuitry providas a continuous check of the RA890H for possible !lame-simu- lating component failure. Comp::nenl failure in lhe elec- Ironic network causes safely shutdown, requiring manual reselling 10 restart the system. The RA890H also i",corporales ~ eutaW rather than "fe-light" ("ignition relurn") It the flame goes out. If the flame faits during the" run" periOd. safely shutdown will occur wnf'l no attempt 10 re-lighllhe burner. APPLICATIONS The RA890H is designed for intermittent pilot appllca- lions. It may be used for continuous pllols only if an auto- matic ialeclrlcally q:lEIrated) pilot valve is used, ard if the pilot is shut oown and re-igniledprior to burner start. It can- nol be used tor interrupted pilot aw1icatlons without exter- nal circuitry. A flame rod is recommended for usa with the RA890H; a rectifying photocell or a C701ZA or C Purple Peeper UI· traviolet Rame Detector may be used, but lhe system dOes not provide a check of theSe delectors dJring the fir- ing cycle. The RA890H fealures (1) a tamper-resistant plastic cover, (2) a green signallighl, (3) a flame current lest jack, (4) a test button, and (5) three alann terminals. (1) The lamper-resistant plastic cover over the load and flame relays (1 K and 2K) lessens the possibility of an cp- erator @nlculatiog them, which could result in an explo- sion. The cover meets the General Services Administration's requirer1"l'lnts for tamper-resistant cOllers. (2) The green signal light blinks whenever the flame de- leclor senses a flame_ When the burner Is out, the liQht Q!QWR slightly to Indicate the control Is operatillQ In the stanctJy l'Tl(Xja ,,!itl'l the power 00. (3) The flame current test jack lets an operator comect a W136A Test Meter (or equivalent microammeter) to RA890H, J, IC SELF·CHECICINC PRIMARY CONTROLS VINYl PROTECTIVE BARRIER " FIG. 17-FEATURE$ OF THE RAS90H. measure Ihe flame signal current while the burner is firing dJrlng the ~run· period. (4) The lest butron prOVides a slead')l reading of Ih& rlame signal current When an cperalor holds il in. WUh the tesl button depressed, the green signal liQhI dJes not blink. (5} The three alarm terminals are for connecting an ex- ternal alarm. They accommodate either a normally-qJen or a nonnally-closed alarm circuit. Contacts are isolated from the rest of the Circuitry, so either a low voltage or a line voltage alarm may be used. The alarm is energized it safety shutdown occurs. COMPARISON OF THE RA890H WITH THE RAS90F The external hookup and the Ignition SEQJer1CEl relay contacts (1K1, 2K1. and 2K2) are the same as for the RA890F. Other similarities are; - a flame siQnal amplifier in the electronic networ1<, -a test jaCk for measuring the flame signal current, - a safely switch (SSj In the load relay (1 K) circuit, i!nd - a thermistor to delay the pull-in of the load relay 11K} dJring the safe start check. The big difference from the RA890F is the sel1-check- ing circuit in the electronic network. Relay 31< pullS in and 31<1 closes to complete the flame deJection circuit when power is a~lied to the electronic netwOrk. When ftame is detected, cheCkillQ action begins. Contacl3K1 opens and Closes and the green signal light blinks atxltJt 3 times a second as 101lQ as flame is detected. Checking action Slops.if the flame coes oul or if there is a CO!l'fXYlBnt failure in the networ1<. Relay 41< pulls in and Slays in whenever cheCking ac· tion takes place. The flame relay (21<) pulls in (thrCll Q1 1K4 and 41(4) when 4K pulls In, and holds itself In thrCll Q12K6. Flame failure or network componant failure will cause 41< (and thuS load retay 1K) fo drop out (4K2 ~J. Conlacl 1K1 operlS to d&energite all fuel valves. and the safety swilch heater starts heating. safety shutdown occurs in about 15 seconds. 'O " " =:.I"~" RA890H-POWER OFF FIG. 19-AAS90H SCHEMATIC OIAGAAII WITH THE POWER OFF. 115 71-97558-1 Other differences from the RA890F are in the low volt- age relay logic circuit. More COl'Tl'lax switChing requires aci:ilional 1K and 2K contacts (11<2, 21<4, 2K5, and 2K6) and new relay. 4-K_ contacts (4K1-4K4). The 'Iollowing fi~res Show the operation of the RA890H Se,,-ehecking Primary Control under bOth nor· mal and abnormal conditIons. Energized circulls are shaded to aid the eKPJanalion. The external hookup shown Is for a gas.system. For an oil system, lhefirst-stage 011 valve and burner motor replace the pilot valve on lermi- nal 3, and the seCond-stage 011 valve Of used) replaces the main valve(sj on'termlnal 5. (See Fig. 7). RA890H NORMAL OPERATION Normal operation can be divided into 4 modas-(1) stancbi, (2) call 'lor heat, (3) the A run A period, and (4) satis- facllon o11heGalifor heat. (1) Standby Mode (Fig. 19) Fig. 19 shows the internal schematic for the RA890H in the stancbi mode with the master switch closed and the low voltage conlroller ~ t1 all limits are closed, lhe power s~1y energizes the transformer, and the elec- tronic network turns on. Relay contacts 3K1 close to com- plete the flame detecllon circuli. (lte line voltage controller were used, as indicated by the dashed line, terminals T·T would be jurrpared. There would be 00 power al terminal 6, and (he trans'lormer and electronic network would not be energized. Relay conlacls 3K 1 would stay open.) Thestancbyperiod is the only lime ciJring which theop- eraUon using a line voltage controller differs from the op- .OLV'''' .~ I- ., TE~ ~ _ , on , .1 Ye'. _moo RA890H·STAIIDBY MODE I,f. ,' FIG. 19-RA890H IN THE STANDBY MODE. eratlon using a low vo1taQ9 controller. After the conlroller closeS, the operation Is the same 'lor either Iype. There- fore. both controllefs wlll be shown energized on the resl of the f1~res. Keep In mind thaI a Jumper replaces the low voltage conlroller t1 a line voltage conlroller is used. (2) Cell for Heel (Fig. 20) On a call 10r heal. lhe controller closes. The trans· former secondary energizes the load relay 1K IhrouQh Ihe sa1ety swilch heater (SS HEATER), 2K3, lhe thermistor, 4K1, lhe low vollage conlroller (or T-T Jumper), and the safely switch contacts (SS). The continuity 01 the safety swilch heater is proven. The lhermistor delays the pull·in 01 1K (aoout4 seconds nominal) to letlhe conlrol check 'lor a flame Of a circuit failure simulating a flame. The delay timemaybeasshort as two seconds at 125 F, or as long as 30 seconds at minus 20 F. As the thermistor warms up. the 1K relay may!'!Y!TI slightly be'lore it pulls in. This is normal and not relay ·qhatler.~ When relay 1K pulls In, relay conlacls 1K1, 1K2. 1K3. and 1K4 close. Closing 01 1K1 energizes Ihe pllot valve and iglition (terminals 3 and 4), and the pilollgniles. Clos· ing 011K2 bypasses 4K1 and the (hermislor. When 1K3 closes, lhe transformer secondary begins heating the safely switch heater through 2K3, 1K2, 1K3, and 2K5. With 1 K4 closed, relay 2K can pullin when 4K4 closes (4K pulls in when flame is detected). RA890H·CALL FOR HEAT r-~-'-I' ~ '- '~==~. ~_.; , ,., >IU ,. , VOLV''''' '" ~~' '" i ~~ , ~ ., ,\ - [ n, • ',,,:. ,. ~ ,. ", '" • • "' '" ,. - ""i ~;o0 , - '" '"" • "" , 0 CO-{] ~.=r-:, • ~ . "CO< ._'~~ _. " + -" " .~, • FIG. 20-RA890H ON A CALL FOR HEAT. 116 [...]... Relay 4K pulls In ard stays In as long as 3K keeps checkIng When 4K pulls in relay con/acts 4K1 and 4K3 open, and conlacts 4K2 and 4K4 close ClosII'lQ of 4K2 holds in rela'll 1K through 1K4, 41 . HONEYWELL FLAME SAFEGUARD PRIMARY CONTROLS The Flame safeguard Primary Control. is the heart of the: bu!'flll' control ~. It lrans/ales inputs 1rom the flame delector, controller,. conlacts 4K2 and 4K4 close. ClosII'lQ of 4K2 holds in rela'll 1K through 1K4, 41 <:2, the low voltage controlfer (or T·T'jllri'1per), ard the SS contacts. When 4K4. place. The flame relay (21<) pulls in (thrCll Q1 1K4 and 41 (4) when 4K pulls In, and holds itself In thrCll Q12K6. Flame failure or network componant failure will cause 41 <