Carlin 702GAS User manual

™
126 Bailey Road North Haven, CT 06473
Ph 203-680-9401 Fx 203-680-9403
Carlin Combustion Technology
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ech support
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©Copyright 2020 — Carlin Combustion Technology
 Exceptwherespecicallystatedotherwise,thismanual
mustbeusedonlybyaqualiedservicetechnician.
 In the state of Massachusetts, this product mustbe
installedbyalicensedPlumberorGasFitter.
 Failuretocomplywiththeaboveorotherrequirements
inthismanualcouldresultinseverepersonalinjury,
deathorsubstantialpropertydamage.
USER—ReferonlytoUsercareandmaintenance
onback pagefor informationregarding operationof
thisburner.TheburnerInstructionManualisintended
onlyforyourservicetechnician.Theburnerandheat
exchangermustbeinspectedandstartedatleastan-
nuallybyyourservicetechnician.
 Checkburner cartonscarefully.The Model702GAS
combinationgasburnerwasassembledandtestedat
thefactorybeforeshipment.Iftheburnerwasordered
withacompletedassembledgastrain,thetrainwas
pressuretested andelectrically checkedfor proper
operation.Wherepossible,thegastrainorcomponents
wereshippedinthesamecartonastheburner.Check
yourpacking slipfor thenumber ofcartonsshipped
fromthefactory.
MODEL 702GAS
Low-High-Low Step Modulating
840 to 1600 MBH Gas
(High-fire input capacities)
Instruction Manual

MN702GE 060320
– 2 –
Contents
PLEASEreadthisrst.................................................................2
Generalinformation.....................................................................3
1.TheCarlinModel702GAS...................................................4
2.Pre-reInspection/Preparation.............................................5
3.Installgaspiping.................................................................13
4.Wiretheburner...................................................................15
5.Checkoutprocedure—beforestartingtheburner.............17
6.Setburnerinitialheadanddamperpositions.....................18
7.Adjusttheburnerusingtestinstruments............................19
8.Maintenanceandserviceprocedures................................23
9.Repairparts........................................................................26
10.Dimensions.........................................................................28
Usercareandmaintenance........................................ Rearcover
PLEASE read this rst . . .
Special attention ags . . .
Pleasepay particular attentionto thefollowing whenyou seethem
throughoutthismanual.
 NotiesyouofhazardsthatWILLcauseseverepersonal
injury,deathorsubstantialpropertydamage.
 NotiesyouofhazardsthatCANcauseseverepersonal
injury,deathorsubstantialpropertydamage.
 Notiesyou of hazardsthat WILL orCAN causeminor
personalinjuryorpropertydamage.
 Notiesyouofspecialinstructionsoninstallation,operation
ormaintenance thatare important,but arenotnormally
relatedtoinjuryorpropertydamagehazards.
Before installing or
servicing:
 (1)Shutofftheoilandgassuppliestotheburner.
 (2)DONOTshutoffthecontrolswitchtotheboiler
circulatorortheburner.
 Followtheguidelinesbelowtoavoidpotentialsevere
personalinjury,deathorsubstantialpropertydam-
age.
Installer/service technician . . .
• Readallinstructionsbeforeproceeding.Performallprocedures,
andintheordergiventoavoidpotentialofseverepersonalinjury,
deathorsubstantialpropertydamage.
• Beforeleavingthesiteafterstartuporservice,reviewtheUser
careandmaintenancepagewiththeuser.Maketheuseraware
ofallpotentialhazardsandperformthetrainingoutlinedbelow.
Installer/service technician —
Train the user . . .
• Toproperlyoperatetheburner/applianceperthismanualand
theapplianceinstructions.SeeUsercareandmaintenance.
• Tokeepthismanualatorneartheburner/applianceforready
accessbytheuserandservicetechnician.
• Tokeeptheappliancespacefreeofammableliquidsorvapors
andothercombustiblematerials.
• Toneveruselaundryproducts,paints,varnishesorotherchemi-
calsintheroomoccupiedbytheburner/appliance.
• Tocontacttheservicetechnicianatleastannuallyforstartupand
burner/applianceservice.
When servicing the burner . . .
• DISCONNECTELECTRICALSUPPLYandallotherelectrical
connectionsto burnerbeforeattempting toserviceto avoid
electricalshockorpossibleinjuryfrommovingparts.
• Burnerandappliancecomponentscanbeextremelyhot.Allow
allpartstocoolbeforeattemptingtohandleorservicetoavoid
potentialofsevereburns.

MN702GE 060320
– 3 –
Burner applications
Followallinstructionsinthismanual,theprimarycontroldatasheetandthe
appliancemanual.
Adjustthenozzleselection/ringrateifnecessaryduetopositiveoverrepres-
sureand/oraltitudesmorethan2,000feetabovesealevel.SeetheNOTICE
undertheRatingsinformationatright.Whereapplianceapplicationinformation
isavailable,therecommendedringrateandburnerinformationwillinclude
appropriateadjustmentsforpositiveoverrepressureandrecommendations
forhighaltitudes.Followtheappliancemanualguidelineswhenavailable.
Damage or shortage claims
Theconsigneeoftheshipmentmustledamageorshortageclaimsimme-
diatelyagainstthetransportationcompany.SeetheNOTICEonpage1for
burnercartoninformation.
When calling or writing about the
burner:
Pleaseprovide uswiththe ULserial number andburner model number
toassistusinlocating information.Thisinformation can behelpful when
troubleshootingorobtainingreplacementparts.
Codes and standards
Certification
702GASburnersareU.L.listedfortheU.S.,certiedtocomplywith:
• UL795,forusewithnaturalgasorpropane.
• CULcertiedCSAB140.2.1.10,CGA3.4-1973
• Burnerlabelslistcompliance,whenrequired,withspeciallocal,stateor
provincialapprovals.
• 702GASburnerscanbeconguredforlocalcodecompliancy.
United States installations
Burner/appliance installations in the United States must comply with the
latesteditionsof:
• InstallationofDomesticGasConversionBurners,ANSIZ21.8.
• NationalFuelGasCode,ANSIZ223.1/NFPA54.
• NationalElectricalCode,ANSI/NFPA70.
• Alladditionalapplicablenational,stateandlocalcodes.Regulationsof
theseauthoritiestakeprecedenceoverthegeneralinstructionsprovided
inthismanual.
Ratings
Altitude2,000feetmax.(seeNOTICEbelow)
Gas Input
.....................................................High re: 840 to 1,600 MBH
Fuels
............................................................Natural gas or propane
Gas Train (available in straight or angled configuration)
....................(2) Main gas valves & RV-61 or RV-81 regulator
................................. Buttery gas valve for input regulation
.... 1" gas train standard; 1¼", 1½" or 2" gas train available
Electrical
Power .......................................................120V/60 Hz/1-Phase
Limit circuit input (RM7895C or RM7897C) .... 120 vac/60 hz
Control circuit load (120 vac)................................... 1.2 amps
Motor ........................ 1/2 hp, 3450 rpm, 48-frame, “N” ange
.................... 115 / 208-230 vac/60 hz/1-ph, 8.4 / 3.8-4.2 amps
Gas valve power................................................ 120 vac/60 hz
Damper motor ...............................................Siemens SQN71
Ignition & Primary Control
..................Carlin Model 41800 solid state electronic ignitor
Ignition voltage ......................................................9,000 volts
Primary control ..................................... Honeywell RM7897C
Agencies
...........................................................................UL Listed (US)
Reducenozzle/ringratewhen required – Maximum burner
capacityisreducedwhenoverrepressureispositiveandfor
altitudesabove2,000 feet. See below, andadjustring rate/
nozzleselectionifnecessary.
General information
702GAS — Maximum firing rate for
positive overfire pressure and high altitude
Overfire pressure (Inches w.c.) Gas – MBH
0.00 1,600
0.10 1,530
0.20 1,500
0.30 1,480
0.40 1,440
0.50 1,430
0.60 1,390
Altitudes: For altitudes more than 2,000 feet above sea
level, reduce the above capacities an additional 4% per
1,000 feet higher than 2,000 feet above sea level.

MN702GE 060320
– 4 –
702GAS overview
TheModel702GASburnerisalow-high-low(stepmodulating)burnerthat
utilizesadampermotortocontrolair(andgasfuelrate).
Seethenextpageforgastraincomponentlocations.
Operation
Ignitionformainameisaccomplishedbyaprovedgaspilotofapproximately
70,000Btuh.PilotgasisintroducedandignitedbyaCarlin9,000-voltelec-
tronicignitorwiredtotheelectrode.Afterthepilotameisproven,thetwo
maingassafetyvalvesopen.Thepilotgasvalveclosesafteratimedelay
toallowmainametoestablish.Flameismonitoredbothforpilotameand
mainamewithaUVscannerpositionedinthemountingange.Theburner
mainamebeginsatlowre.Ifadditionalinputisrequired,thedampermo-
toropensthegasbutteryvalveandairdampertotheirhighrepositions.
Gasisintroducedintotheburnerthroughamanifoldaroundtheairtube.The
gasthencirculatesthroughasetoffouroricespudsintotheairstream,
upstreamoftheretentionring.Thespinoftheairowattheretentionring
thoroughlymixesthegas/airbeforeitreachesthecombustionzone.
Firing rate adjustment
• Thengasowisadjustedtomatchtheairowatlowandhighrerates.
NOTE:HighFiremustbesetbeforeLowFire.
• Seethe“Startingandoperating”sectiononpage12ofthismanualfor
thecompletedescriptionoftheadjustmentprocess.Thefollowingisa
briefsummaryonly.
• High-reairissetbyadjustingthecombustionheadposition(tocontrol
airowthroughandaroundtheretentionring).
• Low-reairisthenadjustedbyalteringthepositionofthelowreadjust-
ingscrew.
Gas pressure requirements
Standardgastrainrequirementsforthe702GASburnerrequiresaminimum
w.c.inletof5"underowconditions(maximum14").Systemswithhighpres-
sure(above14"w.c.)requirealinepressureregulatorupstream.
1. The Carlin Model 702GAS burner

MN702GE 060320
– 5 –
2. Pre-re inspection • preparation
Vent system
Vent/chimney sizing
1. Followalllocalcodeswhensizingtheventandchimney.
2. Refertotheappliancemanufacturer’smanual,whenavailable,forventing
recommendations.
Combustion air/ventilation openings
Combustion air/ventilation opening checklist
• Verifythatairopeningsareunobstructed.
• Verifythatappliancespaceandairsourcespacesarefreeof:
• Gasolineorotherammableliquidsorvapors.
• Combustiblematerials.
• Aircontaminants,suchaslaundryproducts,paint,thinner,varnish,etc.
• Conrmwithuserthattheareawillbekeptfreeofthesematerialsat
alltimes.
• Allairfrominsidebuilding(buildingmustbewell-ventilated):
 Sizeairopeningsforafreearea(afterlouverdeduction)ofatleast1
squareinchper1,000Btuhinputofallappliancesinthespace.
• Allairthroughopeningsdirectlyfrom outside the buildingthrough an
adjacentoutsidewall:
 Ifairopeningsconnectdirectlytooutside,providetwoopenings,one
within12inchesoftheceiling,theotherwithin12inchesoftheoor.Each
openingmusthaveafreearea(afterlouverdeduction)of:
• Ifdirectlythroughsidewall:1squareinchforeach4,000Btuhofall
appliancesinthespace.
• Ifthroughverticalducts:1squareinchforeach4,000Btuhofall
appliancesinthespace.
• Ifthroughhorizontalducts:1squareinchforeach2,000Btuhofall
appliancesinthespace.
Donotinstalloroperatetheburnerifanycomponentisdam-
agedorifburnerdoesnotcomplywithotherguidelinesofthis
manualandtheappliancemanual.
Inspect, repair and/or replace vent
system
Donot installthisburner unlessyouhave veried
theentire ventsystem and theappliance are in
goodconditionandcomplywithallapplicablecodes.
And...
 Theventandchimneymustbesizedandconstructed
inaccordancewithallapplicablecodesforgasring.
 Theventsystemmustnotbepressurizedunlessthe
ventpipingandventsystemaredesignedaccordingly.
Theventmustprovidedraftatalltimes(negativepres-
sureinvent).
 Donotinstalloruseanexistingmanualdamperinthe
ventconnectororvent.
 Donot connectthe appliance ventconnector to a
chimneyor ventserving a replace,incinerator or
solid-fuel-burningapparatus.
 Inacoldclimate,donotventintoamasonrychimney
thathasoneormoresidesexposedtotheoutside.
Installa listedstainlesssteel liner tovent the ue
products.
 Adefectiveventsystemcouldresultinseverepersonal
injury,deathorsubstantialpropertydamage.
Mount burner in appliance
1. Verifythe boltpatternon theappliance chamber matchesthe ange
pattern.
2. Verify the insertion depth (UTL) matches the depth of the appliance
opening(sotheendoftheairtubeisushwith,orslightlyshortof,the
insidesurfaceofthecombustionchamber).
3. Placegasketontoboilerfrontplate.
4. Slidetheendoftheairtubeintotheopeningandsecuretheangeto
theboilerfrontplate.

MN702GE 060320
– 6 –
2. Pre-re inspection • preparation (continued)
Prepare vent/chimney
1. Secureallmetalventjointswithscrews,followingtheventmanufacturer’s
instructions.Sealalljointsintheventsystemandchimney.Repairma-
sonrychimneyliningandrepairallmortarjointsasneeded.
2. Wheredraftuctuationsarelikely,installadouble-actingbarometricdraft
regulatorintheventpiping.(Thedampermustbelocatedinthesame
spaceastheappliance.)Installamanualresetspillswitchpermanu-
facturer’sinstructions.Wiretheswitchintotheappliancelimitcircuitto
shutofftheappliance/burnerifsustaineddowndraftshouldoccur.Refer
totheappliancemanufacturer’sinstructionmanualforrecommendations
regardingtheneedforabarometricdraftregulator.
3. Providesupportfortheventpiping.Donotresttheweightofanyofthe
ventpipingontheapplianceueoutlet.
Clearances
Check codes, standards and the equipment
manual
• Verifythattheburner/appliancewillmaintainallclearancestocombustible
wallsor oorandall clearances requiredforservice/maintenance as
requiredintheappliancemanualandapplicablecodes.
Figure 1 Vent and vent connector installations, typical

MN702GE 060320
– 7 –
2. Pre-re inspection • preparation (continued)
Combustion air/ventilation openings
Sizing air openings
Follow all applicable codes and the appliance instruction manual (when available)
to size combustion air openings. Use the following guidelines when appliance
instructions are not available.
• All air from inside building (building must be well-ventilated):
Size air openings for a free area (after louver deduction) of at least 1 square
inch per 1,000 Btuh input of all appliances in the space.
• All air through openings directly from outside the building through an
adjacent outside wall:
If air openings connect directly to outside, provide two openings, one within
12 inches of the ceiling, the other within 12 inches of the floor. Each opening
must have a free area (after louver deduction) of:
• If directly through side wall: 1 square inch for each 4,000 Btuh of all
appliances in the space.
• If through vertical ducts: 1 square inch for each 4,000 Btuh of all
appliances in the space.
• If through horizontal ducts: 1 square inch for each 2,000 Btuh of all
appliances in the space.
Locating air openings
Follow all applicable codes and the appliance instruction manual (when available)
to size combustion air openings. Refer to Figure 2 when appliance instructions
are not available.
Estimating free area
When specific information on the free area of louvers is not available, estimate
free area as follows:
1. Wood louvers — free area = area times 0.25.
2. Metal louvers or grilles — free area = area times 0.60.
3. Screens, when used must be no smaller than ¼ inch mesh.
Motorized vent dampers
Wire the vent damper end switch to prevent operation of the burner until the
air opening louvers are fully open.
Combustion air/ventilation opening checklist
• Verify that air openings are unobstructed.
• Verify that appliance space and air source spaces are free of:
• Gasoline or other flammable liquids or vapors.
• Combustible materials.
• Air contaminants, such as laundry products, paint, thinner, varnish, etc.
• Confirm with user that the area will be kept free of these materials at all
times.
Figure 2 Locating combustion air/ventilation openings
Installing the burner/appliance in a space that does not
provide enough air for combustion and ventilation can
result in severe personal injury, death or substantial
property damage. Follow all applicable codes and
guidelines below to ensure space has sufficient air
openings.
Exhaust fans and negative pressure conditions — Isolate
the boiler room from areas subject to negative pressure.
Size combustion air openings to ensure neutral air pres-
sure in the boiler room whenever the burner operates.
Make sure the space provides enough ventilation
to prevent overheating of the appliance, burner and
controls. If there is risk of overheating, you must install
ventilation air openings sized large enough to provide air
for cooling the equipment. Failure to provide ventilation
can result in severe personal injury, death or substantial
property damage.
The space and combustion air supply must not contain
corrosive contaminants, such as laundry products,
paints, varnishes or other chemicals.

MN702GE 060320
– 8 –
Prepare the appliance
Burnerinput:Installaburnersizedforthenormalinputrating
oftheappliance.Donotinstallaburnerwithahigherringrate
thantheappliancerating.Donotinstallaburnerwitharing
ratemorethan10%lowerthantheappliancerating.Theappli-
anceandventsystemcouldbedamagedduetocondensation.
 Cleantheappliance:Cleantheappliancethoroughly.Testall
electricalcomponentsandverifythereliefvalveworks(boilers
only).
 Sealtheappliance:Sealallue-gascontainingjoints.Sealall
connectionstotheventpipingorbreeching.
 Verifycombustionchamberdimensionscomplywiththemini-
mumdimensionsrecommendedonpage9.Installorreplace
chamberlinerifrequiredbytheappliancemanufacturer.The
burnermustnotextendintothecombustionchamber.Theend
oftheburnerairtubemustbewithi1/4"oftheinsidefaceof
thechamber.Ifthespacearoundtheburnerairtubeismore
than1/4",wraptheburnerairtubewithminimum2300-°F-rated
ceramicberblankettosealoffthegap.
 Repairorreplacedamagedappliancecomponents.Inspect
theappliance thoroughly.Follow appliancemanufacturer’s
guidelinesforrepairorreplacementofanycomponentfound
defective.
 Whencleaning theappliance or workingwith ceramic ber
refractories or berglass insulation, see WARNING on this
page.
 Failuretocomplywiththeabovecouldresultinseverepersonal
injury,deathorsubstantialpropertydamage.
Prepare appliance for burner mounting
Positiveoverrepressureapplications:Whenringwithpositive
overrepressure,donotexceedthepressurespeciedinthe
appliancemanual.
 Positiveoverrepressurereducesmaximumburnercapacity.
SeePage3forestimatedreductionin burner capacity with
pressurizedringandhighaltitudeapplications.
 Failuretocomplycouldresultinseverepersonalinjury,death
orsubstantialpropertydamage.
Ceramic ber or
Fiberglass insulation
Ceramicbermaterials,suchaschamberliners,may
containcarcinogenic particles (chrystobalites)after
exposuretoheat.Airborneparticlesfromberglass
orceramicbercomponentshavebeenlistedaspo-
tentiallycarcinogenicbytheStateofCalifornia.Take
thefollowingprecautionswhenremoving,replacing
andhandlingtheseitems.
Avoid breathing dust and avoid contact with skin or
eyes.Wearlong-sleeved,loose-ttingclothing,gloves
andeyeprotection.UseaNIOSHN95certiedrespira-
tor.Thisrespiratormeetsrequirementsforprotection
fromchrystobalites.ActualjobrequirementsorNIOSH
regulationsmay requireotheror additional protec-
tion.For information,referto theNIOSHwebsite,
http://www.cdc.gov/niosh/homepage.html.
Ceramic ber removal:To preventairborne dust,
thoroughlywetceramicberwithwaterbeforehan-
dling.Placeceramicbermaterialsinaplasticbag
andsealtodispose.
Avoid blowing, tearing, sawing or sprayingber-
glassorceramicbermaterials.Ifsuchoperationsare
necessary,wearextraprotectiontopreventbreathing
dust.
Wash work clothes separately from other laundry.
Rinseclotheswasherthoroughlyafterwardstoprevent
contaminationofotherclothing.
NIOSH First aid procedures:
 Eyeexposure—irrigateimmediately
 Breathing—freshair.
2. Pre-re inspection • preparation (continued)

MN702GE 060320
– 9 –
2. Pre-re inspection • preparation (continued)
Figure 3 Chamber dimensions & tube congurations
Table 2 Minimum combustion chamber dimensions
(see Figure 3)
Prepare burner and components
 Donotinstalloroperatetheburnerifanycomponentisdam-
agedorifburnerdoesnotcomplywiththespecicationsof
Table2andotherguidelinesinthismanual.
Combustion chamber minimum dimensions
1. Forapplicationsthathavenotbeenspecicallytested(OEMapplications),
verifythatthecombustionchamberprovidestheminimumdimensions
showninTable2andFigure3.ForspecicOEMapplications,the
appliancetestingensuressuitabilityofthechamber.
2. ChamberdimensionsmaybelargerthanlistedinTable2,butshould
notbeexcessivelylarge.
 Combustionchambersshouldbesizedasrecommendedin
Table2.Theyshould be constructedofrefractorymaterials
withthecapacitytowithstand2600°Forhigher.
 Itisdifculttoincludeallpossiblechamberconstructionsinthis
manual.Therefore,youshouldusetheinformationpresented
inthismanualcombinedwithcommonlypracticedtechniques
whendeterminingchamberdesign.Ifcertainconditionsarein
question,consultthefactory.
Using chamber linings
1. When using refractoryliners orlightweight chambers, useinsulating-
typerefractoryrated2600°Fminimum,orasspeciedbytheappliance
manufacturer.
2. Youmustinstallatargetwalllinerifamelengthisclosetothelength
ofthechamber.
3. Useaoorlinerwhenpossible.Theoorlinerwillimproveringinmost
applications.Extendoorliner3to4inchesupthesidewalls.
4. Targetwallliners—Extendtargetwalllinersatleast3to4inchesabove
thecenteroftheamecorbelthetop1½to2½inchesdeep.
5. Usepreformedchamberlinerswhenavailable.Liningtheoorandtar-
getwallwater-backedcombustionchamberswithlightweightinsulating
refractorywillaccomplishthesame.
6. Whenconvertingcoal-redunits,installacombustionchamberinthe
ashpitarea,orlltheashpitwithsandupto2inchesabovethe“mud
ring”oftheboiler(ringthroughthedoor).Installalightweightrefractory
lineronthetargetwall.
Air tube insertion length (UTL)
1. Usableairtubelength(UTL)isthedistancefrommountingangetoend
ofairtube.Verifythattheendoftheairtubewillbeushwith,ornomore
than1/4inchshortof,theinsideoftheappliancecombustionchamber
frontwallwhentheburnerismounted.SeeFigure3forfurtherinformation.
NOTE:Aangespacerisavailableforapplianceswithlessthan4"UTL.
High fire input Refactory combustion chamber applications
(all dimensions in inches)
Gas–MBH “L” “W” “C” “H”
840 21 15.0 7.5 15
910 23 15.5 8.0 16
966 25 16.0 8.0 16
1092 28 17.0 8.5 17
1218 31 17.5 9.0 18
1330 34 18.0 9.0 18
1456 38 19.0 9.5 19
1568 43 20.0 10.0 20
High fire input Refactory combustion chamber applications
(all dimensions in inches)
Gas–MBH “L”
W/ target
“L”
No target “W”“C” “D”
840 21 25 17.0 8.5 10.5
910 23 27 17.5 9.0 11.0
966 25 29 18.0 9.0 11.0
1092 28 32 19.0 9.5 11.5
1218 31 35 19.5 10.0 12.0
1330 34 38 20.0 10.0 12.0
1456 38 42 21.0 10.5 12.5
1568 43 47 22.0 11.0 13.0

MN702GE 060320
– 10 –
2. Pre-re inspection • preparation (continued)
Mount burner in appliance
1. Welded-angeburners
2. Verifytheboltpatternontheappliancechambermatchestheange
pattern.
3. Verifytheinsertiondepth(UTL)matchesthedepthoftheappliance
opening(sotheendoftheairtubeisushwith,orslightlyshortof,the
insidesurfaceofthecombustionchamber).
4. Placegasketontoboilerfrontplate.
5. Slidetheendoftheairtubeintotheopeningandsecuretheangeto
theboilerfrontplate.
Inspect components and wiring
• Visuallyinspectallburnercomponentsandwiring.
• Verifythatwiringisintactandleadsaresecurelyconnected.
• Verifythatallburnercomponentsareingoodcondition.

MN702GE 060320
– 11 –
2. Pre-re inspection • preparation (continued)
Installingtheburner/applianceinaspacethatdoesnot
provideenoughairforcombustionandventilationcan
resultinseverepersonalinjury,deathorsubstantial
propertydamage. Followallapplicable codes and
guidelinesbelowtoensure space hassufcientair
openings.
 Exhaustfans andnegativepressure conditions—
Isolatetheboilerroomfromareassubjecttonegative
pressure.Size combustionairopenings to ensure
neutralairpressureintheboilerroomwheneverthe
burneroperates.
 Makesure thespaceprovides enoughventilation
topreventoverheatingoftheappliance,burnerand
controls.Ifthereisriskofoverheating,youmustinstall
ventilationairopeningssizedlargeenoughtoprovide
airforcoolingtheequipment.Failuretoprovideven-
tilationcanresultinseverepersonalinjury,deathor
substantialpropertydamage.
 Thespaceandcombustionairsupplymustnotcontain
corrosive contaminants, such as laundry products,
paints,varnishesorotherchemicals.
Removing the combustion head
assembly
1. Shutofftheburner.
2. Removethefourgasoricespudsfromthemanifold(Figure4).
3. Removethetwohousingcoverlockingscrewsandswingthehousing
open.
4. Removethecombustionheadassemblyandinspectasneeded.
Figure 4 Gas orice location
Gas orifice spuds
(non-directional, 4 total)

MN702GE 060320
– 12 –
2. Pre-re inspection • preparation (continued)
Install gas train on burner
1. Thestandardburnergastrainisshippedfullyassembled,withthepiping
disconnectedatthegastrainunions.Seeseparateinstructionsifinstalling
anoptionalknockeddowngastrain.Thegastrainisavailableineither
anangled(standard)orstraight(optional)conguration.
2. Connectthemaintrainsattheunions(Figure5).
 Toavoiddamagetogastraincomponents,donotholdcompo-
nentswithapipewrenchorovertighten.Useonlyacrescent
wrenchorothermeans.Failuretocomplycouldresultinsevere
personalinjury,deathorsubstantialpropertydamage.
3. Connecttheexibleconduit,pre-attachedtotheburnerJ-box,tothegas
trainJ-box,andattachthewirestotheterminalstripinsidethegastrain
J-box.
a. Matchwirecolorsoftheincomingwirestothosepre-wiredtothe
terminalstripinsidethegastrainJ-box.
b. Seethelabelintheburnerjunctionboxincluded
 Gasvalveventopening—TheV48diaphragmgasvalveis
NOTttedwithaventlimitingoriceintheventconnection.If
localcodesrequire,installpipingfromtheventconnectionto
outside,sizedandinstalledasrequiredbycodes.Becausethis
isadiaphragm-assistedsolenoidvalve,asmallamountofgas
willexitfromtheventoriceeachtimethevalveopens.
Figure 5 Gas train installation (shown with straight gas train)
Connect pilot gas train at union
Connect main gas train at union
Figure 5A Gas piping schematic
GAS FUEL TRAIN
OIL FUEL TRAIN
Gas Input
F A
A
FS P
R
A
M
Test
To Main Burner
To Pilot Burner
J
R1 B S
R2 S C
S
Sediment Trap
Oil Supply
Connection
Oil Return
Connection
U V W Y
HF
LF
FS Fuel Strainer U Oil Pressure Interlock Switch (if required)
HF High FIre Nozzle V Low Fire Safety Shutoff Valve
LF Low FIre Nozzle W High FIre Safety Shutoff Valve
P Fuel Pump Y Fuel Pressure Gauge (if required)
R Mechanical Shutoff Valve
A Manual Valve
B Firing Rate Valve
C Orifice
D Manual Reset Low Gas Pressure Switch (optional)
E Manual Reset High Gas Pressure Switch (optional)
F Gas Filter or Strainer (if required)
J Leakage Test Valve
M Pipe Cap
R1 Main Gas Pressure Regulator
R2 Pilot Gas Pressure Regulator
S Safety Shutoff Valve
D E

MN702GE 060320
– 13 –
3. Install gas piping
Connectfromthegassupplytotheburnergastrain
inletusingnew,cleanblackironpipeandmalleable
ironttingsonly.Donotusecopper,brass,castiron
orgalvanizedpipeorttings.
 Providesupportforgaspiping.Donotresttheweight
ofthegaspipingonburnergastrain.
 Provideasupportfortheburnergastrain.
 Applypipedopesparinglyatalljoints.Useonlypipe
dopelistedforusewithpropanegas.Donotusepipe
sealingtape.
 Donot holdthe gas valvewith pipewrench. Use
crescentwrenchorothersmooth-jaweddevice.Do
notovertighten.
 Failuretocomplywithabovecouldresultinsevere
personalinjury,deathorsubstantialpropertydamage.
 Donot exposethegas traintogas pressurein
excessof14incheswatercolumn.Higherpressure
coulddamagethevalveseat,resultinginpotentially
hazardous condition. When pressure testing piping
athigherpressures,disconnectburnerfromgasline
beforetesting.
 Ifthegassupplypressurecanexceed14incheswater
columnatanytime,youmustinstallalockuptypegas
pressureregulatorinthegassupplypiping,aheadof
themainmanualgasvalveinstalledattheburner.
Figure 5A Connecting gas supply piping to burner
(shown with angled gas train)
Piping from gas meter to burner
1. Verifythegastrainontheburneriscorrectlysized.Thegastrainpres¬sure
dropmustnotbemorethanthegaspressureattheburnergastrainen-
tranceminus3.4"w.c.(pressurerequiredatentrancetobutteryvalve).
SeeFigure6forgastrainpressuredropinformation.Thestandardgas
trainis1inch.
2. Ifpossible,installanewgaslinedirectlyfromthegasmeter.Ifyouare
usinganexistinggasline,verifyitiscleanandingoodcondition,and
verifyitislargeenoughtohandletheloadofallconnectedappliances.
3. Whenbranchingfromacommongasline,donottapofffromthebottom
ofhorizontalsections–onlyfromthesideortop.
4. Installamainmanualshutoffvalve,sedimenttrapandgroundjointunion
neartheburnergastrainconnectionasshowninFigure5A.
5. Iftheburnerisinstalledinsideanappliancejacket,installthemainmanual
gasvalveandsedimenttrapexternaltothejacket.
6. Sizepiping(orverifysize)usingTable3.Youwillndadditionalinforma-
tionongaslinesizingintheNationalFuelGasCode,ANSIZ223.1.
Gassupplypressure–natural gas or propaneMaximumsupplypressure:
14 inchesw.c.
Minimumsupplypressure:5 inches w.c.
Test and purge gas line
ReadWARNINGabove.
Pressuretestandpurgetheline.Pressuretestingshouldbedonebythegas
supplierorutility,followingallapplicablecodes.
1Pipetometerorbranch
2 T-handlemainmanualgasvalve
3 Useclean,burr-freeblackiron
pipeandmalleableironttings
4 Groundjointunion
5 Sedimentleg
6Pressuretap,1/4"(upstream
shown,outletnotshown)
7 Gasregulatoraccessscrew
(theregulatorspringislocated
undertheadjustingscrew)
8 Gastrainwirejunctionbox

MN702GE 060320
– 14 –
NATURAL GAS
Capacities in Cubic feet per hour
for Schedule 40 metal pipe
Pipe size
(inches)
Total length of gas piping,
from meter to burner connection (feet)
20 40 60 80 100
Natural gas @ .60 specific gravity, pressure drop 0.3 in. w.c. (note 1)
1¼ 730 500 400 350 305
1½ 1,100 760 610 530 460
22,100 1,450 1,150 990 870
2½ 3,300 2,300 1,850 1,600 1,400
Natural gas @ .60 specific gravity, pressure drop 0.5 in. w.c. (note 1)
1¼ 950 660 530 460 400
1½ 1,460 990 810 690 620
22,750 1,900 1,520 1,300 1,150
2½ 4,350 3,000 2,400 2,050 1,850
Note 1 For natural gas with specific gravity other than 0.60,
consult National Fuel Gas Code for correction factor.
PROPANE GAS
Capacities in Btuh for
Schedule 40 metal pipe
Propane gas @ 1.5 specific gravity, pressure drop 1 psi
½1,839 1,264 1,015 869 770
¾3,845 2,643 2,122 1,816 1,610
17, 2 4 3 4.978 3,998 3,422 3,033
Propane gas @ 1.5 specific gravity, pressure drop 0.5 in. w.c.
1787 541 434 372 330
1¼ 1,616 1 , 111 892 677 543
1½ 2,422 1.664 1,337 1 , 11 4 1,014
Table 3 Capacities of black iron pipe, cubic feet gas/hour Figure 6 Gas train pressure drop
3. Install gas piping (continued)

MN702GE 060320
– 15 –
Figure 7
702GAS burner wiring
using Honeywell
RM7897C primary
control (see appliance
manual or separate
wiring information for
burner equipped with
a primary control not
covered in this manual);
see Figure 7A for a
legend to callouts.
Turnoffpowertoappliancewhenservicingburner.Failure
tocomplycouldresultinsevere personal injury,deathor
substantialpropertydamage.
Figure 7A Legend for Figure 7
4. Wire the burner — RM7897C primary control

MN702GE 060320
– 16 –
Low-High-Low step modulation
1. Totakeadvantageoftheenergy-savingpotentialoftheModel701GAS
burner,itshouldbewiredtooperateatlow-high-lowcycles.Thering
cyclecanbemuchlongerusinglow-high-lowring,becausetheburner
cancycletolowreasdemanddecreases.Thiskeepstheburneron
longer,reducingcycliclosses.
2. Theappliancemustbeequippedwithahighrecontrol.Thiswouldbea
make-on-fallcontrol,eithertemperature(waterboiler)orpressure(steam
boiler)activated.Readtheappliancemanualforthelocationofthehigh
recontrol,whenused.
3. SeeFigures7and8toconnectthehighrecontroltotheburnerring
ratecircuit.
4. Theburnerincludesapre-wiredmanualhigh-reswitch.Closethisswitch
toholdtheburnerinhighremode.Opentheswitchtoholdtheburner
inlowremode.
4. Wire the burner — RM7897C primary control (continued)
Turnoffpowertoappliancewhenservicingburner.Failure
tocomplycouldresultinsevere personal injury,deathor
substantialpropertydamage.
Figure 8A Legend for Figure 8
Figure 8
702GAS Mass Code
wiring diagram (burners
with RM7897C primary
only); see Figure 8A for
a legend to callouts

MN702GE 060320
– 17 –
5. Checkout procedure — before starting the burner
 Followtheproceduresonthefollowingpagestoensuretheburneriscorrectlyadjusted.
 Youmustperformtheadjustmentsinthesequencegiveninthismanual.
 Failuretofollowthecorrectprocedurescouldresultinseverepersonalinjury,deathorsubstantialpropertydamage.
Before firing the burner . . .
 Shouldoverheatingoranemergencyoccur,immediately
dothefollowing:
 • Shutoffgassupplyvalves.
 • Undersomecircumstancespowershouldremainonfor
waterpumpsorblowers.Determineproperresponse
beforeattemptingstart-up.
 • Ifburnerfailsignitiononseveralattempts,useburner
blowertopurgeappliancechamberbeforerestart.
 Ifburnerisrunningonnaturalgasonly,couplingmustbe
removed.
Checklist before firing . . .
❏Burnerand applianceinstalledper thismanual and appliance
instructionmanual?
❏Burner/applianceinstalledperallapplicablecodes?
❏Installationsitehasadequatecombustion/ventilationairopenings
andventsystem?
❏Arevoltagescorrect?Burner,applianceandmotorcorrectlywired
perburnerandappliancemanualsandwiringdiagrams?
❏Gasmanifoldspudoricessealedwithpipedopeandtight?
❏Gaslinesingoodcondition,sizedanddesignedcorrectly?
❏Gaslineconnectionsandttingstight?
❏Burner, appliance and all components inspected and in good
condition?
❏Appliancelimitandoperatingcontrolsproperlyinstalled,wiredand
adjusted?
❏Boilerwatersupply,feedpumps,automaticfeeders,andlowwater
cut-offsproperlypipedandwired?
❏Breeching,draft regulator, draftinducer(if required)properlyin-
stalledandoperational?
❏Gastrain pipingand components correctly installed, testedand
veriedgastight?
❏Ventlinesinstalledwhenrequired?
❏Gaslinespurged?
❏Sufcientgaslinepressurepresent?
Figure 9 Set initial combustion head position
6. Set burner initial head and damper positions
Before firing the burner . . .
Set combustion head (Dimension “A”)
1. Thecombustionheadadjustingscrewisusedtosetthespacingbetween
theretentionringandthrottlering(oraircone),regulatinghowmuchair
passesaroundtheretentionring.
2. SeeFigure9.Loosenthetwohousingcoverscrews.Thenrotate the
headadjustingscrewuntilthedistancefromthehousingdetenttothe
beginningofthescaleorscribedlineoncombustionheadequalsthe
valuegiveninTable5(Dimension“A”).Tightenthehousingcoverscrews.

MN702GE 060320
– 18 –
Set air damper (low fire position)
SeeFigure10.Adjustthebluecamondampermotoruntiltheairopening
betweenthedamperbladeandthedamperhousingequalstheinitiallow-re
openinginTable5.
Set air damper linkage
MakesureAirDamperLinkageissetat¾"fromthetopoftheDamperMotor
andthebottomofthelinkagescrew(seeFigure10A).Ifyoursettingsareoff,
loosenthetwohexheadscrewsfoundonthelinkagearmbossesatthetop
andbottomoftheAirDamperLinkage.Adjustthelinkageaccordingly,then
tightenscrewstosetposition.
Figure 10 Set initial low re air damper setting
Figure 10A Set air damper linkage
Table 5 Initial burner settings (see the pages 18 through 22 for nal adjustments using test instruments)
6. Set burner initial head and damper positions (continued)
3/4"
Determining final adjustments
Theburnerisnowadjustedtotheapproximateairsettingsfortheringrate
used.Followtheproceduresonthefollowingpagestouse test instruments
andmakenalburneradjustments.
Natural Gas MBH Combustion head
position
Dimension “A”
Inches (approximately)
Air damper low-fire
opening
Inches (approximately)
Siemens
Blue Cam
Setting
Butterfly valve
open – low fire
(factory set)
% (approximately)
Low-fire
Input
High-Fire
Input
490 840 0 3/8 25 30
525 910 1/16 3/8 25 30
560 966 1/8 7/16 27 30
630 1092 3/16 7/16 27 30
700 1218 3/8 1/2 30 30
770 1330 5/8 1/2 30 30
840 1456 1-1/8 9/16 35 30
910 1568 1-3/8 9/16 35 30

MN702GE 060320
– 19 –
Adjustment procedure, summary
Step 1: Setgaspilotoperation.Seedetailsfollowing.
Step 2 Sethigh-regasowtomatchhigh-reair.Seedetailsfollowing.
Step 3 Adjustthebutteryvalvelinkagetomatchlow-regastolow-re
air.Seedetailsfollowing.
Step 4: Verifyoperationofburner,appliance,andcontrols.
Use test instruments
1. Usecombustion test equipmentandan accurate manometerordraft
gaugetocorrectlysettheburnerasrequired.
2. Overrepressuremustnotexceedtheappliancemanufacturer’srecom-
mendations.Theburnermustneverberedatanoverrepressuremore
than0.60inchesw.c.
 Whentheoverrepressureispositive,themaximumburner
ringrate isreduced.The ringrateis alsoreduced for
altitudeshigherthan2000feetabovesealevel.Seepage3
forratinginformation.
3. Adjusttheburnerfuelandairsettingsusingthefollowingprocedures.
Whenadjustmenthasbeencompleted,theCO2(orO2)shouldbewithin
therangesinTable6,atbothlowreandhighre.
Table 6 Allowable values of CO2and O2
Fuel
CO 2 O 2
Minimum Maximum Maximum Minimum
Natural Gas 8.5 % 10.0 % 6.2 % 3.6 %
Propane 9.5 % 11.2 % 6.0 % 3.5 %
7. Adjust the burner using test instruments
ThesettingsgiveninSection6areinitialsettingsonly.You must use test instrumentstocheckcombustion,andadjusttheburner
asnecessary,followingtheproceduresgiveninthefollowingpagesofthismanual.Failuretoproperlyadjusttheburnercanresultin
severepersonalinjury,deathorsubstantialpropertydamage.

MN702GE 060320
– 20 –
Step 1
Check gas pilot operation
TheModel702GASusesagaspilotforignitionofthegas
mainame.Thegaspilotisignitedbythepilotelectrode.The
butterygasvalveisfactorysettoapreliminarysettingof30%
openforlowre,and100%openforhighre.
1. Makesurethegaslinehasbeencompletelybled.Thenturntheservice
switchtoON.
2. Thepilotwillusuallylightthersttimeoncethepilotgastrainhasbeen
completelypurgedofair.
3. Thepilotameisapproximately70MBH.Ifthepilotfailstolight,besure
thegaslinehasbeenbledproperly.Iftheprimarycontrolisequipped
withapilottestholdswitch,itcanbeusedtoholdthepilot“on”while
adjustingpilotgaspressure.
4. Followtheinstructionsintheprimarycontrolinstructionmanualtocheck
amesignal.Makesuretheamesignalissteady,andgreaterthanthe
requiredminimumfortheUVsensor.
5. Check and ensurethat the bentignitor (Figure11) isapproximately
centeredinpilotassembly.
6. Tocheckstaticpressureonpilotair,drilla#60holeinthepilotairtube
(redcircle,Figure12)anduseamanometerforthereading.Pressure
mustbemorethan.45”w.c.
Step 2 (ring on gas)
Set main gas pressure regulator
Thebutterygasvalveisfactorysettoapreliminarysettingof
30%openforlowre,and100%openforhighre.Thepilot
regulatorissetfor3.0inchesw.c.Usemanometerinthepilot
testport(Figure12)providedtoconrmsettings.
1. Leavethelow-reswitchinlowre.
2. Withthegaspilotoperatingcorrectly,andtheUVsensoramesignal
aboveminimum required,the primarycontrol will cyclethe burnerto
maingas.
7. Adjust the burner using test instruments (continued)
Checkalljointswithasoapsudsmixtureorelectronic
gasleakdetectortoensurethegastrainandallcompo-
nentsaretightandleak-free.Shutdowntheburnerand
correctanyleakimmediately.Failuretocomplycould
resultinseverepersonalinjury,deathorsubstantial
propertydamage.
3. Checktheamesignalafterthepilothasshutdowntoensurethesignal
isstillstrongwithmainameon.
4. MovetheburnerfuelselectorswitchtoOFF.Theburnerwillshutdown.
5. TemporarilyinstalltwoU-tubemanometerconnectionstocheckgaspres-
sures.Installconnectionsattheinletpressuretapofthemainmanual
gasvalveandatthedownstreampressuretapofthemanualgasvalve
nexttothebutteryvalve.
6. The gas pressureat the inletto thegastrain mustneverexceed
14inchesw.c.,eitherwhentheburnerisofforringongas.
7. MovetheburnerfuelselectorswitchtoGAS.Theburnershouldstart.
8. Withtheburnerringinlowre,checkthegaspressureatthedownstream
ofthebutteryvalve.Adjustthemaingaspressureregulatorifnecessary
untilthegaspressurereads1.0inchw.c.asastartingpressure.
9. Switchthelow-reswitchtohighre.CAUTION:Bepreparedtoturn
theburneroffimmediatelyifitbeginstopulsateasitattemptstomove
tohighre.
10. Iftheamepulsates,itisprobablytoorich.Switchthelow-reswitchto
lowreandreducethegaspressurebyadjustingthemaingaspressure
regulator.Thenreturnto9,above.
11. Ifthereistoolean,itwillappearsmallandcanevenblowoutduringthe
swingtohighre.Ifitblowsout,shutofftheburnerimmediately.Switch
thelow-reswitchtolowreandstarttheburneragain.Adjustthemain
gaspressureregulatortoincreasethegaspressure.Returnto9,above.
Withtheburnerrunninginhigh re,inspectthebuttey
valveindicator(Figure13).Theindicatormustbeat90°.
IFNOT,turn theburner off. Loosenthe two hex-head
screwssecuringthevalvelinkagearm.Withthedamper
motorlinkagearmpulledup,useascrewdrivertorotatethe
butteryvalveslotuntilitishorizontal.Tightenthetwohex
headscrewswhilestillholdingthedampermotorlinkage
armup.Returntostep9,above.DONOTproceedwith
combustionadjustmentunlessthebutteryvalveposition
hasbeenveried,andcorrectedifnecessary.
Figure 12 Pilot Test Port
Figure 11 Pilot Spark Gap
3/32"-1/8"