EngA DJM3

A DJM3
IOM-17 19 of 27 Mar 99 R3
2. Bringvoltagetogasvalveat2.25VDCandadjustthespringactivatedlowfireadjustment
located in thehead with the electric modulator(smaller screw under cap) to achieve the
sameO
2
readingastheoneachievedat0VDC(16.8%to17.5%O
2
).Afterthisiscomplete
thenadjusttheCurveMatchingpotasdescribedinpoint5above.
PilotSetUp(HighTurndownBurner)
1. Onhighturndownunits,ensureairtubetopilotisfreeofdebrisandblockagesandthenset
pilotpressureto3.5"WC.
2. Pilotsetupisnotascriticalonthehighturndownburnerasthereisnotasmuchheatonit
asontheregularburner.
Standard(Round)Burner
MoststandardturndownDJunitswillemployoneofthefollowingMaxitrolmodulatingDCvoltgas
valves.
Series20M520,M620 Thesevalvesdonothavehighfireregulators.Highfire
pressureissetupattheapplianceregulator.Ifusedonthe
standardburner,thelowfireadjustmentlocatedonthe
bottomsideofthevalveistobeadjustedfullyclockwise
(nobypass).

Series50M550,M650,ES350 Thesevalvesdonothavehighfireregulators.Highfire
pressureissetupattheapplianceregulator.Thisseriesof
valvehasbeenreplacedwiththeM520/620series.

ES345D‐LThisvalvehasabuiltinhighfireregulator.

HighFireSetUp
1. Turnontheserviceswitch(dipswitch5).
2. SetmanualfiringPotHiService(locatednexttothe+terminal)tohighfire.Adjustthehigh
fireinputtothecorrectclockedrate.Adjustthecombustionairsliderorinletdamperuntil
thehighfireO
2
readingisbetween3.5and4.2%.

LowFireSetUp
Lowfireblowerinputis40%ofhighfireblowerinput.
Thelowfireproceduresetupissimilartothatforthehighturndownburnersnotedabove.The
differenceisthemaximumallowableCOatlowfireis200PPM.ThelowfireO
2
readingshould
bebetween10.9%to11.3%.Thecombustionsliderisdifferentthanthehighturndownslider.It
isaplatethatslidesbetweenthebloweroutletandtheburnerbox.ThelowfireRPMis
adjustedusingLowFirePotto185010RPM(30.5Hz).
Aftersettingupthelowfire,adjustthecurvematchingpotasdescribedinpoint5above.
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