EngA DJM3

A DJM3
IOM-17 15 of 27 Mar 99 R3
LOWLIMIT
Thelowlimitsetpointisfixedat40°F.Therearetwolowlimitbypasstimers,start‐upandanti‐noise.
Thestart‐upautobypasslowlimittimerisstartedeverytimeterminal“K”,“SA”or“FS”energized
statuschanges(on/off).Thestart‐uptimerwillbypassthelowlimitfor5minutes.Afterthe5minute
startupbypass,a30‐secondanti‐noiselowlimitbypasstimerisstartedeverytimealowlimit
conditionisdetected.Thistimerisdesignedtopreventnuisancetripscausedbyanyelectricalnoise
pickedupbythedischargesensor.Ifthelowlimitconditionexistsformorethan30seconds,alow
limitlockoutwilloccur.ThiswillactivatethealarmcontactontheDJM3,terminal“AL”.
ResettingLowLimit
Toresetthelowlimit,cyclepowertotheDJM3controlterminals"T1"and/or"T2";orinterruptpower
toterminals"FS,HS,andK"allatthesametime.
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SERVICE
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SERVICEMODE
PlacingtheDJM3intoservicemodeallowsfordirectcontroloftheburnerfiringrate.DIPswitch5will
activateservicemodeandenabletheheatimmediately.TheservicePOT,locatedtotherightofthe
setpointdial,willmanuallysettheburnertoanyfiringrate.Wheninservicemode,thesupplyairfan
mayneedtobeactivatedmanually.
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Note:DONOTleaveDJM3inservicemode,burnerwillnotcycleoff.Servicemodeshouldonlybeused
forcombustionset‐upandoperationalchecks.
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BURNERSETUP
ServicePot
Thispotisdesignedtoallowaservicetechniciantomanuallysettheburnertoanyfiringratehe
chooses.Iftheserviceswitch(dipswitch5)isonandtheblowerswitch(terminalFS)ispowered,the
burnerfiringrateiscontrolledbytheServicePot.TheServicePotislocatedclosetothe“+"terminal
andabovethedipswitches.Rotatingthispotwillallowthefiringratetobesetatanyratebetweenlow
andhighfire.
LowFirePot
ThelowfirepotislocatedbelowthePV1terminal.Thelowfirepotisusedtoadjustthecombustionair
atlowfire.Thelowfirespeedisadjustablefrom1150to1400RPM(highturndown)or1800to2000
(standardburner).Thelowfirepotistobeadjustedbyaqualifiedservicetechnicianonly.
CurveMatchingPot
ThecurvematchingpotislocatedbelowtheCSterminal.TheDJM3canbeusedwithseveraldifferent
Maxitrolvalves.Eachofthesevalveshasaslightlydifferentopeningcurve.TheCurveMatchingPotis
tobeadjustedbyaqualifiedservicetechnicianonly.