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XIII Troubleshooting

Thefollowingpagescontaintroubleshootingchartsforuseindiagnosingcontrolproblems.Tousethesecharts,goto

theboxmarked“Start”atthetopofthechartonpage34or36andfollowtheappropriatepaththoughthechartuntila

boxwithalistofpossiblecausesisreached.Iftheproblemisknowntobewithintheignitionsystem,godirectlytothe

appropriatetroubleshootingguidefortheboiler.Inusingthesecharts,thefollowingshouldbekeptinmind:

1) Thesechartsareonlymeanttobeusedbyaprofessionalheatingtechnicianasanaidindiagnosingcontrolprob-

lems.

leastlikelycause.Beforereplacingacomponent,trytoruleoutallotherpossiblecauses.

5) Thesetroubleshootingchartsassumethattheventdamperisclosedatthebeginningofthetroubleshootingprocess.

Withthe120voltsappliedtotheboilerandnocallforheat,thedampershouldgototheclosedposition.Ifitdoes

not,dothefollowing:

• Conrmthat120voltsisappliedtotheboilerandthatthereisnocallforheat.

• Makesurethattheswitchonthedamperisinthe“automatic”position.

• Unplugtheharnessfromthedamperandcheckfor24voltsacrosspin#1(blue)andpin#4(yellow).

• Ifvoltageispresent,thedamperisdefectiveorthereisanobstructioninthepathofthedamperblade.

• Ifnovoltageispresent,thereiseitheralooseconnectioninthedamperharnessorthelimitcontrol(L8148E

orL8124E)isdefective.

present,makesurethatthebrassjumperispresentbetweenWandZandthatthescrewsholdingthisjumper

inplacearebothtight.IftheboilerisequippedwithaL8124E,voltagewillonlybepresentacrossTandW

whenthereisacallforheatANDtheboilerwatertemperaturehighenoughtosatisfythelowlimit.

• Ifnotalreadydone,temporarilyreplacethethermostatacrossTVandTwithajumper.Iftheboilerreswhen

thisisdone,thereisaproblemwiththethermostatorzonewiring.

• If24voltsispresentacrossTandWandtherelayintheL8148EorL8124Edoesnotpullin,therelayinthis

controlisprobablydefective.Inspectthecoilofthisrelayforvisibleheatdamage.Ifsuchdamageisfound,

thereisagoodchancethatasecondtransformerispresentinthethermostatorzonevalvecircuit,resultingin

theapplicationof48voltsacrosstherelaycoil.Inolderbuildings,thistransformermaybehiddeninaloca-

tionfarfromtheboiler.Ifthissecondtransformerexists,itmustbefoundandremovedbeforetheL8148Eor

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Caution: Read page 33 before

attempting to use this chart