Install Instructions

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Method2:DirectConnectiontoHeatingSystem(GenerallyNOTRecommended)
 TheFCMcanbeconnecteddirectlytotheheatingsystemasisdonewithconventionalboilers(Figure9.8).If 
thisisdone,theowratethroughtheboilerwillequaltheowratethroughthesystem.Theowratethroughthe
systemmustthereforealwaysremainwithinthelimitsshowninTable9.1.Forthisreason,thepressuredropthrough
theentiresystemmustbeknown,addedtotheboilerpressuredrop,andacirculatorselectedwhichwillprovidethe
requiredowatthetotalcalculatedpressuredrop.
 Thismethodisgenerallynotrecommendedbecauseitisoftenverydifculttoaccuratelycalculatethepressure
dropthroughthesystem.Inreplacementinstallations,itmaybeimpossibletogetanaccuratemeasurementofthe
amountofpipingandnumberofttingsinthesystem.Inaddition,ifthesystemiszoned,thesystemowmaydrop
wellbelowtheminimumrequiredwhenonlyonezoneiscallingforheat.
 Theoneadvantagetothismethodisitsinstallationsimplicity.Itmaymakesensetousethismethodwhenthe 
boileristobeinstalledwithanewsinglezonesystemhavingalow-pressuredrop.Pressuredropcurvesforthe
FCMSeriesboilersareshowninFigure9.9.Calculationofthesystempressuredrop,andselectionofthe 
circulator,mustbeperformedbysomeonehavingfamiliaritywithpressuredropcalculations,suchasanHVAC
engineer.
Figure 9.8: Piping Method #2 - Direct Connection of Boiler to Heating System