Fluegasspillage

\'ENTTNG PlOBLEMS

TROUBLE SHOOTING

Mostventingproblemsarecausedbyincorrect ventsizing,improperinstallation,or inadequate air supply.A preliminarycheck for a field problemmightinclude:

. Usinga draftmeterto determineif venting systemdraftmeetsmanufacturer'sspecifica- tions.

rCheckingthe vent sizing accordingto manufacturer'sspecifications,appliance input,andventingconfiguration.

rExaminingthe entireventingsystemfor faults such as disconnectedjoints or damagedventsections.

oMakingsureventandairopeningsarenot obstructed.

lf theseproceduresdo not revealthe source of the problem,troubleshootingmayinclude attentionto common venting problems discussedbelow.

Spillageoccurswhenflue gasescannotexit theventsystemandbackupintothedwelling.

Aprimarysymptomof appliancesequipped with a VentSafetyShutoffSystem(fluespill switch)is unexplainedapplianceshutoffs. Othersymptomsoffluegasspillageatthedraft hood include cendensationon walls and windowsand/ornoticeableodoursBut.spillage may also result in the releaseof carbon monoxide,a colourless,odourless,highlytoxic gas.A simplespillagetestcanbe conducted if spillageis suspected;seeownersmanual.

CAUSESOF SPILLAGEAND CORRECTIVEACTION

IncorrectVentSizing(H)

lf theventistoosmallortooshort,spillagemay occur.lf theventistoolarge,excessivedilution air may cool flue gasesand reducedraft, causingspillageThe.ventcapsizeshouldalso be checked.Checkmanufacturer'sinstruc- tions,applianceinputrating,andappropriate sizingtables.

Venting Condltion

Loosejointscanaffectdraftandcausespillage. Mashed-inventsectionsand damagedvent caps can restrictflow and causespillage. Examineand replaceas needed.

Obsfructions

Smallanimalsor birdsmaygetintoandblock the ventor drafthoodoutlet.Dust,lint,and foreignobjectsmayobstructairinletsRemove. obstructionsand cleanoPenings.

LateralRun (L)

Lengthyhorizontalor non-verticalrunscause resistancetoflowandmayreducedraftenough tocausespillageThe. pitchof lateralrunscan also be a problem;lateralruns shouldbe pitched114"riseperfootof horizontalrunfrom

the applianceto the vent.

Elbows

Toomanyelbowscauseexcessiverestriction of flowand mayresultin spillageUsually,.two 90 degreeturnscanbetoleratedin a properly sizedventingsystemMore.thantwo may-- causeproblemsandnecessitatechangingthe system.

Negativepressure in the Dwelling

An extremellytight house may not supply adequatecombustionandventingair.Useof mechanicalexhaustsuchas a dryerventor rangeventmayworsenthe problemAn. air exchangesystemmustbeinstalledInthedwell' ing to correctthis Problem.

Flue Gas Cooling

Venting exposed to extremelY cold temperaturesorventingofsinglewallconstruc- tion lose heat needed to maintaindraft;

massivemasonrychimneysabsorbneeded heat.lf the flue gasescool excessively,draft isreducedandspillagemayresultUse.proper materials,insulateandprotectproperly'reline

when necessary.

Down Drafts

tn certainwind conditionsand in certain relationshipswith nearby structuresand objects,high pressureconditionsrnayatfect

draftnegativelyRelocate. the ventcap, raise itsheighl,or usean approvedhighwindcap.

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