Harman® • PF-120 Installation Manual_R1 • 2014 -___ • 03/1414
3-90-08121i
F. Avoiding Smoke and Odors
Negative Pressure, Shut-down, and Power Failure:
To reduce the probability of back-drafting or burn-back in
the pellet burning appliance during power failure or shut-
down conditions, the stove must be able to draft naturally
withoutexhaustbloweroperation.Negativepressureinthe
buildingwillresistthisnaturaldraftifnotaccountedforinthe
pelletapplianceinstallation.
Heatrisesandleaksoutatupperlevels.Thisairmustbe
replacedwithcoldairfromoutdoors,whichowsintolower
levelsofthebuilding.
Vent Pipe
Besure to use approved pelletventpipe wall and ceiling
pass-throughttingstogothroughcombustiblewallsand
ceilings.Besuretouseastartingcollartoattachtheventing
systemtothefurnace.Thestartingcollarmustbesecured
totheuestubwithatleastthreescrews,andsealedwith
hightempsiliconecaulking.
Pelletventingpipe(alsoknownasPLvent)isconstructed
of two layers with air space between the layers. This air
spaceactsasaninsulatorandreducestheoutsidesurface
temperaturetoallowaclearancetocombustiblesofonly1
inches.Thesectionsofpipelocktogethertoformanairtight
sealinmostcases;however,insomecasesaperfectseal
isnotachieved.ForthisreasonandthefactthatthePF-120
operateswithapositiveventpressure,wespecifythatthe
jointsalsobesealedwithsilicone.
Wherepassingthroughanexteriorwallorroof,besuretouse
theappropriatepass-throughdeviceprovidinganadequate
vaporbarrier.Ventingmanufacturersgenerallyprovidethese
pas-throughdevices.
D. Draft
Draftisthepressuredifferenceneededtoventappliances
successfully.Whenanapplianceisdraftingsuccessfully,all
combustionbyproductsareexitingthroughthechimney.
Considerationsforsuccessfuldraftinclude:
• Preventingnegativepressure
• Locationofapplianceandchimney
Tomeasurethedraftornegativepressureonyourappliance
use a magnahelic or a digital pressure gauge capable of
reading0-1inchesofwatercolumn(W.C.).
The appliance should be running on high for at least 30
minutesforthetestofhighburndraft.
Withthefurnacerunningonhighyoushouldhaveanegative
pressureequaltoorgreaterthanthenumbergiveninthe
chartbelow.Ifyouhavealowerreadingthanyoundonthe
chart,yourappliancedoesnothaveadequatedrafttoburn
thefuelproperly.
Colddrafttestshouldbedonepriortolightingunit.Minimum
shouldbe:
Minimum Vacuum Requirements: .35
INSPECT FLUE PIPES, FLUE PIPE JOINTS, AND
FLUE PIPE SEALS REGULARLY TO ENSURE THAT
SMOKE AND FLUE GASES ARE NOT DRAWN INTO,
AND CIRCULATED BY, THE AIR-CIRCULATION
SYSTEM.
WARNING
E. Negative Pressure
Negativepressureresultsfromtheimbalanceofairavailable
fortheappliancetooperateproperly.Itcanbestrongestin
lowerlevelsofthehouse.
Causesinclude:
• Combustionairrequirementsforfurnaces,waterheaters
andothercombustionappliances
•
Locationofreturn-airventstofurnaceorairconditioning
• ImbalancesoftheHVACairhandlingsystem
• Upperlevelairleakssuchas:
- Recessedlighting
Tominimizetheeffectsofnegativeairpressure:
• Installtheoutsideairkitwiththeintakefacingprevailing
windsduringtheheatingseason
• Ensureadequateoutdoorairforallcombustionappliances
andexhaustequipment
Risk of Asphyxiation!
Negative pressure can cause
spillageofcombustionfumesandsoot.
WARNING
• Ensurefurnaceandairconditioningreturnventsarenot
locatedintheimmediatevicinityoftheappliance
• Avoidinstallingtheapplianceneardoors,walkwaysor
smallisolatedspaces
• Recessedlightingshouldbea“sealedcan”design
• Attichatchesweatherstrippedorsealed
• Atticmountedductworkandairhandlerjointsandseams
tapedorsealed
NOTICE: Hearth & Home Technologies assumes no
responsibilityfortheimproperperformanceofthechimney
systemcausedby:
• Inadequatedraftduetoenvironmentalconditions
• Downdrafts
• Tightsealingconstructionofthestructure
• Mechanicalexhaustingdevices