FMI MM39/44/49VF Outdoor Fireplace User Manual


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11
Unconned Space
An unconned spacehas a minimum total airvolume of
50cu.ft.(cubic feet)for each1,000 Btu/Hrinputratingofall
appliancesinthetotalspace(cu.ft.=lengthxwidthxheight
ofspace).Include adjoiningroomsonlyif thereare doorless
passagewaysorventilationgrillsbetweentherooms.IftheBtu
per 50cu.ft.is lessthan 1,000Btu/Hr, thenfreshair willbe
providedbythenaturalairowintothehouse.
Conned Space
Aconnedspacehasanairvolumeoflessthan50cu.ft.for
each1,000Btu/Hrinputratingofallappliancesinthespace(cu.
ft.=lengthxwidthxheightofspace).Includeadjoiningrooms
only if there are door less passageways or ventilation grills
betweentherooms.
Determining Total Air Volume
Use thisworksheet todetermine ifyou havea conned
orunconnedspace.Thespacetobeconsideredincludesnot
onlytheroominwhichyouwillinstallthereplacebutalsoany
adjoining rooms with ventilation grills between them or door
lesspassageways.
1. Determinethetotalvolumeofyourspace
LxWxH=_______cu.ft.
Example:Spacesize=20ft.longx20ft.widex8ft.high
(ceilingheight)=3,200cu.ft.
If adjoining ventilation to adjoining room is supplied with
grillsoropenings,addthevolumeoftheseroomstothetotal
volumeofthespace.
2. Divide the space volume by 50 cu.ft. to determine the
maximumBtu/Hrthespacecansupport.
_______cu.ft.(volumeofspace)
50cuft.=(MaximumBtu/Hrthespacecansupport)
Example:3200cuft.(Volumeofspace)/50cu.Ft.=64.0or
64,000(maximumBtu/Hrthespacecansupport.)
3. AddtheBtu/Hrofallfuelburningappliancesinthespace.
Vent-freereplace _______ Btu/hr
Gaswaterheater*  _______ Btu/hr
Gasfurnace  _______ Btu/hr
Ventedgasheater _______ Btu/hr
Gasreplacelogs  _______ Btu/hr
Othergasappliances*  _______ Btu/hr
Total=  _______ Btu/hr
Example: Gaswaterheater40,000Btu/hr
Vent-freereplace+36,000Btu/hr
Total=76,000Btu/hr
*Donotincludedirect-ventedgasappliances.Directventdraws
combustionairfromtheoutdoorsandventstotheoutdoors.
4. ComparethemaximumBtu/Hrthespacecansupportwith
theactualamountofBtu/Hrused.
_________Btu/Hr(maximumthespacecansupport)
_________Btu/Hr(actualamountofBtu/Hrused)
Example:
64,000Btu/Hr(maximumthespacecansupport)
76,000Btu/Hr(actualamountofBtu/Hrused)
Thespaceinthepreviousexamplewasaconnedspace
becausetheactualBtu/Hrusedwasmorethanthemaximum
Btu/Hrthespacecouldsupport.IfyoundyouhaveaConned
Space,youmustprovideadditionalfreshair.Youroptionsare
asfollows:
a)Re-workworksheet,addingthespaceofanadjoiningroom
thatmaynothavequaliedfortheextravolume.Iftheextra
spaceprovidesenough volumetoconvertthe areato an
unconnedspace, removedoortoadjoining roomoradd
ventilationgrillsbetweenrooms.
b)Ventroomdirectlytotheoutdoors.
c)Install alowerBtu/Hr gaslog(iflower Btu/Hrsizemakes
roomunconned).
IftheactualBtu/HrusedislessthanthemaximumBtu/Hrthe
spacecansupport,thespaceisanunconnedspace.Youwill
neednoadditionalfreshairventilation.
WARNING:Ifthe areain whichtheheatermay beoperated
issmallerthanthatdenedasanunconnedspace,provide
adequatecombustionandventilationairbyoneofthemethods
describedintheNationalFuelGasCode,ANSIZ223.1Section
5.3orapplicablelocalcodes.
Local codesmay havestricter denitionsfor connedspace
and/or forunusually tightconstruction. Installingour optional
outsideairkitmayallowthespacetobeclassiedasnotbeing
unusuallytightorbeinganunconnedspace.Checkyoulocal
codes.
IMPORTANT: Do not provide openings for inlet or outlet air
intoanatticiftheattichasathermostat-controlledpowervent.
Heatedairenteringtheatticwillactivatethepowervent.
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