Owner`s manual

30816-3-0113 Page 9
3. AddtheBTU/Hrofallfuelburningappliancesinthespace.
Vent-free heater
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: Ventedgasheater 20,000 BTU/Hr
  Vent-freeheater + 18,000 BTU/Hr
Total = 38,000 BTU/Hr
*Donotincludedirect-vent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:
  25,600 BTU/Hr(maximumthespacecansupport)
38,000 BTU/Hr (actual amount of BTU/Hr used)
WARNING
Iftheareainwhichtheheatermaybeoperatedissmallerthanthat
denedasanunconnedspaceorifthebuildingisofunusually
tightconstruction,provideadequatecombustionandventilation
airbyoneofthemethodsdescribedintheNational Fuel Gas
Code,ANSIZ223.1/NFPA54,AirforCombustionandVentilation,
orapplicablelocalcodes.
Thespaceintheaboveexampleisaconnedspacebecausethe
actualBTU/HrusedismorethanthemaximumBTU/HRthespace
can support. You must provide additional fresh air. Your options
are as follows:
A. Reworkworksheet,addingthespaceofanadjoiningroom.If
theextraspaceprovidesanunconnedspace,removedoor
toadjoiningroomoraddventilationgrillsbetweenrooms.See
Ventilation Air From Inside Building.
B. Vent room directly to the outdoors. See Ventilation Air From
Outdoors.
C. InstallalowerBTU/Hrheater,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

space.
Thisheater shallnotbe installedina connedspaceor unusu-
allytightconstructionunlessprovisionsareprovidedforadequate
combustionandventilationair.
Aconnedspaceisanareawithvolumelessthan50cubicfeetper
1,000Btuhofthecombinedinputratesofallappliancesdrawing
combustionairfromthatspace.Smallareassuchasequipment
roomsareconnedspaces.Furnacesinstalledinaconnedspace
which supply heated air to areas outside the space must draw return
air from outside the space through tightly sealed return air ducts. A
connedspacemusthave2openingsintothespaceforcombus-
tionair.Oneopeningmustbewithin12inchesoftheceilingand
theothermustbewithin12inchesoftheoor.Therequiredsizing
oftheseopeningsisdeterminedbywhetherinsideoroutsideairis
usedtosupportcombustion,themethodbywhichtheairisbrought
tothespace(verticalorhorizontalduct)andbythetotalinputrate
of all appliances in the space.
Unusually Tight Construction
Theairthatleaksarounddoorsandwindowsmayprovideenough
freshairforcombustionandventilation.However,inbuildingsof
unusually tight construction, you must provide additional fresh air.
      
where:
a. Wallsandceilingsexposedtotheoutsideatmospherehave
a continuous water vapor retarder with a rating of one perm
orlesswithopeningsgasketedorsealed,and
b. Weatherstrippinghasbeenaddedonopenablewindowsand
doors, and
c. Caulking or sealants are applied to areas such as joints
aroundwindowanddoorframes,betweensoleplatesand
oors,betweenwall-ceilingjoints,betweenwallpanels,at
penetrationsforplumbing,electrical,andgaslines,andat
other openings.
 Ifyourhomemeetsallofthethreecriteriaabove,youmustprovide
additional fresh air. See “Ventilation Air From Outdoors,” page
10.

Usethisworksheettodetermineifyouhaveaconnedorunconned
space.
Space: Includes the room in which you will install heater plus any
adjoining rooms with doorless passageways or ventilation grills
betweentherooms.
1.Determinethevolumeofthespace(lengthxwidthxheight).
 LengthxWidthxHeight=
cu. ft. (volume of
space)
Example:Spacesize16ft.(length)x10ft.(width)x8ft.(ceiling
height) = 1,280 cu. ft. (volume of space)
If additional 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 cubic feet to determine the
maximumBTU/Hrthespacecansupport.
(volumeofspace)÷50cu. ft. = (maximum
BTU/Hr the space can support)
Example:1,280cu.ft.(volumeofspace)÷50cu.ft.=25.6or
25,600(maximumBTU/Hrthespacecansupport)
PROVISIONS FOR ADEQUATE COMBUSTION & VENTILATION AIR