Heatilator CONSTITUTION C-40 - Section 2: Getting Started; Design and Installation Considerations; Negative Pressure

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Heatilator • Constitution EPA Fireplace • 480-1091C
November 11, 2008
2
Getting Started
A. Design and Installation Considerations
Draft is the pressure difference needed to vent replaces
successfully.Considerationsforsuccessfuldraftinclude:
• Preventing negative pressure
• Locationofreplaceandchimney
B. Negative Pressure
Negative pressure results from the imbalance of air avail-
able for the replace to operate properly. Causes for this
imbalanceinclude:
• Exhaust fans (kitchen, bath, etc.).
• Range hoods.
• Combustion air requirements for furnaces, water heaters
and other combustion appliances.
• Clothes dryers.
• Locatio n of retur n-air vents to furn ace or air
conditioning.
• Imbalances of the HVAC air handling system.
Asphyxiation Risk
Negative pressure can cause spillage of
combustion fumes and soot. Fire needs to draft
properly for safe operation.
WARNING
Check building codes prior to installation.
• Installation MUST comply with local, regional,
state and national codes and regulations.
• Consult insurance carrier, local building inspector,
reofcialsorauthoritieshavingjurisdictionabout
restrictions, installation inspection and permits.
CAUTION
Whenplanningareplaceinstallation,itisnecessarytode-
termine the following information beforeinstalling:
• Where the fireplace is to be installed. See Sections
3 and 4.
• Theventsystemcongurationtobeused.SeeSections
5 and 6.
• Electrical wiring. See Section 3.
• Framingandnishingdetails.SeeSections3,6and8.
• Whether optional accessories are desired. See
Section 12.
TheConstitutionFireplacerequiresaminimumuedraftof
-0.10 inches of water column on High, and -0.04 inches of
watercolumnonLow,asmeasuredwithadraftmeter.Most
dealershavedraftmetersavailabletomeasureyouruedraft
if you suspect a problem.
Ifthereisdifculttostart,andsmokespillsoutofthedoor,
or you nd ithard to establish and maintaina moderately
highburnrate,thentheuedraftistoolowandcorrective
measures must be taken.
NOTE: Cold air inltration can cause frosting on glass.
• Upper level air leaks: recessed lighting, attic hatch
opening, duct leaks.
To minimize the effects of negative air pressure, the follow-
ingmustbeconsidered:
• Install the outside air kit.
• Ensure adequate outdoor air is supplied for combustion
appliances and exhaust equipment.
• Ensure furnace and air conditioning return vents are not
locatedintheimmediatevicinityofthereplace.
• Avoidinstallingthereplaceneardoors,walkwaysorsmall
isolated spaces.
• Recessed lighting should be a “sealed can” design; attic
hatches weather stripped or sealed; attic mounted duct
work and air handler joints and seams taped or sealed.
Locationofthereplaceandchimneywillaffectperformance.
AsshowninFigure7.1,onpage7,thechimneyshould:
• Be installed through the warm airspace enclosed by the
building envelope. This helps to produce more draft,
especiallyduringlightinganddie-downofthere.
• Penetrate the highest part of the roof. This minimizes the
effects of wind turbulence.
• Be located away from trees, adjacent structures, uneven
roof lines and other obstructions.
Offsetscanrestrictdraftsotheiruseshouldbeminimized.
Consider the replace location relative to oor and ceiling
and attic joists.