Heatilator • CST42A • 4012-012 Rev J • 08/06
5
2
2
Getting Started
A. Design and Installation Considerations
Draft is the pressure difference needed to vent
fi
replaces
successfully. Considerations for successful draft include:
• Preventing negative pressure
• Location
of
fi
replace and chimney
B. Negative Pressure
Negative pressure results from the imbalance of air avail-
able for the
fi
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.
• Location of return-air vents to furnace or air
conditioning.
• Imbalances of the HVAC air handling system.
• 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. Install the intake on the side of
the house towards prevailing winds during the heating
season.
• 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
fi
replace.
• Avoid
installing
the
fi
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.
• Basement installations should be avoided due to stack
effect. Stack effect creates negative pressure in lower
levels. Hearth & Home Technologies recommends the
use of direct vent
fi
replaces in basements.
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,
fi
re of
fi
cials or authorities having jurisdiction about
restrictions, installation inspection and permits.
CAUTION
When planning a
fi
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
fi
guration to be used. See Sections
5 and 6.
• Gas supply piping. See Section 7.
• Framing
and
fi
nishing details. See Sections 3 and 8.
• Whether optional accessories are desired. See
Section 12.
