OWNER'S OPERATION AND INSTALLATION MANUAL VENT-FREE HEARTH HEATER BTU/Hr
8 49D0090
49D0090 9
FRESH AIR FOR COMBUSTION AND VENTILATION
WARNING: This heater shall not be installed in a confined space or unusually tight
construction unless provisions are provided for adequate combustion and ventilation
air. Read the following instructions to insure proper fresh air for this and other fuel-
burning appliances in your home.
WARNING
Today’s homes are built more energy efcient than ever. New materials, increased insulation, and new construction methods
help reduce heat loss in homes. Home owners weather strip and caulk around windows and doors to keep the cold air out
and the warm air in. During heating months, home owners want their homes as airtight as possible.
While it is good to make your home energy efcient, your home needs to breathe. Fresh air must enter your home. All fuel-
burning appliances need fresh air for proper combustion and ventilation.
Exhaust fans, replaces, clothes dryers, and fuel burning appliances draw air from the house to operate. You must provide
adequate fresh air for these appliances. This will insure proper venting of vented fuelburning appliances.
PROVIDING ADEQUATE VENTILATION
The following are excerpts from National Fuel Gas Code, NFPA 54/ANSI Z223.1, Section 5.3, Air for Combustion and
Ventilation. All spaces in homes fall into one of the three following ventilation classications:
1. Unusually Tight Construction
2. Unconned Space
3. Conned Space
The information on pages 9 and 10 will help you classify your space and provide adequate ventilation.
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. Unusually tight construction is dened as
construction where:
a. walls and ceilings exposed to the outside atmosphere have a continuous water vapor retarder with a rating
of one perm (6x10-11 kg per pa-sec-m2) or less with openings gasketed or sealed and
b. weather stripping 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 floors, 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 Out-
doors,” page 10.
If your home does not meet all of the three criteria above, proceed to “Determining Fresh- Air Flow For Heater Location,”
page 9.
CONFINED AND UNCONFINED SPACE
The National Fuel Gas Code, ANSI Z223.1 denes a conned space as a space whose volume is less than 50 cubic feet per
1,000 Btu per hour (4.8 m
3
per kw) of the aggregate input rating of all appliances installed in that space and an unconned
space as a space whose volume is not less than 50 cubic feet per 1,000 Btu per hour (4.8 m
per kw) of the aggregate input
rating of all appliances installed in that space. Rooms communicating directly with the space in which the appliances are
installed*, through openings not furnished with doors, are considered a part of the unconned space. This heater shall not
be installed in a conned space or unusually tight construction unless provisions are provided for adequate combustion and
ventilation air.
* Adjoining rooms are communicating only if there are doorless passageways or ventilation grills between them.