Everwarm EW18NM - Air for Combustion and Ventilation

5
WARNING: If the area in which the heater may be operated does not meet the required volume for indoor
combustion air, combustion and ventilation air shall be provided by one of the methods described in the
National Fuel Gas Code, ANSI Z223.1/NFPA 54, the International Fuel Gas Code, or applicable local codes.
Today’s homes are built more energy efcient than ever. New materials, increased insulation, and new construction
methods help reduce heat loss in homes. Homeowners weather strip and caulk around windows and doors to keep
the cold air out and the warm air in. During heating months, homeowners want their homes as airtight as possible.
While it is good to make your home energy efcient, 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 appli-
ances. This will insure proper venting of vented fuel-burning appliances.
PRODUCING ADEQUATE VENTILATION
All spaces in homes fall into one of the three following ventilation classications:
1. Unusually Tight Construction
2. Unconned Space
3. Conned Space
The information on pages 5 through 7 will help you classify your space and provide adequate ventilation.
Conned and Unconned Space
A conned space is a space whose volume is less than 50 cubic feet per 1,000 Btu per hour (4.8 m
3
per kw) of the ag-
gregate input rating of all appliances installed in that space, and an unconned space as a space whose volume is not
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. Rooms connecting directly with the space in which the appliances are installed*, through openings not
furnished with doors, are considered a part of the unconned space.
This heater shall not be installed in a conned space or unusually tight construction unless provisions are provided for
adequate combustion and ventilation air.
*Adjoining rooms are connecting only if there are doorless passageways or ventilation grills between them.
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 dened as construction where:
a) walls and ceilings exposed to the outside atmosphere have a continuous water vapor retarder with a rating
AIR FOR COMBUSTION AND VENTILATION
of one perm (6x10
-11
kg per pa-sec-m
2
) or less with openings gasketed or sealed
and
b) weather stripping has been added on windows that can be opened 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 7).
If your home does not meet all of the three criteria above, proceed to "Determining Fresh-Air Flow For Heater
Location" (below).