4
105509
UNVENTED 32" FIREBOX
FIREPLACE MANUFACTURERS INC.
Today’s homes are built more energy effi-
cient 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
efficient, your home needs to breathe. Fresh
air must enter your home. All fuel-burning
appliances need fresh air for proper com-
bustion and ventilation.
Exhaust fans, fireboxes, clothes dryers, and
fuel burning appliances draw air from the
house to operate. You must provide ad-
equate fresh air for these appliances. This
will insure proper venting of vented fuel-
burning appliances.
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from National
Fuel Gas Code. NFPA 54/ANS Z223.1, Sec-
tion 5.3, Air for Combustion and Ventilation.
All spaces in homes fall into one of the three
following ventilation classifications:
1. Unusually Tight Construction
2. Unconfined Space
3. Confined Space
The information on pages 4 through 6 will
help you classify your space and provide
adequate ventilation.
Unusually Tight Construction
The air that leaks around doors and win-
dows may provide enough fresh air for
combustion and ventilation. However, in
PRODUCT
FEATURES
OPERATION
This firebox is designed for use with ap-
proved ANS Z21.1.2 decorative type
unvented room heaters. (Physical size limi-
tations apply. Refer to minimum firebox
requirements supplied with log heater.) It
requires no outside venting or chimney mak-
ing installation easy and inexpensive. When
used without the blower (models UV32C
and NLUV32C only), the firebox requires
no electricity making it ideal for emergency
back-up heat.
BLOWER ACCESSORY
The UV32C and NLUV32C fireboxes will
accept the FA3700 accessory. The variable
blower allows you to select the fan speed
you desire. The blower circulates heated air
from the firebox into the room. Use of
blower is optional.
LOCATING
FIREBOX
PLANNING
Plan where you will install the firebox. This
will save time and money later when you
install the firebox. Before installation, con-
sider the following:
1.
Where the firebox will be located. Al-
low for wall and ceiling clearances (see
Installation Clearances, page 7).
2.
Everything needed to complete instal-
lation.
3.
These models CANNOT be installed in
a bedroom or bathroom.
4.
Proper air for combustion and ventila-
tion (see below).
AIR FOR
COMBUSTION AND
VENTILATION
WARNING: This firebox shall
not be installed in a confined space
or unusually tight construction
unless provisions are provided
for adequate combustion and ven-
tilation air. Read the following in-
structions to insure proper fresh
air for this and other fuel-burning
appliances in your home.
buildings of unusually tight construction,
you must provide additional fresh air.
Unusually tight construction is de-
fined as construction where:
a.
walls and ceilings exposed to the
outside atmosphere have a con-
tinuous water vapor retarder with
a rating of one perm (6x10
-11
kg
per pa-sec-m
2
) or less with open-
ings 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, be-
tween sole plates and floors, be-
tween wall-ceiling joints, be-
tween wall panels, at penetra-
tions 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 6.
If your home does not meet all of the
three criteria above, proceed to
Deter-
mining Fresh-Air Flow For Firebox
Location, page 5.
Confined Space and Unconfined
Space
The National Fuel Gas Code (ANS Z2123.1,
1992 Section 5.3) defines a confined 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
unconfined 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 communicating directly with
the space in which the appliances are in-
stalled*, through openings not furnished
with doors, are considered a part of the
unconfined space.
This heater shall not be installed in a con-
fined 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 ventila-
tion grills between them.
