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Adjoining rooms can be considered part of an unconfined area if
there are no doors between rooms.
An attic or crawl space may be considered an unconfined space
provided there are adequate ventilation openings directly to out-
doors. Openings
MUST
remain open and
NOT
have any means of
being closed off. Ventilation openings to outdoors
MUST
be at
least 1 square inch of free area per 4,000 BTUH of total input rating
for all gas appliances in area.
In unconfined spaces, infiltration should be adequate to provide
air for combustion, ventilation and dilution of flue gases. However,
in buildings with unusually tight construction, additional air
MUST
be provided using the methods described in section titled
Con-
fined Space Installation
:
Unusually tight construction is defined as: Construction with
1
Walls and ceilings exposed to the outside have a continuous,
sealed vapor barrier. Openings are gasketed or sealed and
2
Doors and openable windows are weather stripped and
3. Other openings are caulked or sealed. These include 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, etc.
Ventilation Air
Some provincial codes and local municipalities require ventilation
or make--up air be brought into the conditioned space as replace-
ment air. Whichever method is used, the mixed return air tempera-
ture across the heat exchanger
MUST
not fall below 60
°
for flue
gases will condense in the heat exchanger. This will shorten the
life of the heat exchanger and possibly void your warranty.
4. Gas Vent Installation
CARBON MONOXIDE POISONING, FIRE AND
EXPLOSION HAZARD.
Read and follow all instructions in this section.
Failure to properly vent this furnace can result in
death, personal injury and/or property damage.
!
Install the vent in compliance with codes of the country having ju-
risdiction, local codes or ordinances and these instructions.
These fan assisted combustion furnaces have been classified as
Category
I
appliances which means that they
MUST
operate with
a negative vent pressure.
Category
I
Safe Venting Requirements
NOTE
: The following instructions comply with the United States
National Fuel Gas Code. Based on the highest input rate on the
furnace rating plate.
1. If a Category
I
vent passes through an attic, any concealed
space or floor, use
ONLY
Type B or Type L double wall vent
pipe. If vent pipe passes through interior wall, use type B vent
pipe with ventilated thimble
ONLY
.
2. Do
NOT
vent furnace into any chimney serving an open fire-
place or solid fuel burning appliance.
3. Use the same diameter Category
I
connector or pipe as per-
mitted by the
United States National Fuel Gas Code
vent-
ing tables.
4. Keep vertical Category
I
vent pipe or vent connector runs as
short and direct as possible.
5. Vertical outdoor runs of type B or
ANY
single wall vent pipe
below the roof line are
NOT
permitted.
6. Slope all horizontal runs up away from furnace a minimum of
1
/
4
²
per foot.
7. Support all horizontal vent pipe every 6
¢
using proper clamps
and metal straps.
8. Check existing gas vent or chimney to ensure they meet
clearances and local codes.
9. The furnace
MUST
be connected to a factory built chimney or
vent complying with a recognized standard.
Venting into a
masonry or concrete chimney is only permitted as out-
lined in the United States National Fuel Gas Code venting
tables or
Masonry Chimney
section in these instruc-
tions.
Venting and Combustion Air Check
NOTE
: If this installation removes an existing furnace from a vent-
ing system serving one or more other appliances, and to make
sure there is adequate combustion air for all appliances,
MAKE
THE FOLLOWING CHECK
. (See
Figure 5
)
