Contaminated Combustion Air; Installation; Duct Work Recommendations - Bryant 349HAV Series Installation, Start-Up, And Operating Instructions Manual

For Example:
349HAV FURNACE FREE AREA PER
INPUT BTUH OPENING (SQ IN.)
50,000
75,000
100,000
125,000
When ducts are used, they must be of the same cross-sectional area
as the free area of the openings to which they connect. The
minimum dimension of rectangular ducts must not be less than 3
in.
IV. CONTAMINATED COMBUSTION AIR
Contaminated combustion air must be avoided in order not to
adversely affect the long term life of furnace, especially heat
exchanger and burners.
The recommended source of combustion air is to use the outdoor
air supply. Use of indoor air in most applications is acceptable as
long as there is no exposure to the types of installation or
substances listed below and all provisions for indoor combustion
air meet the requirements for combustion air supply indicated in
the NFGC Section 5.3; CAN1-B149 Installation Codes; and/or any
applicable local codes.
A. Installations Requiring Outdoor Combustion Air
1. The following types of installations require OUTDOOR
AIR for combustion due to chemical exposures:
a. Commercial buildings
b. Buildings with indoor pools
c. Furnaces installed in laundry rooms
d. Furnaces installed in hobby or craft rooms
e. Furnaces installed near chemical storage areas
2. Exposure to the following substances in the combustion air
supply also require OUTDOOR AIR for combustion:
a. Permanent wave solutions
b. Chlorinated waxes or cleaners
c. Chlorine based swimming pool chemicals
d. Water softening chemicals
e. De-icing salts or chemicals
f. Carbon tetrachloride
g. Halogen-type refrigerants
h. Cleaning solvents (such as perchloroethylene)
i. Printing inks, paint removers, varnishes, etc.
j. Hydrochloric acid
k. Cements and glues
l. Anti-static fabric softeners for clothes dryers
m. Masonry acid washing materials

INSTALLATION

I. DUCT WORK RECOMMENDATIONS
IMPORTANT: This furnace is equipped with a metal heat
exchanger shipping bracket which must be removed before install-
ing furnace. The No. 10 screws which fasten bracket to furnace
will interfere with attachment of outlet duct if not removed.
Remove bracket by removing No. 10 screws located on bottom
panel duct supply flange, rotating bracket forward and lifting out.
The proper sizing of warm air ducts is necessary to ensure
satisfactory furnace operation. Duct work should be in accordance
with the latest editions of U.S. NFPA-90A (Air Conditioning
Systems) and NFPA-90B (Warm Air Heating and Air Condition-
ing Systems) or Canadian equivalent.
ROUND PIPE
(IN. DIA)
25.0 6
37.5 7
50.0 8
62.5 9
The following recommendations should be followed when install-
ing duct work:
1. Install locking type dampers in all branches of individual
ducts to balance out system. Dampers should be adjusted to
impose proper static at outlet of furnace.
2. Noncombustible flexible duct connectors are recommended
to connect both supply- and return-air ducts to furnace.
3. In cases where return-air grille is located close to fan inlet,
there should be at least one 90° air turn between fan and
inlet grille. Further reduction in sound can be accomplished
by installing acoustical air turning vanes and/or lining
inside of duct with acoustical material.
4. It is recommended that outlet duct be provided with a
removable access panel. The opening shall be accessible
when furnace is installed and shall be of such a size that
heat exchanger can be viewed for possible openings using
light assistance or so a probe can be inserted for sampling
air stream. The access panel shall be designed so as to
prevent leaks when locked in position. If an air conditioning
coil is installed, access panel to coil can be used for this
purpose.
CAUTION: Air openings, intake and outlet pipes,
return-air grilles, and warm air registers must not be
obstructed.
WARNING: When supply ducts carry air circulated by
furnace to areas outside spaces containing furnace, return
air shall also be handled by a duct sealed to furnace
casing and terminating outside space containing furnace.
Incorrect duct work termination and sealing will create a
hazardous condition which could lead to bodily harm.
5. When installing furnace with cooling equipment for year-
round operation, the following recommendations must be
followed for series or parallel airflow:
a. In series airflow applications, coil is mounted after
furnace in an enclosure in supply-air stream. The furnace
blower is used for both heating and cooling airflow.
WARNING: The coil MUST be installed on air dis-
charge side of furnace. Under no circumstances should
airflow be such that cooled, conditioned air can pass over
furnace heat exchanger. This will cause condensation in
heat exchanger and possible failure of heat exchanger
which could lead to a fire hazard and/or a hazardous
condition which may lead to bodily harm. Heat exchanger
failure due to improper installation may not be covered by
warranty.
b. In parallel airflow installation, dampers must be pro-
vided to direct air over furnace heat exchanger when
heat is desired and over cooling coil when cooling is
desired.
IMPORTANT: The dampers should be adequate to prevent
cooled air from entering furnace. If manually operated, dampers
must be equipped with means to prevent operation of either
cooling unit or furnace unless damper is in full cool or full heat
position.
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