Chemical Vapor Corrosion - Kenmore 153.331350 Use & Care Manual

4. When ducts are used, they shall be of the same
cross-sectional area as the free area of the
openings to which they connect. The minimum
short side dimension of rectangular air ducts
shall not be less than 3" (76mm) (see Figure
18).
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Figure 18
5. Alternatively a single permanent opening
may be used when communicating directly
with the outdoors, or with spaces that freely
communicate with the outdoors. The opening
shall have a minimum free area of 1 square inch
per 3,000 Btu/hr (7.3cm2/kW) of total input rating
of all equipment in enclosure (see Figure 19).
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Figure 19
6. Louvers and Grilles: In calculating free area,
consideration shall be given to the blocking
effect of louvers, grilles or screens protecting
openings. Screens used shall not be smaller
than 1/4" (6.4mm) mesh. If the free area through
a design of louver or grille is known, it should be
used in calculating the size opening required to
provide the free area specified. If the design and
free area is not known, it may be assumed that
wood louvers will be 20-25 percent free area
and metal louvers and grilles will have 60-75
percent free area. Louvers and grilles shall be
fixed in the open position or interlocked with the
equipment so that they are opened automatically
during equipment operation.
7. Special Conditions Created by Mechanical
Exhausting or Fireplaces: Operation of
exhaust fans, ventilation systems, clothes dryers
or fireplaces may create conditions requiring
special attention to avoid unsatisfactory
operation of installed gas utilization equipment.
Chemical Vapor Corrosion
CORROSION OF THE FLUEWAYS AND VENT
SYSTEM MAY OCCUR IFAIR FOR COMBUSTION
CONTAINS CERTAIN CHEMICAL VAPORS. SUCH
CORROSION MAY RESULT IN FAILURE AND
RISK OF ASPHYXIATION.
Spray can propellants, cleaning solvents,
refrigerator and air conditioning refrigerants,
swimming pool chemicals, calcium and sodium
chloride (water softener salt), waxes, and process
chemicals are typical compounds which are
potentially corrosive. Do not store products of this
sort near the heater. Also air which is brought in
contact with the heater should not contain any of
the chemicals. If necessary, uncontaminated air
should be obtained from remote or outside sources.
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