Aerovent ES-2-06 - Manual (Page 10)

10 Twin City Fan Companies Engineering Supplement 2-06
Drive Maintenance
V-belt drives need periodic inspection, re-tensioning, and
occasional belt replacement. Follow Table 5 on page 11
for drive inspections and maintenance. Proper belt ten-
sion can be found on the included datasheet specific to
each fan. A log should be kept with belt tension and
replacement information.
Bearing Maintenance
Proper lubrication of the fan drive bearings helps assure
maximum bearing life. All fans are equipped with decals
indicating re-lubrication intervals for normal operating
conditions. Bearings should be inspected after the first
24 hours of operation and then inspected each time they
are lubricated. Lubrication schedules for the included
type of bearings are attached to the fan. Note that all
speeds shown do not apply to all shaft sizes in that
group. Consult the factory if in doubt of maximum speed
for a particular bearing. Note that every installation is
different and the frequency of re-lubrication should be
adjusted accordingly.
On high moisture applications the lubrication fre-
quency may need to be doubled or tripled to adequately
protect the bearings. Double the relubrication frequency
on fans with vertical shafts.
Observation of the conditions of the grease expelled
from the bearings at the time of relubrication is the best
guide as to whether regreasing intervals and amount of
grease added should be altered.
Greases are made with different bases. There are
synthetic base greases, lithium base, sodium base, etc.
Avoid mixing greases with different bases. They could be
incompatible and result in rapid deterioration or break-
down of the grease. The lubrication sticker identifies a
list of acceptable lubricants. All fan shaft bearings are
filled with a lithium-based grease before leaving the fac-
tory unless otherwise specified. When the fans are start-
ed, the bearings may discharge excess grease through
the seals for a short period of time. Do not replace the
initial discharge because leakage will cease when the
excess grease has worked out. Sometimes the bearings
have a tendency to run hotter during this period. This
is no reason for alarm unless it lasts over 48 hours or
gets very hot (over 200°F, 93°C).
If bearings are exhibiting excessive vibration at any
time or are running hotter than 200°F, 93°C, the bear-
ings should be inspected for proper lubrication, align-
ment, tightness of set screws, cap bolts, and collars,
and inspected for signs of contamination in the lubricant.
The bearings or damaged bearing components shall be
replaced if found faulty or showing signs of wear. When
relubricating, use a sufficient amount of grease to purge
the seals. Rotate bearings by hand during relubrication.
Wheel and Shaft Maintenance
Inspect the shaft and wheel for dirt buildup, corrosion,
and signs of excess stress or fatigue after one month
of service. Future inspection interval shall be based on
findings in this initial inspection. Clean the components.
If any signs of damage, stress, or fatigue are present
(deformation, cracks, excessively worn surfaces) the
part shall be replaced. Any material buildup on rotating
parts or parts that could contact rotating parts shall be
cleaned. If the wheel is removed for any reason, make
sure that it is securely attached to the shaft before
restarting the fan. The wheel and shaft shall also be
inspected any time excessive vibration is observed (filter
in readings should be 7.2 mm/s RMS or less). Reference
ISO 14694:2003, “Industrial Fans – Specifications for
Balance Quality and Vibration Levels” for more details
on acceptable fan vibration levels.
Structural Maintenance
All structural components or devices used to support
or attach the fan to a structure should be checked at
regular intervals. Vibration isolators, bolts, foundations,
etc., are all subject to failure from corrosion, erosion,
and other causes. Improper mounting can lead to poor
operation characteristics or fan fatigue and failure. Check
metallic components for corrosion, cracks, or other
signs of stress. Replace any components showing any
of these signs. Concrete should be checked to insure
the structural integrity of the foundation and repaired or
replaced if any signs of damage are found.
Where the fan is used to handle toxic gasses or
vapors, the housing, and welds shall be inspected for
signs of corrosion or cracking at regular intervals to
assure no toxic gasses can escape. The condition of
the coating shall be inspected as well to verify that
bare parts of the fan are not exposed. All gaskets and
ducting shall be inspected for signs of erosion as well.
An initial inspection after one month of service shall be
used to determine an appropriate inspection interval.
Fan Operation
Proper Use and Application
It is critical that fans are operated only as their design
intended. Standard construction is designed for standard
applications as defined below:
• Clean air – no solids, particles, or corrosive or abra-
sive gasses.
• Air stream temperatures between 120°F (49°C) and
-20°F (-29°C) with a maximum temperature fluctua-
tion of 15°F (8°C) per minute.
• Ambient temperatures shall not exceed 104°F (40°C)
for standard design fans.
• Constant speed operation.
Operating a fan in any of the following conditions could
cause a safety hazard:
• Do not operate a fan in an environment that it was
not designed for. This includes operating the fan in
temperatures or with abrasive or corrosive vapors
or chemicals or solid material (including fly ash)
other than the fan was designed for. Operating at
elevated temperatures or with abrasive or corrosive
vapors requires special considerations that must be
incorporated in the design, material selection, coat-
ing, and maintenance of the fan.
• Do not operate a fan at a higher speed than the
fan, drives, seals, bearings, or other components
were designed for.
• Do not use variable rotational speed service without
first consulting Twin City Fan Companies, Ltd.
• Do not operate a fan without the bearings and cou-
plings properly lubricated. Lubrication intervals are
explained in corresponding maintenance sections of
this manual.
• Do not operate a fan exhibiting increased vibration
levels. Filter in readings should be 7.2 mm/s RMS
or less.
• Do not operate the fan in stall.
• Do not operate the fan with replacement or added
components that are not recommended by Twin
City Fan Companies, Ltd. The use of insufficient
components could cause premature wear and
failure.