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7. The adjustable motor pulley is factory set for
the RPM specified. Speed can be increased by
closing or decreased by opening the adjustable
motor sheave. Two groove variable pitch pulleys
must be adjusted an equal number of turns open
or closed. Any increase in speed represents a
substantial increase in the horsepower required
by a unit. Motor amperage should always be
checked to avoid serious damage to the motor
when speed is varied.
Operation: BDF
1. Before starting up or operating fan, check all
fasteners for tightness. In particular, check
the setscrews in wheel hub (and pulleys, if
applicable).
2. While in the OFF position or before connecting
the fan to power, turn the fan wheel by hand
to be sure it is not striking the venturi or any
obstacle.
3. Start the fan and shut it off immediately to check
rotation of the wheel with directional arrow in the
motor compartment, see figure 4.
4. When the fan is started, observe the operation
and check for any unusual noises.
5. With the system in full operation and all
ductwork attached, measure current input to the
motor and compare with the nameplate rating to
determine if the motor is operating under safe
load conditions.
6. Keep inlets and approaches to fan clean and
free from obstruction.
Inspection: BDF
Inspection of the fan should be conducted at the
first 30 minute and 24 hour intervals of satisfactory
operation.
30 Minute Interval
Inspect bolts, setscrews and motor mounting bolts.
Adjust and tighten as necessary.
24 Hour Interval
Check all internal components and inspect belt
alignment and tension. Adjust and tighten as
necessary.
WARNING
The fan has been checked for mechanical noises at
the factory prior to shipment. If mechanical noise
should develop, suggested corrective actions are
offered in the Troubleshooting section.
IMPORTANT
Over tightening will cause excessive bearing wear
and noise. Too little tension will cause slippage at
startup and uneven wear.
IMPORTANT
Adjust (tighten) belt tension after the first 24-48
hours of operation.
®
Maintenance: BDF
Installation and maintenance are to be performed
only by qualified personnel who are familiar
with local codes and regulations and who are
experienced with this type of equipment.
Motor maintenance is generally limited to cleaning
and lubrication (where applicable). Cleaning should
be limited to exterior surfaces only. Removing dust
buildup on motor housing ensures proper motor
cooling.
Greasing of motors is only intended when fittings
are provided. Many fractional horsepower motors
are permanently lubricated and should not be
lubricated after installation. Motors supplied with
grease fittings should be greased in accordance
with manufacturers' recommendations. Where
motor temperatures do not exceed 104°F (40°C),
the grease should be replaced after 2,000 hours of
running time as a general rule.
Wheels require very little attention when moving
clean air. Occasionally, oil and dust may accumulate
causing imbalance. When this occurs the wheel and
housing should be cleaned to ensure smooth and
safe operation.
All fasteners should be checked for tightness each
time maintenance checks are performed prior to
restarting unit.
A proper maintenance program will help these units
deliver years of dependable service.
WARNING
Always disconnect, lock and tag power source
before servicing. Failure to disconnect power
source can result in fire, shock or serious injury.
CAUTION
Uneven cleaning of the wheel will produce an out
of balance condition that will cause vibration in the
fan.
WARNING
This unit should be made non-functional when
cleaning the wheel or housing (fuses removed,
disconnect locked off).
Belt/Bearing Maintenance BDF Unit
1. Belts tend to stretch after a period of time. They
should be checked periodically for wear and
tightness. When replacing belts, use the same
type as supplied with the unit.
2. Matched belts should always be used on units
with multi-groove pulleys.
3. For belt replacement, loosen the tensioning
device enough to allow removal of the belt by
hand. Do not force belts on or off. This may
cause cords to break, leading to premature belt
failure.
Model BDF • Belt Drive Duct Fan
5
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