Specifications

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The frequency of cleaning and replacing air filters ap-
plies twelve months of the year, where blowers are
used for ventilation and heating.
D. Belt Tensions and Adjustments
Belt tension is adjusted during the initial run-in and test
periods at the factory. However, the belts are run as
slack as possible to prevent excessive damage to the
bearings, yet tight enough to prevent slippage.
It is necessary, therefore, to tighten all belts during the
first few months of operation, and to check for proper
tension weekly during the first 60 days, after which
30-day check intervals are sufficient.
NOTE: Turn off all power to the equipment before
checking belt tensions.
CAUTION: Do not attempt to tighten any belt or
belts by changing the pitch of an adjustable pulley,
as this will change the speed of a driven pulley,
causing the unit to be rendered OUT OF AIR
BALANCE. Do Not over tighten belts.
Suggested Belt Tension Method
1. Check tension frequently during the first 24-48
hours of run-in operation. Ideal tension is the
lowest tension at which the belt will not slip under
peak load conditions. Over tensioning shortens
belt and bearing life.
2. To properly tension a conventional V-belt drive use
the following procedure:
a. Measure the span length.
b. At the center of the span, apply a force
perpendicular to the span to deflect the belt
1/64 inch for every inch of span length. For
example, for a 40 inch span, apply a force
that will deflect the belt 40/64 or 5/8 of an
inch.
c. Compare the force you have applied with
the values given in the following table. If the
force is between the values for normal
tension and 1-1/2 times normal tension, the
belt tension should be satisfactory. If the belt
tension is not within this range, it can be
adjusted by loosening the motor mounting
bolts, and adjusting the position of the motor on
its base.
NOTE: A new drive can be tightened to two times
the minimum value shown to allow for normal drop
in tension during the run-in period.
B Section
small Pounds
pulley Pounds Force for
diameter Belt Force for 1
1
/2 times
range in Manufacturer Normal Normal
inches & Type Belt Tension Tension
3.4 – 4.2 Gates Hi-Power 4.4 6.6
4.4 – 4.6 Gates Hi-Power 4.9 7.4
5.8 – 8.6 Gates Hi-Power 5.8 8.7
Note: For recommendation of other types of belts, con-
sult respective manufacturers.
E. Optional Coils and Related Items
1. Coils – Coil surfaces must be kept clean of dirt and
lint in order to operate at rated efficiency. Coils
should be inspected on a regular basis and cleaned
as required.
CAUTION: Solutions used to clean coils must not
be corrosive to metals or materials used in the
manufacturer of this equipment. If cleaning
solutions are applied through means of high
pressure spray, care must be taken to avoid
damaging coil fins.
2. Condensate Drain Pan – Periodically flush the con-
densate pan and drain system.
F. Gaskets
Gaskets are used on doors, inspection covers, some
filter racks, and some outdoor air dampers. Inspect
gaskets periodically and repair or replace as required.
G. Support Means
Inspect the entire unit support means to be sure every-
thing is firmly in place.