Lennox ALLIED Commercial TCA180S2B Standard Manual page 28

Check Belt Tension
Overtensioning belts shortens belt and bearing life. Check
belt tension as follows:
1− Measure span length X. See figure 10.
2− Apply perpendicular force to center of span (X) with
enough pressure to deflect belt 1/64" for every inch of
span length or 1.5mm per 100mm of span length.
Example: Deflection distance of a 40" span would be
40/64" or 5/8".
Example: Deflection distance of a 400mm span would
be 6mm.
3− Measure belt deflection force. For a used belt, the
deflection force should be 5 lbs. (35kPa). A new belt
deflection force should be 7 lbs. (48kPa).
TO INCREASE CFM
LOOSEN ALLEN SCREW &
TURN PULLEY CLOCKWISE
TO DECREASE CFM
TURN PULLEY
COUNTERCLOCKWISE
BLOWER
ASSEMBLY
SLIDING BASE
LOOSEN (4) SCREWS TO
ADJUST BELT TENSION
SIDE VIEW
MOTOR
BLOWER ASSEMBLY
BLOWER
MOTOR
ALLEN
SCREW
PULLEY
A force below these values indicates an underten-
sioned belt. A force above these values indicates an
overtensioned belt.
DEFLECTION 1/64" PER INCH OF SPAN
OR 1.5mm PER 100mm OF SPAN
BELT TENSION
ADJUSTING
SCREW
FIGURE 11
Page 28
MEASURE BELT TENSION
FORCE
FIGURE 10
TO INCREASE BELT TENSION
1−Loosen four screws securing blower motor to
sliding base.
2−Turn adjusting screw to the left, or counter-
clockwise, to move the motor downward and
tighten the belt.
3−Tighten four screws.
BLOWER
WHEEL
PULLEY
REMOVE SCREWS TO
SLIDE BLOWER
ASSEMBLY OUT OF UNIT