Lennox LGA Series Unit Information page 22

TO INCREASE CFM
TURN PULLEY CLOCKWISE
TO INCREASE BELT TENSION
1 - Loosen 2 locking bolts.
2 - Pull motor mounting plate.
3 - Tighten motor mounting
plate so plate is vertical.
TO DECREASE CFM
TURN PULLEY
COUNTERCLOCKWISE
Check Belt Tension
Overtensioning belts shortens belt and bearing life. Check
belt tension as follows:
1- Measure span length X. See figure 12.
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).
BLOWER SPEED ADJUSTMENT
KEY
SET SCREW
MOTOR
PULLEY
MOTOR
MOUNTING PLATE
FIGURE 11
A force below these values indicates and underten-
sioned belt. A force above these values indicates an
overtensioned belt.
Page 22
BLOWER PULLEY
LOCKING BOLTS
(2-TOP & BOTTOM)
MEASURE BELT TENSION
FORCE
DEFLECTION 1/64" PER INCH OF SPAN
OR 1.5mm PER 100mm OF SPAN
FIGURE 12
BLOWER