Pulley Alignment - Lennox KGA Series Service Literature

4- The blower RPM can be adjusted at the motor pulley.
Loosen Allen screw and turn adjustable pulley clock­
wise to increase CFM. Turn counterclockwise to de­
crease CFM. See figure 7. Do not exceed minimum and
maximum number of pulley turns as shown in table 1.
TABLE 1
MINIMUM AND MAXIMUM PULLEY ADJUSTMENT
Minimum
Belt
Turns Open
A Section No minimum
B Section
*No minimum number of turns open when B belt is used on
pulleys 6" O.D. or larger.
Blower Belt Adjustment
Maximum life and wear can be obtained from belts only if
proper pulley alignment and belt tension are main­
tained. Tension new belts after a 24-48 hour period of op­
eration. This will allow belt to stretch and seat grooves.
Make sure blower and motor pulley are aligned as shown in
figure 8.

PULLEY ALIGNMENT

ALIGNED
BLOWER
PULLEY BELT
NOT ALIGNED
FIGURE 8
1- Loosen four bolts securing motor base to mounting
frame. See figure 7.
2- To increase belt tension -
Turn adjusting bolt to the right, or clockwise, to move
the motor outward and tighten the belt. This increases
the distance between the blower motor and the blower
housing.
To loosen belt tension -
Turn the adjusting bolt to the left, or counterclockwise
to loosen belt tension.
IMPORTANT - Align top edges of blower motor base and
mounting frame base parallel before tightening two bolts on
the other side of base. Motor shaft and blower shaft must be
parallel.
3- Tighten bolts on side of base.
Maximum
Turns Open
5
1* 6
MOTOR
PULLEY
Check Belt Tension
Overtensioning belts shortens belt and bearing life. Check
belt tension as follows:
1- Measure span length X. See figure 9.
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).
A force below these values indicates an underten­
sioned belt. A force above these values indicates an
overtensioned belt.
MEASURE BELT TENSION
DEFLECTION 1/64" PER INCH OF SPAN
OR 1.5mm PER 100mm OF SPAN
Page 19
FORCE
FIGURE 9