Lennox LHT180 Installation Instructions Manual page 13

4- The blower RPM can be adjusted at the motor pulley.
Loosen Allen screw and turn adjustable pulley
clockwise to increase CFM. Turn counterclockwise to
decrease CFM. See figure 12. Do not exceed
minimum and maximum number of pulley turns as
shown in table 3.
INSTALLATIONS WITH DUCTWORK
ROOFTOP UNIT
SUPPLY
TURN
MAIN
DUCT RUN
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
ALLEN
SCREW
PULLEY
LOCATION OF STATIC PRESSURE READINGS
RETURN AIR
READING LOCATION
RE­
FIRST BRANCH
OFF OF MAIN RUN
SUPPLY AIR
READING
LOCATION
BLOWER ASSEMBLY
BELT TENSION
BLOWER
MOTOR
MINIMUM AND MAXIMUM PULLEY ADJUSTMENT
Belt
A Section
B Section
*No minimum number of turns open when B belt is used on
pulleys 6" O.D. or larger.
INSTALLATIONS WITH CEILING DIFFUSERS
SUPPLY AIR
READING
LOCATION
FIGURE 11
ADJUSTING
SCREW
FIGURE 12
Page 13
TABLE 3
Minimum Turns Open Maximum Turns Open
No minimum
1*
ROOFTOP UNIT
RE­
SUPPLY
TURN
DIFFUSER
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
508336-01
5
6
RETURN AIR
READING
LOCATION
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