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Blower Operation
NOTE-The following is a generalized procedure and does
not apply to all thermostat control systems.
1 - Blower operation is dependent on the thermostat
control system option that has been installed in the
units. Refer to operation sequence of the control
system installed for detailed descriptions of blower
operation.
2 - Generally, blower operation is set at the thermostat
fan switch. With the fan switch in “ON” position
and the OCP input is “ON”, the blower operates
continuously. With the fan switch in “AUTO” position,
the blower cycles with demand.
3 -
when the system switch is in the “OFF” position.
The only exception is immediately after a heating
demand when the blower control keeps the blower
on until all heat is extracted from the heat exchanger.
Determining Unit Air Volume
IMPORTANT - Staged-Blower units are factory-set to run
the blower at full speed when there is a blower (G) de-
mand without a heating or cooling demand. Refer to the
eld-provided, design specied CFM for all modes of op-
eration. Use the following procedure to adjust motor pulley
to deliver the highest CFM called for in the design spec.
See Staged-Blower Start-Up section to set blower CFM
for all modes once the motor pulley is set. On VAV units
duct static feedback will control indoor blower CFM for
beltdrive with a VFD.
BLOWER ASSEMBLY
BLOWER MAY NEED TO BE
REMOVED TO INSPECT HEAT
EXCHANGER, REAR BLOWER
BEARINGS, ETC.
TO INCREASE BELT TENSION
tor to sliding base.
ward and tighten the belt.
3-Tighten four screws.
TO INCREASE AIR VOLUME
LOOSEN ALLEN SCREW & TURN
PULLEY CLOCKWISE
TO DECREASE AIR VOLUME
TURN PULLEY COUNTERCLOCKWISE
BLOWER WHEEL
PULLEY
ALLEN SCREW
BLOWER ASSEMBLY
SLIDING BASE
BELT TENSION
ADJUSTING
SCREW
LOOSEN (4) SCREWS TO
ADJUST BELT TENSION
BLOWER WHEEL BRACKET
BLOWER
MOTOR
REMOVE SCREWS TO
SLIDE BLOWER
ASSEMBLY OUT OF UNIT
FIGURE 10
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