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Blower Operation and Adjustments
IMPORTANT
Three phase scroll compressors must be phased
sequentially for correct compressor and blower
rotation. Follow "COOLING START-UP" section of
installation instructions to ensure proper compres
sor and blower operation.
A-Blower Operation
Initiate blower demand at thermostat according to
instructions provided with thermostat. Unit will cycle on
thermostat demand. The following steps apply to
applications
using
a
thermostat.
1- Blower operation is manually set at the thermostat
subbase fan switch. With fan switch in ON position,
blowers will operate continuously.
2- With fan switch in AUTO position, the blowers will
cycle with demand. Blowers and entire unit will be off
when system switch is in OFF position.
In zone sensor applications the blower will cycle with
demand (default). For continuous blower operation
change ECTO 6.17 to option 1. Refer to the IMC manual.
B-Blower Access
1- Remove screws on either side of blower assembly
sliding base. See figure 20, 21, or 22.
2- Pull base toward outside of unit.
TO INCREASE BELT TENSION
1-Loosen four screws securing blower
motor to sliding base.
2-Turn adjusting screw to the left, or
counterclockwise, to move the motor
downward and tighten the belt.
3-Tighten four screws.
typical
electro-mechanical
BLOWER ASSEMBLY (SW 036 & 060)
BLOWER ASSEMBLY
SLIDING BASE
BLOWER
MOTOR
LOOSEN (4)
SCREWS TO
ADJUST BELT
TENSION
C-Determining Unit CFM (with wet coil)
1- Run blower with a cooling demand. Measure the
indoor blower shaft RPM. Air filters must be in place
when measurements are taken.
2- With all access panels in place, measure static
pressure external to unit (from supply to return).
3- Referring to tables 2 through 5, use static pressure
and RPM readings to determine unit CFM.
4- Constant Air Volume (CAV) Supply Air Blowers -
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 20, 21, or 22. Do not
exceed minimum and maximum number of pulley
turns as shown in table 1.
MINIMUM AND MAXIMUM PULLEY ADJUSTMENT
Belt
A Section
B Section
*No minimum number of turns open when B belt is used on
BELT TENSION
ADJUSTING
SCREW
FIGURE 20
Page 16
TABLE 1
Minimum Turns Open
Maximum Turns Open
No minimum
1*
pulleys 6" O.D. or larger.
TO INCREASE CFM
LOOSEN ALLEN SCREW &
BLOWER
TURN PULLEY CLOCKWISE
WHEEL
TO DECREASE CFM
COUNTERCLOCKWISE
BLOWER
PULLEY
PULLEY
ADJUSTMENT
BOLTS
ALLEN
SCREW
MOTOR
PULLEY
REMOVE SCREWS TO SLIDE
BLOWER ASSEMBLY OUT OF UNIT
5
6
TURN PULLEY
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