Page 11
507348-04 12/2015
Blower Operation and Adjustments
KG/KC 024 and 030 units are equipped with direct drive
blowers only. KG/KC 036, 048 and 060 units are equipped
with either direct drive or belt drive blowers. KG/KC 072,
074 and 090 units are available with belt drive blowers
only. KG/KC 074 units are equipped with two-stage
blowers. The blower will operate at high speed with a Y2
thermostat demand and low speed with a Y1 thermostat
demand. Low speed operation delivers approximately ⅔
of the air volume of high speed. Two-speed blower
operation results in lower energy consumption.
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 typical electro-mechanical
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.
B-Determining Unit CFM - Direct Drive Blowers
1- The following measurements must be made with air
filters in place.
2- With all access panels in place, measure static
pressure external to unit (from supply to return). Add
any additional air resistance for options and
accessories shown in accessory air resistance tables.
Blower performance data is based on static pressure
readings taken in locations shown in figure 15.
Note - Static pressure readings can vary if not taken
where shown.
3- Use figure 16 to determine the factory set blower
speed.
BLOWER SPEED FACTORY SETTINGS
FIGURE 16
1
2
3
4
Com
Hi
Med
Low*
1
2
3
4
Com
Hi
Med
*
Low
1
2
3
4
Com
Hi
Low
*
Unused
*Factory Setting
036 Units
024, 030, &
048 Units
060 Units
4- Use direct drive blower tables, the measured static
pressure and the factory-set blower speed to
determine CFM. If CFM is lower or higher than the
design specified CFM, move the leads as shown in
figure 17 for 208/230 volt units and figure 18 for
460/575 volt units.
HIGH SPEED - ALL UNITS
L1-Terminal COM
L2-Terminal HIGH
FIGURE 17
SPEED
TAPS
FIELD-ADJUSTABLE BLOWER SPEEDS - DIRECT DRIVE 208/230V
TERMINAL 1
REMAINS AT
COMMON
1-COM
2-HI
3-MED
4-LOW
LOW SPEED
024, 030, 036, 048, UNITS
L1-Terminal COM
L2-Terminal LOW
1-COM
2-HI
3-MED
4-LOW
1-COM
2-HI
3-MED
4-LOW
MEDIUM SPEED
024, 030, 036, 048 UNITS
L1-Terminal COM
L2-Terminal MED
1-COM
2-HI
3-LOW
4-
LOW SPEED
060 UNITS
L1-Terminal COM
L2-Terminal LOW
