Lennox KGC Series Unit Information page 18

C-Blower Compartment
NOTE - Units equipped a Variable Frequency Drive (VFD)
are designed to operate on balanced, three-phase power.
Operating units on unbalanced three-phase power will re-
duce the reliability of all electrical components in the unit.
Unbalanced power is a result of the power delivery system
supplied by the local utility company. Factory-installed in-
verters are sized to drive blower motors with an equiva-
lent current rating using balanced three-phase power. If
unbalanced three-phase power is supplied; the installer
must replace the existing factory-installed inverter with an
inverter that has a higher current rating to allow for the im-
balance. Refer to the installation instructions for additional
information and available replacements.
The blower compartment in all units is located between
the evaporator coil and the condenser coil section. The
blower assembly is accessed by disconnecting the blower
motor .See Blower Access in the Operation/ Adjustment
section.
1-Blower Wheels
All units have one 15 in. x 15 in. (381 mm x 381 mm)
blower wheel.
2-Indoor Blower Motor B3
All units use three-phase single-speed blower motors.
CFM adjustments are made by adjusting the motor
pulley (sheave). Motors are equipped with sealed
ball bearings. All motor specifications are listed in the
SPECIFICATIONS(table of contents) in the front of this
manual. Units may be equipped with motors manufactured
by various manufacturers, therefore electrical FLA and
LRA specifications will vary. See unit rating plate for
information specific to your unit.
Operation and Adjustments
A-Three Scroll Compressor Voltage Phasing
Three phase scroll compressors must be phased
sequentially to ensure correct compressor and blower
rotation and operation. Compressor and blower are wired
in phase at the factory. Power wires are color-coded as
follows: line 1-red, line 2-yellow, line 3-blue.
1 - Observe suction and discharge pressures and
blower rotation on unit start-up.
If pressure differential is not observed or blower rotation
is not correct:
2 - Suction pressure must drop, discharge pressure
must rise, and blower rotation must match rotation
marking.
3 - Disconnect all remote electrical power supplies.
4 - Reverse any two field-installed wires connected to
the line side of K3, TB2 or F4. Do not reverse wires
at blower contactor or compressors.
5 - Make sure the connections are tight.
Discharge and suction pressures should operate at their
normal start-up ranges.
Supply Air Inverter Units - Units are equipped with a
phase monitor located in the control compartment. The
phase monitor will detect the phasing of incoming power.
If the incoming power is out of phase or if any of the three
phases are lost, the indicating LED on the phase monitor
will turn red and the unit will not start. In normal operation
with correct incoming power phasing, the LED will be
green.
B-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.
C-Blower Access
The blower assembly is secured to a sliding frame which
allows the blower motor to be pulled out of the unit. See
figure 10.
1 - Loosen the reusable wire tie which secures the
blower wiring to the blower motor mounting plate.
2 - Remove and retain screws on either side of sliding
frame. Pull frame toward outside of unit.
3 - Slide frame back into original position when finished
servicing. Reattach the blower wiring in the previous
location on the blower motor base using the wire tie.
4 - Replace retained screws on either side of the sliding
frame.
Page 18