Lennox LGT Series Unit Information page 21

C-Blower Compartment
The blower compartment is located between the evapora-
tor coil and the condenser coil section. The blower assem-
bly is secured to a sliding frame which allows the blower
motor assembly to be pulled out of the unit.
Units are equipped with variable speed, direct drive blow-
ers. The supply CFM can be adjusted by changing the
percentage of motor output using the Unit Controller set-
tings. Measure the intake air CFM and adjust the RPM%
to get design-specified supply air CFM.
1-Blower Wheels
Units are be equipped with a backward inclined blower
wheel. See "SPECIFICATIONS" at the front this manual
for more detail.
2-Indoor Blower Motor B3
Units are equipped with a direct drive blower assembly
with a three-phase, variable speed, direct drive blower
motor.
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 manu-
facturers, therefore electrical FLA and LRA specifications
will vary. See unit rating plate for information specific to
your unit.
IMPORTANT
Compressor two is the only component that must
be checked to ensure proper phasing. Follow
"COOLING START-UP" section of installation
instructions to ensure proper compressor and
blower operation.
The Unit Controller checks the incoming power during
start-up. If the voltage or phase is incorrect, the Unit Con-
troller will display an alarm and the unit will not start.
A-Blower Operation
Refer to the Unit Controller Setup Guide to energize blow-
er. Use the mobile service app menu; see SERVICE >
TEST.
In thermostat control mode, the Unit Controller will stage
the blower between low and high speed. In zone sensor
control mode, the Unit Controller will vary (VAV) the blow-
er between low and high speed.
1- Make sure that unit is installed in accordance with
the installation instructions and applicable codes.
2- Inspect all electrical wiring, both field- and
factoryinstalled, for loose connections. Tighten
as required.
3- Check to ensure that refrigerant lines do not rub
against the cabinet or against other refrigerant
lines.
4- Check voltage at disconnect switch. Voltage must
be within range listed on nameplate. If not, consult
power company and have voltage condition
corrected before starting unit.
5- Make sure filters are new and in place before start-
up.
Initiate blower only (G) demand at thermostat according
to instructions provided with thermostat. Unit will cycle on
thermostat demand. The following steps apply to applica-
tions using a typical electro-mechanical thermostat.
1- Blower operation is manually set at the thermostat sub-
base 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 sys-
tem switch is in OFF position.
NOTE - Blower operation mode can also be initiated by
the mobile service app.
Direct-drive motor may not immediately stop when power
is interrupted to the Unit Controller. Disconnect unit power
before opening the blower compartment. The Controller's
digital inputs must be used to shut down the blower. See
Unit Controller manual for operation sequences.
B-Blower Access
The blower assembly is secured to a sliding frame which
allows the blower assembly to be pulled out of the unit.
See figure 10.
1 - Loosen the reusable wire tie which secures the
controls and high voltage blower wiring to the
blower housing. Disconnect the pressure sensor
low voltage wire harness.
2 - Remove and retain screws on either side (and on
the front for direct drive) of sliding frame. Use the
metal handle to pull frame toward outside of unit.
3 - Slide frame back into original position when finished
servicing. Reattach the blower wiring in the previous
location using the wire tie. Reconnect pressure
sensor low voltage wire harness.
4 - Replace retained screws.
Page 21
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