I Unit Components - Lennox LGM Series Unit Information

CORE Unit Controller (A55)
J384
J383
J382
J381
4−Character Seven
J380
J379
Duct Sensor
J378
Sensor
IAQ
I-UNIT COMPONENTS
All 3 through 6 ton (7 through 21 kW) units are configure to
order units (CTO). The LGM unit components are shown
in figure 1. All units come standard with hinged unit pan-
els. All L1, L2, and L3 wiring is color coded; L1 is red, L2
is yellow, and L3 is blue.
A-Control Box Components
LGM control box components are shown in figure 2. The
control box is located in the upper right portion of the com-
pressor compartment.
1-Control Transformers T1/T43
208/230V TRANSFORMER
PINK
SECONDARY
230 VOLTS
PRIMARY
ORANGE
FIGURE 4
All use a single line voltage to 24VAC transformer mount-
ed on the hinged control panel. Transformer supplies pow-
er to control circuits in the unit. The transformer is rated at
70VA and is protected by a 3.5 amp circuit (CB8).
J385
J386 J387
Segment LED
White Push
Button
TX
Black Push
Button
J298
J297
Sensor
IAQ Sensor Inputs
A12 C R
A11 HUM TMP
R + C
Room
Spare
and RH Thermostat
Analog
Service Relays
Sensors
Inputs
Service Relays
GRAY
208 VOLTS
BLACK
Wireless Control (W4)
J388 J389 J390 J391 J392
Gnd
24VAC
Gnd
24VAC
J299
Humidistat
Smoke
24VAC
P5
Digital
S−BUS
Inputs
Factory Test
FIGURE 3
The 208/230 (Y) voltage transformers use two primary
voltage taps as shown in figure 4, while the 460 (G) volt-
age transformer use a single primary voltage tap. T43 is
used for units with hot gas reheat for additional 24VAC.
2-Transformer T4 (J voltage)
All J volt units are equipped with a line voltage to 460V
3-phase transformer to power the indoor blower motor. T4
is mounted in the back panel of the compressor section
above T5.
3-Transformer T5 (G and J voltage)
All units use transformer T5 mounted in the back panel
in the compressor section. T5 is a line voltage to 230V
transformer to power the combustion air inducer, outdoor
fan motor, and optional UVC light ballast.. It is connected
to line voltage and is powered at all times.
4-Unit Controller A55 (Figure 3)
The Unit Controller provides all unit control functions, unit
status information, unit diagnostics, programmable pa-
rameters, and USB verification and profile sharing. The
unit controller can only be interfaced with via the CORE
Service mobile app. Refer to the Unit controller instruc-
tions provided for additional details on pairing and app
functions
Page 15
J393
J394
J358
LONTalk
Module
S−BUS SmartWire
System J304
J395
P2 Expansion
Card Connection
(C4)
MODBUS
J413