I Unit Components - Lennox LCH Series Unit Information

I-UNIT COMPONENTS
All 3 through 6 ton (7 through 21 kW) units are configure to
order units (CTO). The LCH unit components are shown in
figure 1. All units come standard with removable unit panels.
All L1, L2, and L3 wiring is color coded; L1 is red/pink, L2 is
yellow, and L3 is blue.
A-Control Box Components
LCH 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 Transformer T1
All use a single line voltage to 24VAC transformer
mounted in the control box. Transformer supplies power
to control circuits in the unit. The transformer is rated at
70VA and is protected by a 3.5 amp circuit breaker
(CB8). The 208/230 (Y) voltage transformers use two
208/230V TRANSFORMER
PINK
GRAY
SECONDARY
208 VOLTS
230 VOLTS
PRIMARY
ORANGE BLACK
FIGURE 3
2-Transformer T4 (G, J voltage)
All (G, J) 460, 575 voltage direct drive units use transformer
T4 mounted in the control box. T4 is a line voltage to 230V
transformer to power the indoor blower and outdoor fan
motor. It is connected to line voltage and is powered at all
times.
3-Transformer T43 (reheat units)
All reheat units and units with phase detection components
are equipped with T43 located in the control box. Trans­
former is rated at 70VA. It is connected to line voltage and is
powered at all times.
4-Unit Controller A55
The Unit Controller provides all unit control functions, unit
status information, unit diagnostics, programmable pa­
rameters, and USB verification and profile sharing. Refer
to the Unit Controller guide provided with the unit.
Thermostat wires are connected to J297 on the Unit Controller.
primary voltage taps as
shown in figure 3, while
460 (G) and 575 (J)
voltage transformers
use a single primary
voltage tap.
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5-Fan Capacitor C1 (three phase, belt drive)
Fan capacitor C1 is used to assist in the start up of condens­
er fan B4. Ratings will be on the side of capacitor or outdoor
fan motor nameplate.
6-Compressor Capacitor C5
Compressor capacitor C5 is used to assist in the start up of
compressor B1 in single phase units. Ratings will be on the
side of capacitor or compressor nameplate.
7-Compressor Contactor K1
In all LCH units, K1 energizes compressor B1 in response
to Unit Controller demand. Three phase units use three
pole double break contactors with a 24 volt coil. Single
phase units use single pole double break contactors with a
24 volt coil.
8-Blower Contactors K3, K37 (belt drive)
K3 and K37 are three-pole, double‐break contactors with
24VAC coils. On -036, --048, -060 and -074 units, K3 ener­
gizes the B3 indoor blower motor on low speed and K37 ener­
gizes the blower motor on high speed. On -072 units, K3 ener­
gizes the B3 single-stage blower motor in response to blower
demand.
9-Blower Overloads S42, S135
(072H M voltage and units built before Nov, 2011)
S42 and S135 are three phase thermal overload relays. See
figure 4 or 5. Switches are connected in line with the blower
motor to monitor the current flow to the motor. When the relay
senses current exceeds the operating limits of the motor, a set
of normally closed contacts open to de-energize the blower.
On -036, -048, -060 and -074 unit blowers, S42 is used on low
speed and S135 is used on high speed. On -072 unit blowers,
S42 is used on single speed. Overload should be set to the full
load current ratings on the motor nameplate.
10-Condenser Fan Relay K10 (belt drive)
Outdoor fan relay K10 is an optional DPDT relay with a
24VAC coil. K10 energizes condenser fan B4.