Page 11
LGT/LCT036, 048, 060, 072
Electrical Connections - Control Wiring
NOTE ‐ Optional wireless sensors are available for use
with this unit. Refer to the instructions provided with
each sensor.
CAUTION
Electrostatic discharge can affect electronic com
ponents. Take precautions during unit installation
and service to protect the electronic controls. Pre
cautions will help to avoid control exposure to elec
trostatic discharge by putting the unit, the control
and the technician at the same electrostatic poten
tial. Neutralize electrostatic charge by touching
hands and all tools on an unpainted unit surface,
such as the gas valve or blower deck, before per
forming any service procedure.
A-Thermostat Location
Room thermostat mounts vertically on a standard 2” X 4”
handy box or on any non-conductive flat surface.
Locate thermostat approximately 5 feet (1524mm)
above the floor in an area with good air circulation at
average temperature. Avoid locating the room
thermostat where it might be affected by:
-drafts or dead spots behind doors and in corners
-hot or cold air from ducts
-radiant heat from sun or appliances
-concealed pipes and chimneys
B-Control Wiring
The Unit Controller will operate the unit from a
thermostat or zone sensor based on the System Mode.
The default System Mode is the thermostat mode. Refer
to the Unit Controller Setup Guide to change the System
Mode. Use the mobile service app menu and select
Settings > Install
.
Thermostat Mode
1- Route thermostat cable or wires from subbase to
control area above compressor (refer to unit
dimensions to locate bottom and side power entry).
IMPORTANT - Unless field thermostat wires are rated
for maximum unit voltage, they must be routed away
from line voltage wiring. Use wire ties located near the
lower left corner of the controls mounting panel to
secure thermostat cable.
Use18 AWG wire for all applications using remotely
installed electro-mechanical and electronic
thermostats.
2- Install thermostat assembly in accordance with
instructions provided with thermostat.
3- Connect thermostat wiring to Unit Controller on the
lower side of the controls hat section.
4- Wire as shown in figure 15 for electro-mechanical
and electronic thermostats. If using other
temperature control devices or energy management
systems see instructions and wiring diagram
provided by manufacturer.
IMPORTANT-Terminal connections at the wall plate or
subbase must be made securely. Loose control wire
connections may allow unit to operate but not with proper
response to room demand.
Zone Sensor Mode
The Unit Controller will operate heating and cooling
based on the Unit Controller internal setpoints and the
temperature from the A2 zone sensor. An optional
Network Control Panel (NCP) can also be used to provide
setpoints. A thermostat or return air sensor can be used
as a back-up mode. Make zone sensor wiring
connections as shown in figure 16.
C-Hot Gas Reheat
1- Install humidity sensor in accordance with
instructions provided with sensor. A DDC input may
be used to initiate dehumidification instead of a
sensor.
2- Make wiring connections as shown in figure 15 for
Thermostat Mode or figure 16 for Zone Sensor
Mode. In addition, connect either a humidity
sensor or a dehumidification input. See figure 17
or 19 for humidity sensor wiring or figure 18 for
dehumidification input wiring.
Humidity Sensor Cable Applications:
Wire runs of 50 feet (mm) or less:
Use two separate shielded cables containing 20AWG
minimum, twisted pair conductors with overall shield.
Belden type 8762 or 88760 (plenum) or equivalent.
Connect both cable shield drain wires to the Unit
Controller as shown in figure 17.
Wire runs of 150 feet (mm) or less:
Use two separate shielded cables containing 18AWG
minimum, twisted pair conductors with overall shield.
Belden type 8760 or 88760 (plenum) or equivalent.
Connect both cable shield drain wires to the Unit
Controller as shown in figure 17.
Wire runs over 150 feet (mm):
Use a local, isolated 24VAC transformer such as
Lennox cat #18M13 (20VA minimum) to supply power
to RH sensor as shown in figure 19. Use two shielded
cables containing 20AWG minimum, twisted pair
conductors with overall shield. Belden type 8762 or
88760 (plenum) or equivalent.
