Electrical Connections - Power Supply; Electrical Connections - Control Wiring - Lennox LHT078H Installation Instructions Manual

Electrical Connections - Power Supply

Route field wiring in conduit between bottom power entry
disconnect. See figure 14. This does not supersede local
codes or authorities having jurisdiction.
Do not apply power or close disconnect switch until
installation is complete. Refer to start-up directions.
Refer closely to unit wiring diagram.
Refer to unit nameplate for minimum circuit ampacity
and maximum fuse size.
1- 230/460/575 volt units are factory wired. For 208V
supply, disconnect the orange wire (230V) at all
control power transformer(s). Reconnect the red
wire (208V). Tape the exposed end of the 230V
orange wire.
2- Route power through the bottom power entry area.
On gas units or units with electric heat, connect
power wiring to TB2. On cooling only units,
connect power to F4. If unit contains an optional
factory-installed circuit breaker or disconnect
switch, connect line voltage to CB10 or S48. See
unit wiring diagram.
3- Connect separate
field-powered GFCI outlet. Route field wiring in
conduit between bottom power entry and GFCI. See
figure 14. For unit-powered GFCI, no additional field
wiring is required.
FIELD WIRE ROUTING
SIDE ENTRY
KNOCKOUTS
SEAL
WATERTIGHT
BOTTOM
POWER ENTRY
FIGURE 14
120v wiring to optional
MAKE-UP
BOX
OPTIONAL
120V GFI
RUN FIELD
WIRING IN
FIELD PRO­
VIDED CONDUIT

Electrical Connections - Control Wiring

NOTE ‐ Optional wireless sensors are available for use
with this unit. Refer to the instructions provided with
each sensor.
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
Applied to units in default thermostat control mode only.
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.
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
IMPORTANT - Unless field thermostat wires are rated
for maximum unit voltage, they must be routed away
from line voltage wiring.
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
thermostats.
2- Install thermostat assembly in accordance with
instructions provided with thermostat.
Page 12
CAUTION
Avoid locating
electro-mechanical and
the room
electronic