Electrical Connections - Lennox LGH480 Installation Instructions Manual

Electrical Connections

POWER SUPPLY
Do not apply power or close disconnect switch until
installation is complete. Refer to start-up directions in
Cooling Start-Up section. Refer closely to unit wiring
diagram.
Refer to unit nameplate for minimum circuit ampacity and
maximum fuse size.
1-T1 Control Transformer -
Units are factory-wired for 240/460/575 volt supply.
For 208V supply, remove the insulated terminal cover
from the 208V terminal on the control transformer.
Move the wire from the transformer 240V terminal to
the 208V terminal. Place the insulated terminal cover
on the unused 240V terminal.
2- T18 Contactor Transformer -
230/460/575 volt units are factory wired. For 208V
supply, disconnect the orange wire (230V) at control
power transformer(s). Reconnect the red wire
(208V). Tape the exposed end of the 230V orange
wire.
3- Route electrical supply through the bottom or rear
electric entry area and connect to line side of TB2.
See unit dimensions in the front of this manual. If unit
has optional disconnect or circuit breaker, connect
power wiring to disconnect or circuit breaker. See
unit wiring diagram.
If unit is equipped with optional electric heat and dual
power supply is specified, refer to electric heat wiring
diagram on inside unit panels. See figure 16.
3- Units With Optional Field-Wired 120v GFCI Outlet -
Route and connect separate 120v wiring to GFCI outlets
which do not have factory-installed wiring.
CONTROL WIRING
A-Thermostat Location
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
507232-04 7/2017
B-Wire Routing
Route thermostat cable or wires from subbase through
knockout or bottom power entry area provided in unit. Use
18 AWG wire for all applications using remotely installed
electro-mechanical and electronic thermostats.
IMPORTANT - Unless field thermostat wires are rated for
maximum unit voltage, they must be routed away from line
voltage wiring.
On hot gas reheat units, route wires from RH sensor or
remote switch through knockout or bottom power entry
area. For sensor installations, use 22AWG stranded, two
twisted pairs, individually shielded, 100% aluminum shield
with drain wire and Teflon jacket.
C-Wiring Connections
This unit is equipped with a Unit Controller which controls
unit function. Refer to the Unit Controller manual provided
with each unit.
The Unit Controller will operate the unit from a thermostat,
zone sensor, or zoning system based on the System Mode.
The default System Mode is the thermostat mode. Refer to
the Unit Controller Installation and Setup Guide to change
the System Mode. Use the menu navigation arrows and
select button; see SETTINGS>CONTROL.
1- Default Thermostat Mode -
The Unit Controller will operate two stages of heating
and cooling based on thermostat demands. Install
thermostat assembly in accordance with instructions
provided with thermostat. See figure 17 and wiring
diagrams on unit for field wiring.
IMPORTANT-Terminal connections at the wall plate or
subbase must be made securely. Loose control wire
connections may result in intermittent operation.
Page 13
2nd Disconnect
Mounting Location
Control Box
(Dual Power Supply)
TB2
Bottom Power Entry
(conduit)
FIGURE 16
Knockout