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SGH/SCH036, 060, 120, 240
Electrical Connections
POWER SUPPLY
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- Units are factory-wired for 230,460,575 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- Route power through the bottom power entry area
and connect to line side of unit circuit breaker. See
unit wiring diagram.
3- Connect separate 120v wiring to GFCI outlet terminal
strip in bottom power entry area.
CONTROL WIRING
CAUTION
Electrostatic discharge can affect electronic compo
nents. Take precautions during unit installation and
service to protect the electronic controls. Precau
tions will help to avoid control exposure to electro
static discharge by putting the unit, the control and
the technician at the same electrostatic potential.
Neutralize electrostatic charge by touching hands
and all tools on an unpainted unit surface, such as the
gas valve or blower deck, before performing any ser
vice 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 Installation and Setup Guide to change the
System Mode. Use the menu navigation arrows and select
button; see Settings - Install.
Thermostat Mode
1- Route thermostat cable or wires from subbase through
knockout provided in unit. For thermostat wire runs up
to 60 feet, use 18 gauge wire. For 60 to 90 feet runs,
use 16 gauge wire.
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.
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 16 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
