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CONTROL WIRING
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 room 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; SETTINGS
> CONTROL. Options are: “WIRED THERMOSTAT”
and “NETWORK”.
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 on the front
border of the control 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 the bottom of the Unit
Controller.
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 Unit Controller
must be made securely. Loose control wire connections
may allow unit to operate but not with proper response to
room demand.
Room Sensor Mode
The Unit Controller will operate heating and cooling
based on the Unit Controller internal setpoints and the
temperature from the A2 room 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 room sensor wiring
connections as shown in figure 14.
C-Hot Gas Reheat Units Only -
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 14 for room sensor
mode. In addition, connect either a humidity
sensor or a dehumidification input. See figure 16
for dehumidification input wiring or figure 17 or 18
for humidity sensor wiring.
FIGURE 14
FIELD WIRING IN ROOM SENSOR MODE
(Room Sensor Mode)
A2 SENSOR
OUTPUTS
SENSOR
SENSOR
24VAC
R
C
IAQ
HUM
AI1
D01
TMP
D02
UNIT CONTROLLER
J298